wikidoc - User contributions [en]

Lymphoid leukemia

2019-10-05T15:18:58Z

Nima Nasiri: /* Pathogenesis */

__NOTOC__

{{CMG}}; {{AE}} {{Nnasiri}}

'''For patient information, click [[Leukemia (patient information)|here]]'''

{{Infobox_Disease |
Name = Lymphoid leukemia |
Image = |
Caption = |
DiseasesDB = |
ICD10 = {{ICD10|C|91||c|81}} |
ICD9 = {{ICD9|204}} |
ICDO = |
OMIM = |
MedlinePlus = |
eMedicineSubj = |
eMedicineTopic = |
MeshID = D007945 |
}}
{{Lymphoid leukemia}}

==Overview==
'''Lymphoid leukemia''' is a [[monoclonal]] disorder which is a result of clonal proliferation and progressive accumulation of functionally incompetent [[lymphocytes]] in circulation, [[Bone marrow|bone]] [[Bone marrow|marrow]], [[spleen]], [[lymphoid]] tissues. [[Lymphocytic]] leukemia is more frequent than non-lymphocytic and other [[Myeloproliferative disease|myeloproliferative]] diseases. The chronic form ([[CLL]]) affects older adult, onset is insidious. [[Acute lymphoblastic leukemia]] (ALL) is more common in children, peak incidence around 2 to 3 years of age. The identification of cytogenetic abnormalities is highly relevant for the prognosis of [[ALL]]. Patients may have findings associated with [[anemia]], [[neutropenia]], and/or [[thrombocytopenia]] due to [[bone marrow]] involvement. The [[white blood cell]] count may be decreased, normal, or markedly elevated. Symptoms can include [[fatigue]], [[infections]], or easy/spontaneous bruising or bleeding. [[Arthralgias]] and constitutional symptoms (eg, [[fever]], [[night sweats]], unintentional [[weight loss]]) are often present but are generally mild. [[Hepatomegaly]], [[splenomegaly]], and/or [[lymphadenopathy]] can be seen as well. [[Central nervous system]] (CNS) involvement may present as cranial [[Neuropathy|neuropathies]] or [[meningeal]] symptoms. [[Lymphoblasts]] can have different surface molecules called [[cluster of differentiation]] (CD) which can be detected by [[flow cytometry]].

==Classification==

=== [[ALL]] classification ===
There are two types of classifications for acute lymphoblastic leukemia :
'''[[World Health Organization]]''' ('''WHO''') and '''French-American-British''' ('''FAB''')<ref name="pmid26980727">{{cite journal |vauthors=Swerdlow SH, Campo E, Pileri SA, Harris NL, Stein H, Siebert R, Advani R, Ghielmini M, Salles GA, Zelenetz AD, Jaffe ES |title=The 2016 revision of the World Health Organization classification of lymphoid neoplasms |journal=Blood |volume=127 |issue=20 |pages=2375–90 |date=May 2016 |pmid=26980727 |pmc=4874220 |doi=10.1182/blood-2016-01-643569 |url=}}</ref><ref name="pmid10643532">{{cite journal |vauthors=Harris NL, Jaffe ES, Diebold J, Flandrin G, Muller-Hermelink HK, Vardiman J, Lister TA, Bloomfield CD |title=The World Health Organization classification of neoplastic diseases of the hematopoietic and lymphoid tissues. Report of the Clinical Advisory Committee meeting, Airlie House, Virginia, November, 1997 |journal=Ann. Oncol. |volume=10 |issue=12 |pages=1419–32 |date=December 1999 |pmid=10643532 |doi= |url=}}</ref><ref name="pmid1">{{cite journal |vauthors=Makar AB, McMartin KE, Palese M, Tephly TR, Schmoldt A, Benthe HF, Haberland G, Anke H, Spector LB |title=Formate assay in body fluids: application in methanol poisoning |journal=Biochem Med |volume=13 |issue=2 |pages=117–26 |date=June 1975 |pmid=1 |pmc=5922622 |doi= |url=}}</ref><ref name="pmid27161658">{{cite journal |vauthors=Wang Y, Miller S, Roulston D, Bixby D, Shao L |title=Genome-Wide Single-Nucleotide Polymorphism Array Analysis Improves Prognostication of Acute Lymphoblastic Leukemia/Lymphoma |journal=J Mol Diagn |volume=18 |issue=4 |pages=595–603 |date=July 2016 |pmid=27161658 |doi=10.1016/j.jmoldx.2016.03.004 |url=}}</ref>

'''[[WHO]] classification of acute lymphoblastic leukemia'''
*B lymphoblastic [[leukemia]]/[[lymphoma]]:
**B lymphoblastic leukemia/[[lymphoma]], Not otherwise specified
**B lymphoblastic leukemia/lymphoma with recurrent [[genetic]] abnormalities:
**B lymphoblastic leukemia/lymphoma with [[t(9;22)]],[[Bcr-abl|BCR-ABL]]<ref name="pmid26514535">{{cite journal |vauthors=Goud TM, Al Salmani KK, Al Harasi SM, Al Musalhi M, Wasifuddin SM, Rajab A |title=Importance of FISH combined with Morphology, Immunophenotype and Cytogenetic Analysis of Childhood/ Adult Acute Lymphoblastic Leukemia in Omani Patients |journal=Asian Pac. J. Cancer Prev. |volume=16 |issue=16 |pages=7343–50 |date=2015 |pmid=26514535 |doi= |url=}}</ref>
**B lymphoblastic leukemia/lymphoma t(11q23); [[MLL]] rearrangement<ref name="pmid16478880">{{cite journal |vauthors=Nagayama J, Tomizawa D, Koh K, Nagatoshi Y, Hotta N, Kishimoto T, Takahashi Y, Kuno T, Sugita K, Sato T, Kato K, Ogawa A, Nakahata T, Mizutani S, Horibe K, Ishii E |title=Infants with acute lymphoblastic leukemia and a germline MLL gene are highly curable with use of chemotherapy alone: results from the Japan Infant Leukemia Study Group |journal=Blood |volume=107 |issue=12 |pages=4663–5 |date=June 2006 |pmid=16478880 |doi=10.1182/blood-2005-11-4728 |url=}}</ref>
**B lymphoblastic leukemia/lymphoma with t(12;21)<ref name="pmid19594616">{{cite journal |vauthors=Peter A, Heiden T, Taube T, Körner G, Seeger K |title=Interphase FISH on TEL/AML1 positive acute lymphoblastic leukemia relapses--analysis of clinical relevance of additional TEL and AML1 copy number changes |journal=Eur. J. Haematol. |volume=83 |issue=5 |pages=420–32 |date=November 2009 |pmid=19594616 |doi=10.1111/j.1600-0609.2009.01315.x |url=}}</ref>
**B lymphoblastic leukemia/lymphoma with hyperdiploidy
**B lymphoblastic leukemia/lymphoma with hypodiploidy<ref name="pmid10512165">{{cite journal |vauthors=Greipp PR, Trendle MC, Leong T, Oken MM, Kay NE, Van Ness B, Kyle RA |title=Is flow cytometric DNA content hypodiploidy prognostic in multiple myeloma? |journal=Leuk. Lymphoma |volume=35 |issue=1-2 |pages=83–9 |date=September 1999 |pmid=10512165 |doi=10.3109/10428199909145707 |url=}}</ref>
**B lymphoblastic leukemia/lymphoma t(5;14)
**B lymphoblastic leukemia/lymphoma t(1;19)
*T lymphoblastic leukemia/lymphoma:
'''FAB classification of acute lymphoblastic leukemia (for historical purposes):'''<ref name="pmid28052366">{{cite journal |vauthors=Canaani J, Beohou E, Labopin M, Socié G, Huynh A, Volin L, Cornelissen J, Milpied N, Gedde-Dahl T, Deconinck E, Fegueux N, Blaise D, Mohty M, Nagler A |title=Impact of FAB classification on predicting outcome in acute myeloid leukemia, not otherwise specified, patients undergoing allogeneic stem cell transplantation in CR1: An analysis of 1690 patients from the acute leukemia working party of EBMT |journal=Am. J. Hematol. |volume=92 |issue=4 |pages=344–350 |date=April 2017 |pmid=28052366 |doi=10.1002/ajh.24640 |url=}}</ref>
*[[ALL]]-L1: Small cells with homogeneous nuclear [[chromatin]], a regular nuclear shape, small or no [[nucleoli]], scanty [[cytoplasm]], and mild to moderate [[basophilia]]
*[[ALL]]-L2: Large, [[heterogeneous]] cells with variable nuclear [[chromatin]], an irregular nuclear shape, one or more [[nucleoli]], a variable amount of [[cytoplasm]], and basophilia
*[[ALL]]-L3: Large, [[homogeneous]] cells with fine, stippled [[chromatin]]; regular [[nuclei]]; prominent [[nucleoli]]; and abundant, deeply [[basophilic]] [[cytoplasm]]. The most distinguishing feature is prominent [[cytoplasmic]] vacuolation.

=== [[CLL]] classification ===
*There are two staging systems in order to classify [[CLL]]:
**'''Rai staging system''' (this is used more often in the United States, it is based on [[lymphocytosis]])
**'''Stage Characteristics:'''
***'''Low Risk (Stage 0):''' Abnormal increase in the number of [[lymphocytes]] in the blood and marrow.
***'''Intermediate Risk (Stages I & II):''' Abnormal increase in the number of [[lymphocytes]] in the blood and the marrow, enlarged [[lymph]] nodes or abnormal increase in the number of [[lymphocytes]] in the circulating blood and the marrow, enlarged [[spleen]] and/or [[liver]].
***'''High Risk (Stages III & IV):''' Abnormal increase in the number of [[lymphocytes]] in the circulating blood and the marrow, [[anemia]] ([[hemoglobin]] <11g/dL) or abnormal increase in the number of [[lymphocytes]] in the circulating blood and the marrow [[thrombocytopenia]] ([[platelets]] counts <100,000/uL).
**'''[[Binet staging system]]''' (this is more often used in Europe) <ref name="pmid28091403">{{cite journal |vauthors=Li H, Yi SH, Xiong WJ, Liu HM, Lyu R, Wang TY, Liu W, Zhong SZ, Yu Z, Zou DH, Xu Y, An G, Li ZJ, Qiu LG |title=Chronic Lymphocytic Leukemia Prognostic Index: A New Integrated Scoring System to Predict the Time to First Treatment in Chinese Patients with Chronic Lymphocytic Leukemia |journal=Chin. Med. J. |volume=130 |issue=2 |pages=135–142 |date=January 2017 |pmid=28091403 |pmc=5282668 |doi=10.4103/0366-6999.197978 |url=}}</ref>
***In the Binet staging system, [[CLL]] is classified by the number of affected lymphoid tissue groups (neck lymph nodes, groin [[lymph nodes]], underarm [[lymph nodes]], [[spleen]], and [[liver]]) and by whether or not the patient has [[anemia]] (too few red blood cells) or [[thrombocytopenia]] (too few blood platelets).<ref name="pmid28120419">{{cite journal |vauthors=Delgado J, Doubek M, Baumann T, Kotaskova J, Molica S, Mozas P, Rivas-Delgado A, Morabito F, Pospisilova S, Montserrat E |title=Chronic lymphocytic leukemia: A prognostic model comprising only two biomarkers (IGHV mutational status and FISH cytogenetics) separates patients with different outcome and simplifies the CLL-IPI |journal=Am. J. Hematol. |volume=92 |issue=4 |pages=375–380 |date=April 2017 |pmid=28120419 |doi=10.1002/ajh.24660 |url=}}</ref>
****'''Binet stage A:''' Fewer than 3 areas of [[lymphoid]] tissue are enlarged, with no anemia or [[thrombocytopenia]].
****'''Binet stage B:''' 3 or more areas of [[lymphoid]] tissue are enlarged, with no [[anemia]] or [[thrombocytopenia]].
****'''Binet stage C:''' [[Anemia]] and/or [[thrombocytopenia]] are present. Any number of lymphoid tissue areas may be enlarged.

==Pathophysiology==
===Physiology===
*All [[lymphocytes]] have a common lymphoid [[progenitor cell]] origin known as a [[Lymphoblasts|lymphoblast]], the formation of lymphocytes is known as [[lymphopoiesis]].
*[[B cells]] mature into [[B lymphocytes]] in the [[bone marrow]], while [[T cells]] migrate to and mature in the [[thymus]]. Following maturation, the [[lymphocytes]] enter the circulation and peripheral [[lymphoid]] organs, where they survey for invading [[pathogens]] and [[cancer]] cells.
*<nowiki/>The lymphocytes involved in [[adaptive immunity]] (B and T cells) differentiate further after exposure to an [[antigen]], which occurs in the [[lymph nodes]] during [[antigen]] presentation from the [[Dendritic cells|dendritic cell]]<nowiki/>[[Dendritic cells|s.]]<ref name="pmid30039426">{{cite journal |vauthors=van de Loosdrecht AA, van Wetering S, Santegoets SJAM, Singh SK, Eeltink CM, den Hartog Y, Koppes M, Kaspers J, Ossenkoppele GJ, Kruisbeek AM, de Gruijl TD |title=A novel allogeneic off-the-shelf dendritic cell vaccine for post-remission treatment of elderly patients with acute myeloid leukemia |journal=Cancer Immunol. Immunother. |volume=67 |issue=10 |pages=1505–1518 |date=October 2018 |pmid=30039426 |pmc=6182404 |doi=10.1007/s00262-018-2198-9 |url=}}</ref>
*The fully differentiated [[B cell|B]] and [[T-Cell|T]] cells are specific to the presented antigen and work to defend the body against [[pathogens]] associated with that [[antigen]].<ref name="pmid28411378">{{cite journal |vauthors=Khoury HJ, Collins RH, Blum W, Stiff PS, Elias L, Lebkowski JS, Reddy A, Nishimoto KP, Sen D, Wirth ED, Case CC, DiPersio JF |title=Immune responses and long-term disease recurrence status after telomerase-based dendritic cell immunotherapy in patients with acute myeloid leukemia |journal=Cancer |volume=123 |issue=16 |pages=3061–3072 |date=August 2017 |pmid=28411378 |doi=10.1002/cncr.30696 |url=}}</ref><ref name="pmid17067945">{{cite journal |vauthors=Cesta MF |title=Normal structure, function, and histology of mucosa-associated lymphoid tissue |journal=Toxicol Pathol |volume=34 |issue=5 |pages=599–608 |date=2006 |pmid=17067945 |doi=10.1080/01926230600865531 |url=}}</ref>
*[[Lymphoid]] tissues are subdivided int<nowiki/>o <nowiki/>primary and secondary [[lymphoid organs]]:<ref name="pmid20154733">{{cite journal |vauthors=Bertrand JY, Chi NC, Santoso B, Teng S, Stainier DY, Traver D |title=Haematopoietic stem cells derive directly from aortic endothelium during development |journal=Nature |volume=464 |issue=7285 |pages=108–11 |date=March 2010 |pmid=20154733 |pmc=2858358 |doi=10.1038/nature08738 |url=}}</ref><ref name="pmid17318232">{{cite journal |vauthors=Dorshkind K, Montecino-Rodriguez E |title=Fetal B-cell lymphopoiesis and the emergence of B-1-cell potential |journal=Nat. Rev. Immunol. |volume=7 |issue=3 |pages=213–9 |date=March 2007 |pmid=17318232 |doi=10.1038/nri2019 |url=}}</ref><ref name="pmid23940259">{{cite journal |vauthors=Vossenkämper A, Blair PA, Safinia N, Fraser LD, Das L, Sanders TJ, Stagg AJ, Sanderson JD, Taylor K, Chang F, Choong LM, D'Cruz DP, Macdonald TT, Lombardi G, Spencer J |title=A role for gut-associated lymphoid tissue in shaping the human B cell repertoire |journal=J. Exp. Med. |volume=210 |issue=9 |pages=1665–74 |date=August 2013 |pmid=23940259 |pmc=3754866 |doi=10.1084/jem.20122465 |url=}}</ref>
**The primary [[lymphoid]] tissues responsible for the initial generation of B and T lymphocytes are the [[bone marrow]] and [[thymus]], respectively.
**Secondary lymphoid tissues include [[lymph nodes]], spleen, [[tonsils]], gut-associated lymphoid tissue ([[GALT]]), bronchus-associated lymphoid tissue ( [[BALT]]).
***Within these lymphoid organs, B and T [[lymphocytes]] tend to home to different domains, leading to the segregation of B and [[T cells]].
***Specifically, [[B cells]] mainly localize to follicles, whereas [[T cells]] mainly localize to interfollicular areas.
***Non-lymphoid cells (eg, [[dendritic cells]], [[monocytes]]/[[Macrophage|macrophages]], [[endothelial cells]], and follicular [[dendritic cells]]) contribute to the formation of these distinct microenvironments, within which specific cell-cell interactions occur that are required for the generation of cellular and [[Humoral immune response|humoral immune responses]].

===Pathogenesis===
*It is understood that lymphoid [[leukemia]] is a result of overproduction of cells which is caused by either activation or inactivation of genes.<ref name="pmid28399885">{{cite journal |vauthors=Quijada-Álamo M, Hernández-Sánchez M, Robledo C, Hernández-Sánchez JM, Benito R, Montaño A, Rodríguez-Vicente AE, Quwaider D, Martín AÁ, García-Álvarez M, Vidal-Manceñido MJ, Ferrer-Garrido G, Delgado-Beltrán MP, Galende J, Rodríguez JN, Martín-Núñez G, Alonso JM, García de Coca A, Queizán JA, Sierra M, Aguilar C, Kohlmann A, Hernández JÁ, González M, Hernández-Rivas JM |title=Next-generation sequencing and FISH studies reveal the appearance of gene mutations and chromosomal abnormalities in hematopoietic progenitors in chronic lymphocytic leukemia |journal=J Hematol Oncol |volume=10 |issue=1 |pages=83 |date=April 2017 |pmid=28399885 |pmc=5387353 |doi=10.1186/s13045-017-0450-y |url=}}</ref><ref name="pmid10577857">{{cite journal |vauthors=Harris NL, Jaffe ES, Diebold J, Flandrin G, Muller-Hermelink HK, Vardiman J, Lister TA, Bloomfield CD |title=World Health Organization classification of neoplastic diseases of the hematopoietic and lymphoid tissues: report of the Clinical Advisory Committee meeting-Airlie House, Virginia, November 1997 |journal=J. Clin. Oncol. |volume=17 |issue=12 |pages=3835–49 |date=December 1999 |pmid=10577857 |doi=10.1200/JCO.1999.17.12.3835 |url=}}</ref><ref name="pmid23987584">{{cite journal |vauthors=Zhang S, Kipps TJ |title=The pathogenesis of chronic lymphocytic leukemia |journal=Annu Rev Pathol |volume=9 |issue= |pages=103–18 |date=2014 |pmid=23987584 |doi=10.1146/annurev-pathol-020712-163955 |url=}}</ref><ref name="pmid30045301">{{cite journal |vauthors=Ge H, Wu X, Shen J, Chen J, Chen Y, Zhang Y |title=A case report of extranodal NK/T-cell lymphoma in patient with chronic lymphocytic leukemia |journal=Medicine (Baltimore) |volume=97 |issue=30 |pages=e11619 |date=July 2018 |pmid=30045301 |pmc=6078727 |doi=10.1097/MD.0000000000011619 |url=}}</ref>

*Several factors, such as chromosomal [[translocations]] as well as genetic or epigenetic alterations, are involved in [[leukemogenesis]].
*Abnormal [[methylation]] of [[DNA]] and [[histone]] modifications are important mechanisms in [[tumor suppressor]] silencing, contributing to leukemogenesis along with genetic alterations.<ref name="pmid19718392">{{cite journal |vauthors=Kondo Y |title=Epigenetic cross-talk between DNA methylation and histone modifications in human cancers |journal=Yonsei Med. J. |volume=50 |issue=4 |pages=455–63 |date=August 2009 |pmid=19718392 |pmc=2730606 |doi=10.3349/ymj.2009.50.4.455 |url=}}</ref>
*The activation of [[oncogenes]] involves [[genetic]] changes to cellular [[Proto-oncogene|proto-oncogenes]].
*Three genetic mechanisms activate [[oncogenes]] in human [[Neoplasm|neoplasms]], these mechanisms result in either an alteration of [[proto-oncogene]] structure or an increase in proto-oncogene expression:
**[[Mutation]]
**[[Gene amplification]]
**[[Chromosome]] rearrangements

===Genetics===
*Activation or/and inactivation of [[genes]] plays an important role in the pathogenesis and prognosis of lymphoid leukemia.
*Epigenetic and [[genetic]] alterations are two mechanisms in [[leukemia]].
*Abnormal [[methylation]] of [[DNA]] and [[histone]] modifications are important mechanisms in [[tumor suppressor]] silencing, contributing to leukemogenesis along with genetic alterations.
*Epigenetic mechanisms are the most prevalent inactivation ones in lymphoid leukemia and involve the [[genes]] implicated in several [[cellular]] mechanisms, including [[gene expression]] and [[transcription]], cell-cycle regulation and [[apoptosis]].<ref name="pmid29125235">{{cite journal |vauthors=Gladkikh AA, Potashnikova DM, Tatarskiy V, Yastrebova M, Khamidullina A, Barteneva N, Vorobjev I |title=Comparison of the mRNA expression profile of B-cell receptor components in normal CD5-high B-lymphocytes and chronic lymphocytic leukemia: a key role of ZAP70 |journal=Cancer Med |volume=6 |issue=12 |pages=2984–2997 |date=December 2017 |pmid=29125235 |pmc=5727315 |doi=10.1002/cam4.1257 |url=}}</ref>
**
*

===Associated Conditions===
Conditions associated with [[lymphoid leukemia]] include:<ref name="pmid29526963">{{cite journal |vauthors=Ito Y, Makita S, Maeshima AM, Hatta S, Suzuki T, Yuda S, Fukuhara S, Munakata W, Suzuki T, Maruyama D, Izutsu K |title=Paraneoplastic Pemphigus Associated with B-cell Chronic Lymphocytic Leukemia Treated with Ibrutinib and Rituximab |journal=Intern. Med. |volume=57 |issue=16 |pages=2395–2398 |date=August 2018 |pmid=29526963 |pmc=6148183 |doi=10.2169/internalmedicine.0578-17 |url=}}</ref>

*[[Anemia]]
*Other cancers such as [[melanoma]]
*[[Lymphadenopathy|Lymph node enlargement]]
*Low grade [[fever]]
*Unexplained [[weight loss]]
*[[Night sweats]]
*[[Splenomegaly|Enlarged spleen]] or [[Hepatomegaly|liver]]
*Infections of the [[skin]], [[lungs]], [[kidneys]] or other sites, as result of low [[immunoglobulin]] levels and decreased [[neutrophil]] counts.
*[[Fatigue]]
*[[Shortness of breath]] during normal physical activity

== Differentiating Lymphoid Leukemia ==
{| class="wikitable"
|+
!Characteristics
!ALL
!CLL
|-
|Microscopy
|[[File:Acute leukemia-ALL.jpg|100x|thumb|center|ALL, hand-mirror cells. [https://commons.wikimedia.org/wiki/File:Acute_leukemia-ALL.jpg Source: wikimedia, transferred from wikipedia]]]
|[[File:Chronic lymphocytic leukemia.jpg|400px|thumb|center|CLL , Smudge cells. [http://en.wikipedia.org en.wikipedia Source: Mary Ann Thompson]]]
|-
|Age of onset
|Children (age < 10 years old)
|Adult onset
|-
|Etiology
|Chromosomal aberration resulting in abnormal [[transcription factors]] that affect development of B and [[T cells]]
|[[Chromosome|Chromosomal]] deletion or possible [[somatic mutation]] of naive [[B cells]]
|-
|Morphology
|Scanty, [[basophilic]] [[cytoplasm]] sometimes with a single long projection (‘hand-mirror cell’), condensed [[chromatin]], small [[nucleoli]]<ref name="pmid3455677">{{cite journal |vauthors=Mazur EM, Wittels EG, Schiffman FJ, South K, Horner RJ |title=Hand mirror cell lymphoid leukemia in adults. A distinct clinicopathologic syndrome. Case report and literature review |journal=Cancer |volume=57 |issue=1 |pages=92–9 |date=January 1986 |pmid=3455677 |doi= |url=}}</ref><ref name="pmid22207681">{{cite journal |vauthors=Tang G, Zuo Z, Thomas DA, Lin P, Liu D, Hu Y, Kantarjian HM, Bueso-Ramos C, Medeiros LJ, Wang SA |title=Precursor B-acute lymphoblastic leukemia occurring in patients with a history of prior malignancies: is it therapy-related? |journal=Haematologica |volume=97 |issue=6 |pages=919–25 |date=June 2012 |pmid=22207681 |pmc=3366660 |doi=10.3324/haematol.2011.057752 |url=}}</ref>
|'''[[Smudge cells]]''', condensed [[chromatin]], scant [[cytoplasm]], small [[nucleoli]]<ref name="pmid27221863">{{cite journal |vauthors=Chang CC, Sun JT, Liou TH, Kuo CF, Bei CH, Lin SJ, Tsai WT, Tan NC, Liou CB, Su MJ, Yen TH, Chu FY |title=Clinical Significance of Smudge Cells in Peripheral Blood Smears in Hematological Malignancies and Other Diseases |journal=Asian Pac. J. Cancer Prev. |volume=17 |issue=4 |pages=1847–50 |date=2016 |pmid=27221863 |doi= |url=}}</ref>
|-
|Cell involved
|Immature B or [[T cells]]
|Peripheral B or [[T cells]]
|-
|Clinical presentation
|Stormy onset, symptoms related to depressed marrow function, bone pain, [[CNS]] manifestations.
|Asymptomatic or nonspecific, [[hepatosplenomegaly]] , [[lymphadenopathy]]
|-
|Demographic
|Most common [[leukemia]] in children
|Most common [[leukemia]] in adults, twice as common in men.
|-
|CBC result
|Anemia, [[thrombocytopenia]], variable [[WBC]]'s, and [[lymphoblast]] > 30%
|[[Lymphocytosis]] > 5000/ul , low [[platelets]] in 20-30%
|-
|CD markers
|[[CD19]], [[CD79a]], [[CD22]] (cytoplasmic), [[CD24]], [[CD10]], [[PAX5]], and TdT (terminal deoxyteransferase)
|[[CD5]], CD19, [[CD20]] (dim), CD 23, and an absence of FMC-7 staining<ref name="pmid10403005">{{cite journal |vauthors=Tiensiwakul P, Lertlum T, Nuchprayoon I, Seksarn P |title=Immunophenotyping of acute lymphoblastic leukemia in pediatric patients by three-color flow cytometric analysis |journal=Asian Pac. J. Allergy Immunol. |volume=17 |issue=1 |pages=17–21 |date=March 1999 |pmid=10403005 |doi= |url=}}</ref>
|}

==References==
{{Reflist|2}}

Nontuberculous mycobacteria

2019-08-26T17:09:56Z

Nima Nasiri: /* Differentiating [disease name] from other Diseases */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==
Non-tuberculous mycobacteria (NTM) are species other than those belonging to the Mycobacterium tuberculosis complex and do not cause leprosy. NTM are generally free-living organisms that are ubiquitous in the environment. There have been more than 150 NTM species identified to-date. They can cause a wide range of infections, with pulmonary infections being the most frequent. NTM are opportunistic pathogens and are abundant in the environment such as peat-rich potting soil and drinking water in buildings and households. Risk factors associated with pulmonary NTM are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
* NTM is most commonly classified by the growth rate, either slowly growing or rapidly growing:
:* Slow-growing mycobacteria are: Mycobacterium avium complex (includes avium and intracellulare species), M. kansasii, M. xenopi, M. simiae
:* Rapid-growing mycobacteria are: M. Abscessus, M. Fortuitium, M. Chelonae

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating nontuberculous mycobacteria from other Diseases==
*NTM lung disease must be differentiated from other chronic pulmonary diseases that cause chronic cough, shortness of breath and hemoptysis such as:
:*Tuverculosis
:*Histoplasmosis
:*Blastomyces
:* Silicosis
:* Pneumonia
:* Granulomatosis of lung

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of NTM lung disease are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs such as TNF-alpha inhibitors, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).<ref name="pmid14980273">{{cite journal |vauthors=Olivier KN |title=The natural history of nontuberculous mycobacteria in patients with cystic fibrosis |journal=Paediatr Respir Rev |volume=5 Suppl A |issue= |pages=S213–6 |date=2004 |pmid=14980273 |doi= |url=}}</ref><ref name="ShteinbergStein2018">{{cite journal|last1=Shteinberg|first1=Michal|last2=Stein|first2=Nili|last3=Adir|first3=Yochai|last4=Ken-Dror|first4=Shifra|last5=Shitrit|first5=David|last6=Bendayan|first6=Danielle|last7=Fuks|first7=Leonardo|last8=Saliba|first8=Walid|title=Prevalence, risk factors and prognosis of nontuberculous mycobacterial infection among people with bronchiectasis: a population survey|journal=European Respiratory Journal|volume=51|issue=5|year=2018|pages=1702469|issn=0903-1936|doi=10.1183/13993003.02469-2017}}</ref>

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*Symptoms of NTM may include the following:
:* Chronic cough
:* Fatigue
:* Shortness of breath (dyspnea)
:* Coughing up of blood (hemoptysis)
:* Excessive mucus (sputum) production
:* Fever
:* Night sweats
:* Loss of appetite
*: Unintended weight loss.

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are two major radiological findings associated with NTM disease: Fibrocavitary and nodular bronchiectatic forms.<ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
*High resolution computed tomography (HRCT) is the imaging modality of choice for NTM lung disease.
*On HRCT, the fibro-cavitary form of NTM is characterized by cavities with areas of increased opacity, usually located in the upper lobes, pleural thickening and volume loss by fibrosis with traction bronchiectasis are frequent. Unlike pulmonary tuberculosis, cavitation in NTM is thin-walled without lymph node calcification, no atelectasis and usually progresses more slowly.
* HRCT of nodular bronchiectatic form may demonstrate bilateral, multilobar bronchiectasis, especially in the middle and lower lung fields, with small nodules.

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

==Prophylaxis and Treatment of NTM Disease==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) is recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued after the resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.

== Surgery ==

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

== Prevention ==

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-26T17:06:03Z

Nima Nasiri: /* Classification */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==
Non-tuberculous mycobacteria (NTM) are species other than those belonging to the Mycobacterium tuberculosis complex and do not cause leprosy. NTM are generally free-living organisms that are ubiquitous in the environment. There have been more than 150 NTM species identified to-date. They can cause a wide range of infections, with pulmonary infections being the most frequent. NTM are opportunistic pathogens and are abundant in the environment such as peat-rich potting soil and drinking water in buildings and households. Risk factors associated with pulmonary NTM are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
* NTM is most commonly classified by the growth rate, either slowly growing or rapidly growing:
:* Slow-growing mycobacteria are: Mycobacterium avium complex (includes avium and intracellulare species), M. kansasii, M. xenopi, M. simiae
:* Rapid-growing mycobacteria are: M. Abscessus, M. Fortuitium, M. Chelonae

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of NTM lung disease are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs such as TNF-alpha inhibitors, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).<ref name="pmid14980273">{{cite journal |vauthors=Olivier KN |title=The natural history of nontuberculous mycobacteria in patients with cystic fibrosis |journal=Paediatr Respir Rev |volume=5 Suppl A |issue= |pages=S213–6 |date=2004 |pmid=14980273 |doi= |url=}}</ref><ref name="ShteinbergStein2018">{{cite journal|last1=Shteinberg|first1=Michal|last2=Stein|first2=Nili|last3=Adir|first3=Yochai|last4=Ken-Dror|first4=Shifra|last5=Shitrit|first5=David|last6=Bendayan|first6=Danielle|last7=Fuks|first7=Leonardo|last8=Saliba|first8=Walid|title=Prevalence, risk factors and prognosis of nontuberculous mycobacterial infection among people with bronchiectasis: a population survey|journal=European Respiratory Journal|volume=51|issue=5|year=2018|pages=1702469|issn=0903-1936|doi=10.1183/13993003.02469-2017}}</ref>

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*Symptoms of NTM may include the following:
:* Chronic cough
:* Fatigue
:* Shortness of breath (dyspnea)
:* Coughing up of blood (hemoptysis)
:* Excessive mucus (sputum) production
:* Fever
:* Night sweats
:* Loss of appetite
*: Unintended weight loss.

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are two major radiological findings associated with NTM disease: Fibrocavitary and nodular bronchiectatic forms.<ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
*High resolution computed tomography (HRCT) is the imaging modality of choice for NTM lung disease.
*On HRCT, the fibro-cavitary form of NTM is characterized by cavities with areas of increased opacity, usually located in the upper lobes, pleural thickening and volume loss by fibrosis with traction bronchiectasis are frequent. Unlike pulmonary tuberculosis, cavitation in NTM is thin-walled without lymph node calcification, no atelectasis and usually progresses more slowly.
* HRCT of nodular bronchiectatic form may demonstrate bilateral, multilobar bronchiectasis, especially in the middle and lower lung fields, with small nodules.

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

==Prophylaxis and Treatment of NTM Disease==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) is recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued after the resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.

== Surgery ==

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

== Prevention ==

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-26T17:04:28Z

Nima Nasiri: /* Classification */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==
Non-tuberculous mycobacteria (NTM) are species other than those belonging to the Mycobacterium tuberculosis complex and do not cause leprosy. NTM are generally free-living organisms that are ubiquitous in the environment. There have been more than 150 NTM species identified to-date. They can cause a wide range of infections, with pulmonary infections being the most frequent. NTM are opportunistic pathogens and are abundant in the environment such as peat-rich potting soil and drinking water in buildings and households. Risk factors associated with pulmonary NTM are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
* NTM is most commonly classified by the growth rate, either slowly growing or rapidly growing:
*: Slow-growing mycobacteria are: Mycobacterium avium complex (includes avium and intracellulare species), M. kansasii, M. xenopi, M. simiae
*: Rapid-growing mycobacteria are: M. Abscessus, M. Fortuitium, M. Chelonae

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of NTM lung disease are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs such as TNF-alpha inhibitors, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).<ref name="pmid14980273">{{cite journal |vauthors=Olivier KN |title=The natural history of nontuberculous mycobacteria in patients with cystic fibrosis |journal=Paediatr Respir Rev |volume=5 Suppl A |issue= |pages=S213–6 |date=2004 |pmid=14980273 |doi= |url=}}</ref><ref name="ShteinbergStein2018">{{cite journal|last1=Shteinberg|first1=Michal|last2=Stein|first2=Nili|last3=Adir|first3=Yochai|last4=Ken-Dror|first4=Shifra|last5=Shitrit|first5=David|last6=Bendayan|first6=Danielle|last7=Fuks|first7=Leonardo|last8=Saliba|first8=Walid|title=Prevalence, risk factors and prognosis of nontuberculous mycobacterial infection among people with bronchiectasis: a population survey|journal=European Respiratory Journal|volume=51|issue=5|year=2018|pages=1702469|issn=0903-1936|doi=10.1183/13993003.02469-2017}}</ref>

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*Symptoms of NTM may include the following:
:* Chronic cough
:* Fatigue
:* Shortness of breath (dyspnea)
:* Coughing up of blood (hemoptysis)
:* Excessive mucus (sputum) production
:* Fever
:* Night sweats
:* Loss of appetite
*: Unintended weight loss.

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are two major radiological findings associated with NTM disease: Fibrocavitary and nodular bronchiectatic forms.<ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
*High resolution computed tomography (HRCT) is the imaging modality of choice for NTM lung disease.
*On HRCT, the fibro-cavitary form of NTM is characterized by cavities with areas of increased opacity, usually located in the upper lobes, pleural thickening and volume loss by fibrosis with traction bronchiectasis are frequent. Unlike pulmonary tuberculosis, cavitation in NTM is thin-walled without lymph node calcification, no atelectasis and usually progresses more slowly.
* HRCT of nodular bronchiectatic form may demonstrate bilateral, multilobar bronchiectasis, especially in the middle and lower lung fields, with small nodules.

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

==Prophylaxis and Treatment of NTM Disease==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) is recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued after the resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.

== Surgery ==

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

== Prevention ==

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-26T17:03:14Z

Nima Nasiri: /* Differentiating [disease name] from other Diseases */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==
Non-tuberculous mycobacteria (NTM) are species other than those belonging to the Mycobacterium tuberculosis complex and do not cause leprosy. NTM are generally free-living organisms that are ubiquitous in the environment. There have been more than 150 NTM species identified to-date. They can cause a wide range of infections, with pulmonary infections being the most frequent. NTM are opportunistic pathogens and are abundant in the environment such as peat-rich potting soil and drinking water in buildings and households. Risk factors associated with pulmonary NTM are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*: NTM is most commonly classified by the growth rate, either slowly growing or rapidly growing:
**: Slow-growing mycobacteria are: Mycobacterium avium complex (includes avium and intracellulare species), M. kansasii, M. xenopi, M. simiae
**: Rapid-growing mycobacteria are: M. Abscessus, M. Fortuitium, M. Chelonae

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of NTM lung disease are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs such as TNF-alpha inhibitors, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).<ref name="pmid14980273">{{cite journal |vauthors=Olivier KN |title=The natural history of nontuberculous mycobacteria in patients with cystic fibrosis |journal=Paediatr Respir Rev |volume=5 Suppl A |issue= |pages=S213–6 |date=2004 |pmid=14980273 |doi= |url=}}</ref><ref name="ShteinbergStein2018">{{cite journal|last1=Shteinberg|first1=Michal|last2=Stein|first2=Nili|last3=Adir|first3=Yochai|last4=Ken-Dror|first4=Shifra|last5=Shitrit|first5=David|last6=Bendayan|first6=Danielle|last7=Fuks|first7=Leonardo|last8=Saliba|first8=Walid|title=Prevalence, risk factors and prognosis of nontuberculous mycobacterial infection among people with bronchiectasis: a population survey|journal=European Respiratory Journal|volume=51|issue=5|year=2018|pages=1702469|issn=0903-1936|doi=10.1183/13993003.02469-2017}}</ref>

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*Symptoms of NTM may include the following:
:* Chronic cough
:* Fatigue
:* Shortness of breath (dyspnea)
:* Coughing up of blood (hemoptysis)
:* Excessive mucus (sputum) production
:* Fever
:* Night sweats
:* Loss of appetite
*: Unintended weight loss.

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are two major radiological findings associated with NTM disease: Fibrocavitary and nodular bronchiectatic forms.<ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
*High resolution computed tomography (HRCT) is the imaging modality of choice for NTM lung disease.
*On HRCT, the fibro-cavitary form of NTM is characterized by cavities with areas of increased opacity, usually located in the upper lobes, pleural thickening and volume loss by fibrosis with traction bronchiectasis are frequent. Unlike pulmonary tuberculosis, cavitation in NTM is thin-walled without lymph node calcification, no atelectasis and usually progresses more slowly.
* HRCT of nodular bronchiectatic form may demonstrate bilateral, multilobar bronchiectasis, especially in the middle and lower lung fields, with small nodules.

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

==Prophylaxis and Treatment of NTM Disease==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) is recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued after the resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.

== Surgery ==

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

== Prevention ==

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-26T17:02:21Z

Nima Nasiri: /* Classification */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==
Non-tuberculous mycobacteria (NTM) are species other than those belonging to the Mycobacterium tuberculosis complex and do not cause leprosy. NTM are generally free-living organisms that are ubiquitous in the environment. There have been more than 150 NTM species identified to-date. They can cause a wide range of infections, with pulmonary infections being the most frequent. NTM are opportunistic pathogens and are abundant in the environment such as peat-rich potting soil and drinking water in buildings and households. Risk factors associated with pulmonary NTM are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*: NTM is most commonly classified by the growth rate, either slowly growing or rapidly growing:
**: Slow-growing mycobacteria are: Mycobacterium avium complex (includes avium and intracellulare species), M. kansasii, M. xenopi, M. simiae
**: Rapid-growing mycobacteria are: M. Abscessus, M. Fortuitium, M. Chelonae

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of NTM lung disease are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs such as TNF-alpha inhibitors, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).<ref name="pmid14980273">{{cite journal |vauthors=Olivier KN |title=The natural history of nontuberculous mycobacteria in patients with cystic fibrosis |journal=Paediatr Respir Rev |volume=5 Suppl A |issue= |pages=S213–6 |date=2004 |pmid=14980273 |doi= |url=}}</ref><ref name="ShteinbergStein2018">{{cite journal|last1=Shteinberg|first1=Michal|last2=Stein|first2=Nili|last3=Adir|first3=Yochai|last4=Ken-Dror|first4=Shifra|last5=Shitrit|first5=David|last6=Bendayan|first6=Danielle|last7=Fuks|first7=Leonardo|last8=Saliba|first8=Walid|title=Prevalence, risk factors and prognosis of nontuberculous mycobacterial infection among people with bronchiectasis: a population survey|journal=European Respiratory Journal|volume=51|issue=5|year=2018|pages=1702469|issn=0903-1936|doi=10.1183/13993003.02469-2017}}</ref>

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*Symptoms of NTM may include the following:
:* Chronic cough
:* Fatigue
:* Shortness of breath (dyspnea)
:* Coughing up of blood (hemoptysis)
:* Excessive mucus (sputum) production
:* Fever
:* Night sweats
:* Loss of appetite
*: Unintended weight loss.

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are two major radiological findings associated with NTM disease: Fibrocavitary and nodular bronchiectatic forms.<ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
*High resolution computed tomography (HRCT) is the imaging modality of choice for NTM lung disease.
*On HRCT, the fibro-cavitary form of NTM is characterized by cavities with areas of increased opacity, usually located in the upper lobes, pleural thickening and volume loss by fibrosis with traction bronchiectasis are frequent. Unlike pulmonary tuberculosis, cavitation in NTM is thin-walled without lymph node calcification, no atelectasis and usually progresses more slowly.
* HRCT of nodular bronchiectatic form may demonstrate bilateral, multilobar bronchiectasis, especially in the middle and lower lung fields, with small nodules.

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

==Prophylaxis and Treatment of NTM Disease==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) is recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued after the resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.

== Surgery ==

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

== Prevention ==

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-26T16:48:52Z

Nima Nasiri: /* Symptoms */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==
Non-tuberculous mycobacteria (NTM) are species other than those belonging to the Mycobacterium tuberculosis complex and do not cause leprosy. NTM are generally free-living organisms that are ubiquitous in the environment. There have been more than 150 NTM species identified to-date. They can cause a wide range of infections, with pulmonary infections being the most frequent. NTM are opportunistic pathogens and are abundant in the environment such as peat-rich potting soil and drinking water in buildings and households. Risk factors associated with pulmonary NTM are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*[Disease name] may be classified according to [classification method] into [number] subtypes/groups:
:*[group1]
:*[group2]
:*[group3]
*Other variants of [disease name] include [disease subtype 1], [disease subtype 2], and [disease subtype 3].

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of NTM lung disease are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs such as TNF-alpha inhibitors, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).<ref name="pmid14980273">{{cite journal |vauthors=Olivier KN |title=The natural history of nontuberculous mycobacteria in patients with cystic fibrosis |journal=Paediatr Respir Rev |volume=5 Suppl A |issue= |pages=S213–6 |date=2004 |pmid=14980273 |doi= |url=}}</ref><ref name="ShteinbergStein2018">{{cite journal|last1=Shteinberg|first1=Michal|last2=Stein|first2=Nili|last3=Adir|first3=Yochai|last4=Ken-Dror|first4=Shifra|last5=Shitrit|first5=David|last6=Bendayan|first6=Danielle|last7=Fuks|first7=Leonardo|last8=Saliba|first8=Walid|title=Prevalence, risk factors and prognosis of nontuberculous mycobacterial infection among people with bronchiectasis: a population survey|journal=European Respiratory Journal|volume=51|issue=5|year=2018|pages=1702469|issn=0903-1936|doi=10.1183/13993003.02469-2017}}</ref>

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*Symptoms of NTM may include the following:
:* Chronic cough
:* Fatigue
:* Shortness of breath (dyspnea)
:* Coughing up of blood (hemoptysis)
:* Excessive mucus (sputum) production
:* Fever
:* Night sweats
:* Loss of appetite
*: Unintended weight loss.

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are two major radiological findings associated with NTM disease: Fibrocavitary and nodular bronchiectatic forms.<ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
*High resolution computed tomography (HRCT) is the imaging modality of choice for NTM lung disease.
*On HRCT, the fibro-cavitary form of NTM is characterized by cavities with areas of increased opacity, usually located in the upper lobes, pleural thickening and volume loss by fibrosis with traction bronchiectasis are frequent. Unlike pulmonary tuberculosis, cavitation in NTM is thin-walled without lymph node calcification, no atelectasis and usually progresses more slowly.
* HRCT of nodular bronchiectatic form may demonstrate bilateral, multilobar bronchiectasis, especially in the middle and lower lung fields, with small nodules.

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

==Prophylaxis and Treatment of NTM Disease==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) is recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued after the resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.

== Surgery ==

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

== Prevention ==

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-24T15:05:42Z

Nima Nasiri: /* Risk Factors */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==
Non-tuberculous mycobacteria (NTM) are species other than those belonging to the Mycobacterium tuberculosis complex and do not cause leprosy. NTM are generally free-living organisms that are ubiquitous in the environment. There have been more than 150 NTM species identified to-date. They can cause a wide range of infections, with pulmonary infections being the most frequent. NTM are opportunistic pathogens and are abundant in the environment such as peat-rich potting soil and drinking water in buildings and households. Risk factors associated with pulmonary NTM are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*[Disease name] may be classified according to [classification method] into [number] subtypes/groups:
:*[group1]
:*[group2]
:*[group3]
*Other variants of [disease name] include [disease subtype 1], [disease subtype 2], and [disease subtype 3].

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of NTM lung disease are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs such as TNF-alpha inhibitors, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).<ref name="pmid14980273">{{cite journal |vauthors=Olivier KN |title=The natural history of nontuberculous mycobacteria in patients with cystic fibrosis |journal=Paediatr Respir Rev |volume=5 Suppl A |issue= |pages=S213–6 |date=2004 |pmid=14980273 |doi= |url=}}</ref><ref name="ShteinbergStein2018">{{cite journal|last1=Shteinberg|first1=Michal|last2=Stein|first2=Nili|last3=Adir|first3=Yochai|last4=Ken-Dror|first4=Shifra|last5=Shitrit|first5=David|last6=Bendayan|first6=Danielle|last7=Fuks|first7=Leonardo|last8=Saliba|first8=Walid|title=Prevalence, risk factors and prognosis of nontuberculous mycobacterial infection among people with bronchiectasis: a population survey|journal=European Respiratory Journal|volume=51|issue=5|year=2018|pages=1702469|issn=0903-1936|doi=10.1183/13993003.02469-2017}}</ref>

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*[Disease name] is usually asymptomatic.
*Symptoms of [disease name] may include the following:
:*[symptom 1]
:*[symptom 2]
:*[symptom 3]
:*[symptom 4]
:*[symptom 5]
:*[symptom 6]

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are two major radiological findings associated with NTM disease: Fibrocavitary and nodular bronchiectatic forms.<ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
*High resolution computed tomography (HRCT) is the imaging modality of choice for NTM lung disease.
*On HRCT, the fibro-cavitary form of NTM is characterized by cavities with areas of increased opacity, usually located in the upper lobes, pleural thickening and volume loss by fibrosis with traction bronchiectasis are frequent. Unlike pulmonary tuberculosis, cavitation in NTM is thin-walled without lymph node calcification, no atelectasis and usually progresses more slowly.
* HRCT of nodular bronchiectatic form may demonstrate bilateral, multilobar bronchiectasis, especially in the middle and lower lung fields, with small nodules.

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

==Prophylaxis and Treatment of NTM Disease==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) is recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued after the resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.

== Surgery ==

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

== Prevention ==

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-24T14:59:24Z

Nima Nasiri: /* Risk Factors */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==
Non-tuberculous mycobacteria (NTM) are species other than those belonging to the Mycobacterium tuberculosis complex and do not cause leprosy. NTM are generally free-living organisms that are ubiquitous in the environment. There have been more than 150 NTM species identified to-date. They can cause a wide range of infections, with pulmonary infections being the most frequent. NTM are opportunistic pathogens and are abundant in the environment such as peat-rich potting soil and drinking water in buildings and households. Risk factors associated with pulmonary NTM are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*[Disease name] may be classified according to [classification method] into [number] subtypes/groups:
:*[group1]
:*[group2]
:*[group3]
*Other variants of [disease name] include [disease subtype 1], [disease subtype 2], and [disease subtype 3].

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of NTM lung disease are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs such as TNF-alpha inhibitors, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*[Disease name] is usually asymptomatic.
*Symptoms of [disease name] may include the following:
:*[symptom 1]
:*[symptom 2]
:*[symptom 3]
:*[symptom 4]
:*[symptom 5]
:*[symptom 6]

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are two major radiological findings associated with NTM disease: Fibrocavitary and nodular bronchiectatic forms.<ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
*High resolution computed tomography (HRCT) is the imaging modality of choice for NTM lung disease.
*On HRCT, the fibro-cavitary form of NTM is characterized by cavities with areas of increased opacity, usually located in the upper lobes, pleural thickening and volume loss by fibrosis with traction bronchiectasis are frequent. Unlike pulmonary tuberculosis, cavitation in NTM is thin-walled without lymph node calcification, no atelectasis and usually progresses more slowly.
* HRCT of nodular bronchiectatic form may demonstrate bilateral, multilobar bronchiectasis, especially in the middle and lower lung fields, with small nodules.

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

==Prophylaxis and Treatment of NTM Disease==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) is recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued after the resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.

== Surgery ==

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

== Prevention ==

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-24T14:57:24Z

Nima Nasiri: /* Overview */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==
Non-tuberculous mycobacteria (NTM) are species other than those belonging to the Mycobacterium tuberculosis complex and do not cause leprosy. NTM are generally free-living organisms that are ubiquitous in the environment. There have been more than 150 NTM species identified to-date. They can cause a wide range of infections, with pulmonary infections being the most frequent. NTM are opportunistic pathogens and are abundant in the environment such as peat-rich potting soil and drinking water in buildings and households. Risk factors associated with pulmonary NTM are included but not limited to prior infection with TB, use of glucocorticoids and other immunosuppressive drugs, some pulmonary diseases such as bronchiectasis and cystic fibrosis (CF).

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*[Disease name] may be classified according to [classification method] into [number] subtypes/groups:
:*[group1]
:*[group2]
:*[group3]
*Other variants of [disease name] include [disease subtype 1], [disease subtype 2], and [disease subtype 3].

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of [disease name] are [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*[Disease name] is usually asymptomatic.
*Symptoms of [disease name] may include the following:
:*[symptom 1]
:*[symptom 2]
:*[symptom 3]
:*[symptom 4]
:*[symptom 5]
:*[symptom 6]

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are two major radiological findings associated with NTM disease: Fibrocavitary and nodular bronchiectatic forms.<ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
*High resolution computed tomography (HRCT) is the imaging modality of choice for NTM lung disease.
*On HRCT, the fibro-cavitary form of NTM is characterized by cavities with areas of increased opacity, usually located in the upper lobes, pleural thickening and volume loss by fibrosis with traction bronchiectasis are frequent. Unlike pulmonary tuberculosis, cavitation in NTM is thin-walled without lymph node calcification, no atelectasis and usually progresses more slowly.
* HRCT of nodular bronchiectatic form may demonstrate bilateral, multilobar bronchiectasis, especially in the middle and lower lung fields, with small nodules.

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

==Prophylaxis and Treatment of NTM Disease==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) is recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued after the resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.

== Surgery ==

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

== Prevention ==

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-24T14:35:21Z

Nima Nasiri: /* Imaging Findings */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*[Disease name] may be classified according to [classification method] into [number] subtypes/groups:
:*[group1]
:*[group2]
:*[group3]
*Other variants of [disease name] include [disease subtype 1], [disease subtype 2], and [disease subtype 3].

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of [disease name] are [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*[Disease name] is usually asymptomatic.
*Symptoms of [disease name] may include the following:
:*[symptom 1]
:*[symptom 2]
:*[symptom 3]
:*[symptom 4]
:*[symptom 5]
:*[symptom 6]

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are two major radiological findings associated with NTM disease: Fibrocavitary and nodular bronchiectatic forms.<ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
*High resolution computed tomography (HRCT) is the imaging modality of choice for NTM lung disease.
*On HRCT, the fibro-cavitary form of NTM is characterized by cavities with areas of increased opacity, usually located in the upper lobes, pleural thickening and volume loss by fibrosis with traction bronchiectasis are frequent. Unlike pulmonary tuberculosis, cavitation in NTM is thin-walled without lymph node calcification, no atelectasis and usually progresses more slowly.
* HRCT of nodular bronchiectatic form may demonstrate bilateral, multilobar bronchiectasis, especially in the middle and lower lung fields, with small nodules.

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

==Prophylaxis and Treatment of NTM Disease==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) is recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued after the resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.

== Surgery ==

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

== Prevention ==

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-24T14:18:39Z

Nima Nasiri: /* Prevention */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*[Disease name] may be classified according to [classification method] into [number] subtypes/groups:
:*[group1]
:*[group2]
:*[group3]
*Other variants of [disease name] include [disease subtype 1], [disease subtype 2], and [disease subtype 3].

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of [disease name] are [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*[Disease name] is usually asymptomatic.
*Symptoms of [disease name] may include the following:
:*[symptom 1]
:*[symptom 2]
:*[symptom 3]
:*[symptom 4]
:*[symptom 5]
:*[symptom 6]

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are no [imaging study] findings associated with [disease name].

*[Imaging study 1] is the imaging modality of choice for [disease name].
*On [imaging study 1], [disease name] is characterized by [finding 1], [finding 2], and [finding 3].
*[Imaging study 2] may demonstrate [finding 1], [finding 2], and [finding 3].

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

==Prophylaxis and Treatment of NTM Disease==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) is recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued after the resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.

== Surgery ==

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

== Prevention ==

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-24T14:17:17Z

Nima Nasiri: /* Treatment */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*[Disease name] may be classified according to [classification method] into [number] subtypes/groups:
:*[group1]
:*[group2]
:*[group3]
*Other variants of [disease name] include [disease subtype 1], [disease subtype 2], and [disease subtype 3].

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of [disease name] are [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*[Disease name] is usually asymptomatic.
*Symptoms of [disease name] may include the following:
:*[symptom 1]
:*[symptom 2]
:*[symptom 3]
:*[symptom 4]
:*[symptom 5]
:*[symptom 6]

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are no [imaging study] findings associated with [disease name].

*[Imaging study 1] is the imaging modality of choice for [disease name].
*On [imaging study 1], [disease name] is characterized by [finding 1], [finding 2], and [finding 3].
*[Imaging study 2] may demonstrate [finding 1], [finding 2], and [finding 3].

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

==Prophylaxis and Treatment of NTM Disease==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) is recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued after the resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.

== Surgery ==

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

=== Prevention ===

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-24T14:16:12Z

Nima Nasiri: /* Surgery */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*[Disease name] may be classified according to [classification method] into [number] subtypes/groups:
:*[group1]
:*[group2]
:*[group3]
*Other variants of [disease name] include [disease subtype 1], [disease subtype 2], and [disease subtype 3].

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of [disease name] are [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*[Disease name] is usually asymptomatic.
*Symptoms of [disease name] may include the following:
:*[symptom 1]
:*[symptom 2]
:*[symptom 3]
:*[symptom 4]
:*[symptom 5]
:*[symptom 6]

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are no [imaging study] findings associated with [disease name].

*[Imaging study 1] is the imaging modality of choice for [disease name].
*On [imaging study 1], [disease name] is characterized by [finding 1], [finding 2], and [finding 3].
*[Imaging study 2] may demonstrate [finding 1], [finding 2], and [finding 3].

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

== Treatment ==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>

===Prophylaxis and Treatment of NTM Disease===
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) is recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued after the resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.
== Surgery ==

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

=== Prevention ===

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-24T14:15:27Z

Nima Nasiri: /* Prophylaxis and Treatment of NTM Disease */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*[Disease name] may be classified according to [classification method] into [number] subtypes/groups:
:*[group1]
:*[group2]
:*[group3]
*Other variants of [disease name] include [disease subtype 1], [disease subtype 2], and [disease subtype 3].

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of [disease name] are [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*[Disease name] is usually asymptomatic.
*Symptoms of [disease name] may include the following:
:*[symptom 1]
:*[symptom 2]
:*[symptom 3]
:*[symptom 4]
:*[symptom 5]
:*[symptom 6]

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are no [imaging study] findings associated with [disease name].

*[Imaging study 1] is the imaging modality of choice for [disease name].
*On [imaging study 1], [disease name] is characterized by [finding 1], [finding 2], and [finding 3].
*[Imaging study 2] may demonstrate [finding 1], [finding 2], and [finding 3].

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

== Treatment ==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>

===Prophylaxis and Treatment of NTM Disease===
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) is recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued after the resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.
=== Surgery ===

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

=== Prevention ===

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-24T14:13:26Z

Nima Nasiri: /* Treatment */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*[Disease name] may be classified according to [classification method] into [number] subtypes/groups:
:*[group1]
:*[group2]
:*[group3]
*Other variants of [disease name] include [disease subtype 1], [disease subtype 2], and [disease subtype 3].

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of [disease name] are [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*[Disease name] is usually asymptomatic.
*Symptoms of [disease name] may include the following:
:*[symptom 1]
:*[symptom 2]
:*[symptom 3]
:*[symptom 4]
:*[symptom 5]
:*[symptom 6]

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are no [imaging study] findings associated with [disease name].

*[Imaging study 1] is the imaging modality of choice for [disease name].
*On [imaging study 1], [disease name] is characterized by [finding 1], [finding 2], and [finding 3].
*[Imaging study 2] may demonstrate [finding 1], [finding 2], and [finding 3].

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

== Treatment ==
* Treatment and prophylaxis for NTM lung disease are based on the particular pathogens involved, the severity of the disease, (whether is cavitary or nodular/bronchiectasis), assessment of risks and benefits of therapy for individual patients. Treatment requires prolonged use of a combination of multiple drugs.<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref><ref name="pmid27066084">{{cite journal |vauthors=Ryu YJ, Koh WJ, Daley CL |title=Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease: Clinicians' Perspectives |journal=Tuberc Respir Dis (Seoul) |volume=79 |issue=2 |pages=74–84 |date=April 2016 |pmid=27066084 |pmc=4823187 |doi=10.4046/trd.2016.79.2.74 |url=}}</ref>

==Prophylaxis and Treatment of NTM Disease==
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) are recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued with resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.
=== Surgery ===

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

=== Prevention ===

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-24T14:03:26Z

Nima Nasiri: /* Diagnostic Criteria */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*[Disease name] may be classified according to [classification method] into [number] subtypes/groups:
:*[group1]
:*[group2]
:*[group3]
*Other variants of [disease name] include [disease subtype 1], [disease subtype 2], and [disease subtype 3].

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of [disease name] are [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of NTM pulmonary disease is made when at least three of the following diagnostic criteria are met:<ref name="pmid17277290">{{cite journal |vauthors=Griffith DE, Aksamit T, Brown-Elliott BA, Catanzaro A, Daley C, Gordin F, Holland SM, Horsburgh R, Huitt G, Iademarco MF, Iseman M, Olivier K, Ruoss S, von Reyn CF, Wallace RJ, Winthrop K |title=An official ATS/IDSA statement: diagnosis, treatment, and prevention of nontuberculous mycobacterial diseases |journal=Am. J. Respir. Crit. Care Med. |volume=175 |issue=4 |pages=367–416 |date=February 2007 |pmid=17277290 |doi=10.1164/rccm.200604-571ST |url=}}</ref>
:* Chest radiograph or, in the absence of cavitation, chest high-resolution computed tomography (HRCT) scan.
:* Three or more sputum specimens for acid-fast bacilli (AFB) analysis.
:* Exclusion of other diseases, such as tuberculosis (TB).

=== Symptoms ===
*[Disease name] is usually asymptomatic.
*Symptoms of [disease name] may include the following:
:*[symptom 1]
:*[symptom 2]
:*[symptom 3]
:*[symptom 4]
:*[symptom 5]
:*[symptom 6]

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are no [imaging study] findings associated with [disease name].

*[Imaging study 1] is the imaging modality of choice for [disease name].
*On [imaging study 1], [disease name] is characterized by [finding 1], [finding 2], and [finding 3].
*[Imaging study 2] may demonstrate [finding 1], [finding 2], and [finding 3].

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

== Treatment ==
=== Medical Therapy ===
==Prophylaxis and Treatment of NTM Disease==
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) are recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued with resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.
=== Surgery ===

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

=== Prevention ===

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-24T13:57:29Z

Nima Nasiri: /* Treatment */

__NOTOC__
{{SI}}
{{CMG}} {{AE}} {{Nnasiri}}
==Overview==

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*[Disease name] may be classified according to [classification method] into [number] subtypes/groups:
:*[group1]
:*[group2]
:*[group3]
*Other variants of [disease name] include [disease subtype 1], [disease subtype 2], and [disease subtype 3].

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of [disease name] are [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of [disease name] is made when at least [number] of the following [number] diagnostic criteria are met:
:*[criterion 1]
:*[criterion 2]
:*[criterion 3]
:*[criterion 4]

=== Symptoms ===
*[Disease name] is usually asymptomatic.
*Symptoms of [disease name] may include the following:
:*[symptom 1]
:*[symptom 2]
:*[symptom 3]
:*[symptom 4]
:*[symptom 5]
:*[symptom 6]

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are no [imaging study] findings associated with [disease name].

*[Imaging study 1] is the imaging modality of choice for [disease name].
*On [imaging study 1], [disease name] is characterized by [finding 1], [finding 2], and [finding 3].
*[Imaging study 2] may demonstrate [finding 1], [finding 2], and [finding 3].

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

== Treatment ==
=== Medical Therapy ===
==Prophylaxis and Treatment of NTM Disease==
* For the treatment of MAC pulmonary disease in most patients with nodular/bronchiectatic disease, a three-times-weekly regimen of clarithromycin (1,000 mg) or azithromycin (500 mg), rifampin (600 mg), and ethambutol (25 mg/kg) are recommended. For patients with cavitary MAC lung disease or severe nodular/bronchiectatic disease, a daily regimen of clarithromycin (500–1,000 mg) or azithromycin (250 mg), rifampin (600 mg) or rifabutin (150–300 mg), and ethambutol (15 mg/kg) with consideration of three-times-weekly amikacin or streptomycin early in therapy is recommended. Patients should be treated until culture negative on therapy for 1 year.

* Treatment of disseminated MAC disease: Therapy should include clarithromycin (1,000 mg/d) or azithromycin (250 mg/d) and ethambutol (15 mg/kg/d) with or without rifabutin (150–350 mg/d). Therapy can be discontinued with resolution of symptoms and reconstitution of cell-mediated immune function.

* Prophylaxis of disseminated MAC disease: Prophylaxis should be given to adults with acquired immunodeficiency syndrome (AIDS) with CD4+ T-lymphocyte counts less than 50 cells/μl. Azithromycin 1,200 mg/week or clarithromycin 1,000 mg/day have proven efficacy. Rifabutin 300 mg/day is also effective but less well tolerated.

* Treatment of M.kansasii pulmonary disease. A regimen of daily isoniazid (300 mg/d), rifampin (600 mg/d), and ethambutol (15 mg/kg/d). Patients should be treated until culture negative on therapy for 1 year.

* Treatment of M.abscessus pulmonary disease. There are no drug regimens of proven or predictable efficacy for treatment of M.abscessus lung disease. Multidrug regimens that include clarithromycin 1,000 mg/day may cause symptomatic improvement and disease regression. Surgical resection of the localized disease combined with multidrug clarithromycin-based therapy offers the best chance for cure of this disease.

* Treatment of nonpulmonary disease caused by RGM (M.abscessus, M.chelonae, M.fortuitum). The treatment regimen for these organisms is based on in vitro susceptibilities. For M.abscessus disease, a macrolide-based regimen is frequently used. Surgical debridement may also be an important element of successful therapy.

* Treatment of NTM cervical lymphadenitis. NTM cervical lymphadenitis is due to MAC in the majority of cases and treated primarily by surgical excision, with a greater than 90% cure rate. A macrolide-based regimen should be considered for patients with extensive MAC lymphadenitis or poor response to surgical therapy.
=== Surgery ===

* Surgical resection in conjunction with multidrug clarithromycin-based therapy is the most common approach to the treatment of localized M.abscessus lung disease.

=== Prevention ===

*Effective measures for the primary prevention of NTM pulmonary disease include avoidance of exposure to NTM rich environments such as soil and water. Some experts believe that decreasing exposure to NTM organisms may be helpful preventive methods.

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-24T13:37:43Z

Nima Nasiri:

Nontuberculous mycobacteria

2019-08-24T13:32:42Z

Nima Nasiri:

__NOTOC__
{{SI}}
{{CMG}}
==Overview==

==Historical Perspective==
*[Disease name] was first discovered by [scientist name], a [nationality + occupation], in [year] during/following [event].
*In [year], [gene] mutations were first identified in the pathogenesis of [disease name].
*In [year], the first [discovery] was developed by [scientist] to treat/diagnose [disease name].

==Classification==
*[Disease name] may be classified according to [classification method] into [number] subtypes/groups:
:*[group1]
:*[group2]
:*[group3]
*Other variants of [disease name] include [disease subtype 1], [disease subtype 2], and [disease subtype 3].

==Pathophysiology==
*The pathogenesis of [disease name] is characterized by [feature1], [feature2], and [feature3].
*The [gene name] gene/Mutation in [gene name] has been associated with the development of [disease name], involving the [molecular pathway] pathway.
*On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
*On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

==Clinical Features==

==Differentiating [disease name] from other Diseases==
*[Disease name] must be differentiated from other diseases that cause [clinical feature 1], [clinical feature 2], and [clinical feature 3], such as:
:*[Differential dx1]
:*[Differential dx2]
:*[Differential dx3]

==Epidemiology and Demographics==
* The prevalence of [disease name] is approximately [number or range] per 100,000 individuals worldwide.
* In [year], the incidence of [disease name] was estimated to be [number or range] cases per 100,000 individuals in [location].

===Age===
*Patients of all age groups may develop [disease name].

*[Disease name] is more commonly observed among patients aged [age range] years old.
*[Disease name] is more commonly observed among [elderly patients/young patients/children].

===Gender===
*[Disease name] affects men and women equally.

*[Gender 1] are more commonly affected with [disease name] than [gender 2].
* The [gender 1] to [Gender 2] ratio is approximately [number > 1] to 1.

===Race===
*There is no racial predilection for [disease name].

*[Disease name] usually affects individuals of the [race 1] race.
*[Race 2] individuals are less likely to develop [disease name].

==Risk Factors==
*Common risk factors in the development of [disease name] are [risk factor 1], [risk factor 2], [risk factor 3], and [risk factor 4].

== Natural History, Complications and Prognosis==
*The majority of patients with [disease name] remain asymptomatic for [duration/years].
*Early clinical features include [manifestation 1], [manifestation 2], and [manifestation 3].
*If left untreated, [#%] of patients with [disease name] may progress to develop [manifestation 1], [manifestation 2], and [manifestation 3].
*Common complications of [disease name] include [complication 1], [complication 2], and [complication 3].
*Prognosis is generally [excellent/good/poor], and the [1/5/10year mortality/survival rate] of patients with [disease name] is approximately [#%].

== Diagnosis ==
===Diagnostic Criteria===
*The diagnosis of [disease name] is made when at least [number] of the following [number] diagnostic criteria are met:
:*[criterion 1]
:*[criterion 2]
:*[criterion 3]
:*[criterion 4]

=== Symptoms ===
*[Disease name] is usually asymptomatic.
*Symptoms of [disease name] may include the following:
:*[symptom 1]
:*[symptom 2]
:*[symptom 3]
:*[symptom 4]
:*[symptom 5]
:*[symptom 6]

=== Physical Examination ===
*Patients with [disease name] usually appear [general appearance].
*Physical examination may be remarkable for:
:*[finding 1]
:*[finding 2]
:*[finding 3]
:*[finding 4]
:*[finding 5]
:*[finding 6]

=== Laboratory Findings ===
*There are no specific laboratory findings associated with [disease name].

*A [positive/negative] [test name] is diagnostic of [disease name].
*An [elevated/reduced] concentration of [serum/blood/urinary/CSF/other] [lab test] is diagnostic of [disease name].
*Other laboratory findings consistent with the diagnosis of [disease name] include [abnormal test 1], [abnormal test 2], and [abnormal test 3].

===Imaging Findings===
*There are no [imaging study] findings associated with [disease name].

*[Imaging study 1] is the imaging modality of choice for [disease name].
*On [imaging study 1], [disease name] is characterized by [finding 1], [finding 2], and [finding 3].
*[Imaging study 2] may demonstrate [finding 1], [finding 2], and [finding 3].

=== Other Diagnostic Studies ===
*[Disease name] may also be diagnosed using [diagnostic study name].
*Findings on [diagnostic study name] include [finding 1], [finding 2], and [finding 3].

== Treatment ==
=== Medical Therapy ===
*There is no treatment for [disease name]; the mainstay of therapy is supportive care.

*The mainstay of therapy for [disease name] is [medical therapy 1] and [medical therapy 2].
*[Medical therapy 1] acts by [mechanism of action 1].
*Response to [medical therapy 1] can be monitored with [test/physical finding/imaging] every [frequency/duration].

=== Surgery ===
*Surgery is the mainstay of therapy for [disease name].
*[Surgical procedure] in conjunction with [chemotherapy/radiation] is the most common approach to the treatment of [disease name].
*[Surgical procedure] can only be performed for patients with [disease stage] [disease name].

=== Prevention ===
*There are no primary preventive measures available for [disease name].

*Effective measures for the primary prevention of [disease name] include [measure1], [measure2], and [measure3].

*Once diagnosed and successfully treated, patients with [disease name] are followed-up every [duration]. Follow-up testing includes [test 1], [test 2], and [test 3].

==References==
{{Reflist|2}}

[[Category:Pick One of 28 Approved]]

{{WS}}
{{WH}}

Nontuberculous mycobacteria

2019-08-24T13:12:16Z

Nima Nasiri:

__NOTOC__

'''For patient information, click [[Nontuberculous mycobacteria (patient information)|here]]'''
{{Nontuberculous mycobacteria}}
{{CMG}}; {{AE}} {{Nnasiri}}

{{SK}}

==[[NTM overview|Overview]]==

==[[historical perspective|Historical Perspective]]==

==[[classification|Classification]]==

==[[pathophysiology|Pathophysiology]]==

==[[causes|Causes]]==

==[[Differentiating Nontuberculous mycobacteria from other Diseases]]==

==[[Xyz epidemiology and demographics|Epidemiology and Demographics]]==

==[[Xyz risk factors|Risk Factors]]==

==[[Xyz screening|Screening]]==

==[[Xyz natural history, complications and prognosis|Natural History, Complications, and Prognosis]]==

==Diagnosis==
[[Xyz diagnostic study of choice|Diagnostic study of choice]] | [[Xyz history and symptoms|History and Symptoms]] | [[Xyz physical examination|Physical Examination]] | [[Xyz laboratory findings|Laboratory Findings]] | [[Xyz electrocardiogram|Electrocardiogram]] | [[Xyz x ray|X-Ray Findings]] | [[Xyz echocardiography and ultrasound|Echocardiography and Ultrasound]] | [[Xyz CT scan|CT-Scan Findings]] | [[Xyz MRI|MRI Findings]] | [[Xyz other imaging findings|Other Imaging Findings]] | [[Xyz other diagnostic studies|Other Diagnostic Studies]]

==Treatment==
[[Xyz medical therapy|Medical Therapy]] | [[Xyz interventions|Interventions]] | [[Xyz surgery|Surgery]] | [[Xyz primary prevention|Primary Prevention]] | [[Xyz secondary prevention|Secondary Prevention]] | [[Xyz cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Xyz future or investigational therapies|Future or Investigational Therapies]]

==Case Studies==
[[Xyz case study one|Case #1]]

[[Category: (name of the system)]]

Nontuberculous mycobacteria

2019-08-24T12:48:11Z

Nima Nasiri: /* Differentiating Xyz from other Diseases */

__NOTOC__
{{Nontuberculous mycobacteria}}
'''For patient information, click [[NTM (patient information)|here]]'''

{{CMG}}; {{AE}}

{{SK}}

==[[NTM overview|Overview]]==

==[[historical perspective|Historical Perspective]]==

==[[classification|Classification]]==

==[[pathophysiology|Pathophysiology]]==

==[[causes|Causes]]==

==[[Differentiating Nontuberculous mycobacteria from other Diseases]]==

==[[Xyz epidemiology and demographics|Epidemiology and Demographics]]==

==[[Xyz risk factors|Risk Factors]]==

==[[Xyz screening|Screening]]==

==[[Xyz natural history, complications and prognosis|Natural History, Complications and Prognosis]]==

==Diagnosis==
[[Xyz diagnostic study of choice|Diagnostic study of choice]] | [[Xyz history and symptoms|History and Symptoms]] | [[Xyz physical examination|Physical Examination]] | [[Xyz laboratory findings|Laboratory Findings]] | [[Xyz electrocardiogram|Electrocardiogram]] | [[Xyz x ray|X-Ray Findings]] | [[Xyz echocardiography and ultrasound|Echocardiography and Ultrasound]] | [[Xyz CT scan|CT-Scan Findings]] | [[Xyz MRI|MRI Findings]] | [[Xyz other imaging findings|Other Imaging Findings]] | [[Xyz other diagnostic studies|Other Diagnostic Studies]]

==Treatment==
[[Xyz medical therapy|Medical Therapy]] | [[Xyz interventions|Interventions]] | [[Xyz surgery|Surgery]] | [[Xyz primary prevention|Primary Prevention]] | [[Xyz secondary prevention|Secondary Prevention]] | [[Xyz cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Xyz future or investigational therapies|Future or Investigational Therapies]]

==Case Studies==
[[Xyz case study one|Case #1]]

[[Category: (name of the system)]]

Nontuberculous mycobacteria

2019-08-24T12:45:19Z

Nima Nasiri:

__NOTOC__
{{Nontuberculous mycobacteria}}
'''For patient information, click [[NTM (patient information)|here]]'''

{{CMG}}; {{AE}}

{{SK}}

==[[NTM overview|Overview]]==

==[[historical perspective|Historical Perspective]]==

==[[classification|Classification]]==

==[[pathophysiology|Pathophysiology]]==

==[[causes|Causes]]==

==[[Differentiating Xyz from other Diseases]]==

==[[Xyz epidemiology and demographics|Epidemiology and Demographics]]==

==[[Xyz risk factors|Risk Factors]]==

==[[Xyz screening|Screening]]==

==[[Xyz natural history, complications and prognosis|Natural History, Complications and Prognosis]]==

==Diagnosis==
[[Xyz diagnostic study of choice|Diagnostic study of choice]] | [[Xyz history and symptoms|History and Symptoms]] | [[Xyz physical examination|Physical Examination]] | [[Xyz laboratory findings|Laboratory Findings]] | [[Xyz electrocardiogram|Electrocardiogram]] | [[Xyz x ray|X-Ray Findings]] | [[Xyz echocardiography and ultrasound|Echocardiography and Ultrasound]] | [[Xyz CT scan|CT-Scan Findings]] | [[Xyz MRI|MRI Findings]] | [[Xyz other imaging findings|Other Imaging Findings]] | [[Xyz other diagnostic studies|Other Diagnostic Studies]]

==Treatment==
[[Xyz medical therapy|Medical Therapy]] | [[Xyz interventions|Interventions]] | [[Xyz surgery|Surgery]] | [[Xyz primary prevention|Primary Prevention]] | [[Xyz secondary prevention|Secondary Prevention]] | [[Xyz cost-effectiveness of therapy|Cost-Effectiveness of Therapy]] | [[Xyz future or investigational therapies|Future or Investigational Therapies]]

==Case Studies==
[[Xyz case study one|Case #1]]

[[Category: (name of the system)]]

Epidural

2019-08-23T12:21:44Z

Nima Nasiri: /* Other types of epidural */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is the space inside the spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with different applications in anesthesiology and it can be a single shot or a continuous infusion for long term pain relief. Epidural is excellent analgesic, it decreases the side effect of other anesthetics and analgesics and reducing their side effects. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==History of epidural anesthesia==
* In 1921, a Spanish surgeon named Fidel Pages developed the epidural anesthesia technique, he was the pioneer of lumbar epidural anesthesia.<ref name="pmid8209988">{{cite journal |vauthors=de Lange JJ, Cuesta MA, Cuesta de Pedro A |title=Fidel Pagés Miravé (1886-1923). The pioneer of lumbar epidural anaesthesia |journal=Anaesthesia |volume=49 |issue=5 |pages=429–31 |date=May 1994 |pmid=8209988 |doi=10.1111/j.1365-2044.1994.tb03480.x |url=}}</ref>
* In 1931, Eugene Aburel, a Romanian obstetrician, performed the lumbar obstetric Epidural analgesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>
* In 1933, an Italian surgen, named Achille M. Dogliotti described a loss-of-resistance technique to identify the epidural space.<ref name="pmid26644619">{{cite journal |vauthors=Dhansura T, Shaikh T, Maadoo M, Chittalwala F |title=Identification of the epidural space-loss of resistance to saline: An inexpensive modification |journal=Indian J Anaesth |volume=59 |issue=10 |pages=677–9 |date=October 2015 |pmid=26644619 |pmc=4645360 |doi=10.4103/0019-5049.167483 |url=}}</ref>
* In 1949, Manuel Martinez Curbelo, a Cuban physician reported the first successful continuous lumbar Epidural anaesthesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>

==Epidural anaesthesia and analgesia indication==
Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anesthetist may use epidural analgesia in addition to general anesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anesthesia '''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
The insertion of epidural catheters for analgesia in labor may be carried out with the patient in the sitting or lateral position.<ref name="pmid15321207">{{cite journal |vauthors=Shapiro A, Fredman B, Zohar E, Olsfanger D, Abu-Ras H, Jedeikin R |title=Alternating patient position following the induction of obstetric epidural analgesia does not affect local anaesthetic spread |journal=Int J Obstet Anesth |volume=7 |issue=3 |pages=153–6 |date=July 1998 |pmid=15321207 |doi= |url=}}</ref><ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position. <ref name="pmid20439562">{{cite journal |vauthors=Figueroa JJ, Basford JR, Low PA |title=Preventing and treating orthostatic hypotension: As easy as A, B, C |journal=Cleve Clin J Med |volume=77 |issue=5 |pages=298–306 |date=May 2010 |pmid=20439562 |pmc=2888469 |doi=10.3949/ccjm.77a.09118 |url=}}</ref>
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>
* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* Suboptimal epidural catheter insertion may occur during the block and complications such as paresthesia and venous and subarachnoid cannulation may occur.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Removing the catheter===
* The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours.<ref name="pmid11375820">{{cite journal |vauthors=Aram L, Krane EJ, Kozloski LJ, Yaster M |title=Tunneled epidural catheters for prolonged analgesia in pediatric patients |journal=Anesth. Analg. |volume=92 |issue=6 |pages=1432–8 |date=June 2001 |pmid=11375820 |doi=10.1097/00000539-200106000-00016 |url=}}</ref>
* The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.
* If prolonged analgesics are needed, tunneled epidural catheters can be used. This might reduce the risk of infection including epidural abscess formation.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* In 2003, Klocke and colleagues first described the ultrasound-guided caudal block, thereafter use of ultrasound-guided epidural gained popularity.<ref name="pmid14620894">{{cite journal |vauthors=Klocke R, Jenkinson T, Glew D |title=Sonographically guided caudal epidural steroid injections |journal=J Ultrasound Med |volume=22 |issue=11 |pages=1229–32 |date=November 2003 |pmid=14620894 |doi=10.7863/jum.2003.22.11.1229 |url=}}</ref>
* The ultrasound transducer is placed at the midline to have the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
* An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.
* The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]).
* The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but the permanent benefit is unlikely
* Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]
* The leak of spinal fluid can cause headache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space).
* Very large doses of epidural anesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post-dural puncture headache in obstetric anesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may, in turn, cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterized by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognized accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognized, large doses of anesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where the anesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a cesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of cesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal-epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a cesarean rate of 28% and only 35% had a normal birth without instrument-assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in cesarean rates, whereas the risk of cesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progression of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population-based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

[[da:Epiduralblokade]]
[[de:Periduralanästhesie]]
[[es:Epidural]]
[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
[[sl:Epiduralna anestezija]]
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Epidural

2019-08-23T12:13:20Z

Nima Nasiri: /* Techniques of Caudal Epidural Block */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is the space inside the spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with different applications in anesthesiology and it can be a single shot or a continuous infusion for long term pain relief. Epidural is excellent analgesic, it decreases the side effect of other anesthetics and analgesics and reducing their side effects. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==History of epidural anesthesia==
* In 1921, a Spanish surgeon named Fidel Pages developed the epidural anesthesia technique, he was the pioneer of lumbar epidural anesthesia.<ref name="pmid8209988">{{cite journal |vauthors=de Lange JJ, Cuesta MA, Cuesta de Pedro A |title=Fidel Pagés Miravé (1886-1923). The pioneer of lumbar epidural anaesthesia |journal=Anaesthesia |volume=49 |issue=5 |pages=429–31 |date=May 1994 |pmid=8209988 |doi=10.1111/j.1365-2044.1994.tb03480.x |url=}}</ref>
* In 1931, Eugene Aburel, a Romanian obstetrician, performed the lumbar obstetric Epidural analgesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>
* In 1933, an Italian surgen, named Achille M. Dogliotti described a loss-of-resistance technique to identify the epidural space.<ref name="pmid26644619">{{cite journal |vauthors=Dhansura T, Shaikh T, Maadoo M, Chittalwala F |title=Identification of the epidural space-loss of resistance to saline: An inexpensive modification |journal=Indian J Anaesth |volume=59 |issue=10 |pages=677–9 |date=October 2015 |pmid=26644619 |pmc=4645360 |doi=10.4103/0019-5049.167483 |url=}}</ref>
* In 1949, Manuel Martinez Curbelo, a Cuban physician reported the first successful continuous lumbar Epidural anaesthesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>

==Epidural anaesthesia and analgesia indication==
Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anesthetist may use epidural analgesia in addition to general anesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anesthesia '''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
The insertion of epidural catheters for analgesia in labor may be carried out with the patient in the sitting or lateral position.<ref name="pmid15321207">{{cite journal |vauthors=Shapiro A, Fredman B, Zohar E, Olsfanger D, Abu-Ras H, Jedeikin R |title=Alternating patient position following the induction of obstetric epidural analgesia does not affect local anaesthetic spread |journal=Int J Obstet Anesth |volume=7 |issue=3 |pages=153–6 |date=July 1998 |pmid=15321207 |doi= |url=}}</ref><ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position. <ref name="pmid20439562">{{cite journal |vauthors=Figueroa JJ, Basford JR, Low PA |title=Preventing and treating orthostatic hypotension: As easy as A, B, C |journal=Cleve Clin J Med |volume=77 |issue=5 |pages=298–306 |date=May 2010 |pmid=20439562 |pmc=2888469 |doi=10.3949/ccjm.77a.09118 |url=}}</ref>
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>
* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* Suboptimal epidural catheter insertion may occur during the block and complications such as paresthesia and venous and subarachnoid cannulation may occur.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Removing the catheter===
* The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours.<ref name="pmid11375820">{{cite journal |vauthors=Aram L, Krane EJ, Kozloski LJ, Yaster M |title=Tunneled epidural catheters for prolonged analgesia in pediatric patients |journal=Anesth. Analg. |volume=92 |issue=6 |pages=1432–8 |date=June 2001 |pmid=11375820 |doi=10.1097/00000539-200106000-00016 |url=}}</ref>
* The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.
* If prolonged analgesics are needed, tunneled epidural catheters can be used. This might reduce the risk of infection including epidural abscess formation.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* In 2003, Klocke and colleagues first described the ultrasound-guided caudal block, thereafter use of ultrasound-guided epidural gained popularity.<ref name="pmid14620894">{{cite journal |vauthors=Klocke R, Jenkinson T, Glew D |title=Sonographically guided caudal epidural steroid injections |journal=J Ultrasound Med |volume=22 |issue=11 |pages=1229–32 |date=November 2003 |pmid=14620894 |doi=10.7863/jum.2003.22.11.1229 |url=}}</ref>
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
* An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.
* The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]).
* The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but the permanent benefit is unlikely
* Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]
* The leak of spinal fluid can cause headache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space).
* Very large doses of epidural anesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post-dural puncture headache in obstetric anesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may, in turn, cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterized by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognized accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognized, large doses of anesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where the anesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a cesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of cesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal-epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a cesarean rate of 28% and only 35% had a normal birth without instrument-assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in cesarean rates, whereas the risk of cesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progression of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population-based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
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Epidural

2019-08-23T12:08:23Z

Nima Nasiri: /* Removing the catheter */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is the space inside the spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with different applications in anesthesiology and it can be a single shot or a continuous infusion for long term pain relief. Epidural is excellent analgesic, it decreases the side effect of other anesthetics and analgesics and reducing their side effects. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==History of epidural anesthesia==
* In 1921, a Spanish surgeon named Fidel Pages developed the epidural anesthesia technique, he was the pioneer of lumbar epidural anesthesia.<ref name="pmid8209988">{{cite journal |vauthors=de Lange JJ, Cuesta MA, Cuesta de Pedro A |title=Fidel Pagés Miravé (1886-1923). The pioneer of lumbar epidural anaesthesia |journal=Anaesthesia |volume=49 |issue=5 |pages=429–31 |date=May 1994 |pmid=8209988 |doi=10.1111/j.1365-2044.1994.tb03480.x |url=}}</ref>
* In 1931, Eugene Aburel, a Romanian obstetrician, performed the lumbar obstetric Epidural analgesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>
* In 1933, an Italian surgen, named Achille M. Dogliotti described a loss-of-resistance technique to identify the epidural space.<ref name="pmid26644619">{{cite journal |vauthors=Dhansura T, Shaikh T, Maadoo M, Chittalwala F |title=Identification of the epidural space-loss of resistance to saline: An inexpensive modification |journal=Indian J Anaesth |volume=59 |issue=10 |pages=677–9 |date=October 2015 |pmid=26644619 |pmc=4645360 |doi=10.4103/0019-5049.167483 |url=}}</ref>
* In 1949, Manuel Martinez Curbelo, a Cuban physician reported the first successful continuous lumbar Epidural anaesthesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>

==Epidural anaesthesia and analgesia indication==
Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anesthetist may use epidural analgesia in addition to general anesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anesthesia '''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
The insertion of epidural catheters for analgesia in labor may be carried out with the patient in the sitting or lateral position.<ref name="pmid15321207">{{cite journal |vauthors=Shapiro A, Fredman B, Zohar E, Olsfanger D, Abu-Ras H, Jedeikin R |title=Alternating patient position following the induction of obstetric epidural analgesia does not affect local anaesthetic spread |journal=Int J Obstet Anesth |volume=7 |issue=3 |pages=153–6 |date=July 1998 |pmid=15321207 |doi= |url=}}</ref><ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position. <ref name="pmid20439562">{{cite journal |vauthors=Figueroa JJ, Basford JR, Low PA |title=Preventing and treating orthostatic hypotension: As easy as A, B, C |journal=Cleve Clin J Med |volume=77 |issue=5 |pages=298–306 |date=May 2010 |pmid=20439562 |pmc=2888469 |doi=10.3949/ccjm.77a.09118 |url=}}</ref>
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>
* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* Suboptimal epidural catheter insertion may occur during the block and complications such as paresthesia and venous and subarachnoid cannulation may occur.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Removing the catheter===
* The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours.<ref name="pmid11375820">{{cite journal |vauthors=Aram L, Krane EJ, Kozloski LJ, Yaster M |title=Tunneled epidural catheters for prolonged analgesia in pediatric patients |journal=Anesth. Analg. |volume=92 |issue=6 |pages=1432–8 |date=June 2001 |pmid=11375820 |doi=10.1097/00000539-200106000-00016 |url=}}</ref>
* The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.
* If prolonged analgesics are needed, tunneled epidural catheters can be used. This might reduce the risk of infection including epidural abscess formation.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
* An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.
* The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]).
* The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but the permanent benefit is unlikely
* Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]
* The leak of spinal fluid can cause headache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space).
* Very large doses of epidural anesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post-dural puncture headache in obstetric anesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may, in turn, cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterized by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognized accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognized, large doses of anesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where the anesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a cesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of cesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal-epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a cesarean rate of 28% and only 35% had a normal birth without instrument-assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in cesarean rates, whereas the risk of cesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progression of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population-based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

[[da:Epiduralblokade]]
[[de:Periduralanästhesie]]
[[es:Epidural]]
[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
[[sl:Epiduralna anestezija]]
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Epidural

2019-08-22T11:20:50Z

Nima Nasiri: /* Side effects */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is the space inside the spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with different applications in anesthesiology and it can be a single shot or a continuous infusion for long term pain relief. Epidural is excellent analgesic, it decreases the side effect of other anesthetics and analgesics and reducing their side effects. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==History of epidural anesthesia==
* In 1921, a Spanish surgeon named Fidel Pages developed the epidural anesthesia technique, he was the pioneer of lumbar epidural anesthesia.<ref name="pmid8209988">{{cite journal |vauthors=de Lange JJ, Cuesta MA, Cuesta de Pedro A |title=Fidel Pagés Miravé (1886-1923). The pioneer of lumbar epidural anaesthesia |journal=Anaesthesia |volume=49 |issue=5 |pages=429–31 |date=May 1994 |pmid=8209988 |doi=10.1111/j.1365-2044.1994.tb03480.x |url=}}</ref>
* In 1931, Eugene Aburel, a Romanian obstetrician, performed the lumbar obstetric Epidural analgesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>
* In 1933, an Italian surgen, named Achille M. Dogliotti described a loss-of-resistance technique to identify the epidural space.<ref name="pmid26644619">{{cite journal |vauthors=Dhansura T, Shaikh T, Maadoo M, Chittalwala F |title=Identification of the epidural space-loss of resistance to saline: An inexpensive modification |journal=Indian J Anaesth |volume=59 |issue=10 |pages=677–9 |date=October 2015 |pmid=26644619 |pmc=4645360 |doi=10.4103/0019-5049.167483 |url=}}</ref>
* In 1949, Manuel Martinez Curbelo, a Cuban physician reported the first successful continuous lumbar Epidural anaesthesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>

==Epidural anaesthesia and analgesia indication==
Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anesthetist may use epidural analgesia in addition to general anesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anesthesia '''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
The insertion of epidural catheters for analgesia in labor may be carried out with the patient in the sitting or lateral position.<ref name="pmid15321207">{{cite journal |vauthors=Shapiro A, Fredman B, Zohar E, Olsfanger D, Abu-Ras H, Jedeikin R |title=Alternating patient position following the induction of obstetric epidural analgesia does not affect local anaesthetic spread |journal=Int J Obstet Anesth |volume=7 |issue=3 |pages=153–6 |date=July 1998 |pmid=15321207 |doi= |url=}}</ref><ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position. <ref name="pmid20439562">{{cite journal |vauthors=Figueroa JJ, Basford JR, Low PA |title=Preventing and treating orthostatic hypotension: As easy as A, B, C |journal=Cleve Clin J Med |volume=77 |issue=5 |pages=298–306 |date=May 2010 |pmid=20439562 |pmc=2888469 |doi=10.3949/ccjm.77a.09118 |url=}}</ref>
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>
* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* Suboptimal epidural catheter insertion may occur during the block and complications such as paresthesia and venous and subarachnoid cannulation may occur.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
* An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.
* The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]).
* The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but the permanent benefit is unlikely
* Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]
* The leak of spinal fluid can cause headache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space).
* Very large doses of epidural anesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post-dural puncture headache in obstetric anesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may, in turn, cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterized by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognized accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognized, large doses of anesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where the anesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a cesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of cesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal-epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a cesarean rate of 28% and only 35% had a normal birth without instrument-assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in cesarean rates, whereas the risk of cesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progression of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population-based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[de:Periduralanästhesie]]
[[es:Epidural]]
[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
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Epidural

2019-08-22T11:12:43Z

Nima Nasiri: /* Epidural steroid injections */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is the space inside the spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with different applications in anesthesiology and it can be a single shot or a continuous infusion for long term pain relief. Epidural is excellent analgesic, it decreases the side effect of other anesthetics and analgesics and reducing their side effects. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==History of epidural anesthesia==
* In 1921, a Spanish surgeon named Fidel Pages developed the epidural anesthesia technique, he was the pioneer of lumbar epidural anesthesia.<ref name="pmid8209988">{{cite journal |vauthors=de Lange JJ, Cuesta MA, Cuesta de Pedro A |title=Fidel Pagés Miravé (1886-1923). The pioneer of lumbar epidural anaesthesia |journal=Anaesthesia |volume=49 |issue=5 |pages=429–31 |date=May 1994 |pmid=8209988 |doi=10.1111/j.1365-2044.1994.tb03480.x |url=}}</ref>
* In 1931, Eugene Aburel, a Romanian obstetrician, performed the lumbar obstetric Epidural analgesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>
* In 1933, an Italian surgen, named Achille M. Dogliotti described a loss-of-resistance technique to identify the epidural space.<ref name="pmid26644619">{{cite journal |vauthors=Dhansura T, Shaikh T, Maadoo M, Chittalwala F |title=Identification of the epidural space-loss of resistance to saline: An inexpensive modification |journal=Indian J Anaesth |volume=59 |issue=10 |pages=677–9 |date=October 2015 |pmid=26644619 |pmc=4645360 |doi=10.4103/0019-5049.167483 |url=}}</ref>
* In 1949, Manuel Martinez Curbelo, a Cuban physician reported the first successful continuous lumbar Epidural anaesthesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>

==Epidural anaesthesia and analgesia indication==
Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anesthetist may use epidural analgesia in addition to general anesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anesthesia '''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
The insertion of epidural catheters for analgesia in labor may be carried out with the patient in the sitting or lateral position.<ref name="pmid15321207">{{cite journal |vauthors=Shapiro A, Fredman B, Zohar E, Olsfanger D, Abu-Ras H, Jedeikin R |title=Alternating patient position following the induction of obstetric epidural analgesia does not affect local anaesthetic spread |journal=Int J Obstet Anesth |volume=7 |issue=3 |pages=153–6 |date=July 1998 |pmid=15321207 |doi= |url=}}</ref><ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position. <ref name="pmid20439562">{{cite journal |vauthors=Figueroa JJ, Basford JR, Low PA |title=Preventing and treating orthostatic hypotension: As easy as A, B, C |journal=Cleve Clin J Med |volume=77 |issue=5 |pages=298–306 |date=May 2010 |pmid=20439562 |pmc=2888469 |doi=10.3949/ccjm.77a.09118 |url=}}</ref>
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>
* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* Suboptimal epidural catheter insertion may occur during the block and complications such as paresthesia and venous and subarachnoid cannulation may occur.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
* An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.
* The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]).
* The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but the permanent benefit is unlikely
* Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. The leak of spinal fluid can cause headache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia, if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered a safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post-dural puncture headache in obstetric anesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may, in turn, cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterized by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognized accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognized, large doses of anesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where the anesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a cesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of cesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal-epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a cesarean rate of 28% and only 35% had a normal birth without instrument-assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in cesarean rates, whereas the risk of cesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progression of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population-based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

[[da:Epiduralblokade]]
[[de:Periduralanästhesie]]
[[es:Epidural]]
[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
[[sl:Epiduralna anestezija]]
[[tr:Epidural anestezi]]

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Epidural

2019-08-21T09:36:32Z

Nima Nasiri: /* Overview */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is the space inside the spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with different applications in anesthesiology and it can be a single shot or a continuous infusion for long term pain relief. Epidural is excellent analgesic, it decreases the side effect of other anesthetics and analgesics and reducing their side effects. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==History of epidural anesthesia==
* In 1921, a Spanish surgeon named Fidel Pages developed the epidural anesthesia technique, he was the pioneer of lumbar epidural anesthesia.<ref name="pmid8209988">{{cite journal |vauthors=de Lange JJ, Cuesta MA, Cuesta de Pedro A |title=Fidel Pagés Miravé (1886-1923). The pioneer of lumbar epidural anaesthesia |journal=Anaesthesia |volume=49 |issue=5 |pages=429–31 |date=May 1994 |pmid=8209988 |doi=10.1111/j.1365-2044.1994.tb03480.x |url=}}</ref>
* In 1931, Eugene Aburel, a Romanian obstetrician, performed the lumbar obstetric Epidural analgesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>
* In 1933, an Italian surgen, named Achille M. Dogliotti described a loss-of-resistance technique to identify the epidural space.<ref name="pmid26644619">{{cite journal |vauthors=Dhansura T, Shaikh T, Maadoo M, Chittalwala F |title=Identification of the epidural space-loss of resistance to saline: An inexpensive modification |journal=Indian J Anaesth |volume=59 |issue=10 |pages=677–9 |date=October 2015 |pmid=26644619 |pmc=4645360 |doi=10.4103/0019-5049.167483 |url=}}</ref>
* In 1949, Manuel Martinez Curbelo, a Cuban physician reported the first successful continuous lumbar Epidural anaesthesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>

==Epidural anaesthesia and analgesia indication==
Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anesthetist may use epidural analgesia in addition to general anesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anesthesia '''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
The insertion of epidural catheters for analgesia in labor may be carried out with the patient in the sitting or lateral position.<ref name="pmid15321207">{{cite journal |vauthors=Shapiro A, Fredman B, Zohar E, Olsfanger D, Abu-Ras H, Jedeikin R |title=Alternating patient position following the induction of obstetric epidural analgesia does not affect local anaesthetic spread |journal=Int J Obstet Anesth |volume=7 |issue=3 |pages=153–6 |date=July 1998 |pmid=15321207 |doi= |url=}}</ref><ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position. <ref name="pmid20439562">{{cite journal |vauthors=Figueroa JJ, Basford JR, Low PA |title=Preventing and treating orthostatic hypotension: As easy as A, B, C |journal=Cleve Clin J Med |volume=77 |issue=5 |pages=298–306 |date=May 2010 |pmid=20439562 |pmc=2888469 |doi=10.3949/ccjm.77a.09118 |url=}}</ref>
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>
* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* Suboptimal epidural catheter insertion may occur during the block and complications such as paresthesia and venous and subarachnoid cannulation may occur.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. The leak of spinal fluid can cause headache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia, if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered a safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post-dural puncture headache in obstetric anesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may, in turn, cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterized by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognized accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognized, large doses of anesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where the anesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a cesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of cesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal-epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a cesarean rate of 28% and only 35% had a normal birth without instrument-assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in cesarean rates, whereas the risk of cesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progression of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population-based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

[[da:Epiduralblokade]]
[[de:Periduralanästhesie]]
[[es:Epidural]]
[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
[[sl:Epiduralna anestezija]]
[[tr:Epidural anestezi]]

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Epidural

2019-08-20T09:38:32Z

Nima Nasiri: /* Overview */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is the space inside the spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with different applications in anesthesiology and it can be a single shot or a continuous infusion for long term pain relief. Epidural is excellent analgesic, it decreases the side effect of other anesthetics and analgesics and reducing their side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==History of epidural anesthesia==
* In 1921, a Spanish surgeon named Fidel Pages developed the epidural anesthesia technique, he was the pioneer of lumbar epidural anesthesia.<ref name="pmid8209988">{{cite journal |vauthors=de Lange JJ, Cuesta MA, Cuesta de Pedro A |title=Fidel Pagés Miravé (1886-1923). The pioneer of lumbar epidural anaesthesia |journal=Anaesthesia |volume=49 |issue=5 |pages=429–31 |date=May 1994 |pmid=8209988 |doi=10.1111/j.1365-2044.1994.tb03480.x |url=}}</ref>
* In 1931, Eugene Aburel, a Romanian obstetrician, performed the lumbar obstetric Epidural analgesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>
* In 1933, an Italian surgen, named Achille M. Dogliotti described a loss-of-resistance technique to identify the epidural space.<ref name="pmid26644619">{{cite journal |vauthors=Dhansura T, Shaikh T, Maadoo M, Chittalwala F |title=Identification of the epidural space-loss of resistance to saline: An inexpensive modification |journal=Indian J Anaesth |volume=59 |issue=10 |pages=677–9 |date=October 2015 |pmid=26644619 |pmc=4645360 |doi=10.4103/0019-5049.167483 |url=}}</ref>
* In 1949, Manuel Martinez Curbelo, a Cuban physician reported the first successful continuous lumbar Epidural anaesthesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>

==Epidural anaesthesia and analgesia indication==
Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anesthetist may use epidural analgesia in addition to general anesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anesthesia '''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
The insertion of epidural catheters for analgesia in labor may be carried out with the patient in the sitting or lateral position.<ref name="pmid15321207">{{cite journal |vauthors=Shapiro A, Fredman B, Zohar E, Olsfanger D, Abu-Ras H, Jedeikin R |title=Alternating patient position following the induction of obstetric epidural analgesia does not affect local anaesthetic spread |journal=Int J Obstet Anesth |volume=7 |issue=3 |pages=153–6 |date=July 1998 |pmid=15321207 |doi= |url=}}</ref><ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position. <ref name="pmid20439562">{{cite journal |vauthors=Figueroa JJ, Basford JR, Low PA |title=Preventing and treating orthostatic hypotension: As easy as A, B, C |journal=Cleve Clin J Med |volume=77 |issue=5 |pages=298–306 |date=May 2010 |pmid=20439562 |pmc=2888469 |doi=10.3949/ccjm.77a.09118 |url=}}</ref>
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>
* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* Suboptimal epidural catheter insertion may occur during the block and complications such as paresthesia and venous and subarachnoid cannulation may occur.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. The leak of spinal fluid can cause headache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia, if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered a safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post-dural puncture headache in obstetric anesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may, in turn, cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterized by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognized accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognized, large doses of anesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where the anesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a cesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of cesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal-epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a cesarean rate of 28% and only 35% had a normal birth without instrument-assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in cesarean rates, whereas the risk of cesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progression of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population-based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[de:Periduralanästhesie]]
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[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
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Epidural

2019-08-20T09:24:05Z

Nima Nasiri: /* Epidural anaesthesia and analgesia indication */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.
==History of epidural anesthesia==
* In 1921, a Spanish surgeon named Fidel Pages developed the epidural anesthesia technique, he was the pioneer of lumbar epidural anesthesia.<ref name="pmid8209988">{{cite journal |vauthors=de Lange JJ, Cuesta MA, Cuesta de Pedro A |title=Fidel Pagés Miravé (1886-1923). The pioneer of lumbar epidural anaesthesia |journal=Anaesthesia |volume=49 |issue=5 |pages=429–31 |date=May 1994 |pmid=8209988 |doi=10.1111/j.1365-2044.1994.tb03480.x |url=}}</ref>
* In 1931, Eugene Aburel, a Romanian obstetrician, performed the lumbar obstetric Epidural analgesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>
* In 1933, an Italian surgen, named Achille M. Dogliotti described a loss-of-resistance technique to identify the epidural space.<ref name="pmid26644619">{{cite journal |vauthors=Dhansura T, Shaikh T, Maadoo M, Chittalwala F |title=Identification of the epidural space-loss of resistance to saline: An inexpensive modification |journal=Indian J Anaesth |volume=59 |issue=10 |pages=677–9 |date=October 2015 |pmid=26644619 |pmc=4645360 |doi=10.4103/0019-5049.167483 |url=}}</ref>
* In 1949, Manuel Martinez Curbelo, a Cuban physician reported the first successful continuous lumbar Epidural anaesthesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>

==Epidural anaesthesia and analgesia indication==
Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anesthetist may use epidural analgesia in addition to general anesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anesthesia '''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
The insertion of epidural catheters for analgesia in labor may be carried out with the patient in the sitting or lateral position.<ref name="pmid15321207">{{cite journal |vauthors=Shapiro A, Fredman B, Zohar E, Olsfanger D, Abu-Ras H, Jedeikin R |title=Alternating patient position following the induction of obstetric epidural analgesia does not affect local anaesthetic spread |journal=Int J Obstet Anesth |volume=7 |issue=3 |pages=153–6 |date=July 1998 |pmid=15321207 |doi= |url=}}</ref><ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position. <ref name="pmid20439562">{{cite journal |vauthors=Figueroa JJ, Basford JR, Low PA |title=Preventing and treating orthostatic hypotension: As easy as A, B, C |journal=Cleve Clin J Med |volume=77 |issue=5 |pages=298–306 |date=May 2010 |pmid=20439562 |pmc=2888469 |doi=10.3949/ccjm.77a.09118 |url=}}</ref>
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>
* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* Suboptimal epidural catheter insertion may occur during the block and complications such as paresthesia and venous and subarachnoid cannulation may occur.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. The leak of spinal fluid can cause headache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia, if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered a safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post-dural puncture headache in obstetric anesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may, in turn, cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterized by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognized accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognized, large doses of anesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where the anesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a cesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of cesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal-epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a cesarean rate of 28% and only 35% had a normal birth without instrument-assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in cesarean rates, whereas the risk of cesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progression of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population-based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
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Epidural

2019-08-20T09:23:12Z

Nima Nasiri: /* History of epidural anesthesia */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.
==History of epidural anesthesia==
* In 1921, a Spanish surgeon named Fidel Pages developed the epidural anesthesia technique, he was the pioneer of lumbar epidural anesthesia.<ref name="pmid8209988">{{cite journal |vauthors=de Lange JJ, Cuesta MA, Cuesta de Pedro A |title=Fidel Pagés Miravé (1886-1923). The pioneer of lumbar epidural anaesthesia |journal=Anaesthesia |volume=49 |issue=5 |pages=429–31 |date=May 1994 |pmid=8209988 |doi=10.1111/j.1365-2044.1994.tb03480.x |url=}}</ref>
* In 1931, Eugene Aburel, a Romanian obstetrician, performed the lumbar obstetric Epidural analgesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>
* In 1933, an Italian surgen, named Achille M. Dogliotti described a loss-of-resistance technique to identify the epidural space.<ref name="pmid26644619">{{cite journal |vauthors=Dhansura T, Shaikh T, Maadoo M, Chittalwala F |title=Identification of the epidural space-loss of resistance to saline: An inexpensive modification |journal=Indian J Anaesth |volume=59 |issue=10 |pages=677–9 |date=October 2015 |pmid=26644619 |pmc=4645360 |doi=10.4103/0019-5049.167483 |url=}}</ref>
* In 1949, Manuel Martinez Curbelo, a Cuban physician reported the first successful continuous lumbar Epidural anaesthesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>

==Epidural anaesthesia and analgesia indication==

* In 1921, a Spanish surgeon named Fidel Pages developed the epidural anesthesia technique, he was the pioneer of lumbar epidural anesthesia.<ref name="pmid8209988">{{cite journal |vauthors=de Lange JJ, Cuesta MA, Cuesta de Pedro A |title=Fidel Pagés Miravé (1886-1923). The pioneer of lumbar epidural anaesthesia |journal=Anaesthesia |volume=49 |issue=5 |pages=429–31 |date=May 1994 |pmid=8209988 |doi=10.1111/j.1365-2044.1994.tb03480.x |url=}}</ref>
* In 1931, Eugene Aburel, a Romanian obstetrician, performed the lumbar obstetric Epidural analgesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>
* In 1933, an Italian surgen, named Achille M. Dogliotti described a loss-of-resistance technique to identify the epidural space.<ref name="pmid26644619">{{cite journal |vauthors=Dhansura T, Shaikh T, Maadoo M, Chittalwala F |title=Identification of the epidural space-loss of resistance to saline: An inexpensive modification |journal=Indian J Anaesth |volume=59 |issue=10 |pages=677–9 |date=October 2015 |pmid=26644619 |pmc=4645360 |doi=10.4103/0019-5049.167483 |url=}}</ref>
* In 1949, Manuel Martinez Curbelo, a Cuban physician reported the first successful continuous lumbar Epidural anaesthesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>

Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anesthetist may use epidural analgesia in addition to general anesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anesthesia '''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
The insertion of epidural catheters for analgesia in labor may be carried out with the patient in the sitting or lateral position.<ref name="pmid15321207">{{cite journal |vauthors=Shapiro A, Fredman B, Zohar E, Olsfanger D, Abu-Ras H, Jedeikin R |title=Alternating patient position following the induction of obstetric epidural analgesia does not affect local anaesthetic spread |journal=Int J Obstet Anesth |volume=7 |issue=3 |pages=153–6 |date=July 1998 |pmid=15321207 |doi= |url=}}</ref><ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position. <ref name="pmid20439562">{{cite journal |vauthors=Figueroa JJ, Basford JR, Low PA |title=Preventing and treating orthostatic hypotension: As easy as A, B, C |journal=Cleve Clin J Med |volume=77 |issue=5 |pages=298–306 |date=May 2010 |pmid=20439562 |pmc=2888469 |doi=10.3949/ccjm.77a.09118 |url=}}</ref>
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>
* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* Suboptimal epidural catheter insertion may occur during the block and complications such as paresthesia and venous and subarachnoid cannulation may occur.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. The leak of spinal fluid can cause headache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia, if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered a safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post-dural puncture headache in obstetric anesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may, in turn, cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterized by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognized accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognized, large doses of anesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where the anesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a cesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of cesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal-epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a cesarean rate of 28% and only 35% had a normal birth without instrument-assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in cesarean rates, whereas the risk of cesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progression of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population-based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[fr:Anesthésie péridurale]]
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[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
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Epidural

2019-08-20T09:21:58Z

Nima Nasiri:

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.
==History of epidural anesthesia==

==Epidural anaesthesia and analgesia indication==

* In 1921, a Spanish surgeon named Fidel Pages developed the epidural anesthesia technique, he was the pioneer of lumbar epidural anesthesia.<ref name="pmid8209988">{{cite journal |vauthors=de Lange JJ, Cuesta MA, Cuesta de Pedro A |title=Fidel Pagés Miravé (1886-1923). The pioneer of lumbar epidural anaesthesia |journal=Anaesthesia |volume=49 |issue=5 |pages=429–31 |date=May 1994 |pmid=8209988 |doi=10.1111/j.1365-2044.1994.tb03480.x |url=}}</ref>
* In 1931, Eugene Aburel, a Romanian obstetrician, performed the lumbar obstetric Epidural analgesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>
* In 1933, an Italian surgen, named Achille M. Dogliotti described a loss-of-resistance technique to identify the epidural space.<ref name="pmid26644619">{{cite journal |vauthors=Dhansura T, Shaikh T, Maadoo M, Chittalwala F |title=Identification of the epidural space-loss of resistance to saline: An inexpensive modification |journal=Indian J Anaesth |volume=59 |issue=10 |pages=677–9 |date=October 2015 |pmid=26644619 |pmc=4645360 |doi=10.4103/0019-5049.167483 |url=}}</ref>
* In 1949, Manuel Martinez Curbelo, a Cuban physician reported the first successful continuous lumbar Epidural anaesthesia.<ref name="pmid26230893">{{cite journal |vauthors=Waurick K, Waurick R |title=[History and Technique of Epidural Anaesthesia] |language=German |journal=Anasthesiol Intensivmed Notfallmed Schmerzther |volume=50 |issue=7-8 |pages=476–82; quiz 483 |date=July 2015 |pmid=26230893 |doi=10.1055/s-0041-100845 |url=}}</ref>

Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anesthetist may use epidural analgesia in addition to general anesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anesthesia '''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
The insertion of epidural catheters for analgesia in labor may be carried out with the patient in the sitting or lateral position.<ref name="pmid15321207">{{cite journal |vauthors=Shapiro A, Fredman B, Zohar E, Olsfanger D, Abu-Ras H, Jedeikin R |title=Alternating patient position following the induction of obstetric epidural analgesia does not affect local anaesthetic spread |journal=Int J Obstet Anesth |volume=7 |issue=3 |pages=153–6 |date=July 1998 |pmid=15321207 |doi= |url=}}</ref><ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position. <ref name="pmid20439562">{{cite journal |vauthors=Figueroa JJ, Basford JR, Low PA |title=Preventing and treating orthostatic hypotension: As easy as A, B, C |journal=Cleve Clin J Med |volume=77 |issue=5 |pages=298–306 |date=May 2010 |pmid=20439562 |pmc=2888469 |doi=10.3949/ccjm.77a.09118 |url=}}</ref>
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>
* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* Suboptimal epidural catheter insertion may occur during the block and complications such as paresthesia and venous and subarachnoid cannulation may occur.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. The leak of spinal fluid can cause headache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia, if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered a safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post-dural puncture headache in obstetric anesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may, in turn, cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterized by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognized accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognized, large doses of anesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where the anesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a cesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of cesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal-epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a cesarean rate of 28% and only 35% had a normal birth without instrument-assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in cesarean rates, whereas the risk of cesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progression of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population-based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[de:Periduralanästhesie]]
[[es:Epidural]]
[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
[[sl:Epiduralna anestezija]]
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Epidural

2019-08-19T14:09:25Z

Nima Nasiri: /* Block height and intensity */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anaesthesia and analgesia indication==

Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
The insertion of epidural catheters for analgesia in labor may be carried out with the patient in the sitting or lateral position.<ref name="pmid15321207">{{cite journal |vauthors=Shapiro A, Fredman B, Zohar E, Olsfanger D, Abu-Ras H, Jedeikin R |title=Alternating patient position following the induction of obstetric epidural analgesia does not affect local anaesthetic spread |journal=Int J Obstet Anesth |volume=7 |issue=3 |pages=153–6 |date=July 1998 |pmid=15321207 |doi= |url=}}</ref><ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position. <ref name="pmid20439562">{{cite journal |vauthors=Figueroa JJ, Basford JR, Low PA |title=Preventing and treating orthostatic hypotension: As easy as A, B, C |journal=Cleve Clin J Med |volume=77 |issue=5 |pages=298–306 |date=May 2010 |pmid=20439562 |pmc=2888469 |doi=10.3949/ccjm.77a.09118 |url=}}</ref>
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>
* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* Suboptimal epidural catheter insertion may occur during the block and complications such as paresthesia and venous and subarachnoid cannulation may occur.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
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Epidural

2019-08-19T13:15:12Z

Nima Nasiri: /* Insertion site */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anaesthesia and analgesia indication==

Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
The insertion of epidural catheters for analgesia in labor may be carried out with the patient in the sitting or lateral position.<ref name="pmid15321207">{{cite journal |vauthors=Shapiro A, Fredman B, Zohar E, Olsfanger D, Abu-Ras H, Jedeikin R |title=Alternating patient position following the induction of obstetric epidural analgesia does not affect local anaesthetic spread |journal=Int J Obstet Anesth |volume=7 |issue=3 |pages=153–6 |date=July 1998 |pmid=15321207 |doi= |url=}}</ref><ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position. <ref name="pmid20439562">{{cite journal |vauthors=Figueroa JJ, Basford JR, Low PA |title=Preventing and treating orthostatic hypotension: As easy as A, B, C |journal=Cleve Clin J Med |volume=77 |issue=5 |pages=298–306 |date=May 2010 |pmid=20439562 |pmc=2888469 |doi=10.3949/ccjm.77a.09118 |url=}}</ref>
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>
* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* Suboptimal epidural catheter insertion may occur during the block and complications such as paresthesia and venous and subarachnoid cannulation may occur.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

[[da:Epiduralblokade]]
[[de:Periduralanästhesie]]
[[es:Epidural]]
[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
[[sl:Epiduralna anestezija]]
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Epidural

2019-08-19T13:08:56Z

Nima Nasiri: /* Position of the patient */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anaesthesia and analgesia indication==

Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
The insertion of epidural catheters for analgesia in labor may be carried out with the patient in the sitting or lateral position.<ref name="pmid15321207">{{cite journal |vauthors=Shapiro A, Fredman B, Zohar E, Olsfanger D, Abu-Ras H, Jedeikin R |title=Alternating patient position following the induction of obstetric epidural analgesia does not affect local anaesthetic spread |journal=Int J Obstet Anesth |volume=7 |issue=3 |pages=153–6 |date=July 1998 |pmid=15321207 |doi= |url=}}</ref><ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position. <ref name="pmid20439562">{{cite journal |vauthors=Figueroa JJ, Basford JR, Low PA |title=Preventing and treating orthostatic hypotension: As easy as A, B, C |journal=Cleve Clin J Med |volume=77 |issue=5 |pages=298–306 |date=May 2010 |pmid=20439562 |pmc=2888469 |doi=10.3949/ccjm.77a.09118 |url=}}</ref>
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[pt:Analgesia epidural]]
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Epidural

2019-08-19T13:06:42Z

Nima Nasiri: /* Position of the patient */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
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{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anaesthesia and analgesia indication==

Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
The insertion of epidural catheters for analgesia in labor may be carried out with the patient in the sitting or lateral position.<ref name="pmid15321207">{{cite journal |vauthors=Shapiro A, Fredman B, Zohar E, Olsfanger D, Abu-Ras H, Jedeikin R |title=Alternating patient position following the induction of obstetric epidural analgesia does not affect local anaesthetic spread |journal=Int J Obstet Anesth |volume=7 |issue=3 |pages=153–6 |date=July 1998 |pmid=15321207 |doi= |url=}}</ref><ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position.
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

[[da:Epiduralblokade]]
[[de:Periduralanästhesie]]
[[es:Epidural]]
[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
[[sl:Epiduralna anestezija]]
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Epidural

2019-08-19T12:45:28Z

Nima Nasiri: /* Combined spinal-epidurals */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anaesthesia and analgesia indication==

Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position.
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).
* The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.
* Many studies have confirmed that low-dose CSE with local anaesthetic and opioid, or low-dose epidural block alone, will provide effective analgesia with minimal motor and proprioceptive block.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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Epidural

2019-08-19T12:40:18Z

Nima Nasiri: /* Combined spinal-epidurals */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anaesthesia and analgesia indication==

Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position.
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
Combined spinal and epidural anaesthesia (CSE) is a regional anaesthetic technique, which combines the rapid spinal block with the flexibility of continuous epidural to extend the duration of analgesia. This is an effective way to reduce the total drug dosage required for anaesthesia or analgesia.<ref name="pmid10935011">{{cite journal |vauthors=Rawal N, Holmström B, Crowhurst JA, Van Zundert A |title=The combined spinal-epidural technique |journal=Anesthesiol Clin North Am |volume=18 |issue=2 |pages=267–95 |date=June 2000 |pmid=10935011 |doi= |url=}}</ref>
* For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).

The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[de:Periduralanästhesie]]
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[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
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Epidural

2019-08-19T11:45:13Z

Nima Nasiri: /* Epidural anesthesia and analgesia */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anaesthesia and analgesia indication==

Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position.
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
{{Main|Combined spinal and epidural anaesthesia}}
For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).

The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[de:Periduralanästhesie]]
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[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
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Epidural

2019-08-19T11:44:07Z

Nima Nasiri: /* Indications */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anesthesia and analgesia==
=== Indications ===

Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position.
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
{{Main|Combined spinal and epidural anaesthesia}}
For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).

The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[de:Periduralanästhesie]]
[[es:Epidural]]
[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
[[sl:Epiduralna anestezija]]
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Epidural

2019-08-19T11:40:55Z

Nima Nasiri: /* Indications */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anesthesia and analgesia==
==Indications==

Indications for epidural anaesthesia and analgesia have expanded over the past decades, a summary of major indications for epidural include:<ref name="pmid22263147">{{cite journal |vauthors=Kim YJ, Cho HM, Yoon CS, Lee CK, Lee TY, Seok JP |title=Thoracic Epidural Anesthesia and Analgesia (TEA) in Patients with Rib Fractures |journal=Korean J Thorac Cardiovasc Surg |volume=44 |issue=2 |pages=178–82 |date=April 2011 |pmid=22263147 |pmc=3249296 |doi=10.5090/kjtcs.2011.44.2.178 |url=}}</ref><ref name="pmid28340013">{{cite journal |vauthors=Jensen CD, Stark JT, Jacobson LE, Powers JM, Leslie KL, Kinsella-Shaw JM, Joseph MF, Denegar CR |title=Implications of Thoracic Epidural Analgesia on Hospital Charges in Rib Fracture Patients |journal=Pain Med |volume=19 |issue=1 |pages=160–168 |date=January 2018 |pmid=28340013 |doi=10.1093/pm/pnw353 |url=}}</ref><ref name="pmid30140495">{{cite journal |vauthors=Gimeno AM, Errando CL |title=Neuraxial Regional Anaesthesia in Patients with Active Infection and Sepsis: A Clinical Narrative Review |journal=Turk J Anaesthesiol Reanim |volume=46 |issue=1 |pages=8–14 |date=February 2018 |pmid=30140495 |pmc=5858898 |doi=10.5152/TJAR.2018.12979 |url=}}</ref><ref name="pmid22477012">{{cite journal |vauthors=Jeon YS, Lee JA, Choi JW, Kang EG, Jung HS, Kim HK, Shim BY, Park JH, Joo JD |title=Efficacy of epidural analgesia in patients with cancer pain: a retrospective observational study |journal=Yonsei Med. J. |volume=53 |issue=3 |pages=649–53 |date=May 2012 |pmid=22477012 |pmc=3343439 |doi=10.3349/ymj.2012.53.3.649 |url=}}</ref>

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position.
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
{{Main|Combined spinal and epidural anaesthesia}}
For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).

The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[de:Periduralanästhesie]]
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[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
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Epidural

2019-08-15T04:18:28Z

Nima Nasiri: /* Overview */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. Low blood pressure, fever, nausea, difficulty urinating are complications of epidural anesthesia. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anesthesia and analgesia==
===Indications===
When a [[catheter]] is placed into the epidural space (see below), the effects of the analgesia may be prolonged for several days, if required. Epidurals may be used:

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position.
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
{{Main|Combined spinal and epidural anaesthesia}}
For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).

The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

[[da:Epiduralblokade]]
[[de:Periduralanästhesie]]
[[es:Epidural]]
[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
[[sl:Epiduralna anestezija]]
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Epidural

2019-08-15T04:15:23Z

Nima Nasiri: /* Overview */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. An epidural is a way of anesthetic which is used for pain relief during labor, it stops pain signals traveling from the spine to the brain. During labor, anesthesiologists injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anesthesia and analgesia==
===Indications===
When a [[catheter]] is placed into the epidural space (see below), the effects of the analgesia may be prolonged for several days, if required. Epidurals may be used:

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position.
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
{{Main|Combined spinal and epidural anaesthesia}}
For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).

The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

[[da:Epiduralblokade]]
[[de:Periduralanästhesie]]
[[es:Epidural]]
[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
[[sl:Epiduralna anestezija]]
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Epidural

2019-08-09T18:18:42Z

Nima Nasiri: /* Bolus or infusion? */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. An epidural is a way to deliver an anesthetic so that it stops pain signals traveling from the spine to the brain. It involves injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anesthesia and analgesia==
===Indications===
When a [[catheter]] is placed into the epidural space (see below), the effects of the analgesia may be prolonged for several days, if required. Epidurals may be used:

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position.
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
* For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

* For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

* There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
{{Main|Combined spinal and epidural anaesthesia}}
For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).

The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[pt:Analgesia epidural]]
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Epidural

2019-08-09T18:16:33Z

Nima Nasiri: /* Prolonged labour and risk of instrumental delivery */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. An epidural is a way to deliver an anesthetic so that it stops pain signals traveling from the spine to the brain. It involves injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anesthesia and analgesia==
===Indications===
When a [[catheter]] is placed into the epidural space (see below), the effects of the analgesia may be prolonged for several days, if required. Epidurals may be used:

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position.
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
{{Main|Combined spinal and epidural anaesthesia}}
For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).

The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
* Epidural analgesia is associated with a longer labor, some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic are conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

[[da:Epiduralblokade]]
[[de:Periduralanästhesie]]
[[es:Epidural]]
[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
[[sl:Epiduralna anestezija]]
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Epidural

2019-08-09T18:15:02Z

Nima Nasiri: /* Historical notes */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. An epidural is a way to deliver an anesthetic so that it stops pain signals traveling from the spine to the brain. It involves injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anesthesia and analgesia==
===Indications===
When a [[catheter]] is placed into the epidural space (see below), the effects of the analgesia may be prolonged for several days, if required. Epidurals may be used:

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position.
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
{{Main|Combined spinal and epidural anaesthesia}}
For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).

The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
Epidural analgesia is associated with longer labor[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]. Some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic is conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
* Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

* In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve-blocking injection was used only toward the end of labor.<ref name="hingson" />

* Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

* Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

* The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[de:Periduralanästhesie]]
[[es:Epidural]]
[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
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Epidural

2019-08-09T18:13:48Z

Nima Nasiri: /* Effects on the baby */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. An epidural is a way to deliver an anesthetic so that it stops pain signals traveling from the spine to the brain. It involves injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anesthesia and analgesia==
===Indications===
When a [[catheter]] is placed into the epidural space (see below), the effects of the analgesia may be prolonged for several days, if required. Epidurals may be used:

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position.
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
{{Main|Combined spinal and epidural anaesthesia}}
For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).

The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
Epidural analgesia is associated with longer labor[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]. Some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic is conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
* Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

* One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia, and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticized for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breastfeeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref>
* In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve blocking injection was used only toward the end of labor.<ref name="hingson" />

Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for a delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[fr:Anesthésie péridurale]]
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[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
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Epidural

2019-08-02T16:03:48Z

Nima Nasiri: /* Techniques of Caudal Epidural Block */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. An epidural is a way to deliver an anesthetic so that it stops pain signals traveling from the spine to the brain. It involves injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anesthesia and analgesia==
===Indications===
When a [[catheter]] is placed into the epidural space (see below), the effects of the analgesia may be prolonged for several days, if required. Epidurals may be used:

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position.
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
{{Main|Combined spinal and epidural anaesthesia}}
For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).

The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

===Techniques of Caudal Epidural Block===
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
Epidural analgesia is associated with longer labor[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]. Some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic is conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticised for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breast feeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref> In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve blocking injection was used only toward the end of labor.<ref name="hingson" />

Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for a delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[de:Periduralanästhesie]]
[[es:Epidural]]
[[fr:Anesthésie péridurale]]
[[it:Anestesia peridurale]]
[[he:אפידורל]]
[[nl:Peridurale anesthesie]]
[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
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Epidural

2019-08-02T16:03:01Z

Nima Nasiri: /* Techniques of Caudal Epidural Block */

[[Image:Epidural.JPG|thumb|An epidural catheter after insertion. The site has been prepared with [[Tincture of iodine]]. Depth markings may be seen along the shaft of the catheter.]]
{{SI}}
{{CMG}} {{AE}}{{Nnasiri}}

==Overview==
The term '''epidural''' is often short for '''epidural anesthesia''', a form of [[regional anesthesia]] involving injection of drugs through a [[catheter]] placed into the [[epidural space]]. The '''epidural space''' (or ''extradural space'' or ''peridural space'') is a part of the [[human]] [[vertebrae|spine]]. It is the space inside the bony spinal canal but outside the membrane called the [[dura mater]] (sometimes called the "dura"). In contact with the inner surface of the dura is another membrane called the [[arachnoid mater]] ("arachnoid"). The arachnoid encompasses the [[cerebrospinal fluid]] that surrounds the [[spinal cord]]. Epidural analgesia (pain relief) is a type of Regional Anesthesia which is commonly used to ease the pain of labor and childbirth but can also be used to provide anesthesia for other types of surgeries. James Leonard Corning, a neurologist in New York City, in 1885 described the use of cocaine for spinal anesthesia. A Spanish surgeon named Fidel Pagés Miravé reported the first single-shot thoracolumbar epidural anesthesia in 1921. After a decade, the Italian surgeon Achille M. Dogliotti described a reproducible loss-of-resistance technique to identify the epidural space. Epidural is a technique for perioperative pain management with multiple applications in anesthesiology and it is useful as a primary anesthetic, but most commonly it is used as pain management adjuvant. It can be a single shot or a continuous infusion for long term pain relief. Aside from the benefit of potentially providing excellent analgesia, its use reduces the exposure to other anesthetics and analgesics, decreasing side effects. The injection can cause both a loss of sensation ([[anesthesia]]) and a loss of pain ([[analgesia]]), by blocking the transmission of signals through nerves in or near the spinal cord. An epidural is a way to deliver an anesthetic so that it stops pain signals traveling from the spine to the brain. It involves injecting a small amount of anesthetic into the epidural space of the spine. The epidural space is filled with fluid and surrounds the spinal cord. Nerves that carry pain signals from the body to the brain (spinal nerves) connect to the spinal cord in certain places. The anesthetic numbs the spinal nerves, blocking the pain signals.
[[spinal anesthesia |Spinal anesthesia]] is a technique whereby a [[local anesthetic]] drug is injected into the cerebrospinal fluid. This technique has some similarity to epidural anesthesia, and the two techniques may be easily confused with each other.

==Epidural anesthesia and analgesia==
===Indications===
When a [[catheter]] is placed into the epidural space (see below), the effects of the analgesia may be prolonged for several days, if required. Epidurals may be used:

* For '''analgesia alone''', where surgery is not contemplated. An epidural for pain relief (e.g. in [[childbirth]]) is unlikely to cause loss of muscle power, but is not usually sufficient for surgery.
* As an '''adjunct to [[general anaesthesia]]'''. The anaesthetist may use epidural analgesia in addition to general anaesthesia. This may reduce the patient's requirement for [[opioid]] analgesics. This is suitable for a wide variety of surgery, for example gynaecological surgery (e.g. [[hysterectomy]]), orthopaedic surgery (e.g. [[hip replacement]]), general surgery (e.g. [[laparotomy]]) and vascular surgery (e.g. open [[aortic aneurysm]] repair). See also caudal epidural, below.
* As a '''sole technique for surgical anaesthesia'''. Some operations, most frequently [[Caesarean section]], may be performed using an epidural anaesthetic as the sole technique. Typically the patient would remain awake during the operation. The dose required for anaesthesia is much higher than that required for analgesia.
* For '''post-operative analgesia''', in either of the two situations above. Analgesics are given into the epidural space for a few days after surgery, provided a catheter has been inserted. Through the use of a [[patient-controlled analgesia]] (PCA) infusion pump, a patient may be given the ability to control post-surgical pain medications administered through the epidural.
* For the '''treatment of back pain'''. Injection of analgesics and [[steroid]]s into the epidural space may improve some forms of back pain. See below.
* For the '''treatment of chronic pain''' or '''palliation of symptoms''' in terminal care, usually in the short or medium term.

Because of the nature of epidurals, they are most suitable for analgesia for the abdomen, pelvis or legs. They are much less suitable for analgesia for the chest, neck, or arms and are not possible for the head.

==Cautions==
There are circumstances where the risks of an epidural are higher than normal. These circumstances include:
* Anatomical abnormalities, such as [[spina bifida]], [[meningomyelocele]] or [[scoliosis]]
* Previous spinal surgery (which may cause an acquired tethered spinal cord)
* Certain problems of the central nervous system, including [[multiple sclerosis]] or [[syringomyelia]]
* Certain heart-valve problems (such as [[aortic stenosis]])

==Contraindications==
These are circumstances in which epidurals should not be used:

'''A relative contraindication to neuraxial anesthesia include:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>
* Low platelets but no bleeding diathesis
* Infection remote from the site of lumbar puncture
* Progressive neurologic diseases
* Raised intracranial pressure
* Hypovolemia
* Fixed cardiac output (eg, severe aortic stenosis)

'''Absolute contraindication:'''<ref name="pmid23144567">{{cite journal |vauthors=Silva M, Halpern SH |title=Epidural analgesia for labor: Current techniques |journal=Local Reg Anesth |volume=3 |issue= |pages=143–53 |date=2010 |pmid=23144567 |pmc=3417963 |doi=10.2147/LRA.S10237 |url=}}</ref>

* Patient refusal
* Lack of adequate staff
* Bleeding disorder ([[coagulopathy]]) or anticoagulant medication (e.g. [[warfarin]])
* Infection near the point of insertion
* Infection in the bloodstream which may "seed" onto the catheter i.e septicemia which antibiotics must be given prior to anesthesia.

==Anatomy==
{{Main|Epidural space}}
[[Image:Epiduraldiagram.png|thumb|right|250px|[[Sagittal]] section of the spinal column. A detailed explanation of the various structures exists within the text (not drawn to scale).]]
The diagram at right depicts the various structures of the spinal column. The spinal cord (yellow core) is in intimate contact with the [[pia mater]] (blue). The arachnoid (red) exists superficial to the pia mater, and is attached to it by many, many trabeculae, giving it a spider-like appearance. This space (light blue) is filled with [[cerebrospinal fluid]] (CSF) and is called the [[subarachnoid space]]. Superficial to the arachnoid is the [[dura mater]] (pink) and although they are unattached, they are kept firmly pressed against one another because of pressure exerted by the CSF. Superficial to the dura mater is a space (pale green), known as the '''epidural space''', that exists between it and the internal surfaces of the [[vertebra|vertebral bones]] and their supporting [[ligament]]ous structures. The vertebral bones (taupe) are attached to one another by the interspinous ligaments (teal), and it is through this ligament that the needle used to place the epidural catheter is put.

==Technique of insertion==
Epidural anesthesia should always be performed by a trained anesthetist, using a strict [[aseptic technique]] to reduce the risk of infection. American Society of
Anesthesiologists Task Force recommends the following steps on infection control during epidural anesthesia:<ref name="pmid20051824">{{cite journal |vauthors= |title=Practice advisory for the prevention, diagnosis, and management of infectious complications associated with neuraxial techniques: a report by the American Society of Anesthesiologists Task Force on infectious complications associated with neuraxial techniques |journal=Anesthesiology |volume=112 |issue=3 |pages=530–45 |date=March 2010 |pmid=20051824 |doi=10.1097/ALN.0b013e3181c4c7d8 |url=}}</ref>

* Removal of jewelry from hands
* Handwashing
* Wearing of caps and sterile gloves
* Wearing masks that cover both mouth and nose; masks should be changed between cases
* Individually packaged skin preparation
* Chlorhexidine with alcohol for skin preparation; this must be allowed to dry before needle insertion; povidone-iodine with alcohol is also acceptable
* Sterile draping
* Sterile occlusive dressing

===Position of the patient===
* Epidural block can be performed in the lateral or sitting position, and the decision is usually based on anesthesiologist and patient preferences.<ref name="pmid15636789">{{cite journal |vauthors=Vincent RD, Chestnut DH |title=Which position is more comfortable for the parturient during identification of the epidural space? |journal=Int J Obstet Anesth |volume=1 |issue=1 |pages=9–11 |date=September 1991 |pmid=15636789 |doi= |url=}}</ref>
* When the spinous processes are not easily palpable, the sitting position is preferred. In patients with easily identifiable landmarks, neither the lateral nor the sitting position is superior with regard to patient comfort, but heavier patients preferred the sitting position.
* In some patients, the sitting position may be associated with orthostatic hypotension and syncope. For this reason, it is important for an assistant to provide continuous support to the patient during the procedure. Maternal cardiac output can be reduced in the left lateral position if held too tightly in position.
* The sitting patient is asked to slouch and bend forward slightly from the waist to increase the curvature of the spine. The lying patient is asked to draw the knees up to the chin for the same reason. In the sitting position, the midline can be found by drawing a straight line between the vertebra of C7 (palpable in most patients) and the coccygeal cleft.
* Ultrasound identification of the midline may be useful to locate the midline, determine the approximate depth to the epidural space, and to determine the level of puncture.<ref name="pmid8485791">{{cite journal |vauthors=Andrews PJ, Ackerman WE, Juneja MM |title=Aortocaval compression in the sitting and lateral decubitus positions during extradural catheter placement in the parturient |journal=Can J Anaesth |volume=40 |issue=4 |pages=320–4 |date=April 1993 |pmid=8485791 |doi=10.1007/BF03009629 |url=}}</ref>

===Insertion site===
The anesthetist palpates the patient's back and identifies a suitable anatomical gap between the bony spinous processes prior to the procedure. Anesthesiologists use ultrasound imaging to detect the anatomic structure of the lumbar spine in order to insert the needle in epidural space.<ref name="pmid24972502">{{cite journal |vauthors=Yu S, Tan KK, Sng BL, Li S, Sia AT |title=Automatic identification of needle insertion site in epidural anesthesia with a cascading classifier |journal=Ultrasound Med Biol |volume=40 |issue=9 |pages=1980–90 |date=September 2014 |pmid=24972502 |doi=10.1016/j.ultrasmedbio.2014.03.010 |url=}}</ref><ref name="pmid16244020">{{cite journal |vauthors=Cesur M, Alici HA, Erdem AF, Silbir F, Yuksek MS |title=Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia and reduces catheter-related complications |journal=Anesth. Analg. |volume=101 |issue=5 |pages=1501–5 |date=November 2005 |pmid=16244020 |doi=10.1213/01.ANE.0000181005.50958.1E |url=}}</ref>

* The level of the spine at which the catheter is best placed depends mainly on the size and type of an intended operation or the anatomical origin of pain.
* During epidural catheter insertion, complications such as paresthesia and venous and subarachnoid cannulation may occur, therefore suboptimal catheter placement can affect the quality of anesthesia.
* Administration of local anesthetic through the epidural needle before catheter insertion improves the quality of anesthesia, a single-injection dose of local anesthetic (20 mL of 2% lidocaine) through the epidural needle into the epidural space before catheter insertion is used to ease the induction.
* Most commonly, the anesthetist conducting an epidural place the [[catheter]] in the mid-[[lumbar]], or lower back region of the [[vertebral column|spine]], although occasionally a catheter is placed in the thoracic (chest) or cervical (neck) region. In adults, the spinal cord terminates at the first lumbar vertebra, below which lies a bundle of nerves known as the [[cauda equina]] ("horse's tail"). Hence, lumbar epidurals carry a very low risk of injuring the spinal cord.

===Locating the epidural space===

* The skin is infiltrated with a local anesthetic such as [[lidocaine]] over the identified space. The insertion point is usually in the midline, although other approaches, such as the '''paramedian approach''', may occasionally be employed. <ref name="pmid10">{{cite journal |vauthors=Schmoldt A, Benthe HF, Haberland G, Sinelnikova EM, Dvoretskova TV, Kagan ZS, Smith RC, Stricker CM, Otteni JC, Haberer JP, Share JB, Leber HW, Geissler RH, Faber M, Post D |title=Digitoxin metabolism by rat liver microsomes |journal=Biochem. Pharmacol. |volume=24 |issue=17 |pages=1639–41 |date=September 1975 |pmid=10 |doi=10.2527/jas1975.4161674x |url=}}</ref><ref name="pmid3354812">{{cite journal |vauthors=McNeill MJ, Thorburn J |title=Cannulation of the epidural space. A comparison of 18- and 16-gauge needles |journal=Anaesthesia |volume=43 |issue=2 |pages=154–5 |date=February 1988 |pmid=3354812 |doi= |url=}}</ref>

* A particular type of needle known as a [[Tuohy needle]] 16 or 18 gauge is almost invariably used. This needle was specially designed for locating the epidural space safely and has several specific features for this purpose.

* The Tuohy needle is inserted to the [[interspinous ligament]] and a '''loss of resistance to injection''' technique is used to identify the epidural space. This technique works because the interspinous ligament is extremely dense, and injection into it is almost impossible. The anesthetist attaches a syringe to the Tuohy needle and advances it slowly.

* The syringe may contain air or saline. The principles are the same, but the specifics of the technique are different due to the greater compressibility of air with respect to saline.

* When the tip of the needle enters a space of negative or neutral pressure (such as the epidural space), there will be a "loss of resistance" and it will be possible to inject through the syringe. There is now a high likelihood that the tip of the needle has entered the epidural space. A sensation of "pop" or "click" may be felt as the needle breaches the [[ligamentum flavum]] just before entering the epidural space.

* Traditionally anesthetists have used either air or [[saline (medicine)|saline]] for identifying the epidural space, depending on their personal preference. however, the evidence is accumulating that saline may result in a more rapid and satisfactory quality of analgesia.<ref>Norman D. ''Epidural analgesia using loss of resistance with air versus saline: does it make a difference? Should we reevaluate our practice?'' AANA J 2003;71:449-53. PMID 15098532</ref>

* In addition to the loss of resistance technique, realtime observation of the progress of the needle is becoming more common. This may be done using a portable [[ultrasound]] scanner, or with [[fluoroscopy]] (moving X-ray pictures).

* The position of an epidural catheter and the distribution of local anesthetic drugs in the epidural space are two of the most important determining factors for successful epidural analgesia.

===Feeding the catheter===
* After placement of the tip of the Tuohy needle into the epidural space the catheter is threaded through the needle. The needle is then withdrawn over the catheter. Generally, the catheter is then withdrawn slightly so that 4-6 cm remains in the epidural space. The catheter has depth markings on it (see photo) so that the length of the catheter in the epidural space can be estimated.

* The catheter is a fine plastic tube, down which anesthetics may be given into the epidural space. Early catheters had a hole at the end ("end-hole catheters"), but were prone to blockage. More modern catheters ("side-hole catheters") have a blind end but three or more side-holes along the shaft near the tip. This not only disperses the anesthetic more widely around the catheter but lessens the likelihood of blockage.

* The catheter is typically secured to the skin with adhesive tape or dressings to prevent it from becoming dislodged.

* In some unusual instances, it may not be required to insert a catheter into the epidural space, e.g. for steroid injections; see below. The anesthesiologist may inject medication into the epidural space through the needle, then remove the needle.

* complications including abscess, spinal hematoma, radiculopathy, breakage, migration may occur during insertion of the catheter. <ref name="pmid19378518">{{cite journal |vauthors=Hobaika AB |title=Breakage of epidural catheters: etiology, prevention, and management |journal=Rev Bras Anestesiol |volume=58 |issue=3 |pages=227–33 |date=2008 |pmid=19378518 |doi= |url=}}</ref>

===Anaesthetic drugs===
* A patient receiving an epidural for pain relief typically receives a combination of local anesthetics and [[opioid]]s. This combination works better than either type of drug used alone. This combination helps to reduce the dose of the local anesthetic agent.
* Local anesthetic agents are combined with morphine, fentanyl or clonidine to prolong the epidural effect or to stabilize the blood pressure. Common [[local anesthetic]]s include [[lidocaine]], [[bupivacaine]], [[ropivacaine]], and [[chloroprocaine]]. Common opioids include [[morphine]], [[fentanyl]], [[sufentanil]], and [[pethidine]] (known as [[meperidine]] in the U.S.). These are injected in relatively small doses.

* Occasionally other agents may be used, such as [[clonidine]] or [[ketamine]].

===Bolus or infusion?===
For a short procedure, the anesthetist may introduce a single dose of medication (the [[Bolus (medicine)|"bolus" technique]]). This will eventually wear off. Thereafter, the anesthetist may repeat the bolus provided the catheter remains undisturbed.

For a prolonged effect, a continuous infusion of drugs may be employed. A common solution for epidural infusion in [[childbirth]] or for post-operative analgesia is 0.2% [[ropivacaine]] or 0.125% [[bupivacaine]], with 2 μg/mL of [[fentanyl]] added. This solution is infused at a rate between 4 and 14 mL/hour, following a '''loading dose''' to initiate the [[nerve block]].

There is some evidence that an intermittent bolus technique provides better analgesia than a continuous infusion technique when the total doses are identical.

===Block height and intensity===
Typically, the effects of the epidural are noted below a specific level on the body ([[dermatome]]). This level (the "block height") is chosen by the anesthetist. The level is usually 3-4 dermatomes higher than the point of insertion. A very high insertion level may result in sparing of very low dermatomes. For example, a thoracic epidural may be performed for upper abdominal surgery, but may not have any effect on the [[perineum]] (the area around the genitals). However, giving very large volumes into the epidural space may spread the block both higher and lower.

The intensity of the block is determined by the concentration of local anesthetic drugs used. For example, 15ml 0.1% bupivacaine may provide good analgesia for a woman in labor but would be unlikely to be sufficient for surgery. 15ml of 0.5% bupivacaine would provide a much more intense block, which is likely to be sufficient for surgery. Since the volume used in each case is the same, the spread of drug, and hence the block height, is likely to be similar.

===Removing the catheter===
The catheter should be withdrawn when it is no longer used. An epidural catheter is likely to be safe if left in for up to 72 hours. The risk of problems such as infection rises sharply after this time. Subcutaneously tunneled epidural catheters may be left in place for longer periods, without as much risk of infection.

==Other types of epidural==
===Combined spinal-epidurals===
{{Main|Combined spinal and epidural anaesthesia}}
For some procedures, the anaesthetist may choose to combine the rapid onset and reliable, dense block of a [[spinal anaesthesia|spinal anaesthetic]] with the post-operative analgesic effects of an epidural. This is called [[combined spinal and epidural anaesthesia]] (CSE).

The anaesthetist may insert the spinal anaesthetic at one level, and the epidural at an adjacent level. Alternatively, after locating the epidural space with the Tuohy needle, a spinal needle may be inserted through the Tuohy needle into the subarachnoid space. The spinal dose is then given, the spinal needle withdrawn, and the epidural catheter inserted as normal. This method, known as the "needle-through-needle" technique, may be associated with a slightly higher risk of placing the catheter into the subarachnoid space.

===Caudal epidurals===
* It is performed by inserting a standard 21G needle through the sacral hiatus to gain entrance into the sacral epidural space. Injecting a volume of local anesthetic here provides good analgesia of the [[perineum]] and genital areas. This is typically a single-injection technique and a catheter is not normally placed. This is known as a caudal epidural or "caudal".<ref name="pmid30815114">{{cite journal |vauthors=Lee EK, Tian H, Lee J, Wie X, Neeld J, Smith KD, Kaplan AR |title=Investigating a Needle-Based Epidural Procedure in Obstetric Anesthesia |journal=AMIA Annu Symp Proc |volume=2018 |issue= |pages=720–729 |date=2018 |pmid=30815114 |pmc=6371386 |doi= |url=}}</ref>
* It is performed by inserting a needle through the sacral hiatus to gain entrance into the sacral epidural space.

* The caudal epidural is an effective and safe analgesic technique in children undergoing pelvic or perineal surgery. It is usually combined with general anesthesia.

* A well-documented epidural complication, a “wet tap,” results in a headache and possible total spinal anesthesia/block, requiring immediate maintenance of the patient’s airway and blood pressure.

==Techniques of Caudal Epidural Block==
There are different techniques to perform caudal epidural block during anesthesia, by advances in diagnostic imaging tools, anesthesiologists can use ultrasound-guided block rather than the blind technique. <ref name="pmid28337460">{{cite journal |vauthors=Kao SC, Lin CS |title=Caudal Epidural Block: An Updated Review of Anatomy and Techniques |journal=Biomed Res Int |volume=2017 |issue= |pages=9217145 |date=2017 |pmid=28337460 |pmc=5346404 |doi=10.1155/2017/9217145 |url=}}</ref>

'''Blind Caudal Epidural Block:'''

* In blind caudal block, the patient can be placed in prone or lateral decubitus position, a line is drawn to connect the bilateral posterior superior iliac crests and used as one side of an equilateral triangle; then the location of the sacral hiatus should be approximated.
* By palpating the sacral cornua as 2 bony prominences, the sacral hiatus could be identified as a dimple in between. A needle is inserted at 45 degrees to the sacrum and redirected if the posterior surface of the sacral bone is contacted.

'''Fluoroscopy-Guided Caudal Epidural Block:'''

* In this technique, the patient is usually placed in a prone position for the fluoroscopy-guided caudal epidural block. In lateral view of fluoroscopy, the sacral hiatus could be identified as an abrupt drop off at the end of S4 lamina.
* The block needle trajectory can be visualized and navigated accordingly into the sacral canal.
* By injecting contrast medium under fluoroscopy, the placement of needle tip within the sacral epidural space can be verified, and intravascular or intrathecal needle tip placement can be detected.

''' Ultrasound-Guided Caudal Epidural Block:'''

* The ultrasound-guided caudal block was first described by Klocke and colleagues in 2003 and has, since then, gained increasing popularity.
* The ultrasound transducer is first placed transversely at the midline to obtain the transverse view of sacral hiatus.
* The two sacral cornua appear as two hyperechoic structures on ultrasound. Between the sacral cornua are two band-like hyperechoic structures; the superficial one is the SCL, and the deep one is the dorsal surface of sacral bone.
* At this level, the ultrasound transducer is rotated 90 degrees to obtain the longitudinal view of sacral hiatus (Figure 5). Under longitudinal view, the block needle is inserted using the “in-plane” technique. The block needle can be visualized in real-time, piercing the SCL, entering the sacral hiatus, but cannot be visualized beyond the apex of sacral hiatus.

===Epidural steroid injections===
An epidural injection, or epidural steroid injection, may be used to help reduce the pain caused by a [[herniated disc]], [[degenerative disc disease]], or [[spinal stenosis]]. These spinal disorders often affect the cervical (neck) and lumbar (lower back) areas of the spine.

The medicine used in the injection is usually a combination of a local anesthetic (e.g. [[bupivacaine]]) and a steroid (e.g. [[triamcinolone]]). The technique and risks of the procedure are similar to those for standard epidural analgesia. The effects of an epidural steroid injection vary, but permanent benefit is unlikely [http://www.jr2.ox.ac.uk/bandolier/band32/b32-6.html]. The technique is believed to work by reducing the inflammation or swelling, or both, of the nerves in the epidural space.

Some patients who have some residual pain after the first injection may receive a second or third epidural steroid injection. Patients who do not receive any relief from the first injection are unlikely to benefit from a second injection.

==Benefits of epidural analgesia after surgery==
Epidural analgesia has been demonstrated to have several benefits after surgery. These include:
* Effective analgesia without the need for systemic opioids <ref>Block BM, Liu SS, Rowlingson AJ, et al. (2003). Efficacy of postoperative epidural analgesia: A meta-analysis. ''JAMA'', 290, 2455-2463.</ref>.
* The incidence of postoperative respiratory problems and chest infections is reduced <ref>Ballantyne JC, Carr DB, deFerranti S, et al. (1998). The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials. ''Anesth Analg'', 86, 598-612.</ref>.
* The incidence of postoperative [[myocardial infarction]] ("heart attack") is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* The stress response to surgery is reduced <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Motility of the intestines is improved by blockade of the sympathetic nervous system <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.
* Use of epidural analgesia during surgery reduces [[blood transfusion]] requirements <ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1038</ref>.

Despite these benefits, no survival benefit has been proven for high-risk patients <ref>Rigg JRA, Jamrozik K, Myles PS, et al. (2002). Epidural anaesthesia and analgesia and outcome of major surgery: a randomised trial. ''Lancet'' 359, 1276-1282.</ref>.

==Potential problems==
===Side effects===
In addition to blocking the nerves which carry pain, local anaesthetic drugs in the epidural space will block other types of nerves as well, in a dose-dependent manner. Depending on the drug and dose used, the effects may last only a few minutes or up to several hours. This results in three main effects:

* Loss of other modalities of [[sensation]] (including touch, and [[proprioception]])
* Loss of muscle power
* Loss of function of the [[sympathetic nervous system]], which controls [[blood pressure]]

Pain nerves are most sensitive to the effects of the epidural. This means that a good epidural can provide analgesia without affecting muscle power or other types of sensation. The larger the dose used, the more likely it is that the side-effects will be problematic.

For example, a laboring woman may have an epidural running during labor which is providing good analgesia without impairing her ability to move around in bed. She requires a Caesarean section, and is given a large dose of epidural [[bupivacaine]]. After a few minutes, she can no longer move her legs, or feel her abdomen. Her blood pressure is noted to be lower and she is given an intravenous infusion of ephedrine or [[phenylephrine]] to compensate. During the operation, she feels no pain. Epidural anesthesia can delay labor, so chances of using forceps, vacuum or episiotomy procedures are increased. Leak of spinal fluid can cause head ache in less than 1% of patients and it is corrected by using blood patch( injecting blood into epidural space). After epidural anesthesia if the mom is lying on one side without moving it will prolong labor.

Very large doses of epidural anaesthetic can cause paralysis of the [[intercostal]] muscles and [[thoracic diaphragm|diaphragm]] (which are responsible for breathing), and loss of sympathetic function to the heart itself, causing a profound drop in heart rate and blood pressure. This requires emergency treatment, and in severe cases may require airway support. This happens because the epidural is blocking the heart's sympathetic nerves, as well as the [[phrenic nerve]]s, which supply the diaphragm.

It is considered safe practice for all patients with epidurals to be confined to bed to prevent the risk of falls.

The loss of the sensation of needing to urinate may require the placement of a urinary [[catheter]] for the duration of the epidural.

Opioid drugs in the epidural space are very safe (as well as effective). However, very large doses may cause troublesome itch, and rarely, delayed respiratory depression.

===Complications of epidural use===
These include:
* Block failure (about 1 in 20). Partial failure may still give satisfactory pain relief. However, if pain relief is inadequate, another epidural may have to be performed.
* Bloody tap (about 1 in 30-50). It is easy to injure an epidural vein with the needle. In patients who have normal blood clotting, it is extremely rare (e.g. 1 in 100,000) for problems to develop. However, in a patient who has a [[coagulopathy]], the patient may be at risk of [[epidural hematoma]]. If blood comes back down the needle, the anesthesiologist will normally site the epidural at another level.
* Accidental dural puncture with headache (common, about 1-3 in 100 insertions<ref>Norris MC, Leighton BL, DeSimone CA. Needle bevel direction and headache after inadvertent dural puncture. Anesthesiology 1989;70:729-31.</ref><ref>Sprigge JS, Harper SJ "Accidental dural puncture and post dural puncture headache in obstetric anaesthesia" Anaesthesia. 2008 Jan;63(1):36-43. </ref><ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>) The epidural space in the adult lumbar spine is only 3-5mm deep, which means it is comparatively easy to cross it and accidentally puncture the dura (and arachnoid) with the needle. This may cause cerebrospinal fluid (CSF) to leak out into the epidural space, which may in turn cause the [[Lumbar puncture#Risks|post dural puncture headache]] (PDPH). This can be severe and last several days, and in some cases weeks or months. It is caused by a reduction in CSF pressure and is characterised by postural exacerbation when the patient raises their head above the lying position. If severe it may be successfully treated with a [[epidural blood patch]] (a small amount of the patient's own blood given into the epidural space via another epidural needle). Most cases resolve spontaneously with time.
* Catheter misplaced into a vein (uncommon, less than 1 in 300). Occasionally the catheter may be misplaced into an epidural vein, which results in all the anaesthetic being injected intravenously, where it can be toxic in large doses (about 1 in 10,000 insertions<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 20</ref>). This also results in block failure.
* High block, as described above (uncommon, less than 1 in 500).
* Catheter misplaced into the subarachnoid space (rare, less than 1 in 1000). If the catheter is accidentally misplaced into the subarachnoid space (e.g. after an unrecognised accidental dural puncture), normally cerebrospinal fluid can be freely aspirated from the catheter (which would usually prompt the anaesthetist to withdraw the catheter and resite it elsewhere). If, however, this is not recognised, large doses of anaesthetic may be delivered directly into the cerebrospinal fluid. This may result in a high block, or, more rarely, a '''total spinal''', where anaesthetic is delivered directly to the brainstem, causing unconsciousness and sometimes [[seizures]].
* Neurological injury lasting less than 1 year (rare, about 1 in 6,700).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Epidural abscess formation (very rare, about 1 in 145,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html] The risk increases greatly with catheters which are left in place longer than 72 hours.
* [[Epidural haematoma]] formation (very rare, about 1 in 168,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* Neurological injury lasting longer than 1 year (extremely rare, about 1 in 240,000).[http://www.jr2.ox.ac.uk/bandolier/band159/b159-3.html]
* [[Paraplegia]] (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>.
* [[Arachnoiditis]] (extremely rare, fewer than 1000 cases in the past 50 years)<ref>Rice I, Wee MY, Thomson K., ''Obstetric epidurals and chronic adhesive arachnoiditis'', Br J Anaesth. 2004 Jan;92(1):109-20. PMID 14665562</ref>
* Death (extremely rare, less than 1 in 100,000)<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 21</ref>) .

The figures above relate to epidurals in healthy individuals.

There is no evidence to support the concern that epidural analgesia increases the risk of [[anastomosis|anastomotic]] breakdown following bowel surgery<ref>Allman KG, Wilson IH (eds) (2006). ''The Oxford Handbook of Anaesthesia'', Oxford University Press, ISBN 0 19 856609 3, p. 1039</ref>.

==Epidural analgesia in childbirth==
===Safety and efficacy===
Epidural analgesia is a relatively safe method of relieving pain in labor. It provides rapid pain relief in most cases. It is more effective than [[nitrous oxide]], [[opioids]], [[TENS]], and other common modalities of analgesia in childbirth.[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]

===Prolonged labour and risk of instrumental delivery===
Epidural analgesia is associated with longer labor[http://www.jr2.ox.ac.uk/bandolier/booth/painpag/Acutrev/labour/AP056.html]. Some researchers claim that it is correlated with an increased chance of operational intervention. The clinical research data on this topic is conflicting. For example, a study in Australia (Roberts, Tracy, Peat, 2000) concluded that having an epidural reduced the woman's chances of having a vaginal birth, without further interventions (such as [[episiotomy]], [[forceps]], [[ventouse]] or [[caesarean section]]) from 71.4% to 37.8%. Conversely, a 2001 study by researchers at the [[National Institute of Child Health and Human Development]] and a 2002 study by researchers at [[Cornell University]] and the University of Ontario demonstrated that epidurals do not increase the likelihood of a caesarean section. In 2005, a meta-analysis of 21 studies also showed that epidurals do not increase the likelihood of caesarean section, but they do increase the chance of a forceps or [[ventouse]] delivery by 40% (Anim-Somuah, Cochrane Review, 2005). The COMET Study, published in The Lancet in 2001 (vol358, No9275 p19-23) showed that a combined spinal epidural in labor may speed up the labor process by a few minutes, although those women receiving an epidural had a caesarean rate of 28% and only 35% had a normal birth without instrument assisted delivery.

These differing outcomes may be explained by data that demonstrates that the likelihood of increased intervention is directly related to the quality of the institution or practitioner providing the care: epidurals administered at top-rated institutions do not generally result in a clinically significant increase in caesarean rates, whereas the risk of caesarean delivery at poorly ranked facilities seems to increase with the use of epidural<ref>Thorp JA, Breedlove G. ''Epidural analgesia in labor: an evaluation of risks and benefits.'' Birth. 1996 Jun;23(2):63-83. PMID 8826170.</ref>

An alternative explanation is that women having difficult labors are more likely to request epidurals, and are also less likely to have an unassisted [[childbirth|vaginal birth]].

===Effects on the baby===
Some mothers worry that epidural analgesia may harm their newborn. However, although epidural labor analgesia may be associated with slower progress of labor, it has no adverse effect on perinatal outcome and perinatal complications.<ref>Sieńko J, Czajkowski K, Swiatek-Zdzienicka M, Krawczyńska-Wichrzycka R., ''Epidural analgesia and the course of delivery in term [[primipara]]s'', Ginekol Pol. 2005 Oct;76(10):806-11. PMID 16417096</ref>

One study concluded that women whose epidurals contain the drug [[fentanyl]] were less likely to fully breastfeed their infant in the few days after birth and more likely to stop breastfeeding in the first 24 weeks.<ref>Torvaldsen S, Roberts CL, Simpson JM, Thompson JF, Ellwood DA., ''Intrapartum epidural analgesia and breastfeeding: a prospective cohort study.'' Int Breastfeed J. 2006 Dec 11;1:24. PMID 17134489</ref> However, this study has been criticised for several reasons, one of which is that the original patient records were not examined in this study, and so many of the epidurals were assumed to contain fentanyl when almost certainly they would not have.<ref>Camann, W. ''Labour analgesia and breast feeding: avoid parenteral narcotics and provide lactation support'' Int J. of Obstetric Anesthesia 2007 16;199:201. PMID 17521903</ref> In addition, all patients who used epidurals in labor had also used systemic pethidine, which would be much more likely to be the cause of any effect on breastfeeding due to the higher amounts of medication used via that route. If that were the case, then early epidurals which avoided the need for pethidine may actually improve breastfeeding outcomes, not worsen them.

==Historical notes==
Prior to 1943, there were few methods of relieving pain in childbirth without risk of harm to the baby. [[Caesarean section]]s under [[general anesthesia]] was used only as an emergency measure. Dr. Robert A. Hingson, Dr. Waldo B. Edwards, and Dr. James L. Southworth working at the United States Marine Hospital at Stapleton, on Staten Island, New York, developed the technique of '''continuous caudal anesthesia'''.<ref name="hingson"> "Robert A. Hingson, et al." ''Current Biography 1943'', pp300-04 </ref>

In 1912, German physicians had found that the injection of an anesthetic, at the base of the spinal cord, would prevent pain impulses from reaching the brain. Doctors in the United States developed the technique further. For expectant mothers, the injection "only reduced the pangs of childbirth; it did not eliminate them," wrote Dr. Morris Fishbein in the March 1943 issue of ''[[Hygeia]]'', and a single nerve blocking injection was used only toward the end of labor.<ref name="hingson" />

Drs. Hingson and Southworth combined the concepts of caudal analgesia and the spinal injection in an operation to strip the varicose veins of a Scottish merchant seaman. The surgeons experimented with a continuous infusion of the local anesthetic, rather than removing the needle after the injection, to originate "continuous caudal analgesia". Dr. Hingson then collaborated with Dr. Edwards, the chief obstetrician at the Marine Hospital, to study the use of this technique in childbirth. The two studied the caudal region to determine where a needle could be safely placed to deliver anesthesia to the spinal nerves ''without'' placing the drugs into the spinal fluid.

Testing on a human being did not occur until January 6, 1942, when the wife of a Coast Guardsman was brought into the Marine Hospital for a delivery. Because the woman suffered from rheumatic [[heart disease]], general anesthesia could not be safely used for an emergency [[Caesarean section]], and it was believed that she would not survive the stress of labor. With the use of continuous local anesthesia, the woman and her baby survived. According to Dr. Fishbein's article in ''Hygeia'', a total of 589 women in more than twenty participating hospitals gave birth relatively painlessly in 1942.<ref> ''Current Biography 1943'', p301 </ref>

The results were published in the January 23, 1943, issue of the ''[[Journal of the American Medical Association]]''.<ref> "Childbirth Made Painless and Safe By New Methods," AP article by Willis Young, reprinted in ''Oakland Tribune'', January 21, 1943 </ref>

==References==
{{reflist|2}}

==Other reading==
* Roberts C, Tracy S, Peat B,''Rates for obstetric intervention among private and public patients in Australia: population based descriptive study'', British Medical Journal (BMJ), v321:p137, 15 July 2000

*Jun Zhang, Michael K. Yancey, Mark A. Klebanoff, Jenifer Schwarz and Dina Schweitzer, ''Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment'', American Journal of Obstetrics and Gynecology, Volume 185, Issue 1, July 2001, Pages 128-134.[http://www.sciencedirect.com/science/article/B6W9P-45V21G6-S/2/f04efd0d9a6ec5c61b5685187fa09836]

*Barbara L. Leighton and Stephen H. Halpern, ''The effects of epidural analgesia on labor, maternal, and neonatal outcomes: A systematic review'', American Journal of Obstetrics and Gynecology, Volume 186, Issue 5, Part 2, May 2002, Pages S69-S77. Also [http://www.sciencedirect.com/science/article/B6W9P-45WRJH2-5/2/2d922d4050b704aaeb949c504e8ca2ad available online].

*Boqing Chen and Patrick M. Foye, UMDNJ: New Jersey Medical School, ''Epidural Steroid Injections: Non-surgical Treatment of Spine Pain'', eMedicine: Physical Medicine and Rehabilitation (PM&R), August 2005. Also [http://www.emedicine.com/pmr/topic223.htm available online].

[[Category:Regional anesthesia]]
[[Category:Obstetrics]]

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[[pt:Analgesia epidural]]
[[ru:Эпидуральная анестезия]]
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