Ultrasound guided injections

Editor-in-Chief: Robert G. Schwartz, M.D. [1], Piedmont Physical Medicine and Rehabilitation, P.A.;

Overview of Ultrasound

Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Although this limit varies from person to person, it is approximately 20 kilohertz (20,000 hertz) in healthy, young adults and thus, 20 kHz serves as a useful lower limit in describing ultrasound. Ultrasound is manually produced in many different fields, typically to penetrate a medium and measure the reflection signature or supply focused energy. The reflection signature can reveal details about the inner structure of the medium. The most well known application of this technique is its use in sonography to produce pictures of fetuses in the human womb. There are a vast number of other applications as well.

'Medical sonography ('ultrasonography) is an ultrasound-based diagnostic medical imaging technique used to visualize muscles, tendons, and many internal organs, their size, structure and any pathological lesions with real time tomographic images. It is one of the most widely used diagnostic tools in modern medicine. The technology is relatively inexpensive and portable, especially when compared with modalities such as magnetic resonance imaging(MRI) and computed tomography (CT). As currently applied in the medical environment, ultrasound poses no known risks to the patient. Utilizing ultrasound for guidance during injections is a relatively recent development compared to its use in medical diagnosis. The adoption of ultrasound guidance in clinical practice is increasing however and can be attributed to improvements in imaging technology.

Clinical Indications

The use of Ultrasound in Medicine has become widespread in recent years. Once only available in a select few Universities advances in technology and price reduction have made this technology more available in both community hospitals and in the office setting. Common uses include as a diagnostic tool in the abdomen, vascular studies including both arteries and veins, a wide array of musculoskeletal applications, and with endocrine disease such as thyroid disorders. Due to its non ionzing imaging ability, relatively low cost, and ease of portability Ultrasound has become more prevalent as a guidance tool for procedures including biopsy, catheter placement, and aspiration.

Given these advancements it is not surprising that the use of ultrasound guidance for percutaneous tenotomy, joint injection, a variety of nerve blocks, and other soft tissue injections has become more common place as well. While there is extensive literature on the use of Ultrasound for guidance in spinal injections there is still controversy over its use for spinal conditions. This seems to stem more from previous overstatements of its effectiveness in replacing MRI for spinal conditions then due to the more current literature that make use of it for para and extra spinal conditions and guidance.