Varicocele pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Pathophysiology
The term varicocele specifically refers to dilatation and tortuosity of the pampiniform plexus, which is the network of veins that drain the testicle. This plexus travels along the posterior portion of the testicle with the epididymis and vas deferens, and then into the spermatic cord. This network of veins coalesces into the gonadal, or testicular, vein. The right gonadal vein drains into the inferior vena cava, while the left gonadal vein drains into the left renal vein at right angle to the renal vein, which then drains into the inferior vena cava.
The small vessels of the pampiniform plexus normally range from 0.5-1.5 mm in diameter. Dilatation of these vessels greater than 2 mm is called a varicocele.
The idiopathic varicocele occurs when the valves within the veins along the spermatic cord don't work properly. This is essentially the same process as varicose veins, which are common in the legs. This results in backflow of blood into the pampiniform plexus and causes increased pressures, ultimately leading to damage to the testicular tissue.
Varicoceles usually develop slowly and may not have any symptoms. There are most frequently diagnosed when a patient is 15-25 years of age, and rarely develop after the age of 40. They occur in 15-20% of all males, and in 40% of infertile males.
98% of idiopathic varicoceles occur on the left side, apparently because the left testicular vein runs vertically up to the renal vein, while the right testicular vein drains directly into the vena cava. Isolated right sided varicoceles are rare, and should prompt evaluation for an abdominal or pelvic mass (see secondary varicocele, below).
A secondary varicocele is due to compression of the venous drainage of the testicle. A pelvic or abdominal malignancy is a definite concern when a varicocele is newly diagnosed in a patient older than 40 years of age. One non-malignant cause of a secondary varicocele is the so-called "nut-cracker SMA" (superior mesenteric artery), a condition in which the superior mesenteric artery compresses the left renal vein, causing increased pressures there to be transmitted retrograde into the left pampiniform plexus.