The Inverse Relationship Between Body Mass Index and the Presence of a Varicocele: An Interesting Epidemiological Finding

353 Varicoceles, characterized as abnormal dilatation of the veins of the pampiniform plexus and present in 15–20% of men, are the most common abnormal finding among men presenting with infertility, 1 yet controversy exists regarding their etiology. It is likely that a combination of factors play a role in the formation of varicoceles. Several anatomical features of the testicular venous system may contribute to excessive hydrostatic pressure that is transmitted caudally to the scrotal pampiniform plexus, causing dilatation and tortuosity of these vessels. Approximately 90% of varicoceles are on the left side. The incidence of bilaterality is anywhere from 15% to 50%, but isolated right varicoceles are fairly rare. One theory postulates that the length of the left internal spermatic vein and the angle at which it drains into the left renal vein can result in increased hydrostatic pressure. The anatomy of the left spermatic vein system in conjunction with the upright posture of humans may also predispose them to varicocele from the effects of gravity and the length of the internal spermatic veins. Absent or incompetent valves within the internal spermatic vein also have long been thought to contribute to the pathophysiology of varicocele. Standard anatomy texts describe valves within the internal spermatic vein. However, in a study of 659 consecutive patients who underwent venography for evaluation of idiopathic left varicocele, 73% had absent internal spermatic venous valves, while 26% had competent valves but absent insertions of the left spermatic vein at the typical point on the left renal vein plus retrograde flow over persistent collateral anastomoses. 2 Therefore, the complete absence of valves, the presence of dysfunctional valves or the presence of functional valves in conjunction with abnormal anatomical features seem to be associated with varicocele formation. The location of the left renal vein between the superior mesenteric artery and aorta may also predispose the vein to compression (the socalled “nutcracker” phenomenon), leading to potential development of collateral drainage and increased venous pressure within the internal spermatic vein. 3 Distal compression of the left common iliac vein by the common iliac artery may also occur, thereby impeding flow through the deferential and external spermatic veins,