Varicocele and the testicular - Renal venous route: Hemodynamic Doppler sonographic investigation

The aim of this study was to quantify the anatomic and hemodynamic componen ts of the testicular venous drainage for the purpose of understanding their mechanisms of interacting in producing mutual effects, such as "nutcracker " phenomenon, reflux, and varicoceles. Seventy-five male subjects were stud ied at rest and during Valsalva maneuver. Aortomesenteric distance and angl e, flow velocity in different segments of the renal veins, testicular vein diameter, and flow inversion were evaluated using standard ultrasound equip ment with spectral and color Doppler capabilities. The velocity of flow in the proximal segment of the left renal vein (17.5 cm/s) was found to be sig nificantly lower than that in both the distal left renal vein (121 cm/s) an d the right renal vein (37 cm/s). The flow velocity in the proximal left re nal vein decreased with decrease in the aortomesenteric distance and angle. Testicular vein diameters greater than 3 mm were statistically associated with decreased superior mesenteric artery angle. A significant association also was found between the left testicular vein diameter tin Valsalva maneu ver) and inversion of flow. The decrease in flow velocity in the left renal vein proximal to the bifurcation of the superior mesenteric artery from th e aorta supports the "nutcracker" theory. An association was found between the decrease of superior mesenteric artery angle and the increase in testic ular vein diameter. Another association exists between the presence of refl ux during Valsalva maneuver and increased testicular vein diameter. These f inding were significant only for testicular vein diameter values greater th an 3 mm.