The correlation of internal spermatic vein palpability with ultrasonographic diameter and reversal of venous flow.

A gold standard that defines the presence of a subclinical varicocele does not exist. No one has accurately demonstrated at what diameter an internal spermatic vein becomes palpable. We correlated the clinical examination of the scrotum with ultrasonographic measurements of internal spermatic vein diameter and reversal of venous flow in 156 testicles. The internal spermatic vein became palpable at diameters of 3.0 to 3.5 mm. Reversal of flow was found in all veins larger than 3.5 mm. and did not occur in any veins smaller than 2.5 mm. In veins with diameters of 2.5 to 3.5 mm. neither palpability nor internal spermatic vein diameter correlated with the reversal of flow by duplex Doppler color ultrasound. If the internal spermatic vein is nonpalpable during the diagnostic evaluation of the infertile man we do not advocate further radiographic studies. If the palpability of the internal spermatic vein is questionable duplex Doppler color ultrasound is indicated.