Intraoperative varicocele anatomy: a microscopic study of the inguinal versus subinguinal approach

The groin approach to varicocelectomy is performed by an inguinal (aponeurosis of external oblique opened) or subinguinal (external oblique aponeurosis intact) technique. We describe the number and relationship of internal and external spermatic arteries, veins and lymphatics within the subinguinal portion of the spermatic cord in infertile men undergoing microscopic varicocelectomy and compare these findings to the microanatomy observed with the inguinal approach.

A total of 48 consecutive patients underwent 84 microsurgical subinguinal varicocelectomies during which the detailed intraoperative microanatomy of the spermatic cord and gubernacula was recorded. These observations were compared with a previously reported group of 83 consecutive patients that underwent 115 inguinal varicocelectomies. Subinguinal microscopic findings were also evaluated relative to clinical varicocele grade.

The spermatic cord in the subinguinal dissection was characterized by a smaller number of large (greater than 5 mm) internal spermatic veins and a greater number of small (less than 2 mm) internal spermatic veins than the cord in the inguinal dissection (mean 0.4 vs 1.9 large veins and mean 7.9 vs 4.7 small veins, respectively). The subinguinal dissection was also characterized by a significantly greater percentage of external spermatic veins greater than 2 mm than that observed during inguinal dissection (93% vs 74%, respectively, p <0.05). Multiple spermatic arteries were identified in 75% of subinguinal dissections and in only 31% of inguinal dissections (p <0.03). Internal spermatic arteries were surrounded by a dense complex of adherent veins in 95% of cases using the subinguinal approach, whereas this finding was true in only 30% of cases with the inguinal approach (p <0.001). The clinical grade of a varicocele was significantly associated with the number of internal spermatic veins greater than 2 mm found intraoperatively (p <0.001) but not with the maximum internal spermatic vein diameter.

Although the subinguinal approach to microsurgical varicocelectomy obviates the need to open the aponeurosis of the external oblique, it is associated with a greater number of internal spermatic veins and arteries compared with the inguinal approach. The primary branch point for the testicular artery occurs most commonly during its course through the inguinal canal. Internal spermatic arteries at the subinguinal level are more than 3 times as likely to be surrounded by a dense network of adherent veins than when they are identified at the inguinal level. Taken together, these data suggest that microscopic dissection is more difficult with a subinguinal incision.