Anatomy of the peritoneal aspect of the deep inguinal ring: implications for laparoscopic inguinal herniorrhaphy

There are a number of important structures to be avoided in suturing or stapling during laparoscopic inguinal herniorrhaphy, not all of which are easily identifiable at laparoscopy. This is particularly so of the ductus deferens. Measurements were taken of the angle made by the ductus deferens with testicular vessels, and of the thickness of tissue in the vicinity of the internal ring into which sutures or staples are likely to be inserted. The angle (mean +/- SD) made by the ductus with testicular vessels was 38.6 degrees +/- 4.4 degrees on the right, and 48.6 degrees +/- 7.2 degrees on the left (P < 0.05) (measurements for right and left sides taken from different cadavers). Thickness of tissue around the ring (peritoneum, transversalis fascia and intervening connective tissue) varies at different sites, being greatest lateral to the testicular vessels (2.2 +/- 0.4 mm) and least over the ductus (0.2 +/- 0.1 mm). The angle measured constitutes the apex of the "triangle of doom" (Spaw et al., 1991. J. Laparoendoscopic Surg. 1:269-277) and with its use the position of the ductus deferens may be predicted and the underlying external iliac vessels avoided when stapling during herniorrhaphy.