Retroperitoneal Tunnelling

Retroperitoneal tunneling, a tunnel underneath the right parietal peritoneum of this small pelvis is created and extended caudally from the promontory to the vaginal vault. Our retroperitoneum tunnel is created from the level of sacral promontory down the length of the posterior cul-de-sac to meet the previously created perineotomy over the posterior aspect of the vagina. It has been preferred over the periotoneal opening all along the full length of right paracolic gutter because it avoids the risk of injury to right ureter or sigmoid colon and also negates the need of full peritoneal closure afterwards. But dissecting tunnel by robotic instrument is time-consuming. There is always the risk of going deeper as you tend to observe directly into the tunnel to keep a track on the area of dissection.

And this occasionally results in entering into the blind path. This also carries the risk of damage of retroperitoneal vital structures including vessels and nerves. To avoid this situation, we used suction cannula from right assistant port for developing retroperitoneal tunnel. Keeping this instrument superficial just beneath the peritoneum results in a straight tunnel formation very quickly and easily.

Careful dissection in this area is essential to avoid shearing off presacral because severe bleeding may occur. It is equally important to avoid the left common iliac vein, which is not infrequently located more medial than the artery and can be injured during exposure of promontory. The middle sacral vessels traverses over the promontory and should also be avoided. The overall median rate of bleeding complications are 4.4%.