Robotic rectal dissection begins posteriorly in total mesorectal excision plane (TME) using 30° down-viewing scope. Posterior dissection in a TME plane provides a relatively bloodless plane of dissection and creates an anatomical reference point from which lateral and anterior dissection can proceed.
With an assistant retracting the rectum anteriorly and cephalad, the robotic single fenestrated grasper retracts the posterior aspect of the mesorectum anteriorly and slightly caudally. When performed correctly the surgeon can visualize a “cotton candy”-like areolar tissue between the fascia propria of the rectum and presacral fascia. The hook cautery is used to divide the tissue in a U-shaped fashion. The dissection is taken to the level of Waldeyer’s fascia.
Lateral Dissection and Division of Lateral Stalks
The lateral dissection proceeds initially on the right side where the surgeon has a safer plane of dissection (away from left ureter). A monopolar hook moves from posterior to anterior at a deliberate pace while applying current. If the right and posterior dissection was performed correctly, the only structures that need to be divided on the left side are a layer of peritoneum and a small amount of remaining lateral stalks. The left lateral side is dissected by dividing the peritoneum over the left pararectal sulcus. The left ureter must be visualized during this step. It is important to control all vessels, even the ones that appear to be only mildly oozing. Failure to do so may result in the field becoming bloody and dark. In this video, a vessel, encounterd within the left stalk is coagulated using a bipolar grasper while retracting the mesorectum with the hook. After the vessel is sealed it is divided with hook cautery.
As the dissection advances inferiorly, the right and left lateral peritoneal incisions that are created during lateral dissection at this point are connected in front of the rectum. At this stage in operation, with the switch to a 0° scope and change of the retraction of the rectum from anterior and cephalad to posterior and cephalad, the rectum is pulled straight out of the pelvis. Because the posterior dissection has now released the mesorectum, the rectum can be easily stretched placing under tension the anterior plane of dissection.
Circumferential Dissection of the Rectum
If the rectal cancer is distal within the rectum, the mobilization proceeds to the level of pelvic floor and occasionally performing some dissection within the levator muscle complex. As the surgeon advances towards the pelvic floor, the dissection alternates between the posterior, lateral and interior planes as the tissue tension changes based on dissection performed. One of the signs that the dissection is at the level of pelvic floor is observation of levator ani skeletal muscle fibers that contract upon contact with electrocautery and the tapering of the mesorectum. As it narrows at the level of pelvic floor, the rectum can be carefully grasped with a robotic grasper and retracted to obtain the necessary tension to provide dissection.
Editor Recruited By: Jeffrey B. Matthews, MD