Rectal resection, open, low anterior with total mesorectal excision (TME)

Median laparotomy starting at the symphysis and terminating a few centimeters superior to the umbilicus. (It is very important to carry the skin incision down to the symphysis because otherwise this would greatly impair access to the lesser pelvis). If necessary, mobilize the bladder somewhat. Insert a circular wound edge protector followed by a retractor. Intraoperative exploration.

Retract the colon mediad and sharply divide the lateral peritoneal adhesions of the colon with the abdominal wall. Carefully ensure that the preparation is not carried too deeply, i.e., down to the psoas muscle and posterior to the kidney, but that only the mesosigmoid will be mobilized. This will automatically expose the left ureter posteriorly which can then be identified. There is no need to dissect the ureter as in ureterolysis.

Mobilize the splenic flexure by alternating between inferiorly dissecting the descending colon off the anterior left kidney in the areolar plane and superiorly by freeing the greater omentum from the transverse colon and entering the lesser sac. As last step divide the links with the spleen.

Now identify the inferior mesenteric artery by medial incision of the mesosigmoid peritoneum anterior to the aorta. Divide the inferior mesenteric artery with its lymph nodes approximately 1–2cm distal to its origin at the aorta. Primary division of the vessel is indicated apriorion oncologic principles, but studies have not demonstrated any benefit for this. Dividing the artery close to the aorta will prevent injury to the nerve plexus coursing there.

Expose and divide the inferior mesenteric vein at the lower aspect of the pancreatic head. Carefully respect the duodenum.

Starting on the left lateral side, incise the peritoneum at its reflection and extend the dissection down into the lesser pelvis. Now enter the areolar mesorectal layer and extend the dissection caudad while carefully sparing the nerves in the lesser pelvis and the mesorectum.

Then complete the dissection posteriorly, laterally on the right and finally anteriorly. Keep respecting the correct layer by applying traction and counter-traction, since this will leave the autonomous nerves in the lesser pelvis unharmed.

Once the mesorectal dissection has been completed, divide the rectum distal to the tumor. After division check the mesorectum for integrity.

Tip: Identification of the nerves
The presacral course of both the right and left iliohypogastric nerves can be identified, if the dissection in the lesser pelvis was carried out in the correct layer and the nerves were not transected.

Unimpaired anastomotic healing requires that the anastomosis between the rectal stump and descending colon is fashioned without any tension. To this end, check whether the length achieved so far is adequate.
Now divide the mesentery at its transition from the descending colon to the sigmoid and transect the specimen with a linear cutter.

After shortening the proximal limb to a section with excellent blood supply, divide the bowel there, arm it with a purse-string suture and tighten it over the inserted anvil of a circular stapler.