Open rectal resection, low anterior with total mesorectal excision (TME)

Median laparotomy, starting at the symphysis up to a few centimeters above the umbilicus. (It is very important to ensure that the skin incision is actually carried down to the symphysis, as otherwise access to the pelvis is significantly impeded). If necessary, some mobilization of the bladder. Insertion of a drape (foil) and a retractor. Intraoperative assessment of findings.

The mobilization of the left flexure is performed alternately from aboral by dissecting the descending colon in an avascular plane in front of the left kidney and from oral by detaching the greater omentum from the colon up to approximately the middle of the transverse colon with opening of the omental bursa. Finally, the connections to the spleen and pancreas are released.

The colon is retracted medially and the lateral adhesions with the peritoneum lateral to the abdominal wall are sharply divided. Care must be taken to ensure that the dissection is not carried too deeply, that is, down to the psoas and behind the kidney, but rather only the mesosigmoid is mobilized. The ureter will then automatically come to lie dorsally and can be identified. Exposure in the sense of a ureterolysis is not required.

Opening of the mesocolon from centrally below the duodeno-jejunal junction (ligament of Treitz). In doing so, the inferior mesenteric vein can be exposed near the lower border of the pancreas and divided between Overholt clamps.