Omental transposition for low pelvic anastomoses.

Surgeons' opinions differ regarding the role of the omentum in low pelvic intestinal anastomoses. This study was undertaken to define the anatomy and surgical technique of omental transposition to the pelvis. We studied 45 cadavers to elucidate surgical aspects of omental mobilization, lengthening, and transposition into the pelvic cavity. In addition, intraoperative studies of omental transposition to the pelvis were performed in 20 patients with chronic ulcerative colitis, familial adenomatous polyposis, and rectal cancer who were undergoing ileal J-pouch anal anastomosis or low anterior resection. The most important anatomic variables for omental transposition are three variants of arterial blood supply: (1) In 56% of patients, there is one right, one (or two) middle, and one left omental artery. (2) In 26% of patients, the middle omental artery is absent. (3) In the remaining 18% of patients, the gastroepiploic artery is continued as a left omental artery but with various smaller connections to the right or middle omental artery. The first stage of omental lengthening is detachment of the omentum from the transverse colon mesentery. This must be performed carefully, as the omentum is closely adherent to the right transverse mesocolon. The second stage is the actual lengthening of the omentum. The third stage is placement of the omental flap into the pelvis. Creation of an omental pedicle is a simple surgical procedure. This procedure can be performed quickly, does not involve significant blood loss, and may reduce the frequency of complications after low pelvic anastomoses.