Omental transposition flap in colorectal carcinoma: adjunctive use in prevention and treatment of radiation complications.

The versatility of the omentum has led to its use as a surgical adjunct in the total oncological management of primary and recurrent colorectal carcinoma. The omentum is used as a transposition pedicle flap, broadly based on the left gastroepiploic vascular supply. Following abdominoperineal resection or low anterior resection of the rectum, the small bowel is elevated out of the pelvis by the omental bulk. The pelvic defect is reperitonealized and the risk of pelvic small bowel adhesions is diminished. With the increasing use of postoperative radiation to the pelvis for rectal carcinoma, the tolerance to therapy may be improved and the incidence of radiation enteritis and enteropathy should be reduced. Surgical complications such as leakage from low anterior anastomoses and pelvic abscesses, which may delay or contraindicate necessary postoperative radiation, are dramatically decreased. Reconstruction of the perineum with omental flap provides adequate soft tissue bulk and contour when a radical resection has been performed. The omentum has the potential for neovascular proliferation and can act to prevent anastomotic dehiscence of intestinal anastomoses involving previously irradiated bowel. Furthermore, covering unresectable recurrent carcinoma in the pelvis and retroperitoneum with the omentum as a palliative measure provides a thick anatomical barrier against potential ureteral, bladder, and small bowel invasion and obstruction. The omental flap has been used in 24 patients with colorectal carcinoma; one flap was lost as a result of distal omental infarction in a patient with recurrent rectal carcinoma and radionecrosis of the perineum. The safety and ease of this procedure has allowed increased surgical innovation, especially in the prevention and treatment of radiation complications.