Use of a colonic pouch as a rectal substitute after rectal excision.

Mid or distal rectal resection with straight coloanal anastomosis effectively treats distal rectal cancer and avoids a permanent stoma. However, the straight colonic segment is a poor reservoir for stools, and patients usually experience varying degrees of impaired rectal function after operation, including frequent bowel movements, incontinence, tenesmus, and soiling. In contrast, a J-shaped colonic pouch provides an adequate neorectal reservoir after operation. Patients with a colonic pouch-anal canal anastomosis have fewer bowel movements per day than patients with straight colorectal or coloanal anastomosis. Furthermore, the morbidity of the colonic pouch is not greater than that of the straight coloanal anastomosis. An important technical aspect of the colonic pouch procedure is that the limbs used to form the pouch must be no longer than 5 to 6 cm. Patients with larger pouches experience emptying difficulties. Also, the level of the anastomosis between the pouch and the anal canal must be no more than 4 cm from the anal verge, again to avoid problems with defecation. With these caveats, the operation should be considered in patients who require excision of the mid and distal rectum for cancer.