Reconstruction of anorectal angle after abdominoperineal resection of rectum and anus--an animal model.

Voluntary control of the bowel movements is a social necessity. Lack of control relegates one to psychological debility and the possible need for a permanent colostomy. Anorectal angle plays an important role in fecal continence. In the normal individual, this angle lies in the range of 60 to 105 degrees. Perineal colostomy, once proposed for patients who had received abdominoperineal resection (APR), has been abandoned because of frank incontinence. This study used a canine model. The anorectal angle, external sphincter, internal sphincter, and the puborectalis were all destroyed after APR. The colon was pulled through the perineal defect. Enteropexy, gracilis muscle transfer, and perineal colostomy were performed to restore the anorectal angle. Barium enema was performed preoperatively and postoperatively. The anorectal angle was reconstructed within normal ranges after abdominoperineal resection of the rectum and anus.