An artificial anal sphincter. Phase 2: Implantable sphincter with a perineal colostomy.

To find an alternative to the stigmata of abdominal colostomy, an artificial anal sphincter (utilizing the currently available artificial urinary sphincter) was implanted around an end perineal colostomy following standard abdominal perineal resection. Of 13 swine, 7 completed full evaluation with working sphincters, 3 animals died prematurely of unrelated causes, and 3 animals were sacrificed due to sphincter slough before inflation was begun. Seven animals had long-term evaluation of the sphincter for 2 to 6 months' duration. In 5 animals (72%) there was complete fecal continence; one animal (14%) had occasional partial incontinence and one had total incontinence, both due to sphincter malfunction from breakage of the connecting tab. Two of the seven animals had delayed slough of the sphincter after 2 months and 4.5 months of success, and 2 animals had erosion of the intraperitoneal balloon reservoir into the small bowel. In addition, 5 of 9 (55%) control pumps were complicated by skin erosion or infection; all were relocated successfully. The fact that an intact artificial anal sphincter can provide excellent continence demonstrates that this concept of perineal placement for bowel control is valid. Refinements in the device to prevent tab breakage, investigation of correct sphincter pressures to prevent sloughing, and better sites for implantation of the pump and balloon reservoir are requisite solutions for a fully implantable system to restore near-normal bowel function after radical abdominal perineal resection.