Coloanal anastomosis: indications and surgical technique.

The coloanal anastomosis has evolved from the older "sleeve" pull through techniques and is used as a sphincter-saving procedure in those patients requiring excision of the rectum where adequate removal of all disease necessitates transection of the rectum close to the dentate line. For very low rectal carcinomas, however, abdominoperineal resection remains the procedure of choice for curative treatment. The appropriate choice of low anterior resection, coloanal pull through anastomosis, or abdominoperineal resection depends on many other variables besides the location of the tumor, and the correct choice may not be apparent until the rectum has been mobilized at surgery. The coloanal procedure requires wide excision of the lesion; full mobilization of the splenic flexure, distal transverse colon, and descending colon; precise transanal removal of the rectum; accurate suturing of the descending colon to the anus; and a temporary defunctioning colostomy. With careful technique, longterm results are good in most patients.