Colo-anal pouches: lessons from a prospective audit.

Objective: Colonic pouch formation with pouch-anal anastomosis is the treatment of choice following restorative anterior resection for low rectal cancers with a proximal loop ileostomy to defunction the anastomosis. Controversy exists as to whether anastomotic integrity needs to be checked prior to ileostomy reversal. The aim of this prospective study was to audit our current practice.

Method: Data on all patients undergoing resectional surgery for rectal cancer in our unit are entered prospectively onto a database. Patients who underwent an anterior resection with pouch formation and defunctioning ileostomy were identified and a review of notes and radiological records was carried out.

Results: Forty-two patients with rectal adenocarcinoma underwent an anterior resection with colo-colonic pouch, colo-anal anastomosis and a covering loop ileostomy. Of these, 38(90.5%) had water-soluble contrast enemas (WSCE) 6-8 weeks postoperatively. Two studies (5.3%) confirmed the presence of normal colo-colonic pouch but 24(63.2%) normal reports made no mention of the presence of pouch. Three studies (7.9%) reported true leaks, one study (2.6%) an anastomotic stricture and eight studies (21.1%) anastomotic leaks. Review by radiologists and surgeons, and examination with flexible sigmoidoscopy of these final eight confirmed that these appearances were consistent with normal colo-colonic pouches and anastomosis with no leak. These patients went on to have uneventful stoma closure.

Conclusion: Our study suggests that Colon pouches are difficult to clearly delineate on WSCE and appearances may be mistaken for leaks leading to questioning of the suitability of WSCE in assessing anastomotic integrity. A true positive leak rate of 7.9% would suggest that postoperative assessment prior to closure is still necessary in some patients.