A systematic review of the function and complications of colonic pouches

PURPOSE: This is a meta-analysis of randomized, controlled trials to compare the function and complications of a straight coloanal anastomosis to a colonic J-pouch after rectal excision at 1 year postoperatively.

MATERIALS AND METHODS: A search for articles from 1980 to 2005 was conducted on Medline, PubMed, and the Cochrane Controlled Trials Register using the keywords "colonic pouches, J-pouch, straight and coloanal anastomosis, rectal cancer, function and complications," either singularly or in combination. Reference lists from short-listed articles were also manually searched for relevant articles, journals, and conference proceedings. Randomized controlled trials (RCTs) in English publications comparing colonic J-pouches to straight coloanal anastomosis were selected. Trials with similar patient characteristics, duration of follow-up, and outcome measures were pooled for analysis. Stool frequency and fecal continence at 1 year postoperatively were used as measures of functional outcome. Complication rates in terms of anastomotic leak and stricture formation were analysed.

RESULTS: Ten RCTs with satisfactory methodology were identified. One trial reported the results at 2 years, while another reported results at 5 years only and were excluded from the meta-analysis, leaving only eight studies for further analysis. Overall, a colonic J-pouch appeared more favorable in terms of stool frequency (weighted mean difference of -1.21, 95% CI: -1.92 to -0.49) and continence (Odds ratio 0.23, 95% CI: 0.08-0.69), with a slightly lower risk of anastomotic dehiscence compared to a straight coloanal anastomosis (relative risk, RR 0.36; 95% CI: 0.12-1.08). Anastomotic stricture was reported in only two trials. They seemed more likely to occur after a pouch-anal anastomosis (RR 2.45, 95% CI: 0.79-7.57). However, the small numbers available for pooled analysis cannot allow these conclusions to be drawn with confidence.

CONCLUSIONS: A straight coloanal anastomosis resulted in poorer function due to loss of a rectal reservoir, while colonic J-pouches have improved frequency and continence up to a year. Although retrospective reports seem to favor the use of a pouch, there are limited longer term randomized trial data to suggest that the function and complications of a coloanal J-pouch is better than a straight coloanal anastomosis. Larger randomized studies are required to further verify the longer-term benefits of a coloanal pouch.