title: A systematic review of the function and complications of colonic pouches.
abstract: OBJECTIVE
  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.
  
  
  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.
authors.affiliation: Department of Colorectal Surgery, Singapore General Hospital, Outram Road, Singapore 169608, Singapore.
authors.forename: Poh-Koon
authors.initials: PK
authors.lastname: Koh
authors.forename: Choong-Leong
authors.initials: CL
authors.lastname: Tang
authors.forename: Kong-Weng
authors.initials: KW
authors.lastname: Eu
authors.forename: Miny
authors.initials: M
authors.lastname: Samuel
authors.forename: Edwin
authors.initials: E
authors.lastname: Chan
mesh_terms: D000714:Anastomosis, Surgical / Q000009:adverse effects; D039021:Colonic Pouches / Q000009:adverse effects; D003251:Constriction, Pathologic / Q000209:etiology; D003672:Defecation; D005242:Fecal Incontinence / Q000209:etiology; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D012004:Rectal Neoplasms / Q000601:surgery; D013529:Surgical Wound Dehiscence / Q000209:etiology