Background: The effect of the gastric pouch or Gastro-Jejunostomy (GJ or stoma) size on weight loss outcomes after Roux-en-Y Gastric Bypass (RYGB) is unclear with studies reporting conflicting results. The purpose of this systematic review was to determine the impact of the gastric pouch or stoma size on weight loss outcomes with RYGB.

Methods: An online search of PubMed was carried out to identify all articles evaluating the effect of the gastric pouch and/or gastric stoma size at the time of surgery on outcomes associated with RYGB. Quality and heterogeneity of data precluded a meta-analysis. So a systematic review was performed without a meta-analysis.

Results: This review found a total of 14 studies (two of which were randomised) evaluating the effect of pouch sizes on weight loss outcomes after RYGB. Nine of these studies did not find any significant association between pouch size and weight loss outcomes whereas five studies found larger pouches to be associated with poorer weight loss outcomes. No study found larger pouches to be associated with better weight loss outcomes.

Out of the 10 studies (one of which was randomised) that evaluated the effect of stoma size on weight loss outcomes after RYGB, six studies did not show any significant effect of stoma size on weight loss outcomes and four found larger stoma sizes to be associated with significantly poorer weight loss outcomes. No study found larger stoma to be associated with better weight loss outcomes.

Conclusions: This review finds that a larger pouch or stoma size may be associated with adverse weight loss outcomes but the quality of data does not allow us to precisely determine optimum pouch or stoma size with RYGB. There is a need for more randomised data comparing long term weight loss outcomes with pouches or stoma of different sizes.