Does pouch size matter?

Mechanical restriction, malabsorption, and hormonal changes appear to play a role in weight loss after Roux-en-Y gastric bypass (RYGBP). This investigation chose to investigate one aspect of the restrictive role of gastric bypass: the pouch size. Our hypothesis was that a small pouch size with no fundus after laparoscopic RYGBP (LRYGBP) would lead to greater loss of excess weight and weight loss success.

Upper gastrointestinal radiological (UGI) studies were retrospectively reviewed by three blinded experts (2 bariatric surgeons and 1 expert radiologist), to determine pouch size and fundus size. The following grading system was utilized: Size I - smaller than average pouch, Size II - average pouch, Size III larger than average pouch, and Size IV - over 3 times the size of an average pouch. Fundus 0 - no fundus appreciated, Fundus I - slight amount of fundus barely noted, Fundus II - fundus noted, Fundus III - large amount of fundus noted, and Fundus IV - majority of the pouch was fundus. Percentage of excess weight loss (%EWL) and successful weight loss (A. >50% EWL, B. within 50% of ideal body weight, C. loss of >25% of preoperative weight) were calculated.

There were 59 patients in this study with 97% follow-up of >1 year. No Size IV or Fundus IV were noted. There were no statistically significant differences between in %EWL or success for either pouch size or fundus size.

While there may be a trend for the mean %EWL to be lower with larger pouches and larger amounts of fundus, no significant differences were found. Larger pouches and the presence of fundus (within reason) still result in a high rate of success after LRYGBP.