Size matters: gastric pouch size correlates with weight loss after laparoscopic Roux-en-Y gastric bypass

Background Over the past 20 years, there has been an ongoing discussion about the importance of gastric pouch size as a key factor influencing weight loss after bariatric surgery. This analysis aimed to determine the relationship between initial gastric pouch size and excess weight loss (EWL) after laparoscopic Roux-en-Y gastric bypass (LRYGB). Methods Between August 2002 and March 2005, 320 LRYGB were performed at Yale New Haven Hospital. The patients’ demographics were entered into a longitudinal, prospective database. Upper gastrointestinal series were routinely performed on postoperative day 1. Pouch size was measured as area (cm²) on an anteroposterior radiograph at maximum pouch distention. Linear regression analysis was performed to determine the association between pouch size and weight loss at 6 and 12 months postoperatively. Adjustments were made for age, gender, and preoperative body mass index (BMI). Results The mean age of the patients was 41.2 years. Of the 320 study patients, 261 were women (81.6%) and 59 were men (18.4%). The mean preoperative BMI was 51.1 kg/m²; the mean 6-month EWL was 50.5%; the mean 12-month EWL was 62.5%; and the mean pouch size was 63.9 cm². A statistically significant, negative correlation between pouch size and EWL was found at 6 months (β = –0.241; p < 0.01) and at 12 months (β = –0.302; p < 0.02). The findings show that male gender (β = 0.147; p < 0.04) and preoperative BMI (β = 0.190; p < 0.01) are positively correlated with pouch size. Conclusion The analysis demonstrates that initial gastric pouch size is not the only significant component for successful weight loss after LRYGB. Male gender and increased preoperative BMI were identified as factors predicting pouch size. Efforts to standardize small pouch size for all patients seems important to the success of surgical therapy for morbid obesity.