The effect of stoma size on weight loss after laparoscopic gastric bypass surgery: results of a blinded randomized controlled trial.

Background: To determine the effect of different stoma sizes on the percent excess weight loss (%EWL) following laparoscopic Roux-en-Y gastric bypass surgery (LRYGBP).

Methods: Blinded randomized prospective controlled study in two American Society for Bariatric Surgeons-designated Centers of Excellence hospitals. Two hundred gastric bypass patients between January 2005 and September 2005 were prospectively randomized into two groups of 100 patients each in the operating room, after the induction of anesthesia. Patients underwent LRYGBP with different stapler sizes of 21 and 25 mm for gastrojejunal (GJ) anastomosis from January 2005 to September 2005. Postoperative %EWL following LRYGBP in both patient groups were calculated using a multivariable linear mixed-effects model with an unstructured covariance matrix and a logistic regression was used to measure clinical comorbidities.

Results: Applying multivariable mixed models and logistical regression, circular stapler size of 21 and 25 mm, which predicted the need for dilations (odds ratio = 0.489), did not predict weight loss. The only predictors of weight loss were male gender and higher initial weight (p < 0.001). Follow-up at 2 years in the 21- and 25-mm groups was 68% and 66%, respectively. Both groups had > 80% EWL at 2 years.

Conclusion: The level of restriction or the presence of stenosis achieved by different circular stapler sizes does not have a significant causative role in weight loss.