Laparoscopic Gastric Bypass Versus Laparoscopic Banded Gastric Bypass Randomized Prospective Clinical Trial

One group of patients of the study will have done the simplified laparoscopic gastric bypass, with a vertical gastric pouch of about 20 ml, a 150 cm Roux-en-Y limb constructed in an antegastric antecolic fashion, and a biliary limb of 100 cm. Anastomosis will be done with endoscopic surgical linear stapler, closing the apertures with continuous absorbable running sutures. The Petersen space and the mesenteric defect will be closed with non-absorbable sutures. The other group of patients will have performed the laparoscopic Roux-en-Y banded gastric bypass. This technique is identical to the one performed in the other group, but differs in that a polypropylene mesh (10x65 mm) is placed 15 mm proximal to the anastomosis around the gastric pouch, and the gastric pouch is about 15 mm longer. The investigators randomly assigned 50 patients to the study group (Laparoscopic Roux-en-Y banded gastric bypass) and 30 to the control group (Laparoscopic Roux-en-Y gastric bypass) , n=80, and were also blinded to the surgeon until surgery. One of the methods is basically the same than the other, but for the placement of the polypropylene mesh around the gastric pouch above the anastomosis, and patient series with Laparoscopic Roux-en-Y banded gastric bypass showed long term better weight loss than other series with not banded gastric bypass, thus it is expected a difference in long term weight loss between groups. Fisher Test will be used for the statistical analysis, assuming a risk of 0.05 and a statistical power of 90%. Sample size is calculated considering bibliographic long term weight loss in both groups, which is 82% in the banded group versus 63% in the not banded group. Thus sample size (n): 67, and adjust by loss sample size: 79 (10% expected loss ratio), not being necessary a 1: 1 ratio between cases and controls and requiring no more than 25 controls, A sample size of 50 cases and 30 controls, total n = 80, will be used. The method of randomization was concealed envelopes.