The gastro-jejunal anastomosis site influences dumping syndrome and weight regain in patients with obesity undergoing Laparoscopic Roux-en-Y Gastric Bypass

Purpose: The Laparoscopic Roux-en-Y Gastric Bypass (LRYGB) is an effective weight loss procedure. The gastro-jejunal (GJ) anastomosis required can be performed on the anterior or posterior gastric pouch wall. No studies have compared these variants in terms of efficacy and onset of dumping syndrome (DS) and weight regain (WR). We aimed at assessing the prevalence of DS in relation to the site of anastomosis together with identifying prognostic factors of DS and WR. Methods: Patients who had undergone LRYGB with anterior (AGJ) or posterior (PGJ) anastomosis in 2010-2019 were retrospectively analyzed. We collected demographic data, medical history and the prevalence of DS evaluated through the Sigstad Score, together with WR data. Results: 213 patients were enrolled, of which 51.6% had an AGJ and 48.4% had a PGJ. The mean follow-up time was 81 ± 18 and 27 ± 13 months in the AGJ and PGJ group, respectively (p < 0.0001). Excess weight loss was 77.59% and 94.13% in patients with AGJ and PGJ, respectively (p < 0.001). WR rate was 16% and 4% in the AGJ and PGJ population, respectively (p < 0.001). DS prevalence was 38% and 76% in the AGJ and the PGJ population, respectively (p < 0.0001). The site of anastomosis was identified as an independent predictor of DS (OR5.15; 95% CI 2.82-9.41; p < 0.0001) and WR (OR5.31; 95% CI 2.32-12.15; p < 0.0001). Obesity-related complications significantly improved after surgery independent of the anastomosis site. Conclusion: LRYGB is effective in determining long-term weight loss and improvement of complications. AGJ is associated with lower prevalence of DS but more frequent WR. The anastomosis site is a factor to be considered when performing LRYGB.