SP9.13 - Influence of Gastrojejunostomy Diameter on Weight Reduction Following Roux-En-Y Gastric Bypass Surgery

Abstract Introduction The debate on whether the diameter of the gastrojejunostomy in Roux-En-Y Gastric Bypass (RYGB) affects long-term weight loss was addressed in this study by comparing outcomes between two different anastomosis diameters. Methods This retrospective study analysed primary RYGB performed from January 2017 to July 2021, comparing 30mm and 45mm gastrojejunostomy diameters. Weight loss was assessed at 12, 24, and 60 months post-operatively. Results Of the 1,081 patients who had RYGB, 79.6% were female, with a median age of 48 (IQR 40-55). The median starting BMI was 44.6 Kg/m2 (IQR: 40.4-50.1). The 30mm group comprised 36.6% (396/1,081) of the participants. There were no notable differences in baseline demographics such as gender, age, ASA classification, and medical history between the groups. At the 12-month follow-up, the average BMI reduction was 12.8 Kg/m2 (IQR: 9.3-17.9), with no significant differences between the 30mm (median: 13.0 Kg/, IQR: 9.4-23.5) and 45mm groups (median: 12.6 Kg/m2, IQR: 9.1-16.9, p=0.053). At 24 months, the BMI reduction was more substantial in the 30mm group (median: -16.2 Kg/m2, IQR: 11.6-40.5) than in the 45mm group (median: -15.3 Kg/m2, IQR: 10.0-35.6, p=0.006). A greater divergence was observed at 60 months, with the 30mm group showing more weight loss (median: -17.2, IQR: 11.3-31.1) compared to the 45mm group (median: -15.8, IQR: 11.9-28.3, p=0.003). Conclusion A smaller gastrojejunostomy diameter of 30mm is linked with greater BMI reduction up to five years post-RYGB. Further study is necessary to evaluate the anastomosis size's impact on long-term weight maintenance and regain.