Sleeve Gastrectomy to Roux-en-Y Gastric Bypass Conversion Versus Primary Roux-en-Y Gastric Bypass: Impact of Robotic Platform on Propensity-Matched Outcomes

Abstract

Purpose:

With the increasing prevalence of sleeve gastrectomy, complications and insufficient weight loss have become more common, making conversion to Roux-en-Y gastric bypass (RYGB) a frequent revisional approach. Given the higher risk of revisional surgery, we aimed to compare primary versus conversion RYGB surgery and assess whether robotic assistance impacts outcomes.

Method:

This retrospective study included 378 patients after 2:1 propensity score matching based on demographic and clinical characteristics, comparing primary Roux-en-Y gastric bypass (P-RYGB) with sleeve gastrectomy–to–Roux-en-Y gastric bypass (SG-RYGB). The matched cohort included both robotic and laparoscopic cases performed at a single tertiary center between 2012 and 2024. A secondary 2:1 matched sub-analysis of robotic cases (n = 297) evaluated whether robotic assistance reduced differences between primary and revisional surgery. Weight-loss outcomes were assessed at 6 and 12 months in the full cohort, with an additional sub-analysis limited to SG-RYGB performed for weight-loss indications.

Results:

In the full cohort (n = 378), SG-RYGB was associated with longer operative time, greater blood loss (P < .001), longer hospital stay (P = .04), and higher late complication rates (P = .04). In the robotic-only matched analysis (n = 297), differences in operative time and blood loss were no longer significant, and early and late outcomes were comparable, although length of stay still remained longer for SG-RYGB (P = .05). Among patients undergoing SG-RYGB for weight loss purposes only, total body weight loss percentage reached 16.5% ± 6.6% at 6 months and 20.4% ± 7.1% at 12 months but remained lower than that observed in the P-RYGB group (P < .001).

Conclusion:

SG-RYGB conversion demonstrated favorable outcomes and meaningful weight loss. Robotic assistance was associated with improved operative time, reduced blood loss, and fewer late complications in the SG-RYGB group, further narrowing differences with P-RYGB, supporting its role in complex revisional bariatric surgery at high-volume centers.