BACKGROUND: Several retrospective studies suggest that adding a non-adjustable silicone ring to a Roux-en-Y gastric bypass (RYGB) results in more weight loss and prevents weight regain in the long term. The aim of this study was to evaluate the effect of a banded Roux-en-Y gastric bypass (B-RYGB) on weight loss outcomes in a randomized controlled trial (RCT). METHODS: In this single center RCT, 130 patients were divided into two groups: a standard Roux-en-Y gastric bypass (S-RYGB) or a B-RYGB using a Minimizer® ring. Subsequently, weight loss, morbidity, reduction of obesity-associated medical conditions, quality of life (QoL), and complication rates were measured during a follow-up period of five years. A two-sided p <
0.05 (with 95% confidence interval) indicated statistical significance. RESULTS: After five years, mean percentage total body weight loss (%TBWL) was 30.5% in the S-RYGB versus 31.8% in the B-RYGB group (p >
0.05). The follow-up percentage was 81%. Overall, no significant differences in complication rates, resolution of obesity-associated medical conditions, and QoL were found between the two groups. In the B-RYGB group, 8 (12%) silicone rings were removed due to symptoms of dysphagia. CONCLUSION: B-RYGB is a safe procedure showing similar comorbidity when compared to a S-RYGB. However, B-RYGB led to a higher rate of postoperative dysphagia which poses a risk of ring removal over time. The results from this RCT do not support the hypothesis that implantation of a non-adjustable silicone ring improves long-term weight loss outcomes.