Study protocol (RCT Clinical trials): Development and implementation of gastric bypass surgery using the "FundoRing" method for the treatment of patients with metabolic syndrome

<ns3:p> Obesity and metabolic syndrome remain major global health challenges, with bariatric surgery being the most effective treatment in cases of severe obesity. Despite satisfactory outcomes, conventional one-anastomosis gastric bypass (OAGB) is often complicated by weight regain, gastroesophageal reflux, and dumping syndrome. To address these issues, we developed a modified approach—FundoRing OAGB—which employs the patient’s own gastric fundus to create an autologous restrictive wrap, thereby enhancing weight control and reducing reflux without the risks associated with synthetic gastric band. This single-center, randomized controlled trial enrolled 1000 patients with body mass index (BMI) 30–50 kg/m <ns3:sup>2</ns3:sup> , allocated into two groups: the experimental group underwent OAGB with the FundoRing modification and hiatal repair when indicated, while the control group underwent standard OAGB. Patients will be followed for up to 60 months. Primary outcomes include changes in BMI, remission of comorbidities, and quality of life improvement. Secondary endpoints assess reflux parameters, gastric pouch dilation, intraoperative perfusion imaging, and cost-effectiveness. The FundoRing technique offers a physiologic, autologous alternative to conventional banding methods, aiming to strengthen the restrictive effect of OAGB while minimizing complications. Results from this large-scale trial are expected to clarify the role of FundoRing OAGB in optimizing long-term bariatric and metabolic outcomes. Trial registration: ClinicalTrials.gov Identifier: NCT04834635. Trial registration: ClinicalTrials.gov ID NCT04834635. Registered on 04 april 2021. </ns3:p>