Prospective Evaluation of Stapled Intact-Duodenum Bipartition With Sleeve Gastrectomy (SIBS)

This is a prospective, single-arm, open-label interventional study evaluating Stapled Intact-Duodenum Bipartition with Sleeve Gastrectomy (SIBS) in adults undergoing metabolic and bariatric surgery.

Standard single-anastomosis duodenoileal bypass with sleeve gastrectomy (SADI-S) combines sleeve gastrectomy with transection of the proximal duodenum and creation of a duodenoileal anastomosis. SIBS modifies this anatomical configuration by preserving continuity of the duodenum and creating a side-to-side duodenoileal anastomosis without duodenal transection. The rationale for this approach is to establish a duodenoileal pathway while avoiding creation of a blind-ending duodenal stump and maintaining continuity of the native proximal intestinal pathway. Whether these anatomical differences translate into clinically meaningful differences in safety, weight loss, metabolic outcomes, nutritional outcomes, or gastrointestinal function requires prospective evaluation.

The procedure is performed laparoscopically. Sleeve gastrectomy is performed using standard bariatric surgical principles. An ileal loop is then identified at a protocol-defined distance proximal to the ileocecal valve and brought ante-colically to the first portion of the duodenum in an isoperistaltic orientation. Small enterotomies are created in the duodenum and ileum, and a conventional laparoscopic linear stapler is used to construct a side-to-side duodenoileal anastomosis. The common enterotomy is closed laparoscopically. The duodenum is not transected, thereby maintaining continuity of the native pyloro-duodenojejunal pathway in addition to the newly created duodenoileal pathway. Anastomotic integrity is assessed intraoperatively before completion of the procedure.

The primary objectives of the study are to assess technical feasibility and short-term safety. Technical feasibility will be evaluated by successful laparoscopic completion of the planned SIBS procedure with creation of the side-to-side duodenoileal anastomosis while preserving an intact duodenum and without conversion to an alternative bariatric procedure or open surgery. Short-term safety will be evaluated by prospectively recording major postoperative complications occurring within 30 days after surgery.

Perioperative outcomes will include operative time, estimated blood loss, conversion, length of hospital stay, postoperative complications, unplanned intervention, readmission, reoperation, and mortality. Particular attention will be given to complications potentially related to the duodenoileal anastomosis, including anastomotic leak, bleeding, obstruction, stenosis, ulceration, intra-abdominal collection, and other gastrointestinal complications.

Participants will undergo standardized postoperative clinical and laboratory follow-up for up to 12 months. Weight-related outcomes will include body weight, body mass index (BMI), percentage total weight loss (%TWL), and percentage excess weight loss (%EWL) at predefined postoperative time points. Metabolic assessment will include glycemic measures such as glycated hemoglobin (HbA1c) and changes in treatment requirements among participants with type 2 diabetes mellitus or prediabetes. Changes in other obesity-associated medical conditions, including hypertension and dyslipidemia, will also be documented where applicable.

Nutritional follow-up will include clinically appropriate laboratory assessment of hematological, protein, mineral, and micronutrient parameters according to the institutional metabolic and bariatric surgery follow-up protocol. Gastrointestinal symptoms and clinically relevant postoperative events will be prospectively recorded throughout follow-up.

Where specified in the final study protocol, postoperative imaging may be used to assess anastomotic patency and passage of contrast through the native duodenojejunal and duodenoileal pathways. Any imaging or metabolic investigations performed specifically for research purposes will be predefined in the approved study protocol.

The study is designed as an initial prospective evaluation of the feasibility, safety, and clinical outcomes of SIBS. It is not designed to establish superiority or noninferiority to SADI-S, Roux-en-Y gastric bypass, sleeve gastrectomy, or other established bariatric procedures. Findings from this study are intended to inform subsequent larger and comparative studies evaluating the longer-term effectiveness, metabolic effects, nutritional consequences, and safety of the procedure.

Inclusion criteria

• Age 18-65 years.
• Body mass index (BMI) ≥35 kg/m², regardless of the presence or severity of obesity-associated medical conditions; or BMI 30.0-34.9 kg/m² with type 2 diabetes mellitus or another clinically significant obesity-associated medical condition and inadequate weight loss or improvement following appropriate nonsurgical management.
• Eligible for metabolic and bariatric surgery following multidisciplinary clinical assessment.
• Considered suitable for laparoscopic Stapled Intact-Duodenum Bipartition with Sleeve Gastrectomy (SIBS) based on preoperative assessment.
• For primary procedures, no previous metabolic or bariatric surgical procedure.
• For revisional procedures, previous sleeve gastrectomy with a clinical indication for revisional metabolic/bariatric surgery and anatomy considered suitable for SIBS.
• Able to understand the investigational nature of the SIBS procedure, its potential risks and benefits, and established alternative bariatric procedures.
• Able and willing to provide written informed consent.
• Willing and able to comply with the scheduled postoperative clinical, nutritional, laboratory, and study follow-up for at least 12 months.

Exclusion criteria

• Age <18 years or >65 years.
• Pregnancy or breastfeeding.
• Planned pregnancy during the 12-month postoperative study period.
• Contraindication to general anesthesia or laparoscopic metabolic/bariatric surgery.
• Previous gastrointestinal surgery resulting in anatomy that precludes safe performance of the planned SIBS procedure, except previous sleeve gastrectomy in participants undergoing an eligible revisional procedure.
• Intraoperative anatomy that prevents safe creation of a tension-free side-to-side duodenoileal anastomosis.
• Active inflammatory bowel disease involving the small intestine.
• Active gastrointestinal malignancy or other active malignancy for which the proposed operation or follow-up would be inappropriate.
• Severe hepatic dysfunction, severe renal dysfunction, or another major systemic illness considered to confer an unacceptable operative or nutritional risk.
• Pre-existing severe protein-calorie malnutrition or clinically significant nutritional deficiency that cannot be adequately corrected before surgery.
• Active gastrointestinal ulceration or another gastrointestinal condition considered to substantially increase the risk of the planned procedure.
• Uncontrolled psychiatric illness or cognitive impairment that precludes valid informed consent or adherence to postoperative care.
• Active alcohol or substance use disorder considered incompatible with safe metabolic and bariatric surgery.
• Inability or unwillingness to adhere to postoperative dietary recommendations, nutritional supplementation, or scheduled follow-up.
• Any medical, surgical, anatomical, or psychosocial condition that, in the judgment of the multidisciplinary bariatric team, makes participation or performance of SIBS inappropriate or unsafe.