Appendix 1. Preoperative Assessment, Surgical Procedure and Post-Operative Management

Appendix 1. Preoperative assessment, surgical procedure and post-operative management.

Pre-operative assessment

All patients were assessed before surgery by a multidisciplinary team.According to the French guidelines for bariatric surgery, all the patients in this study fulfilled the following criteria: a) initial body mass index (BMI)>40kg/m² or BMI>35kg/m² with significant obesity-related co-morbidity, b) age older than17 years and c) failure of conservative treatment for at least 1 or 2 years.All patients were evaluated before surgery by a multidisciplinary team including a surgeon, an endocrinologist, a nutritionist, a psychiatrist, an anesthetist and other specialists if needed according to the patient’s condition. The preoperative assessment procedures comprised polysomnography, abdominal ultrasound, upper gastrointestinal series and gastroscopy with biopsies to rule out the presence of helicobacter pylori and Barrett’s esophagus.

Surgical procedure

All patients were operated by the same surgical team using a standardized procedure. A laparoscopic approach was used in all patients using a five trocar technique. The greater curve was mobilized from 6 cm above the pylorus to the angle of hiss using the harmonic scalpel. All posterior adhesions to the pancreas were divided completely mobilizing the posterior fundus. A long sleeve conduit was then created using Covidien Endo GIA staplers with a 34 French Bougie placed along the lesser curve to tailor the gastrectomy. Stapling began within 6 cm of the pylorus and terminated just lateral to the angle of hiss ensuring complete excision of all posterior fundus. The staple line was not buttressed or reinforced. At the end of the procedure, a methylene blue test was performed to rule out a leak and a Jackson Pratt drain was left along the staple line of the sleeve. In patients with previous gastric banding, all foreign material was taken out and, wherever possible, a resection of the scar-tissue was carried out.

In patients in whom gallstones were detected by abdominal ultrasound during the preoperative assessment, a laparoscopic cholecystectomy was performed simultaneously to the laparoscopic sleeve gastrectomy (LSG). In patients who underwent LSG for failure and or side effect of LAGB (laparoscopic adjustable gastric banding) the band was removed simultaneously to the LSG in a one-step conversion procedure.

Post-operative management

Post-operatively, a clear liquid diet was started on postoperative day (POD) 1 after an oral methylene blue test, and an upper gastrointestinal series was performed on POD 3 before removal of the drain. In addition to multivitamin-supplementation, patients received a proton-pump inhibitor therapy and low-molecular-weight heparin for 4 weeks. Transit oeso-gastro-duodenal tests were systematically performed on POD 3 or 4.