The purpose of this study is to gather clinical and economic evidence on the use of robotics for bariatric surgery (gastric bypass).

This monocentric, randomized, single blind, controlled study will evaluate post-operative pain, quality of life and appetite, post-operative complication incidence. It will also provide information on direct and indirect costs of surgery.

Robot-assisted Surgery Versus Conventional Laparoscopy in Bariatric Surgery (Gastric Bypass): a prospective, single-blind, randomized, non-inferiority, and controlled study The main evaluation criterion is 24h post-operative pain assessed using visual analog scale (VAS). Secondary criteria included for clinical assessment: post 24h pain, excess weight loss, quality of life, appetite, complications, conversion rate; and for health-economics assessment : duration of surgical steps, length of stay, return to normal activity and their conversion to cost, consumables, estimation of indirect costs and benefits (e.g., robotics perception, publication).

In this study, main inclusion criteria include major obesity (IMC ≥ 35) with co-morbidities or morbid obesity (IMC ≥ 40), scheduled gastric bypass surgery Main contraindications are previous bariatric surgery and previous major abdominal surgeries To test robotic-assisted surgery non-inferiority on VAS pain score 24h post-surgery, a total of 128 patients (64 per arm) is to be included (alpha 2,5%; power 90%; drop-out rate: 5%).

The study will include 12 months of follow-up post-surgery for each patient. The total study duration is 2 years and 3 months.

Inclusion Criteria:

• Patient presenting with major obesity (BMI ≥ 35) with co-morbidities or morbid obesity (BMI ≥ 40)according to French HAS (Haute Autorité de Santé) and CNAMTS (Caisse nationale de l'assurance maladie des travailleurs salariés)criteria for whom gastric bypass is scheduled
• Male or female between 18 and 65 years old
• Patient registered with the French Social Security
• Patient having provided a written informed consent prior to enrolment
• Patient accepting to attend follow-up visits as required by study protocol

Exclusion Criteria:

• Patient with a BMI ≥ 60
• Patient with a contraindication for laparoscopic gastric bypass with or without robotic assistance
• Patient having had prior bariatric surgery
• Patient having had prior major abdominal surgery
• Patient in exclusion period of another clinical study
• Patient pregnant or breastfeeding
• Patient without sufficient knowledge of french language or unable to receive or understand study related information and answer to questionnaires
• Patient with no or limited legal capacity