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NCT Number: NCT02139813

Omega Loop Versus Roux-en-Y Gastric Bypass

Several prospective trials and metaanalysis have demonstrated the superiority of bariatric surgery on the medical treatment of obesity. The Roux-en-Y Gastric ByPass (RYGBP) procedure has been practiced for more than 30 years, and is the procedure of choice for morbidly obese with metabolic disorders in most of the reference centers. Nevertheless, the RYGBP is a technically demanding procedure with a learning curve of more than 75 cases. The complication rate is around 10% in expert centers.

More recently another procedure has been described which seems as efficient on weight loss and co-morbidities as the RYGBP, with the advantage of being less technically difficult and less morbid, especially for multi-complicated obese and/or the super obese. It consists of a unique gastro-jejunal anastomosis between a long gastric pouch and a jejunal Omega loop. However, this procedure could be at risk of biliary reflux and anastomotic ulcers with dysplastic changes of the gastric and esophageal mucosa. As a result, the Omega loop bypass (OLB) has only been developed by a few teams and remains a controversial subject, particularly as only one monocentric randomized trial has compared it to the RYGBP, which is remains the gold standard. The first litterature results show similar or even better weight loss efficiency than RYGBP with a better feasibility. The early complication rate seems lower, but there are still insufficient data on long term morbidity and biliary reflux consequences.

By performing a randomized and prospective comparison of OLB to RYGBP, the aim of the investigators study is to analyze the weight loss efficiency, the morbidity and mortality, the feasibility, and the quality of life of both techniques, in order to validate the Omega loop bypass as a procedure of choice in bariatric surgery

Hypothesis :

The OLB, while being as efficient as RYGBP on weight loss and metabolic complications, could be less morbid.

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Key information

Conditions

Obesity Body Weight Nutrition Disorders Nutritional and Metabolic Diseases Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Clinique Universitaire de Chirurgie Digestive et de l'Urgence - CHU de Grenoble, Grenoble, France

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Aged between 18 and 65 years old
  • Morbid obesity with BMI ≥ 40 kg/m2 or BMI ≥ 35 kg/m2 associated with one or more co-morbidities (type 2 diabetes, arterial hypertension, sleep apnea, dyslipidemia, arthritis)
  • Patient who has benefited from an upper GI endoscopy with biopsies
  • Patient who has benefited from a pluridisciplinary evaluation, with a favorable opinion for a gastric bypass
  • Patient who understands and accepts the need for a long term follow-up
  • Patient who agrees to be included in the study and who signs the informed consent form
  • Patient affiliated to a healthcare insurance plan

Exclusion criteria

  • History of esophagitis on upper GI endoscopy (Los Angeles classification)
  • Severe gastroesophageal reflux disease (GERD), resistant to medical treatment
  • Presence of dysplastic modifications of the gastric mucosa or a history of gastric cancer, on upper gastrointestinal endoscopy.
  • Presence of Helicobacter Pylori resistant to medical treatment
  • Presence of an unhealed gastro-duodenal ulcer or an ulcer diagnosed less than 2 months previously
  • History of previous bariatric surgery (gastric band, sleeve gastrectomy, vertical banded gastroplasty)
  • Presence of a severe and evolutive life threatening pathology, unrelated to obesity
  • Presence of chronic diarrhea (≥ 3 loose or liquid stools per day, over a period of more than 4 weeks)
  • Pregnancy or desire to be pregnant during the study
  • Binge eating disorders or other eating disorders according to DSM V criteria
  • Mentally unbalanced patients, under supervision or guardianship
  • Patient who does not understand French/is unable to give consent
  • Patient not affiliated to a French or European healthcare insurance
  • Patient who has already been included in a trial which has a conflict of interests with the present study

Treatment and study plan

Laparoscopic Mini-gastric bypass

Procedure

The laparoscopic Omega Loop Bypass will consist of:

  • a long gastric tube, stapled approximately 1.5 cm from the left of the lesser curvature of the antrum to the angle of His
  • a narrow gastric tube will be calibrated to be approximately 1.5 cm wide
  • an Omega loop of 200 cm
  • a unique gastro-jejunal anatomosis of 200cm from the ligament of Treitz, using a linear stapler

Procedure of reference in bariatric surgery

Procedure

The laparoscopic Roux-en-Y Gastric Bypass will consist of:

  • a small gastric pouch (about 30cc)
  • an antecolic alimentary limb
  • a gastro-jejunal anastomosis using a linear stapler
  • a 150cm long alimentary limb
  • a 50cm biliary limb
  • a latero-lateral jejuno-jejunal anastomosis
  • closure of the mesenteric defects

Primary outcomes

  1. Weight loss assessment according to Excess BMI Loss percentage (EBL%)

    Time frame: 2 years after surgery

    Weight loss assessment according to Excess BMI Loss percentage (EBL%), calculated using the following formula:

    ((BMI 2 years after surgery - initial BMI) / (initial BMI - 22.5)) X 100

Secondary outcomes

  1. Weight loss according to absolute weight loss (aWL in kg), Excess Weight Loss percentage (EWL%), EBL%

    Time frame: 1, 3, 6, 12, 18 and 24 months after surgery

  2. Waist size reduction according to absolute waist size (in cm)

    Time frame: 1, 3, 6, 12, 18 and 24 months after surgery

  3. Medical and surgical complication rates

    Time frame: 1, 12 and 24 months after surgery

    Medical and surgical complication rates (anastomotic leaks, biliary reflux, bowel obstruction, anastomotic ulcers, anastomotic stenosis, internal hernia, chronic gastritis, esophagitis, iron deficiency anemia …)

  4. Type and severity of complications

    Time frame: During the month following surgery (for early complications) and from one month to 24 months postoperatively (for late complications)

    Type and severity of early and late complications for each procedure, according to the Dindo-Clavien classification

  5. Operative time

    Time frame: Recorded on the day of surgery (Day 0)

    Operative time (expressed in minutes)

  6. Mean length of stay

    Time frame: Average period of 5 days from surgery (Day of surgery = D0) until the end of hospitalization, recorded on Visit 4 (Month1 +/- 10 days)

    Mean length of stay based on the number of days of hospitalization from surgery (Day of surgery = D0) until the end of hospitalization

  7. Patient's quality of life

    Time frame: The day before surgery (D-1) and 6, 12 and 24 months after surgery

    Patient's quality of life score according to the IWQOL questionnaire and the BAROS questionnaire adapted to bariatric surgery

  8. Metabolic and lipid profile

    Time frame: During the period of inclusion (D-60 to D-2) and at 6, 12 and 24 months after surgery

    Metabolic profile of glucose homeostasis and the lipid profile according to antidiabetic and anitilipidemic treatments, HbA1c level, fasting glycemia, HDL, LDL and TG.

  9. Dumping syndrome and hypoglycemia symptoms

    Time frame: At 1, 3,6,12,18 and 24 months after surgery

    Dumping syndrome and hypoglycemia symptoms will be assessed using the Sigstad questionnaire

  10. Gastroesophageal reflux

    Time frame: The day before surgery (Day-1) and 6, 12, and 24 months after surgery

    Gastroesophageal reflux assessed by items 5 and 27 of the GIQLI questionnaire

  11. Modifications of the gastric and esophageal mucosa

    Time frame: 2 years after surgery

    Histological modifications of the gastric and esophageal mucosa, based on upper GI endoscopy with biopsies

  12. Frequency of diarrhea

    Time frame: The day before surgery (day-1) and 6, 12, and 24 months after surgery

    Frequency of diarrhea based on items 7, 30, 31 and 36 of the GIQLI questionnaire

  13. Nutritional status

    Time frame: During the period of inclusion (D-60 to D-2) and 6, 12, and 24 months after surgery (The 24-hour steatorrhea will be quantified at 6 months).

    Nutritional status, assessed by PTH, vitamin B1, B9, B12, and D levels before and 12 and 24 months after surgery and assessed by hemoglobin, albumin, prealbumin, ferritin, saturation coefficient, before and 6, 12 and 24 months after surgery .

Sponsors and collaborators

Lead sponsor

Hospices Civils de Lyon

Other

Registry information

Official study title

Prospective Multicentric Randomized Trial of Efficiency and Safety of Laparoscopic Omega Loop Bypass Versus Roux-en-Y Gastric Bypass

Acronym: YOMEGA

Important dates

Study start
2014
Primary completion
2018
Study completion
2018
First posted
May 15, 2014
Registry last updated
Dec 19, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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