Small Bowel Length and Bariatric Surgery Outcomes

Study Overview
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Brief Summary
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The purpose of this study is to determine whether or not the total length of small intestine effects outcomes after bariatric surgery in a cohort of patients preoperatively and up to ten years postoperatively. Roux-en-Y gastric bypass and vertical sleeve gastrectomy will be the surgical groups in this study. We aim to determine if bowel length has a significant effect on long term weight loss or other nutritional deficiencies in this bariatric cohort.

Detailed Description
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Bariatric surgery (also known as weight loss surgery) is the most effective treatment for obesity as well as a number of other obesity-related conditions, including type 2 diabetes, hypertension, and hypercholesterolemia. Interestingly, not all patients respond with significant weight loss following surgery and some patients even lack much weight loss at all over the long-term. Even though variability in treatment response is observed in a variety of diseases, the biological basis for this variability in weight loss after bariatric surgery is poorly understood. Recent data from our group as well as others, however, suggest that differences in the total length of the small intestine may significantly contribute to these differences in weight loss over time. For example, Roux-en-Y gastric bypass is thought to exert its weight loss effect because of a bypass of small intestine that causes a degree of nutrient malabsorption. The bypassed small intestine (<100cm) is near the proximal end of the intestines closest to the stomach. Hypothetically, an individual with the greater total small intestine length may not benefit as much from the bypass as someone who has a much shorter length of total small intestine. Whether or not this hypothetical relationship is true remains unknown, but a recent study demonstrated that small intestine length does differ significantly between individuals with lengths ranging from 300cm to >1200cm. The total length of small intestine is not routinely measured during any bariatric procedure, as the lengths of the bypass limbs are determined from the portion of the intestines closest to the stomach. The purpose of this study is to determine whether the amount of total small intestine significantly affects weight loss in patients undergoing bariatric surgery - both the Roux-en-Y gastric bypass (RYGB) or the Vertical Sleeve Gastrectomy (VSG). If there is a significant effect of total small intestine length on long-term weight loss in bariatric patients, then it would justify the conduct of a further study to determine whether or not these operations should be performed differently in individuals to account for the differences in small intestine length. This is an observational study that will be looking at body weight (primary endpoint) and other nutritional endpoints (other pre-specified outcome measure) over time up to ten years in this patient cohort. The body weight measurements and any laboratory data will be collected that are part of the routine clinical care of these patients.

Official Title
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Observational Study of the Effect of Small Intestine Length on Bariatric Surgical Patient Outcomes

Conditions
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Malnutrition, Obesity, Weight Loss, Micronutrient Deficiency

Intervention / Treatment
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* Procedure: Small bowel length measurement


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients undergoing laparoscopic bariatric surgery, either vertical sleeve gastrectomy or Roux-en-Y gastric bypass Able to give informed consent Exclusion Criteria: Prior small intestine resection. Inability to safely obtain total small intestinal length measurements in the operating room. Any small bowel tethering due to intestinal adhesions identified in the operating room.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| RYGB<br>Roux-en-Y Gastric Bypass - these are patients that undergo a Roux-en-Y gastric bypass operation for their bariatric operation. | Procedure: Small bowel length measurement<br>* The total length of the small bowel with be measured at the time of the bariatric surgical operation.<br>|
| VSG<br>Vertical Sleeve Gastrectomy - these are patients that undergo a vertical sleeve gastrectomy operation for their bariatric operation. | Procedure: Small bowel length measurement<br>* The total length of the small bowel with be measured at the time of the bariatric surgical operation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Body Weight | Body weight will be measured preoperatively (within 30 days of the operation) as the baseline body weight, then postoperatively up to ten years from the time of initial surgery. Measurements will be made per routine clinical care and not solely for research purposes. Exact time points before and after surgery that body weight will be measured, except for the day of surgery, will differ between patients in the study. Change in body weight over time will be measured annually, adjusted for baseline body weight at the time of surgery. Regression will be used to test for a significant interaction of total bowel length and body weight over time in the patient cohorts (RYGB vs. VSG) - this is our primary outcome measurement. We are examining whether there is a significant interaction between any change in body weight over time and the small bowel length in the patient cohorts. | Up to 10 years postoperatively as measured for routine clinical care | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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obesity, bariatric surgery, bowel length