Small Bowel Length and Bariatric Surgery Outcomes

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.

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.