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Which bypass in super-obese patients?

Proximal betters distal bypass in super-obese patients

No general consensus as to the optimal intestinal limb lengths used in gastric bypass for super-obese patients

In a randomised clinical trial comparing proximal vs. distal gastric bypass, distal bypass was associated with longer operating time, a higher frequency of reoperations and severe perioperative complications than proximal bypass surgery in super-obese patients (BMI50–60). The outcomes by researchers from the Vestfold Hospital Trust, Tønsberg, University of Oslo and Oslo University Hospital, Oslo, Norway, were published in the paper, ‘Perioperative Outcomes of Proximal and Distal Gastric Bypass in Patients with BMI Ranged 50–60 kg/m2—A Double-Blind, Randomized Controlled Trial.‘, and feature in the journal Obesity Surgery.

According to the authors, as there is no general consensus as to the optimal intestinal limb lengths used in gastric bypass for super-obese patients, the aim of the study was to compare the perioperative outcomes of laparoscopic proximal and distal gastric bypass in a double-blind randomised controlled trial of super-obese patients.

The primary endpoint of the study is change in BMI two years after surgery, with the secondary endpoints including body composition, anthropometry, obesity related comorbidities, health-related quality of life, gastrointestinal symptoms, and adverse events including nutritional deficiencies. All patients will be followed for five years.

Between January 2011 to March 2013, 113 patients were randomly assigned to a proximal (n=56, 150cm alimentary limb) or a distal (n=57, 150cm common channel) gastric bypass. At enrolment, patients’ BMI was 48-62 and the age range was 20-60 years. All patients referred to bariatric surgery at the study centres were reviewed for inclusion in the period.

All patients followed standard pre-operative logistics, including schooling on nutrition, exercise, and what to expect after surgery. All patients were prescribed a low-calorie diet (<1000 kcal/day) three weeks before surgery and recommended a pre-operative weight loss of 5–10%.


Both procedures were performed with an antegastric antecolic Roux-en-Y configuration using linear staplers and an omega loop. Standard port placement was applied with four bladeless trocars and a Nathanson liver retractor (Cook Medical), and an extra 5mm port was inserted if needed. All stapling was performed using a linear stapler, with blue cartridges for the stomach and white cartridges for the small bowel. The pouch was created by stapling the stomach horizontally from the minor curvature and vertically to create a gastric pouch of about 25ml. The gastrojejunostomy was created using a 45mm stapler with blue cartridge and completed with a running suture. The omentum was not transected routinely. The biliopancreatic limb was 50cm in both procedures. Limb lengths were measured sequentially using 5cm markers on the graspers; the bowel was held taut but not stretched.

Following the creation of the gastrojejunostomy, the alimentary limb was measured to 150cm from the gastrojejunostomy in preparation for a proximal gastric bypass, with a side-to-side jejunojejunostomy created using a 45mm stapler cartridge and closed with a running suture. In preparation for a distal gastric bypass, the common channel was measured to 150cm from the ileocecal junction and marked with a suture. The bowel was then run from the gastric pouch until reaching the marker, and a side-to-side jejunoileostomy was created using a 45mm stapler cartridge and closed with a running suture. The Roux-en-Y configuration was completed by dividing the jejunum between the anastomoses, with the patency of the gastrojejunostomy evaluated by instilling diluted methylene blue in a nasogastric tube. The fascial defects after trocars were not closed (Figure 1).

Figure 1: Anatomical differences between a proximal gastric bypass and b distal gastric bypass


The patients lost mean 8.4kg from inclusion to the day of surgery, corresponding to a mean weight loss of 5.3%, p=0.12 between groups. The median operating time was 72 (36–151) min in the proximal group and 101(59–227) min in the distal group, p<0.001. The median lengths of hospital stay after proximal and distal gastric bypass were two (1–4) and two (1–24) days, respectively, p= 0.29. However, no patients in the proximal group stayed longer than four days, while seven patients in the distal group stayed longer than five days, including two who stayed for more than 20 days.

The number of patients with complications (5 vs 10, p=0.18) and the distribution of complications (p=0.11) did not differ significantly (Table 1). All patients with severe (grade 3) complications, all resulting in reoperation, had received a distal gastric bypass (0 vs 6, p=0.01). There were no deaths.

Table 1: Perioperative complications in superobese patients randomised to either proximal or distal gastric bypass stratified according to the Contracted Accordion Classification

Six patients, all in the distal gastric bypass group, underwent a total of seven reoperations (three were completed laparoscopically and were the result of staple line bleeding, internal herniation, and small bowel entrapment under an intraperitoneal on lay mesh, and three reoperations were performed by laparotomy). One was the result of a leakage from the enteroenterostomy and one the obstruction of the enteroenteroanastomosis, with both requiring a new anastomosis. The third patient had an iatrogenic small bowel injury requiring suture, and had a second laparotomy due to bleeding after the removal of a non-suction abdominal drain.

“To the best of our knowledge, five randomized controlled trials have compared intestinal limb lengths in bariatric surgery, of which four included super-obese patients,” the authors write. “In the present double-blind, randomized controlled trial, we found that in patients with a BMI of 50 to 60kg/m2, distal gastric bypass was associated with longer operating time than proximal gastric bypass. The overall frequency of complications did not differ; however, distal gastric bypass resulted in more severe postoperative complications requiring reoperation than proximal gastric bypass.“

To access this paper, please click here

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