Biliopancreatic diversion

Last revised by Calum Worsley on 7 Dec 2021

Biliopancreatic diversion was a development on the jejunoileal bypass type of bariatric surgery. It can be performed with or without a duodenal switch.

Biliopancreatic diversion was originally described by Scopinaro in 1979 as an alternative to jejunoileal bypass surgery for morbidly obese patients 1.

The procedure comprises 1

  • partial distal gastrectomy in which the duodenal stump is closed
  • transection of the small bowel approximately halfway between the ligament of Treitz and the ileocecal valve
  • Roux-en-Y gastroenterostomy from the gastric pouch to the distal bowel loop creating an alimentary limb, and
  • a biliopancreatic limb anastomosed with the alimentary limb to form a common limb, which continues to join the colon at the ileocecal valve 

Postgastrectomy syndrome led to the development of a duodenal switch variant. In this variant, the stomach is restricted along the greater curvature (like a sleeve gastrectomy), and the shortened Roux limb is attached end-to-end to the proximal duodenum. The biliopancreatic limb is attached similarly to the normal biliopancreatic diversion.

The bypass is designed to have a mixture of restrictive and malabsorptive effects: a partial gastrectomy reduces the capacity of the stomach, and the diversion of biliopancreatic contents, which only join the alimentary limb in its distal portion, mean that fats and sugars are digested much less efficiently.

The biliopancreatic diversion has been reported to result in 70% of long term weight loss in >90% of patients 2. The duodenal switch variant may be even more effective 3. These procedures may occasionally be used when other more conservative bariatric procedures have failed.

Although the procedure avoids the bypass enteritis of jejunoileal bypass (with an associated risk of hepatic failure), it does have a number of side effects, including

  • risk of nutritional deficiency: calcium, fat-soluble vitamins, and protein
  • postgastrectomy syndrome: marginal ulcers and dumping syndrome
    • decreased with duodenal switch
  • bowel obstruction, internal hernia, anastomotic leak
  • diarrhea, caused by poor absorption in the small bowel

According to a study that followed patients with biliopancreatic diversion 32% of postoperative bowel obstructions were at or near the distal anastomosis site and more often involved biliary limb than the alimentary limb 5. Remote post-operative obstructions occurring years after surgery was mostly due to adhesions and strictures at the anastomosis site 5. CT with oral and intravenous contrast is recommended for its evaluation 5.

Biliopancreatic limb obstruction has unique complications, and adverse events are more frequent with this type of obstruction compared to routine postoperative small bowel obstructions 6. Increased pressure caused by biliopancreatic limb obstruction may result in pancreatitis, bile duct dilation or perforation.

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