A biliopancreatic diversion changes the normal process of digestion by making the stomach smaller and allowing food to bypass part of the small intestine so that you absorb fewer calories. You will feel full more quickly than when your stomach was its original size, which reduces the amount of food you eat and thus the calories consumed. Bypassing part of the intestine also means that you will absorb fewer calories. This leads to weight loss.

There are two biliopancreatic diversion surgeries: a biliopancreatic diversion and a biliopancreatic diversion with duodenal switch.

• In a biliopancreatic diversion, a portion of the stomach is removed. The remaining portion of the stomach is connected to the lower portion of the small intestine. See an illustration of a biliopancreatic diversion.
• In a biliopancreatic diversion with duodenal switch, a smaller portion of the stomach is removed, but the remaining stomach remains attached to the duodenum (the upper part of the small intestine). The duodenum is connected to the lower part of the small intestine. See an illustration of a biliopancreatic diversion with a duodenal switch.

These procedures can be done by making a large incision in the abdomen (an open procedure) or by making a small incision and using small instruments and a camera to guide the surgery (laparoscopic approach).

What To Expect After Surgery

Surgery for obesity usually involves a 4- to 6-day hospital stay (2 to 3 days for a laparoscopic approach). Most people can return to their normal activities within 3 to 5 weeks. After biliopancreatic surgery, you generally see your surgeon 3 weeks after surgery and then every 3 months for 1 year. After 1 year, see your surgeon once per year.

A biliopancreatic diversion may cause dumping syndrome. This occurs when food moves too quickly through the stomach and intestines. It causes nausea, weakness, sweating, faintness, and possibly diarrhea soon after eating. These symptoms are made worse by eating highly refined, high-calorie foods (like sweets). In some cases you may become so weak that you have to lie down until the symptoms pass. Dumping syndrome does not occur in a biliopancreatic diversion with duodenal switch.

Why It Is Done

Many doctors will only consider the procedure for people who have not been able to lose weight with other treatments and who are at high risk for developing other health problems because of their weight.

Although guidelines vary, surgery is generally considered when your body mass index is 40 or higher or you have a life-threatening or disabling condition related to your weight.

The following conditions may also be required or are at least considered:

• You have been obese for at least 5 years.
• You do not have a history of alcohol abuse.
• You do not have untreated depression or another major psychiatric disorder.
• You are between 18 and 65 years of age.

All surgeries have risk, and it is important for you and your health professional to discuss your treatment options to decide what is best for your situation.

How Well It Works

Biliopancreatic diversion surgeries are effective. Most people lose 75% to 80% of their excess weight (the weight above what is considered healthy) and maintain their new weight.

Risks

Risks common to all surgeries for weight loss include an infection in the incision, a leak from the stomach into the abdominal cavity or where the intestine is connected (resulting in an infection called peritonitis), and a blood clot in the lung (pulmonary embolism). About one-third of all people having surgery for obesity develop problems related to poor nutrition, such as anemia or osteoporosis

Fewer than 3 in 200 (1.5%) people die after surgery for weight loss.

Biliopancreatic diversion surgeries result in reduced absorption of protein, fat, calcium, iron, and vitamins B12, A, D, E, and K. You may have frequent, bad-smelling stools and a higher risk for developing osteoporosis.

Within 1 year of biliopancreatic diversion surgery:

• 30 out of 100 people develop anemia.
• 30 to 50 people out of 100 develop a deficiency in vitamins A, D, E, K, and beta-carotene.
• About 4 people out of 100 need hospitalization because of lack of protein. Protein deficiency is somewhat less of a risk in the biliopancreatic diversion with duodenal switch.

What To Think About

Biliopancreatic diversion surgeries are complex surgeries that should only be done by a very experienced surgeon.

Early studies of the laparoscopic approach to surgery for obesity suggest that it reduces recovery time and postsurgery complications. A laparoscopic approach for these surgeries has not been used long enough to draw significant conclusions.

In a biliopancreatic diversion, the part of the intestine where many minerals and vitamins are most easily absorbed is bypassed. Because of this, you may have a deficiency in iron, calcium, magnesium, or vitamins. To prevent vitamin and mineral deficiencies, you may need to work with a dietitian to plan meals, and you may need to take nutrient supplements and injections of vitamin B12.