Bilio-Pancreatic Diversion with Duodenal Switch

Barry N. Haicken, M.D.
January 2002

The Bilio-Pancreatic Diversion with Duodenal Switch (BPD-DS) is an operation for morbid obesity that has been used and in evolution for 20 years. It is now becoming "main stream", as the 20 year results have become widely available.

BPD-DS is a type of intestinal bypass which creates malabsorption. It also employs a moderate degree of gastric restriction. This type of operation (long limb intestinal bypass) fell out of favor when the original jejuno-ileal bypass operations had so many complications, including liver failure and death. The new operation has been designed to avoid the many complications of past operations, yet provide effective weight loss.

The great advantage of BPD-DS is that weight loss is excellent and predictable. On average patients lose 70-80 % of their excess weight, and the weight loss is sustained over the next 20 years. Yet the patients may eat fairly large portions of food, and the diet is unrestricted. There is no dumping syndrome, and no sugar intolerance.

Perhaps the worst side effect of this operation is a tendency toward several foul smelling, loose stools per day, and foul smelling flatus. This is often related to the ingestion of excessive amounts of fatty foods, and patients learn which foods will cause gas, flatus, and frequent stools, and can avoid such foods.

This operation has the potential to cause protein malnutrition, and deficiencies in iron, magnesium, calcium, B-12, folate, and other vitamins, and thus life-long follow-up is needed. Patients will need to follow some modification of their diet for life, to avoid malnutrition, dietary deficiencies of vitamins, minerals and trace metals, and to minimize foul smelling flatus and frequent loose stools.

A description of the operation

The operation is done through an upper abdominal midline incision. While this author is often able to perform the RYGB through a 4 inch incision, the BPD-DS operation will almost always require a longer incision. This may be 6 - 10 inches in length.

The first step involves removing half of the stomach in the long axis of the stomach, as shown in Figure 2.


This part of the surgery is NOT REVERSIBLE. There are 2 reasons for removing half of the stomach. First, the smaller capacity of the stomach provides early satiety (the patient feels full after a smaller meal), and (2) Much of the acid producing area of the stomach is removed, and this helps to prevent ulcers where the small intestine has been anastomosed (joined) to the duodenum, as shown in Figure 2.

A word about anatomy here (see Figure 1):


the small bowel begins at the outlet of the stomach, and ends at the right colon. There are three parts to the small intestine: the duodenum, jejunum, and the ileum. The small intestinal length varies from person to person, but in general it is about 22 feet long. See Figure 1. In the BPD-DS operation, about I I feet of intestine is bypassed, and used as the " biliary limb." Eight feet are used as the "alimentary limb," and only 3 feet are available for digestion: the "common channel" where bile and pancreatic juices mix with the food.

In the Roux en Y Gastric Bypass Operation 90% of the stomach is bypassed, but only about 5 feet of small intestine. In the BPD-DS operation, 50% of the stomach is removed, and more than half is bypassed.

The second part of the operation begins with the measurement of the small intestine (see Figure 2), beginning at the right colon, and measuring back upstream. The common channel will be the last 100 cm. (3.3 feet) of small intestine. The next 8.3 feet will be the alimentary limb, which will carry food from the duodenum.

The intestine (ileum) is divided at that site: 100 + 250 cm. = 350cm, or 11.6 feet from the right colon. The duodenum is divided 2 -3 inches from the stomach. Now the Switch (see Figures 3 & 4): The ileum is anastomosed (joined ) to the duodenum. The GI tract is thus " short-circuited". Food will now bypass the final 12 inches of duodenum and upper I I feet of small intestine. The food will leave the first part of the duodenum to enter the ileum.


The surgical division of the ileum and duodenum, and the duodenal switch, are all reversible.


Dr. Haickens Report.docThe ileum is not usually prone to dumping. Preservation of half of the stomach, and the valve at the outlet of the stomach (the pylorus), also work to protect against the Dumping Syndrome. Thus, while dumping is a significant part of the RYGB operation, it is uncommon after the BPD-DS.

The long segment of bypassed intestine is not as prone to bacterial overgrowth as in the original jejunoileal bypass. This is because bile and pancreatic juice are constantly flowing down this biliary segment. Bacteria tend to grow in areas of stasis - where there is no movement of fluid. The constant flow of digestive juices helps to cleanse this area of intestine and prevent bacterial overgrowth.

This bacterial overgrowth may be the cause of bouts of diarrhea and foul smelling gas and feces. It often responds to brief courses of antibiotics given orally, especially metronidazole.

Difficult areas in this operation

Removal of half of the stomach in a morbidly obese patient is difficult and time consuming. There is a risk of bleeding, and injury to the nearby spleen. The spleen is a delicate organ, with a thin capsule and a large blood supply. If it tears accidentally, it may be necessary to remove the spleen, which would increase the scope of the operation, and create a risk of abscess formation and other possible complications. One of the reasons for a longer incision with the BPD-DS operation, is so that the surgeon can see the upper end of the stomach for accurate and safe resection.

The division of the first portion of the duodenum is a difficult step. The duodenum in this area is closely applied to the pancreas. Just below the area of division runs the common bile duct, a structure necessary for normal digestion. Injury to the pancreas can create a severe inflammation, pancreatitis, which can lead to multiple complications, the need for corrective operations, and even to death, Injury to the bile duct can have similar dire consequences. Thus, dissection in this area is critical and difficult.

Division of the ileum is much less difficult, but anastomosing the ileum to the duodenum, to effect the "switch", is indeed difficult. If this anastomosis were to leak, severe infection and the need for reoperations might result.

Despite the above described difficulties, the vast majority of these operations proceed without major problems.

Post Operative Care

Following surgery the patient will routinely stay in the recovery room for 2 - 4 hours, and then be transferred to a regular room or to the ICU if the patient has sleep apnea or other conditions that require close monitoring.

The patient may have an N/G tube (naso-gastric) in the nose to drain any fluid from the stomach. If the stomach were to fill with fluid, this might be aspirated down the airway and cause a pneumonia. As the gastric pouch is quite small, the risk of aspiration is low, and thus an N/G tube is not needed in every case.

A central venous IN. line may be present in either the right or left subclavian area Oust below the collar bone) on the anterior chest wall. This provides a reliable line to give IN. fluids and medications. It will be removed on the day of discharge.

Results of Surgery

Five years after surgery, 90% of patients have a BMI of 35 or less, are eating a normal unrestricted diet, and are pleased with the results of surgery.

96% of diabetics, 60% of hypertensives, and 50% of patients with pulmonary problems are able to discontinue medications and treatments. Patients report improvements in self confidence, relations with others, and marital and functional capacities.

Immediate Complications and Side Effects

The most problematic side effect of BPD-DS is frequent foul smelling flatus and unpleasant odor of the stool. This was considered to be a major problem by 30% of patients. Many patients learn to avoid certain foods to minimize these side effects. An occasion course of metronidazole, an antibiotic, may also help, presumably by decreasing bacterial overgrowth in the bypassed intestine (Bilio-pancreatic limb).

The long limb bypass results in difficulties with absorption of calcium and iron. It may be necessary for patients to take supplements of these minerals for life.

Seventeen percent of patients had an elevated parathroidhormone level, despite adequate calcium intake and normal calcium blood levels. Parathyroidhormone aka PTH is a hormone which helps control calcium levels in the blood and bone. It is feared that the elevated level might result in late osteoporosis, but this has not been seen in a 20 year follow-up of thousands of patients in Italy and Canada.

The operation is as safe as the RYGB operation, with an operative mortality of 2%, and a 16 % perioperative morbidity. The problems which can occur around the time of surgery (peri-opertive) include: bleeding, infection, preumonia, heart attack, stroke, death, DVT (deep vein thrombosis), pulmonary embolism (blood clots to the lungs), and leakage or bleeding from the gastric or intestinal suture lines.

Late Complications

Re-operation to revise the surgery is required in 0. 1% of patients per year, chiefly for protein malnutrition.

About 20 - 25% of patients may develop incisional hernias.

A bowel obstruction secondary to adhesions or an internal hernia is uncommon, but may occur at anytime, and might need surgery to correct. A bowel obstruction in the bypassed limb might be very difficult to diagnose, and might require re-operation for diagnosis and treatment.

Twenty year follow-up shows strong bones, but the elevated parathyroidhormone levels remain a concern, of uncertain cause and outcome.

Pregnancy

Due to rapid weight loss, and potential injury to the fetus, it is strongly recommended that patients NOT become pregnant for 2 years after surgery. Fertility is increased after BPD-DS, and thus some form of birth control is recommended for 2 years after surgery. Over 80 infants born to mothers after BPD-DS have not had any significant problems attributed to the bariatrric surgery.

Post Op Care and Medications

Patients should take supplement vitamins, iron and calcium for life, and be seen by a physician knowledgeable in bariatric post op problems, FOR LIFE.

A program of regular exercise is strongly recommended FOR LIFE, to maintain good health, and to promote utilization of ingested calories.