Biliopancreatic Diversion BPD

Biliopancreatic diversion (BPD) is one of the oldest surgical procedures developed for weightloss. Using an open or laparoscopic approach, the distal (lower) portion of the stomach is resected leaving a small proximal portion of the stomach. It is then anastomosed (connected) to the ileum (distal small bowel). After this operation, food travels from the reduced stomach to the distal intestine by passing a long segment of the small bowel (Figure). This procedure decreases oral intake and reduces the absorption of the nutrients and calories eaten.

The BPD has been demonstrated to be one of the most effective bariatric procedures in terms of total weightloss, the long-term maintenance of this weightloss, and for improvement of associated diseases. The weightloss achieved is reported to be on average 70-80% of excess of weight and it is generally maintained long-term. Among all current bariatric procedures, the BPD provides the highest likelihood of improvement, or even resolution of many different diseases secondary to the obesity such as type 2 diabetes, hypertension, dyslipidemia, metabolic syndrome, fatty liver disease and obstructed sleep apnea.

Due to the complexity of the operative technique, the risk of postoperative complications after BPD is higher when compared with other bariatric procedures. Perioperative complications include bleeding, infections, gastrointestinal leakage, deep venous thrombosis, pulmonary embolism, and wound issues.

Long-term complications are mainly nutritional in nature and are due to the malabsorption created by the BPD. They include dehydration, protein, vitamin and mineral deficiencies. The vitamin and minerals at risk include iron, zinc, calcium, folate B12, and the fat soluble vitamins (A, D, E, K). Therefore, patient sunder going the BPD procedure must have close medical monitoring, strict adherence to proper dietary guidelines, and must be compliant with vitamin and mineral supplementation.

The Biliopancreatic Diversion (BPD) was developed in the 1970s by Nicola Scopinaro from Genoa, Italy [1]. The biliopancreatic diversion with duodenal switch (BPD-DS), known simply as “Duodenal Switch (DS)” was created in 1988 by Douglas Hess, Bowling Green, Ohio, [2] and was first published by Picard Marceau, Québec, Canada [3] in 1993.

Hess incorporated four main components into the DS:

Vertical gastrectomy with excision of the greater curvature to significantly reduce gastric volume capacity to create nutrient intake restriction (essentially a sleeve gastrectomy).
Division of the duodenum between the pyloric valve and the sphincter of Oddi. This preserves the normal pyloric emptying and avoids the dumping syndrome seen with procedures that bypass the pyloric valve.
Anastomosing (connecting) the ileum (distal small intestine) to the duodenum so that nutrients can move down the small intestine.
Bypassing the jejunum (proximal small bowel) resulting in malabsorption as desired for weight loss. Deriving from experience with the BPD. the BPD-DS has a longer common channel to reduce the likelihood of vitamin, mineral, and protein deficiencies.

The first laparoscopic BPD-DS was performed by Michel Gagner in 1999. In fact, the Laparoscopic Sleeve Gastrectomy (LSG), was initially conceived as the first of a two-step procedure to create the DS. The sleeve would be performed and after some period of time and weight loss, the patient would then undergo the second stage of the DS, which was the small intestinal bypass. The goal of staging the DS was to reduce the perioperative morbidity of this complex procedure. Subsequently, the sleeve gastrectomy was adapted as an autonomous procedure. For this purpose smaller bougies were used to achieve more restriction. Today the LSG is the most popular bariatric operation worldwide.

DS- The Procedure:

The first step of the procedure is to do the sleeve gastrectomy. Unlike the LSG, the bougie size for the DS is larger. It should not be smaller than 60 French, (if the DS will be performed as a one step-procedure). If 2 steps are planned, bougie size is more similar to the LSG. Hiatal hernias, if identified, are closed selectively by most surgeons. The stapling begins at the distal antrum with preservation of the antrum. The duodenum is then dissected posteriorly, clearly separating it from the duodeno-hepatic ligament. After mobilization, the duodenum is divided with the linear cutting stapler and a 60 mm cartridge 1.5 to 2 cm distal to the pylorus. Staple-line reinforcement can be useful.

The intestinal bypass starts distally at the ileo-cecal valve, The common channel is created to be only 75 cm to 100 cm from the ileo-cecal valve. The alimentary limb is divided at 250 cm from the ileo-cecal valve and connected to the post-pyloric duodenum. This duodeno-ileostomy may be performed with different techniques (circular stapled, linear stapled or totally hand-sewn). The hand sewn end-to-side anastomosis is considered by many surgeons to be preferable and is the most common applied technique (5). The entero-entero-anastomosis 75 – 100 cm proximal to the ileo-cecal valve, is created similarly to other intestinal anastomoses. The mesenteric spaces and the Petersen space should be closed with non-absorbable sutures to avoid internal herniation. Drainage is not necessarily routine, and testing for leaks (methylene blue, air with gastroscopy) are both left up to the surgeon.

Outcomes

Both short-term and long-term weight loss following DS exceed that of any other operation. The benefits for patients with the metabolic syndrome are well documented as well as the proportionate resolution of co-morbidities. Generally speaking, the performance of the DS is superior to the Roux-Y-gastric-bypass procedure (RYGB). However, DS patients need strict and strong vitamin supplementation including the fat-soluble vitamins, calcium and minerals.

Despite the great results, the number of DS cases yearly, continues to decrease, driven by patient preference for other bariatric procedures. Currently Sleeve gastrectomy and RYGBP are the most widely used bariatric procedures in the U.S.A as well as worldwide.

Recently the DS was modified. The SADI procedure (Single anastomotic duodeno ileostomy) is a different type of bypass reconstruction than the traditional DS. Furthermore, transformation of the sleeve to an omega-loop gastric bypass is an option for patients with failed LSG. Further results with these variants are needed before they can be considered to be mainstream procedures.

References

[1] S c o p i n a ro N, Gianetta E, C iva l l e ri D et al. Biliopancreatic bypass for obesity: initial experience in man. Br J Surg 1979; 66: 618-20.

[2] Hess DS, Hess DW. Biliopancreatic diversion with a duodenal switch. Obes Surg 1998; 8: 267-82.

[3] Marceau P, Biron S, Bourque RA et al. Biliopancreatic diversion with a new type of gastrectomy. Obes Surg 1993; 3: 29-36.

[4] Chu C, Gagner M, Quinn T, Voellinger DC, Feng JJ, Inabnet WB, Herron D, Pomp A: Two-stage laparoscopic BPD/DS. An Alternative Approach To Super-Super Morbid Obesity. Surgical Endoscopy 2002; S187.

[5] Weiner, R.A., Pomhoff I, Schramm M, Weiner S, Blanco-Engert R.: Laparoscopic biliopancreatic diversion with duodenal switch: three different duodeno-ileal anastomotic techniques and initial experience. Obes Surg. 2004 Mar;14(3):334-40