Laparoscopic Biliopancreatic Diversion Surgery

Introduction

After jejunoileal bypass was abandoned, most of the bariatric community focused on restrictive operations. However, Scopinaro revisited the value of malabsorption in his description of the BPD in the late 1970s. Since then, modifications have included the duodenal switch, the sleeve gastrectomy, and the laparoscopic approach. DS diminishes the most severe complications of BPD, including dumping syndrome and peptic ulceration of the anastomosis. Sleeve gastrectomy spares the lesser curvature, vagus nerves and pylorus, in contrast to the original distal gastrectomy, though theoretical beneficial effects on eating behavior, weight loss and side-effects are not universally reported. The laparoscopic approach decreases wound complications, pain and hospital length of stay.

Technical considerations

Standard technique for BPD+DS involves dividing the small bowel 250 cm above the ileocecal valve with a stapler, and then forming a biliopancreatic limb by connecting the bowel proximal to the transection to a point 100 cm above the ileocecal valve. The bowel distal to the transaction is elevated as an alimentary limb to the upper abdomen. Sleeve resection creates a tubularized stomach of approximately 100 cm3. The duodenum is divided 3 cm distal to the pylorus, and duodenoileostomy establishes continuity of the alimentary limb. Limb lengths determine weight loss and complications. A common limb that is too long will provide inadequate weight loss, whereas one too short will cause debilitating diarrhea and nutritional deficiencies. Gastric remnant size should provide some restriction but not prevent initiation of protein digestion. Whether BPD should be tailored to patient characteristics such as age, size or BMI is uncertain. Scopinaro, in his original animal study, found ‘‘insertion of the bypass into the ileum at a distance from the ileocecal valve equivalent to one-sixth of the intestinal length allows adequate weight loss with minimal complications. However, by the time of his human studies, he noted that ‘‘the exact length of the common ileal segment and the length of the jejunum in the biliopancreatic tract required to achieve maximum weight reduction with minimum complications have yet to be determined. Hess reports excellent results by measuring small bowel length and then distributing 10% to the common channel and 40% to the alimentary limb. A large Spanish series reports excellent outcomes with a common channel of 60 cm and an alimentary limb of 200-360 cm. A US study suggests common channels longer than 100 cm result in inferior results. In a comparative study of outcomes and complications, 100 cm common channel was superior to 50 cm, and sleeve gastrectomy was superior to distal gastrectomy. Though there is a paucity of comparative data between open and laparoscopic BPD, a few comments can be made on the utility of the minimally invasive procedure. Firstly, because the details of the resection and reconstruction are the same, long-term outcomes are likely to be similar. Indeed, at 1 and 3 years follow-up, weight loss is similar to that achieved by open surgery. Laparoscopic BPD has reduced hospital stay and complications, mainly due to a lower rate of wound infections and dehiscence. Laparoscopic BPD is an advanced, complex and feasible technique in bariatric surgery, and one which has a steep learning curve.

Outcomes

BPD ± DS initiates dramatic weight loss during the first 12 postoperative months, which continues at a slower rate over the next 6 months. Weight loss is durable up to at least 5 years postoperatively. Ninety-five percent of patients with BMI>50 kg/m2, and 70% of those with BMI>50 kg/ m2, achieve greater than 50% excess body weight loss. Weight may be regained over time, highlighting the importance of long-term follow-up. BPD dramatically impacts comorbidities. At least 90% of patients with type 2 diabetes will cease diabetic medications by 12-36 months. Of hypertensive patients 50-80% will be cured, with another 10% experiencing improvement. Up to 98% of patients with obstructive sleep apnea symptoms will have resolution. Although BPD, RGB, and AGB are all superior to nonsurgical therapy, the relative effectiveness of these procedures has not been fully compared. Data available are rarely randomized or controlled, and often compare non-equivalent cohorts. Nonetheless, available data suggest the weight loss effect of BPD is greater and more durable than laparoscopic AGB. Likewise, BPD may be superior to RGB in patients with BMI 50 kg/m2. A meta-analysis examining studies published between 1990 and 2003 found BPD resulted in more weight loss and improvement of diabetes, hyperlipidemia, hypercholesterolemia, hypertriglyceridemia, and obstructive sleep apnea than any other type of bariatric procedure. Despite the favorable reports of the biliopancreatic diversion and duodenal switch procedure for the treatment of morbid obesity, it has been slow to gain widespread acceptance.

Postoperative

An upper gastrointestinal series is typically performed in the early postoperative period to exclude contrast extravasation. If normal, a clear liquid diet is commenced, with gradual introduction of solids. Discharge is usually within 4-5 days. Close follow-up is recommended in the postoperative period. For example, visits at 2 and 6 weeks, then quarterly for the first year, biannually for the second year, and annually thereafter would be one acceptable strategy. Assessments are made by both the surgeon and nutritionist, and biochemical surveillance by complete blood count, chemical metabolic profile, and parathormone level is performed at intervals. An exercise program is helpful, as are multivitamin, iron, vitamin D, and calcium supplements.

Complications

The 30-day mortality of early laparoscopic BPD series ranges from 2.6 to 7.6%. Major complications, which occur in up to 25% of cases, may include early occurrence of anastomotic leak, duodenal stump leak, intra-abdominal infection, hemorrhage, and venous thromboembolism, or later bowel obstruction, incarceration or stricture. The performance of a sleeve gastrectomy as part of the BPD+DS allows patients two-thirds of their preoperative dietary volume without specific food intolerances. Between 70 and 98% maintain normal serum albumin 3 years after surgery. Diarrhea is a frequent chronic complication of BPD. Common channel length of 50 cm is associated with reports of diarrhea in most patients, whereas length of 100 cm is not. Iron deficiency is common, with serious iron deficiency anemia (hemoglobin <10 mg/dl) occurring in 6% of patients. Surveillance of biochemical and hematological markers of iron deficiency should drive replacement. Calcium and vitamin D malabsorption are also common, manifesting as secondary hyperparathyroidism. Supplements do not prevent development of secondary hyperparathyroidism. Increase in bone resorption is known to occur irrespective of parathormone levels, suggesting a phenomenon of bone reshaping parallel to the loss of weight. Due to fat malabsorption resulting from BPD, supplementation of fat-soluble vitamins is recommended. Deficiency of these vitamins is more likely with a shorter common channel. Cholelithiasis postoperatively occurs in 6% to 25%. Some surgeons advocate for routine cholecystectomy given the alteration in endoscopic accessibility to the biliary tract, whereas others argue for delayed cholecystectomy only if symptoms develop, since cholecystitis occurs uncommonly after BPD.