It is estimated that two-thirds of the US population is overweight or obese, with the subset of the most severely obese increasing at an alarming rate. The prevalence of obesity mirrors the burden of several life-limiting comorbidities that impact virtually every organ system. Various public health, lifestyle, and pharmaceutical interventions have attempted to curb this problem with limited success. Bariatric surgery, however, has demonstrated effectiveness in treating morbid obesity with consistency and longevity. In addition, bariatric surgery demonstrates the ability to induce remission of several comorbidities previously thought to be incurable, such as type II diabetes mellitus (T2DM) [1]. Given these observations, together with the increased implementation of laparoscopy that has increased patient safety, it is no wonder that the utilization of bariatric surgery is dramatically increasing.

While Roux-en-Y gastric bypass (RYGB) and laparoscopic adjustable gastric banding (LAGB) are the most popular weight loss procedures, biliopancreatic diversion with duodenal switch (BPD/DS) is the most effective bariatric operation, resulting in the greatest magnitude of excess weight loss (EWL). The effectiveness of this procedure is not limited to its impact on weight, but also it generally results in superior resolution of comorbidities, particularly type II diabetes. Despite this, BPD/DS is not widely practiced, accounting for <1 % of all bariatric surgeries performed in the USA. The procedure requires a high level of technical skill and also requires clinical expertise in choosing patients appropriate for the procedure, as well as managing postoperative care. No doubt the procedure is perceived to have higher perioperative morbidity as well as negative long-term nutritional consequences, both of which contribute to its unpopularity.

Nevertheless, due to its effectiveness, it should have a place in the arsenal for surgical weight loss specialists. Particular areas that BPD/DS may play a significant role are in the management of the super morbidly obese (BMI > 50 kg/m²) and in patients with weight regain after prior bariatric surgery. The aims of this chapter will be to (1) review the history of the procedure; (2) describe the indications, contraindications, and patient selection; (3) describe the surgical technique; and (4) review the outcomes from the procedure.

Nicola Scopinaro is credited with describing the original biliopancreatic diversion (BPD). His procedure was developed to maintain the malabsorptive component of the now abandoned jejunoileal bypass (JIB) while eliminating the long blind limb that contributed to many of the problems with JIB. He performed a distal gastrectomy and anastomosed a 250 cm distal Roux limb to the proximal stomach, with the long biliopancreatic limb anastomosed 50 cm from the ileocecal valve to create a short common channel. Weight loss with the BPD is excellent and sustainable out to 15 years. The original Scopinaro procedure (BPD), however, is associated with a relatively high rate of dumping and marginal ulcers. The duodenal switch (DS) is a subsequent modification of the BPD, which is done by creating a vertical (or sleeve) gastrectomy rather than a distal gastrectomy and then anastomosing the Roux limb to the stapled proximal duodenum. This technique preserves the pylorus and reduces the parietal cell mass, which contribute to a lower rate of both dumping and ulcer formation. The DS modification of the BPD was first described by Marceau in 1993, which combined the Scopinaro procedure with the DS procedure described by DeMeester for bile reflux [2]. In 1998, Hess and Hess further modified the duodenal switch with the division of the duodenum, leading to the modern-day BPD/DS [3].

Gagner described the first laparoscopic performance of this procedure, which represents the current standard technique. The current laparoscopic BPD/DS consists of a sleeve gastrectomy over a 60 Fr bougie with an alimentary limb of 250 cm anastomosed to the proximal duodenum and a 50–100 cm common channel [4].

Similar to other bariatric procedures, all candidates for DS must have a BMI > 40 kg/m² or >35 with a comorbidity and meet the National Institutes of Health (NIH) criteria for weight loss surgical intervention. For DS, however, we generally limit our recommendation to those with a BMI >50, as literature suggests this group is likely to have poorer weight loss results with RYGB and LAGB [5]. The added benefits of DS in this group are positively weighed against the potentially increased perioperative and nutritional risks of the procedure. For lower BMI patients, other weight loss surgeries are generally adequate. An important exception to this may be in those with severe diabetes where DS may be superior in inducing remission of disease. It may be reasonable to offer DS to other non-super obese individuals, but greater caution is employed for fear of macro- and micronutrient deficiencies. Certainly, Scopinaro’s group has performed the BPD procedure in patients with lower BMI with no major increase in long-term complications [6].

In the super-super obese (those with a BMI > 60), Gagner’s group has described a two-stage procedure, with sleeve gastrectomy (SG) performed as first step, followed after an interval 6–18 months by duodenoileostomy and ileoileostomy [7]. This strategy can limit the often-lengthy procedure in larger and sicker patients, thereby reducing perioperative morbidity and mortality. We find, rather than using a BMI cutoff, intraoperative findings (presence of adhesions, hepatomegaly, torque on instruments) can guide the feasibility of completion of the procedure.

Contraindications to laparoscopic DS are similar to those of laparoscopic RYGB. Medical contraindications include the inability to safely tolerate general anesthesia, non-correctable coagulopathy, massive abdominal wall hernia, preexisting potentially malabsorptive disorder such as inflammatory bowel disease or celiac disease, or malignancy. Severe gastroesophageal reflux is a relative contraindication to DS, as the physiology of the sleeve gastrectomy can potentially exacerbate reflux symptoms. Psychosocial contraindications are important to assess for; these include poor understanding of the nutritional consequences of the procedure, inadequate social support, inability to maintain follow-up, and active alcohol or substance abuse. Additionally, we do not offer bariatric surgery to smokers, given the increased perioperative pulmonary, wound-healing, and anastomotic risks associated with cigarette use. Finally, it is important to assess the patient’s willingness and financial ability to purchase postoperative vitamin supplements, as these are often not covered by insurance.

A thorough history and physical exam should always be obtained. History should include a diet history, with documentation of attempts at nonsurgical means of weight loss. In addition, patients should meet with a registered dietician and psychologists. Any maladaptive behavior should be addressed and treated prior to surgery, if possible. Any preoperative vitamin or mineral (e.g., vitamin D, iron) deficiencies should have treatment initiated. The presence or absence of a full list of obesity-related comorbidities should be documented. If not known, screening for diabetes, hyperlipidemia, and obstructive sleep apnea should be performed. These comorbidities should be identified and optimized prior to surgery. Patients should also be asked about a history of hypercoagulable states and history of venous thromboembolism (VTE). Some groups advocate the use of pre-op inferior vena cava (IVC) filters, though this has recently become controversial [8].

Pertinent points in the physical exam should examine areas that may make surgery challenging, such as android fat distribution or prior surgeries or hernias. Patients that are immobile and are short of breath are generally poor candidates for surgery.

Preoperative diet is somewhat controversial. Certainly nutritional education should begin before surgery. Weight loss prior to surgery can reduce the amounts of visceral fat and decrease hepatomegaly, which can make surgery safer and easier to perform. We generally do not require a prescribed weight loss before surgery and do not believe in “testing” patients to see if they are good candidates for surgery. But certainly active weight gain, particularly in the super-super obese, should be strongly discouraged.

Before undertaking the operation, it is essential to have a dedicated operating room team that is knowledgeable about advanced laparoscopic bariatric procedures and the DS in particular. As with all complex procedures, the importance of a team of anesthesiologists and nurses familiar with the setup cannot be stressed enough.

Immediately prior to surgery, all patients should receive appropriate antibiotic prophylaxis to limit wound infection. Dosing should be appropriate for the patient’s size, and re-dosed as necessary. In addition, patients should have appropriate VTE prophylaxis. There have not been adequate studies to determine the optimal means of VTE prophylaxis, weighing risk of VTE against the risk of postoperative bleeding, and it is unlikely that such a study can be performed given the large number of patients required to measure differences. Generally, all patients should wear pneumatic compression stockings prior, during, and after surgery while in bed. It is also generally recommended that some chemoprophylaxis be used. We administer an intravenous (IV) infusion of heparin of 500–750 u/h, which is transitioned to subcutaneous prophylaxis 24 h after surgery.

The first part of the operation is the vertical sleeve gastrectomy. While technically the easiest component of the operation, performing this first may allow for staging the procedure if it is deemed that the operation is taking too long or is not safe to complete. Accurate assessment of the duration of the operation is important, as complications tend to increase with longer time under anesthesia. The surgeon initially stands on the patient’s right with working ports in the right subcostal and mid-abdomen. The camera is in the left mid-abdomen, and the assistant is operating through the left subcostal port. A liver retractor may be inserted from the extreme right-sided port if the liver is particularly enlarged. Marking the pylorus with a seromuscular permanent suture can serve as an important visual landmark during mobilization of the greater curvature, which begins 4–6 cm from the pylorus. An ultrasonic or bipolar energy device is used to devascularize the greater curvature. Mobilization is carried on to the left crus of the diaphragm. Notation of a hiatus hernia should prompt repair with permanent suture. This may prevent postoperative reflux and retained fundus that can contribute to poor weight loss. After mobilization is complete, a 60 Fr bougie is passed. Creation of the sleeve occurs by several serial firings of a linear stapler. The initial staple firing should be with a cartridge used for the thickest tissue (5.00–4.00 mm) and begins 4–6 cm from the pylorus, preserving much of the antrum. Cartridge height for subsequent staple firings is gauged by the thickness of the tissue but can be reduced after the first one or two firings. We routinely use bioabsorbable buttressing to limit staple line bleeding on all but the first staple fire. Care must be noted to fire the stapler in the same horizontal plane to prevent a spiral sleeve configuration, which can cause a functional obstruction. In addition, tightly hugging the bougie, particularly at the GE junction, may not be prudent and can result in improper staple firing. Finally, angulating too sharply towards the incisura or away from the angle of His can result in functional intrasleeve obstruction or an hourglass configuration and poor weight loss, respectively. Once the stomach is completely divided, the specimen can be set aside, with notation by the team that it must be removed prior to completion of the case. This allows maintenance of pneumoperitoneum throughout the case without dilating the port sites.

At this point of the operation, if there has been any physiologic compromise of the patient or the surgeon judges the efficient technical feasibility of the remaining malabsorptive portion of the operation to be questionable, the specimen can be retrieved and the procedure terminated. The second stage of the operation can take place after a 100–150 lb weight loss plateau is reached, usually between 9 and 18 months after surgery. This possibility should be discussed with the patient preoperatively, and if the staged approach was unplanned, the rationale needs to be carefully documented.

The duodenal transection may be the most technically demanding part of the procedure. It is critical to avoid excessive devascularization of the duodenum or injury to the duodenum and pancreas. Excessive visceral fat can make the dissection quite difficult, and bleeding can blur tissue planes. The dissection begins by having the assistant grasp the antrum and retracting it laterally, which linearizes the first portion of duodenum. Using hook monopolar energy, the peritoneum overlying the inferior and superior portions of the duodenum is freed. Care is taken to avoid injury to the right gastric vessels. The mobilization is performed until the point where the duodenum fuses posteriorly with the pancreas. The retroduodenal dissection can generally be performed bluntly with judicious bipolar cauterization of vessels. A right-angled or curved dissector can be used to complete the retroduodenal tunnel. The gastroduodenal artery is typically encountered posterior to this window, which should be large enough to deliver the stapler cartridge. Excessive force during cartridge passage can result in bleeding or trauma to the duodenum, porta hepatis, or pancreas. We use a 3.5 mm staple load with bioabsorbable buttressing applied only on the anvil side. This allows for easier passage of the stapler in the retroduodenal tunnel. The buttress material not only serves to reduce bleeding but also linearizes the staple line, facilitating subsequent anastomosis. After this, a seromuscular 2-0 braided permanent suture is placed near the inferior corner of the duodenal cuff staple line, with its tail cut 3–4 cm in length to facilitate the proximal anastomosis as described later. An additional 2-0 braided polyester suture cut 23–25 cm in length, used to create the posterior outer layer of the anastomosis, is placed through the cephalad aspect of the duodenal cuff staple line and left in place while the Roux limb is constructed.

While still standing on the patient’s right side, the greater omentum is divided towards the patient’s right. This window will facilitate bringing of the ileum towards the duodenum. Next, the surgeon moves to the patient’s left side. If the left lateral mid-abdominal port had not been inserted previously, it should be at this point. Working through the LUQ/subcostal port and this port, the terminal ileum should be identified at its junction with the cecum. In patients with prior abdominal surgery, one should examine this area for adhesions prior to duodenal transection. The bowel is run in a retrograde fashion, carefully measuring with either a graduated bowel grasper or premeasured tape. At the 100 cm point, we place two marking stitches to mark the site of the future ileoileostomy. This can help maintain orientation, which can prevent later confusion. The bowel is then run for another 150 cm at which point it is transected with a 60 mm, 2.5 mm stapler with bioabsorbable buttressing. The distal end of the biliopancreatic limb should be marked with a suture or a clip to distinguish it from the Roux limb. Once divided, determine if the alimentary limb is able to reach the duodenum. If there is significant tension, it may be necessary to perform a second sagittal vascular stapler firing through the mesentery, taking care to preserve blood supply to the ends of the bowel segments. The alimentary limb is then brought through the omental window towards the duodenal cuff. In the rare instance of excessive tension on the alimentary limb, the limb can be brought through a mesocolic window.

This anastomosis can be performed in a variety of fashions, with advantages and disadvantages to each technique. It is important to be familiar with each technique to allow for flexibility and use with varying anatomy and in bailout situations. With each approach, the surgeon stands on the patient’s left side working though the 12 mm LUQ port and the 15 mm right mid-abdominal port with the camera in the left mid-abdominal port.