The Duodenal Switch Revisited

| June 18, 2009 | 0 Comments

by Daniel J. Rosen, MD, and Alfons Pomp, MD, FACS

Both from Weill Medical College of Cornell University, New York Presbyterian Hospital, New York, New York.

Introduction
It has been over a decade since Hess described a significant modification of the Scopinaro bilio-pancreatic diversion (BPD).[1,2] In the duodenal switch (DS), a vertical sleeve gastrectomy provides intake restriction, replacing the horizontal gastric pouch of the Scopinaro operation with its distensible fundus. A pylorus-sparing duodenoileostomy accomplishes a very distal intestinal bypass, contributing a malabsorptive component to the weight loss. This can be construed as a bariatric application of the duodeno-jejunostomy DeMeester pioneered to treat bile reflux, and decreases the incidence of marginal ulcerations seen with antrectomy and Roux-en-Y biliary diversion.[3] The DS provides excellent weight loss and achieves significant improvement of obesity-related comorbidities.[4,5]

The laparoscopic era of bariatric surgery was pioneered by Alan Wittgrove in 1994 with an initial report of five patients undergoing laparoscopic Roux-en-Y gastric bypass (RYGB).[6] The DS was first performed laparoscopically by Michel Gagner’s team in 1999.[7] With the wider adoption of laparoscopic techniques over the last 10 years there has been an explosion in the number of bariatric procedures performed.[8] This increase has mostly been represented in the numbers of laparoscopic RYGB and more recently by adjustable gastric bandings (AGB).

Despite being extraordinarily effective in terms of weight loss and comorbidity resolution, the DS still accounts for only a small minority of the primary bariatric operations performed in America.[5] There are numerous and complex reasons for this. The extensive malabsorptive component certainly deters many surgeons. Past experiences with the jejunoileal bypass (JIB) resulted in patients with severe malnutrition who were rendered more medically compromised by the operation than by their morbidly obese state. In the standard DS, only the distal 15 percent of the small bowel is exposed to both nutrients and the biliopancreatic secretions required for digestion and absorption of fats and proteins.[9] The DS, whether attempted open or laparoscopic, is certainly a more technically challenging procedure, and accordingly carries greater morbidity and mortality than the gastric bypass or adjustable band. The greater risk of complications evidently serves as a dissuading factor. Should the DS command wider application? Ten years of surgical experience with this operation has yielded certain insights.

Indications
When evaluating bariatric patients for surgery, the decision of which operation to perform, if any, can influence the weight loss outcome and resolution of comorbidities. The DS is effective, with durable excess weight loss (EWL) of 64 to 70 percent and diabetes resolution of 90 to 98 percent.[5,10] We also know the DS carries a higher morbidity and mortality than other operative options and therefore should be offered selectively. The irony for the super-obese patient is that their best option is the most challenging, and they are the most dangerous patients upon which to perform it. In most cases, we reserve the laparoscopic DS for super-obese patients (BMI>50kg/m2). In a study by Prachard et al, the percent EWL at three years was greater for DS than RYGB (68.9% vs. 54.9%; p<0.05). They also found a significant difference in the likelihood of weight loss failure (EWL<50%) at three years, with a 41.7 percent failure rate in the RYGB group and only 15.8 percent in the DS group.[11]

Early laparoscopic DS series showing higher complications in the super-obese has led to a treatment algorithm based on a staged procedure.[7] Specifically, a laparoscopic sleeve gastrectomy (LSG) achieves initial weight loss, and then the duodenoileostomy is performed 8 to 12 months later for ongoing weight loss maintenance.[12] While it was certainly expected that the initial procedure would lessen the cumbersome visceral fat and abdominal wall torque that the laparoscopic surgeon must combat in a single-stage operation, we were also pleasantly surprised to find that the two-stage laparoscopic operation resulted in a lower complication rate than a single-stage open procedure in this high risk group.[12]

Buchwald et al, in a recent review of his first 190 DS cases (most performed open), did not show a statistically greater rate of complications in the super-obese patients, though a trend seemed to be present (p<0.1).[13] He reported in his 2007 meta-analysis that 30-day mortality was 0.7 percent for open DS and 1.1 percent for laparoscopic DS.[14] He suggests that advocacy for the two-stage procedure in patients with BMI >50kg/m2 may have been premature, based on early/poor outcomes from low-powered series.[13] This supposition has been supported with a number of more recent DS series with excellent outcomes.[11,15-17]

A DS patient can become malnourished even while consuming a “normal” diet. It is therefore critical that he or she understand the implications of a malabsorptive operation and know the steps required to achieve optimal results with minimal nutritional complications. From the initial visit, patients must be made aware that the DS carries an ongoing, lifetime cost for vitamins and supplements that can approach $1,000 to $1,500 per year. If a patient is from a socioeconomic strata that will make purchasing these necessary supplements a burden, the patient may be best served by performing a different weight loss procedure. Even when money is not a prohibitive factor, compliance regarding medication can be an issue. It is often difficult to ensure that some patients adhere to a simple daily medication to treat hypertension. A duodenal switch requires that patients take 10 to 15 supplements a day for the rest of their lives. The psychological assessment provides a good opportunity to assess compulsiveness of each patient, as he or she will need to be diligent with the vitamins, supplements checkups, and regular blood work.

In our experience, the patient who comes to a bariatric surgeon requesting a DS has often already done substantial amounts of research on the internet. The internet is a tremendous resource offering pictures, video, the description of the procedure, and outcome data, as well as online support groups. The latter can be especially helpful for patients to get answers about postoperative lifestyle adjustments directly from those who have already undergone the operation. It is the patient who comes to meet the surgeon already educated—weight loss chronicle in hand—who often does the best with the surgery.

Contraindications
Though less often encountered in the morbidly obese patient, we consider a strict vegan lifestyle to be a contraindication to the performance of a DS. Patients must be willing to eat a significantly high proportion of their calories in the form of protein of high biological value to avoid hypoproteinemia. The number and quality (odor) of bowel movements per day increases significantly after the DS procedure, and patients must be in a work/social situation that allows easy access to facilities on a regular basis.
Significant gastroesophageal reflux disease (GERD) is a relative medical contraindication that should lead the surgeon to council the patient toward a RYGB rather than a DS, as gastric bypass achieves the greatest resolution of GERD-like symptoms. Furthermore, if a DS is performed on a patient with GERD and the symptoms persist despite maximal medical therapy, options for operative intervention are limited as the fundus of the stomach has been resected.

Both inflammatory bowel disease (IBD) and severe irritable bowel syndrome (IBS) serve as contraindications to DS. The increased frequency of bowel movements in these patients and the recurring nature of the disease, as well as chronic symptoms of abdominal pain, make restrictive weight loss operations the procedures of choice. Multiple or complicated previous abdominal or pelvic operations may contraindicate DS. Elevating the ileum out of the lower abdomen to the level of the duodenum is difficult and exacerbated by the excess friability and shortening of the mesentery seen with these conditions. Scarred could leave the duodenoileal anastomosis with excess tension and increase the incidence of anastomotic problems.

Technique
An experienced team, including anesthesiologists, scrub technicians, and circulating nurses that work together on a regular basis, leads to optimal outcomes in any complex (laparoscopic) operation. From a technical prospective, the lap DS is significantly more difficult than a lap RYGB. To locate the ileocecal valve and run the bowel for limb length measurements, the patient must be placed in Trendelenburg position. Patients in higher BMI ranges often cannot tolerate this “head down” position for prolonged periods. Handling the bowel gently with graspers and during suturing is critical, as ileum and duodenum are more fragile than stomach and jejunum, and missed perforations or anastomotic breakdown due to excessive trauma can be fatal. Fashioning the duodenoileal anastomosis requires advanced laparoscopic skills, for both EEA-stapled and hand-sewn techniques. Operative times should not exceed 3.5 to 4 hours, as respiratory complications, deep vein thrombosis, and rhabdomyolysis may develop. In prolonged cases, aborting and opting for a staged procedure may prove judicious.

Following the sleeve gastrectomy, the duodenum is divided 2 to 3cm distal to the pylorus. The duodenal dissection may be difficult, especially in patients with severe android adipose distributions and especially in patients with a prior (open) cholecystectomy. A 21 EEA anvil is introduced into the abdomen and then into the duodenum with a purse-string suture. In most of our patients, the ileum is marked at 100cm from the ileocecal valve and the bowel is divided at 250cm in order to set up a 150cm Roux (food) limb and a 100cm common channel. The right side of omentum is mobilized off the hepatic flexure. We then intubate the bowel destined to become Roux limb with the EEA stapler and rotate it up into the right upper abdomen in an antecolic fashion, avoiding torsion of the mesentery to perform the anastomosis. Methylene blue or endoscopy are used to rule out leak. The ileoileostomy is formed using a linear stapler. Care in closing the residual enterotomy should focus on avoiding reducing the lumen, as the ileum is narrower caliber than jejunum. All mesenteric defects are closed. We perform a cholecystectomy only in the presence of symptomatic cholelithiasis, as the incidence of cholecystitis is low after LDS.[18]

Techniques that might simplify the duodenoileal anastomosis in order to make the procedure less complex have been utilized. The robot has been employed to improve dexterity and control in performing this difficult anastomosis. Average case lengths of over 8.5 hours have been reported with an eight-percent leak rate. Patients that are ASA III at baseline and carry a risk of rhabdomyolysis and deep venous thrombosis because of their increased size need to be taken off the operating room table expeditiously.[19] At this point use of the robot does not seem warranted.

The duodenoileal anastomosis is particularly difficult because of the fixed retroperitoneal position of the duodenum. Effort is often made to minimize dissection around the pylorus for fear of disturbing blood supply and compromising the anastomosis. This prevents full mobilization of the distal stomach and proximal duodenum, a maneuver that may decrease anastomotic tension and improve exposure. Studies by Marchesini clearly demonstrate a robust submucosal network of vessels that prevent ischemia of the pyloric region or proximal duodenum, even in the face of only left gastric perfusion. Marchesini has reported on his personal series of 500 cases of DS over nine years. He suggests division of the right gastric so that the duodenal bulb can be more fully mobilized to limit tension. He reported no duodenoileal anastomotic leaks over nine years.[20]

Patients are not routinely admitted to an intensive care unit or step-down setting. Any hemodynamic instability, tachycardia, low urine output, or unexpected excess of abdominal pain prompts a thorough evaluation by the attending surgeon. There should be a low threshold for returning to the operating room for diagnostic laparoscopy to rule out staple line leak or hemorrhage. On the first postoperative day, the patients undergo an upper gastrointestinal water-soluble contrast study to assess the anatomy and rule out any staple line leaks. If this study is normal, the patients are advanced to clears. In our experience, postoperative ileus is more common in DS patients than RYGB patients, possibly due to the manipulation of the ileum. We therefore usually hold patients’ discharges until a return of bowel function (flatus). The patients are instructed to return to the office at four weeks and to call the office should signs of any complications begin to develop. Appointments are scheduled at three-month intervals during the first postoperative year, and yearly after that.

Routine blood work and ongoing nutrition follow-up is critical. We routinely schedule DS patients to see the nutritionist at the same interval as the surgical visits. Patients are seen at one month, three months, six months, one year, and then semi-annually (6 months). Abnormal labs or symptoms will prompt an earlier visit. Nutritional counseling in the postoperative period reinforces the importance of regular lab work and supplements. Patients are screened for signs and symptoms of vitamin and mineral deficiency (e.g. changes of skin, hair, nails, energy level). Conservative measures to combat diarrhea and gas are discussed, and the importance of getting adequate protein is stressed. Our lab regimen follows the “Suggested Biochemical Monitoring Tools for Nutrition Status.”[21] It involves monitoring of serum albumin, serum total protein, plasma retinol (vitamin A), serum vitamin B12, RBC folate, PT (vitamin K screen), plasma zinc, vitamin D, and PTH levels. We include copper/ceruloplasmin levels as well.

Results and outcomes
All bariatric surgery requires some compromise; the DS involves a more dramatic anatomical rearrangement and difficulty in reversal for greater weight loss and independence from implantable devices that require adjustment and may have mechanical failure. DS—open or laparoscopic—will achieve a durable weight loss on most patients with obesity. In the Buchwald meta-analysis, a review of studies published between 1990 and 2003, it was concluded that BPD/DS resulted in more weight loss, and greater improvement in diabetes, hyperlipidemia, hypercholesterolemia, hypertriglyceridemia, and obstructive sleep apnea syndrome (OSAS) than any other type of bariatric procedure.[5] The benchmark for a successful bariatric operation is the durable loss of greater than 50 percent of excess body weight. The DS is an effective weight loss operation in 95 percent of patients with a BMI <50kg/m2, and for the super-obese it achieves a success rate of 70 percent.[22,23,11]

DS is also the most effective procedure currently available for comorbidity resolution. Cure rates for type 2 diabetes approach 90 to 98 percent following DS.[9,24] DS achieves cure rates for hypertension that exceed 50 percent, and in some studies approach 80 percent.[25]

Resolution of OSAS occurs in up to 98 percent of patients after DS.[26] All of these results are superior to outcomes seen after AGB and RYGB.[5,27,28]

Complications of the DS
All bariatric operations carry the risk of long-term or late complications that are unique to the procedure. For the RYGB, the most common complications are marginal ulcer and late weight regain. For the AGB, they are slippage, erosion, pouch/esophageal dilation, or port complications. For the LSG, as a stand-alone procedure, they are new-onset gastroesophageal reflux disease (GERD) or stenosis. Inherent to the DS are the complication risks of the LSG, as it is constitutes the restrictive part of the procedure. The malabsorptive component, with bypass of up to two-thirds of the small bowel, brings other complications classically associated with the DS. These relate to bowel habits, namely diarrhea, frequent foul-smelling stools, and flatulence, and complications of malnutrition such as hypoproteinemia and vitamin/mineral deficiencies. These complications, especially in those who develop debilitating malnutrition, can be devastating. Before performing a DS, a clear incidence of these complications must be known and the ability to treat them with non-surgical interventions must be evaluated when making the ultimate decision about performing this operation.

A review of the complications following DS should first begin with the complications it avoids. Comparing it to the other procedures that rely on a gastrojejunal anastomosis to achieve some degree of bypass and nutrient delivery to the distal small bowel (BPD and RYGB), the DS lessens the complications of dumping syndrome, marginal ulceration, and vagus nerve transaction during pouch formation.[29] Reviewing their series of over 700 open DS cases during a 10-year period, Hamoui et al found that five percent of their patients (33/701) needed reversal of their DS. Malnutrition, noted in 20/33 patients, followed by chronic diarrhea, was the most commonly given reason for reversal. The development of these complications is variable and not necessarily correlated to the degree of small intestinal bypass. Patients who required reversal and cited diarrhea as a motivating factor had up to five bowel movements per day, but in a cohort study comparing DS to RYGB, the average number of bowel movements for the DS group was 1.68 per day. This did not reach a statistically significant difference from the 1.18 bowel movements per day seen in the RYGB group.[30] For those with intractable diarrhea necessitating revision, Hamoui was able to decrease the number of daily bowel movements from 5 to 1. His revision involved performing a proximal “kissing ‘X’” enteroenterostomy in most patients, without repositioning of the original ileoileostomy. Reversal of the DS does not tend to bring full weight regain, as patients still maintain some restriction due to the sleeve gastrectomy. A return of glucose intolerance or complete re-emergence of diabetes following DS reversal is not guaranteed. In the aforementioned series, 7 out of 10 patients (70%) maintained their diabetes remission after proximal enteroenterostomy for reversal.[31]

Following DS, vitamin and mineral deficiencies and severe protein/calorie malnutrition can happen in the face of normal meal consumption.[32] Fat-soluble vitamin deficiencies make strict adherence to daily supplementation a necessity. Vitamin A deficiencies can present as difficulty with night vision. Serum calcium levels are low, secondary to binding with intraluminal fats. This sets the stage for oxalate absorption and may increase the incidence of nephrolithiasis. Hypocalcemia paired with vitamin D deficiencies can cause osteopenia and osteoporosis. Preventing iron deficiency anemia at times requires the prescription of oral iron preparations, or in some cases where this is poorly tolerated or ineffective, intravenous iron infusions.[33]

A rare complication that develops outside the first month postoperatively can be stricture of the sleeve gastrectomy. It usually occurs at the angularis incisura and is most often managed by endoscopic balloon dilation. Long-segment stenosis of the sleeve develops in less than one percent of patients, and is less amenable to balloon dilation. Dupri, Cadiere, and Himpens employ a laparoscopic seromyotomy of the stenotic segment akin to a Heller myotomy of the esophagus. This serves to restore passage of enteral contents and avoids a complicated gastric resection with additional Roux limb drainage.[34] Wound complications, hernias, abdominal pain, and length of stay are all decreased when the laparoscopic approach to the DS is employed.[35]

Revisional surgery and DS
Revisional surgery after DS can be for inadequate weight loss or development of late complications. In the event of inadequate weight loss following LDS, a re-sleeve gastrectomy can be attempted.[36] Another option is to place a band over the sleeve gastrectomy to augment restriction.[37] In revisions necessitated by excessive weight loss or intractable diarrhea, vitamin deficiency, or protein malnutrition, one option is to transect and relocate the alimentary limb proximally on the BP limb.[36] An alternate technique for reversal is an enteroenterostomy proximal to the junction of the alimentary limb and the BP limb. This will facilitate earlier upstream mixing of the limb contents.[31]

Conclusion
The duodenal switch evolved, in part, from a procedure to prevent reflux of bile into the stomach and esophagus, into an operation to achieve massive weight loss. The application of laparoscopic techniques to the DS improved wound-related morbidity and recovery. Duodenal switch remains a powerful tool to lose weight, but the operation requires an intelligent patient who will be compliant with post-operative care and has the financial resources that will allow him or her to purchase the appropriate supplements to prevent the serious metabolic consequences of deficiencies. The duodenojejunal bypass (DJB) with sleeve gastrectomy, basically a short-limb DS, is now being performed laparoscopically in nonobese patient with diabetes with early, encouraging results.[39] Larger series of metabolic surgery on low-BMI patients with diabetes are eagerly anticipated.

References
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3.    DeMeester TR, Fuchs KH, Ball CS, et al. Experimental and clinical results with proximal end-to-end duodenojejunostomy for pathologic duodenogastric reflux. Ann Surg. 1987;206:414–426.
4.    Marceau P, Biron S, Bourque RA, et al. Biliopancreatic diversion with a new type of gastrectomy. Obes Surg. 1993;3:29–35.
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9.    Hess DS. Limb measurement in duodenal switch. Obes Surg. 2003;966.
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11.    Prachard VN, Davee RT, Alverdy JC. Duodenal switch provides superior weight loss in the superobese (BMI>50kg/m2) compared with gastric bypass patients. Ann Surg. 2006;244:611–619.
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13.    Buchwald H, Kellogg TA, Leslie DB, Ikramuddin S. Duodenal switch operative mortality and morbidity are not impacted by body mass index. Ann Surg. 2008;248(4):541–548.
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16.    Weiner RA, Blanco-Engert R, Weiner S, et al. Laparoscopic biliopancreatic diversion with duodenal switch: Three different duodeno-ileal anastomotic techniques and initial experience. Obes Surg. 2004;14:334–340.
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21.    Allied Health Sciences Section Ad Hoc Nutrition Committee. Aills L, Blankenship J, Buffington C, et al. ASMBS Allied Health Nutritional Guidelines for the Surgical Weight Loss Patient. Surg Obes Relat Dis. 2008;4(5):S73–108.
22.    Anthone GJ. The duodenal switch operation for morbid obesity. Surg Clin North Am. 2005;85:819–833.
23.    Anthone GJ, Lord RV, DeMeester TR, Crookes PF. The duodenal switch operation for the treatment of morbid obesity. Ann Surg. 2003;238:618–627.
24.    Marinari GM, Papadia FS, Briatore L, et al. Type 2 diabetes and weight loss following biliopancreatic diversion for obesity. Obes Surg. 2006;16:1440–1444.
25.    Adami G, Murelli F, Carlini F, et al. Long-term effect of biliopancreatic diversion on blood pressure in hypertensive obese patients. Am J Hypertens. 2005;18:780–784.
26.    Simard B, Turcotte H, Marceau P, et al. Asthma and sleep apnea in patients with morbid obesity: outcome after bariatric surgery. Obes Surg. 2004;14:1381–1388
27.    Dolan K, Hatzifotis M, Newbury L, Fielding G. A comparison of laparoscopic adjustable gastric banding and biliopancreatic diversion in superobesity. Obes Surg. 2004;14:165–169.
28.    O’Brien PE, McPhail T, Chaston TB, Dixon JB. Systemic review of medium-term weight loss after bariatric operations. Obes Surg. 2006;16:1032–1040.
29.    Marceau P, Hould FS, Simard S, et al. Biliopancreatic diversion with duodenal switch. World J Surg. 1998;22:947–954.
30.    Wasserberg N, Hamoui N, Petrone P, et al. Bowel habits after gastric bypass versus the duodenal switch operation. Obes Surg. 2008;18:1563–1566.
31.    Hamoui N, Chock B, Anthone GJ, Crookes PF. Revisions of the duodenal switch: Indications, Technique, and Outcomes. J Am Coll Surg. 2007;204(4):603-608.
32.    Faintuch J, Matsuda M, Cruz ME, et al. Severe protein-calorie malnutrition after bariatric procedures. Obes Surg. 2004;14:175–181.
33.    Farrell TM, Haggerty SP, Overby DW, et al. Clinical application of laparoscopic bariatric surgery: an evidence-based review. Surg Endosc. 2009 Jan 6 (Published online).
34.    Dapri G, Cadiere GB, Himpens J. Laparoscopic seromyotomy for long stenosis after sleeve gastrectomy with or without duodenal switch. Obes Surg. 2009;19 (Published online).
35.    Gagner M, Matteotti R. Laparoscopic biliopancreatic diversion with duodenal switch. Surg Clin North Am. 2005;85:141–149.
36.    Gagner M, Rogula T. Laparoscopic reoperative sleeve gastrectomy for poor weight loss after biliopancreatic diversion with duodenal switch. Obes Surg. 2003;13:649–654.
37.    Jacob BP, Greenstein AJ. Placement of a laparoscopic adjustable gastric band after failed sleeve gastrectomy. Surg Obes Relat Dis. 2008;4(4):556–558
38.    Almahmeed T, Pomp A, Gagner M. Laparoscopic reversal of biliopancreatic diversion with duodenal switch. Surg Obes Rel Dis. 2006;2:468–471.
39.    Cohen RV, Schiavon CA, Pinheiro JS, et al. Duodenal-jejunal bypass for the treatment of type 2 diabetes in patients with body mass index of 22–34kg/m2: a report of 2 cases. Surg Obes Relat Dis. 2007;3(2):195–197.

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