Duodenal Switch

The Duodenal Switch procedure (also called vertical gastrectomy with duodenal switch, biliopancreatic diversion with duodenal switch, gastric reduction duodenal switch, DS, BPD-DS, or GR-DS) is an operation that is performed by only a minority of bariatric surgeons. The Duodenal Switch surgery generates weight loss by restricting the amount of food that can be eaten through a reduction in stomach size, by limiting the amount of food that is absorbed into the body through a re-routing of the intestines, and by a metabolic effect induced by manipulating intestinal hormones as a result of intestinal re-routing. It is a more involved procedure because it has a significant component of malabsorption and metabolic effect - achieved by the intestinal bypass effect of the duodenal switch component of the operation - which acts to augment and maintain long-term weight loss. The overall effect is that patients are able to engage in fairly normal, free eating, while having the benefit of taking on the metabolism of a lean individual.

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Duodenal Switch: How it works:

Restriction (Vertical/Sleeve Gastrectomy): The stomach is restricted in size removing the vast majority of its volume. This is done by cutting away the left-hand side of the stomach in an up-and-down fashion. This reduces the stomach down from a 1-2 quart bag to a long skinny tube. This part of the procedure is not reversible; once this part of the stomach is removed from the body, it is gone forever. The stomach that remains measures from 3 to 4 oz. (90-120cc) in size. There are other aspects of how this portion of the Duodenal Switch procedure works to create restriction, which can be found in the description of the Vertical/Sleeve Gastrectomy procedure. The amount of restriction that patients experience changes with time. This is a process known as pouch maturation, and it is a process that is, for the most part, complete at 9-12 months after surgery. The stomach seems very small immediately after surgery - which helps to jump start weight loss - and stretches out to the point that patients report being able to eat only one-half to two-thirds the amount of food that they were able to eat prior to surgery. Since the stomach basically functions like a normal stomach, but only significantly smaller, patients are able to eat a wide variety of normal foods. With this configuration, it has been my observation that patients are able to follow the diet that has the best of all possible circumstances: they are able to control their intake while, at the same time, limit their intake to the healthiest of foods. Unlike Gastric Bypass, patients with this procedure are generally able to eat beef, steak, pork, stew meat, and other dense proteins without difficulty. These sources of protein are among the healthiest of protein sources, and this anatomic configuration allows patients the freedom to engage in the healthiest of eating habits. I say "allows", for with freedom comes responsibility, and the freedom to engage in free-eating needs to be accompanied by a devotion to eat in the healthiest way that our bodies allow. In essence, one has the ability to have dietary restriction in a way that allows for healthy eating in a way that they can realistically live with long-term.

Malabsorption (Duodenal Switch, Common Limb Effect): The intestines are divided and rearranged to separate food from the digestive juices, therefore creating malabsorption. The part of intestine that carries food - the food or alimentary limb - is attached to the duodenum and receives food from the stomach. The food limb is less than half the length of the total amount of intestine in the body, and consists of the downstream part of the intestine. This part of the intestine reacts differently to food than the upstream part of the intestine, which is bypassed. The bypassed part of the intestine carries digestive juices from the liver and the pancreas, but no food. This bypassed part of the intestine - which consists of over half of the length of the total intestines - joins up with the food limb for only the last 75-100cm (about 3 feet) of intestine known as the common limb. This common limb is the only part of the body that is capable of absorbing complex carbohydrates, starches, and fats. Since the patient's body is absorbing nutrients over only 40% or so of the total intestinal length, the patient's body works to be as efficient as possible in absorbing nutrients. As efficient as the human body can be, however, there is only so many calories that can be absorbed through a 75-100cm length of intestine. The excess of ingested fats and starches - which cannot be absorbed - are excreted from the body and passed in the stool. With appropriate eating, most patients have anywhere from 2-4 bowel movements per day. With increased intake of indigestible starches and fats, patients can have may more bowel movements per day.

Metabolic Effect: In addition to the effect of dietary restriction and malabsorption, Duodenal Switch has a metabolic effect to affect weight loss and improvement in health as well. The portion that food passes through - the alimentary limb - has the ability to absorb protein and sugars. This portion of intestine also has the ability to secrete a hormone - GLP-1, or Enteroglucagon - in the presence of undigested food. Since this portion of intestine is presented to undigested food earlier on as a result of the anatomic re-arrangement induced by Duodenal Switch, secretion of GLP-1 is enhanced. Enteroglucogan (GLP-1) has the effect of suppressing the secretion of insulin in response to a carbohydrate meal, resulting in a lesser amount of ingested carbohydrates being converted to body fat.

The portion of intestine that is bypassed holds an important role as well. Enterogastrone is a hormone that is secreted by the upstream small intestine when food passes through it. This hormone has the effect of converting food to fat. When the upstream portion of the intestine is bypassed - as is the case with Duodenal Switch - enterogastrone secretion is suppressed. The effect of this bypass is that the patient's body after Duodenal Switch has less of a tendency to convert food to fat.

Duodenal Switch: Balancing Freedom and Responsibility

A simplified way to explain the sum of these metabolic effects is that the patient after Duodenal Switch takes on the metabolism of a lean individual. We all know people who are able to eat large amounts of food, and yet are able to maintain a lean physique. These people have a metabolism that tolerates a sizeable caloric intake without resulting in obesity, yet their bodies are able to maintain normal protein levels and keep from becoming malnourished. Patients undergoing Duodenal Switch are able, for the most part, to eat normal amounts of food, but they must eat healthy foods if they are to keep from becoming malnourished. Duodenal Switch patients can't eat junk food all day and expect to remain healthy; with the freedom they have in eating freely, they must exercise responsibility in order to keep from becoming malnourished. Most patients after Duodenal Switch take in anywhere from 80 to 100grams of protein in their diet each day in order to remain healthy. You can't get this level of high quality of protein eating junk all day, but if one chooses to after Duodenal Switch, they can, due to the relatively ability to eat freely.

How Do We Decide How Long To Make Each Intestinal Limb?

Deciding how much intestine to bypass, how much to carry food, and how much to allow for mixing of food and digestive juices, is a process that has evolved with our understanding of how the Duodenal Switch procedure works. Most surgeons typically make the food limb 150cm, and the remainder of the intestine - however long it may be - to carry the digestive juices. While this "one size fits all" approach works well for most patients, it is possible to customize the limb lengths to fit the characteristics of the individual patient. We have had good results using "proportional limb lengths" in Duodenal Switch procedures. The entire intestinal length is measured at the time of surgery, and the lengths of the individual intestinal limbs determines based on this total length. Within certain parameters, the total food and common limb length - added together - is roughly 40% of the total intestinal length. The remaining 60% of intestine carries the digestive juices. The common limb by itself is roughly 10% of the total intestinal length. The rationale for using proportional limb lengths is to maximize weight loss while at the same time minimizing protein-calorie malnutrition and other malabsorptive complications. Minor variations to these limb lengths can be made based on other individual characteristics of the patient.

Duodenal Switch: Risks and Complications

As a general rule, the greater the magnitude of the surgery, and the less healthy the patient, the higher the risk of surgery. In the spectrum of weight-loss operations, Duodenal Switch is the most aggressive, and, therefore, has the highest potential for complications. These potential complications include leaks, blood clots forming in the legs, blood clots traveling to the lungs (otherwise known as pulmonary embolus), infections, abscesses, bowel obstruction, pneumonia, and problems with healing of the incision. Other possible complications include kidney failure, injury to the spleen (requiring its removal at the time of surgery), and bleeding. Some patients may need to spend extra time in the ICU as a result of these complications, or if their underlying health is marginal to begin with.

Some complications are more long term, and are not manifest until some time after surgery. These are nutritional and vitamin deficiencies, which may be for the most part preventable with proper supplementation. Deficiencies in protein, vitamin-D, vitamin-A, iron, and calcium can occur, resulting in osteoporosis, anemia, and generalized poor health. Patients undergoing Duodenal Switch should be vigilant in taking their vitamin and mineral supplements, eating a high-protein diet, and having their blood tested on an annual basis.

Duodenal Switch: Revision Considerations

Duodenal Switch is a procedure that can be either the source of - or the solution to - a revision procedure. Some Duodenal Switch patients may need to undergo revision of their procedure for inadequate weight loss, although this likelihood is small. Some patients have the opposing problems of excessive weight loss, malnutrition, or vitamin deficiency. The likelihood of requiring a revision of a Duodenal Switch procedure is small, less than five percent. For patients with inadequate weight loss, further reduction of stomach size may yield benefit, as well as shortening of the common limb. For patients with excessive weight loss and deficiencies, surgically lengthening the common limb and the food limb offer a good solution, effectively partially reversing the procedure. How much intestinal elongation to add, and the timing of performing such a procedure, are determined on an individual basis. These revision procedures are much smaller procedures than the original Duodenal Switch surgery.

Patients with other failed or complicated weight loss operations may benefit from revision/conversion to Duodenal Switch. LapBand patients with inadequate weight loss or other complications can be revised to Duodenal Switch, as well as patients with gastroplasties. Patients with Vertical/Sleeve Gastrectomy can be fairly straightforwardly converted to Duodenal Switch, as Vertical/Sleeve Gastrectomy is one component of Duodenal Switch already. Gastric Patients may require revision to Duodenal Switch not only for inadequate weight loss, but for severe dumping syndrome and marginal ulcers as well.

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For a comparison of the procedures our surgeons offer click here. Please note VERGITO and Vertical/Sleeve Gastrectomy will be added to chart soon.