The Duodenal Switch weight loss surgery procedure is performed by only a minority of bariatric surgeons. Duodenal Switch is a more involved weight loss surgery procedure do to the significant malabsorptive and metabolic components. This is accomplished with the intestinal bypass effect of the Duodenal Switch. As a result, Duodenal Switch patients are able to engage in relatively normal and free eating while also adopting a metabolism similar to that of a lean individual.
For reference, Duodenal Switch is also referred to as vertical gastrectomy with duodenal switch, biliopancreatic diversion with duodenal switch, gastric reduction duodenal switch, DS, BPD-DS, or GR-DS.
Duodenal Switch - How It Works
The Duodenal Switch causes weight loss via the following mechanisms:
Restriction (Vertical/Sleeve Gastrectomy): The majority of a patient?s stomach volume is removed by cutting away the left-hand side of the stomach in an up-and-down fashion. As a result, stomach size is reduced down from a 1-2 quart bag, to a long slender tube. This portion of the Duodenal Switch is not reversible and the remaining stomach measures approximately 3-4 oz or 90-1200cc in size. Since the Vertical Sleeve Gastrectomy makes up this portion of the Duodenal Switch, a further explanation of the restrictive aspects of the Vertical Sleeve Gastrectomy can be found in the Vertical Sleeve Gastrectomy Forum.
The amount of restriction that Duodenal Switch patients experience changes over time. This process is known as pouch maturation and is generally complete 9-12 after Duodenal Switch. Initially, a patients stomach seems very small after Duodenal Switch which helps to ?jump start? weight loss. The stomach gradually stretches out to the point where patients are generally able to eat only 1/2 - 2/3 of the amount of food they were able to eat prior to Duodenal Switch. The stomach of a Duodenal Switch patient is significantly smaller than it is prior to weight loss surgery but essentially functions the same as a normal stomach. This allows Duodenal Switch patients to eat a wide variety of foods. With this configuration, Duodenal Switch patients are generally capable of following a diet with the best of all possible circumstances. Duodenal Switch patients are able to control their food intake while simultaneously limiting their intake to the healthiest foods. Unlike Gastric Bypass patients, Duodenal Switch patients are normally able eat dense protein such as beef, steak, pork and stew meat without difficulty. These protein sources are some of the healthiest protein sources and the anatomic configuration of the Duodenal Switch allows patients to employ the healthiest eating habits. While this freedom is certainly desirable, freedom does come with responsibility. With the ability to eat freely, Duodenal Switch patients must be devoted to eating the healthiest way their bodies will allow.
Malabsorption (Duodenal Switch, Common Limb Effect): Malabsorption is created by dividing and rearranging the intestines in order to separate food from digestive juices. The alimentary limb, or the portion of the intestine that carries food, is attached to the duodenum and receives food from the stomach. Less than half of the total length of the bodies intestines are comprised of the food limb, which consists of the downstream portion of the intestine. The food limb reacts differently to food than the upstream part of the intestine, which is bypassed. The bypassed portion of the intestine is not responsible for carrying food; rather, it is responsible for carrying digestive juices from the liver and the pancreas. Making up more than half of total intestinal length, the bypassed portion of intestine joins the food limb at the final 75-100 cm of intestine known as the common limb. The common limb is the only portion of the intestines that is capable of absorbing fats, starches and complex carbohydrates. Since the body of a Duodenal Switch patient is absorbing nutrients through less than half of the total intestinal length, the body works to absorb nutrients efficiently.
While the human body can be extremely efficient, the body can only absorb so many calories through 75-100 cm of intestine. Excess fats and starches ingested get excreted from the body in stool. Duodenal Switch patients average 2-4 bowel movements a day with proper eating but indigestible starches and fats may cause patients to experience more bowel movements each day.
Metabolic Effect: In addition to the restrictive and malabsorptive nature of Duodenal Switch, it also has a positive impact on weight loss and health via metabolic mechanisms. The alimentary limb absorbs proteins and sugars from ingested food, but also secretes the hormone GLP-1 or Enteroglucagon in the presence of undigested food. Duodenal Switch rearranges this portion of the intestine which causes food to be introduced into the alimentary limb earlier and ultimately enhances GLP-1 secretion. When carbohydrate is consumed, the body secretes insulin in response. On the other hand, Enteroglucagon (GLP-1) suppresses this insulin response when carbohydrate is ingested, which in turn reduces the amount of carbohydrate that is converted to and stored as fat.
The bypassed portion of the intestine plays a pivotal role as well. Enterogastrone, not to be confused with GLP-1 or Enteroglucagon, is a hormone secreted by the upstream small intestine when food passes through it. Enterogastrone has the effect of converting ingested food to fat. Since the upstream portion of the intestine is bypassed during Duodenal Switch, the secretion of Enterogastrone is suppressed. As you can imagine, this reduces the body?s tendency to convert food to fat.
Intestinal Limb Lengths With Duodenal Switch
As our understanding of the Duodenal Switch, so does our knowledge of how much intestine to bypass, how much to carry food, and how much to allow for the mixing of food and digestive juices. Typically, most bariatric surgeons will make the food limb 150 cm in length and allow the remaining intestine, whatever the length, to carry digestive juices. The mixing of digestive juices and food takes place in the common limb and is generally measured out to 100 cm. This combination represents the most common configuration for Duodenal Switch; that is a total alimentary limb of 250 cm in length consisting of a 100cm common limb and an additional 150cm of intestine attached to a cuff of duodenum just downstream from the pylorus.
With this said, customization of intestinal lengths can be made based upon the Duodenal Switch patient?s total small intestinal length and/or based upon other specific characteristics of a patient. Similar to any other surgical operation, the primary goal is to maximize the benefit while minimizing risk. In Duodenal Switch, this means maximizing weight loss while minimizing malnutrition. The choice of intestinal limb lengths ultimately seeks to reach a balance between these two competing needs.
This information has been provided by Dr. John Husted. To learn more about Dr. Husted, please visit http://www.johnhustedmd.com/.