Duodenal switch surgery, known also as Biliopancreatic Diversion with Duodenal Switch (BPD/DS) and SADI-S, are both a malabsorptive and restrictive approach to weight loss surgery. It is known for its greater weight loss surgery than other surgeries. It is the most complications of all bariatric surgery options, leading to a higher risk of nutritional deficiencies.

Stage 1 – Restrictive

In Stage 1 or Restrictive, nearly 70% of the stomach is removed (also known as a vertical sleeve gastrectomy). The remaining portion of the stomach fully functions and is a banana shape and about 3-5 ounces in size (which will restrict the amount of food consumed). The pylorus valve will continue to control the stomach’s emptying process into the small intestine. Because of this, patients do not experience dumping syndrome like many other weight loss surgery patients.

The upper portion of the duodenum is useful which helps food digest into a good consistency before going to the small intestine. This allows the body to better absorb nutrients and vitamins such as Calcium, Iron, and Protein when compared to gastric bypass surgery patients.

Many surgeons believe that removing a portion of the stomach significantly reduces the amount of ghrelin-producing tissue and acid in the stomach. Ghrelin is well known as the hunger hormone and reducing the amount of the hormone in the body helps to reduce a patient’s appetite, leading to greater weight loss.

Over time the stomach will stretch, nearly 9-12 months post-op the stomach will double in size and many patients will be able to consume about 60% of what they occur before surgery occurred. The restrictive part of the Duodenal Switch procedure is not reversible.

Stage 2 – Malabsorptive

The intestines are switched so food from the stomach and to the digestive juices travel on different paths and never mix until they meet at the end of the small intestine. The alimentary limb is responsible for carrying the food while the biliopancreatic limb carries bile and other digestive liquids.

The common channel or limb meets in the small intestine where they move to the large intestine. This is where the patient’s food, bile and digestive liquids mix and where nutrients are absorbed into the body. Since the common channel makes up such a small section of the small intestine, fats, scratches and complex carbohydrates are never fully absorbed, leading to weight loss.

Because of the malabsorption of the fats, many fat-soluble vitamins such as A, D, E & K become low in the body leading to deficiencies. All Duodenal Switch patients are required to take regular vitamin and mineral supplements for their lifetime. The intestinal switch portion of Duodenal switch surgery is fully reversible.

Hess Method

Many surgeons will change the common channel length. They calculate this by taking the length of the alimentary limb and multiplying is by the small bowl length by 40%. The remaining 60% will carry the digestive juices through the biliopancreatic limb. The Hess Method is best known for determining limb lengths and common channel length, while thinking of the patient’s BMI, overall weight loss goals, age, and weight. Not all surgeons use this method, but some do to achieve the best results for each patient.

Appendix/Gallbladder Removal

Many surgeons also suggest an appendix or gallbladder removal during the procedure. Some surgeons even require the gallbladder to be removed because of the 30% chance of developing gallstones after surgery and rapid weight loss. The appendix may be removed so that there is no future confusion regarding stomach issues and symptoms and whether they are a result of surgery or appendicitis.

Related:

Duodenal Switch Compared to Gastric Bypass