The Duodenal Switch procedure (also called vertical gastrectomy with duodenal switch, biliopancreatic diversion with duodenal switch, DS or BPD-DS) is performed by approximately 50 surgeons worldwide. It generates weight loss by restricting the amount of food that can be eaten (removal of stomach or vertical gastrectomy) and by limiting the amount of food that is absorbed into the body (intestinal bypass or duodenal switch).

It is more controversial because it has a significant component of malabsorption (bypass of the intestinal tract), which seems to augment and help maintain long-term weight loss. Of the procedures that are currently performed for the treatment of obesity, it seems to be the most powerful and effective, but may also have more complications associated with it. Because of this, some insurance companies will not authorize it and consider it investigational. Most surgeons do not perform this procedure because of concerns about the long term effects of malabsorption.

Restriction (Vertical Gastrectomy): The stomach is restricted by dividing it vertically and removing more than 85% of it. This part of the procedure is not reversible. The stomach that remains is shaped like a banana and measures from 4-7 ounces (120-250cc) depending on the surgeon performing the procedure. The nerves to the stomach and the outlet valve (pylorus) remain intact with the idea of preserving the functions of the stomach while reduing the volume.

By comparison, in a Roux-en-Y gastric bypass, the stomach is divided, not removed, and the pylorus is excluded. The Roux-en-Y gastric bypass stomach can be reconnected(reversed) if necessary.

Duodenal Switch: What is Malabsorption?

Malabsorption (Duodenal Switch):

The intestines are divided and rearranged to separate food from the digestive juices, thereby creating malabsorption. The food limb is attached to the duodenum and receives food from the stomach. This limb is 150 cm long. The digestive juices are now separated from the food and travel for over 500 cm in the bypassed small intestine. Both food and digestive juices mix together and travel together for 100 cm in the common limb. Thus, food and digestive juices are separated for most of the length of the intestines. This prevents you from absorbing all of the calories that you eat. By comparison, the intestinal bypass in a Roux-en-Y gastric bypass is much less extensive, and the common limb for digestive juices and food to mix is approximately 5 times longer. Therefore, the Roux-en-Y gastric bypass has minimal malabsorption compared to the Duodenal Switch procedure.

The Advantages of the Duodenal Switch Weight Loss Surgery Procedure

The more normal stomach allows for better eating quality but may possibly result in more diarrhea and foul smelling bowel movements and gas

No dumping syndrome because the pylorus is preserved

Minimizes the chance of an ulcer occurring

Very effective for high BMI patients (BMI>55 kg/m2)

The intestinal bypass is partially reversible for those having malabsorptive complications

Laparoscopic approach is offered by some surgeons

The Disadvantages of the Duodenal Switch Weight Loss Surgery Procedure

Greater chance of chronic diarrhea

Significant malabsorption leads to anemia, protein deficiency and metabolic bone disease in up to 5% of patients

More foul smelling stools and gas

Carbohydrates can be well absorbed and lead to inadequate weight loss

This procedure is the most complex surgical weight loss procedure and may yield an unacceptable level of complications in high risk patients(heart failure, sleep apnea)

Duodenal Switch: Risks and Complications

As with any surgery, there can be complications. This list can include:

Deep vein thrombophlebitis 0.7%

Non-fatal pulmonary embolus 0.5%

Pneumonia 0.5%

Acute respiratory distress syndrome 0.25%

Splenectomy 0.9%

Gastric leak and fistula 2.0%

Duodenal leak 1.5%

Distal Roux-en-Y leak 0.25%

Postoperative bleeding 0.5%

Duodenal stomal obstruction 0.75%

Small bowel obstruction 2.0%

Death 1.0%