It is one of the procedures that has been started to be performed in the 1980s and is still performed today. Just like gastric bypass surgery, the procedure both reduces the size of the stomach and restricts the absorption. Unlike gastric bypass, the reduction of the size of the stomach is less and the absorption-reduction effect is much greater. The indications for the surgery are the same as for all other bariatric surgeries. The difference of duodenal switch surgery from conventional biliopancreatic diversion is that the natural valve, called ‘pylorus’, in the output of the stomach, is preserved.
In duodenal switch (SADI-S) procedure with single anastomosis, the stomach is reduced in the form of a tube. Compared to the conventional sleeve gastrectomy, a larger stomach is prepared. We use a 60-F calibration tube (a tube that is inserted into the stomach and helps to adjust the thickness of the remaining stomach during incising the stomach) in DS surgery while a 32-36-F calibration tube is used in conventional sleeve gastrectomy surgery. The duodenum is then separated 3 cm beyond the stomach output. The point found by counting 2.5-3 meters from the junction of the small and large intestine is anastomosed to the upper part of the previously separated duodenum. In this way, both the stomach becomes smaller and the vast majority of the small intestine is bypassed, considerably reducing the absorption. This method is more effective than other methods in terms of the control of diabetes and permanent weight loss. However, vitamin and mineral deficiencies are more common as they lead to severe malabsorption.