In recent years, we have heard more about a new bariatric procedure called the SADI-S (single anastomosis duodeno–ileal bypass with sleeve gastrectomy), replacing the traditional duodenal switch (biliopancreatic diversion with duodenal switch). Both bariatric procedures are excellent options to help patients lose an extreme amount of weight. In this blog, we will specifically talk about the differences between the DS and the SADI-S. 

The Classic Duodenal Switch

The duodenal switch, formally known as the biliopancreatic diversion with duodenal switch, is the second oldest current bariatric procedure after the gastric bypass. The duodenal switch was first developed around the 1990s. The DS was an operation similar to the sleeve gastrectomy but added an intestinal bypass, like the gastric bypass, for even more aggressive weight loss. 

The duodenal switch operation will remove about 75 to 85% of the stomach and shorten the small intestines by about 75%, almost always resulting in 100% excess weight loss. The duodenal switch combines the weight loss achieved from the gastric sleeve's metabolic kick and the restrive component of this operation while bypassing most of the intestines, so less absorption takes place. 

When food travels through the new anatomy, it will empty into the second half of the intestines, while the other portion of the intestines carries digestive enzymes to help absorb dietary fat. The overall effect results in significant weight loss and the reduction in the body's ability to absorb dietary fats and other fat-soluble vitamins such as vitamins A, D, E, and K. 

Most bariatric surgeons reserve the duodenal switch for patients who have a BMI of 55 or greater due to how aggressive the weight loss is. Like every operation, there are risks to this procedure. Risks of the duodenal switch include nutritional deficiencies, acid reflux, change in bowel habits, or more severe complications such as hernias, blood clots, or intestinal leaks. 

Yet, despite these risks of surgery, there is also a risk of living with obesity, including the development of health complications and early mortality. 

The New Duodenal Switch, SADI-S

SADI-S stands for single anastomosis duodeno–ileal bypass with sleeve gastrectomy and is otherwise known as the Loop-DS. This operation is making news as an effective modification of the standard duodenal switch, particularly for patients with pre-existing illnesses or who are older, in which a surgeon may not feel as comfortable doing a classic DS. 

The main difference between the standard duodenal switch and the SADI-S is there is one less connection to the intestines with the SADI-S. We still perform a sleeve gastrectomy to create a narrow tube of a stomach, and we still divide the small bowel right after the stomach. We find the mid-portion of the intestine and connect it to the end of the new stomach. But what we don’t do is reconnect the intestines further downstream. Instead, we leave it as a loop of bowel.

So on one end of the intestines, you have the digestive enzymes coming around, and on the other end, you have the food. The digestive enzymes meet the food as soon as it leaves the stomach and mix with the food the rest of the way down. 

This loop of bowel allows your body to absorb fat-soluble vitamins better, limiting the amount of nutritional deficiencies long term. The SADI-S doesn’t have as significant weight loss as the standard DS, but it still offers better weight loss results than the gastric sleeve or gastric bypass. Also, the SADI-S is more likely to cure and control diabetes than the bypass or sleeve. 

Although the SADI-S is an effective operation, we don’t see it as often because many insurance companies don’t currently cover this procedure, unlike the classic DS, the gastric sleeve, and the gastric bypass. However, we are optimistic that as more SADI-S procedures are done, and the efficacy of this operation is proven, more insurance companies will begin to include this in their bariatric coverage and benefits packages.