What is Duodenal Switch (SADI-S) Surgery?
How is Duodenal Switch Surgery Performed?
1. Reduction of the Stomach (Sleeve Gastrectomy)
The first stage of the surgery is the removal of most of the stomach. This stage is performed in a similar way to a sleeve gastrectomy. The surgeon removes approximately 70-80% of the stomach, turning it into a tube. When the stomach is narrowed into a tube shape, patients feel full more quickly with less food. During this stage, the stomach capacity is greatly reduced, and since the stomach area responsible for hormone production (the part that secretes the ghrelin hormone) is removed, appetite also decreases.
2. Ligation of the Duodenum
After the stomach is reduced, the first section of the small intestine, the duodenum, is cut. This allows food to partially follow its normal path through the digestive system. The connection between the duodenum and the stomach outlet is preserved, which is why the surgery is called a "duodenal switch."
3. Small Intestine Reorganization
The most important stage of duodenal switch surgery is the reconstruction of the small intestine. The surgeon bypasses, or disables, a portion of the small intestine and allows food to go directly to the lower part of the small intestine. Digestive juices continue to be produced in the bypassed portion of the intestine, and these juices combine with food in the lower part of the intestine. In other words, food passes through a large portion of the small intestine without being digested, which seriously reduces the absorption of nutrients and calories.
4. Connection (Anastomosis)
The final stage of the surgery is the connection of the last section of the small intestine (ileum) to the outlet of the stomach. This connection (anastomosis) allows food to pass quickly through both the restricted stomach and the lower digestive system. This stage is one of the main reasons why the duodenal switch provides greater weight loss and metabolic improvement than other bariatric surgeries.
5. SADI-S Version (Single Connection Duodenal Switch)
SADI-S (Single Anastomosis Duodeno-Ileal Bypass with Sleeve Gastrectomy) or Loop DS, unlike the classic duodenal switch, has fewer intestinal connections. While two separate anastomoses are made in the classic DS, only one connection is made in SADI-S. This version was developed as a technically easier alternative to the surgery with fewer complications.
How is the Current SADI-S Surgery Different from the Traditional Duodenal Switch?
The current SADI-S (Single Anastomosis Duodeno-Ileal Bypass with Sleeve Gastrectomy) surgery is a simplified and technically slightly less risky version of the traditional Duodenal Switch (DS) surgery. Both surgeries aim to treat obesity and metabolic diseases and have similar mechanisms, but there are important differences between them. Here are the differences between the SADI-S surgery and the traditional Duodenal Switch:
1. Number of Intestinal Connections (Anastomoses)
- Traditional Duodenal Switch (DS): In this surgery, two separate anastomoses (connections) are made. First, after the stomach is reduced, the duodenum is cut and connected to a later part of the small intestine. The part where digestive juices pass is then reconnected to another part of the small intestine. This double connection makes the DS surgery technically more complex and longer.
- SADI-S (Single Anastomosis Duodenal Switch): In SADI-S, only a single anastomosis is made. After the stomach is reduced, the exit part of the duodenum is connected to a later part of the small intestine, and a second anastomosis is not made. This makes the surgery technically simpler and less time-consuming. It also reduces the risk of complications.
2. Operative Time and Technical Ease
- Traditional Duodenal Switch: Since it is a more complex surgery, it usually takes longer. Performing two anastomoses increases technical difficulties and requires the surgeon's experience. The longer the surgery, the higher the risk of complications.
- SADI-S: Since a single anastomosis is performed, the surgical time is shorter and it is technically less complex. This makes the surgeon's job easier and can reduce the potential risk of complications with the shortening of the surgery time.
3. Intestinal Bypass and Absorption Restriction
- Traditional Duodenal Switch: A larger portion of the intestine is bypassed (leaving about 8 inches of active intestine). This shortens the section of intestine where food meets digestive juices, significantly reducing calorie and nutrient absorption. More severe malabsorption (absorption restriction) occurs in traditional DS.
- SADI-S: The bypassed portion of the intestine is shorter in SADI-S. This is still effective in reducing calorie and nutrient absorption, but it does not create as severe absorption restriction as traditional DS. So SADI-S may be a bit more advantageous in terms of nutrient and vitamin deficiencies.
4. Risk of Complications
- Traditional Duodenal Switch: It carries a higher risk of complications due to the presence of two anastomoses. In particular, intestinal obstruction, anastomotic leaks, infection and vitamin-mineral deficiencies may be more common. In addition, patients may have to take high-dose vitamin and mineral supplements for life due to severe malabsorption in the long term.
- SADI-S: Performing a single anastomosis may reduce the risk of postoperative complications. Since a smaller portion of the intestines is bypassed in the SADI-S surgery, vitamin and mineral deficiencies are less common than in the traditional DS. Nutritional supplements may still be required, but the rates may be lower.
5. Vitamin and Mineral Deficiencies
- Traditional Duodenal Switch: Since a large portion of nutrients and digestive fluids are bypassed, the absorption of vitamins and minerals such as iron, vitamin B12, vitamin D, and calcium is significantly reduced. Therefore, patients may need to take high-dose vitamin and mineral supplements for life.
- SADI-S: Since it is a less malabsorptive surgery, the risk of vitamin and mineral deficiencies is lower. However, supplements may still be required, and deficiencies should be monitored by regular blood tests, especially in the early years.
6. Weight Loss and Metabolic Effects
- Traditional Duodenal Switch: It is one of the most aggressive and effective methods for weight loss. It provides effective weight loss especially in morbidly obese patients with a BMI over 50. At the same time, excellent results are obtained in the treatment of metabolic diseases such as type 2 diabetes. Weight control is quite successful in the long term due to the greater malabsorption.
- SADI-S: It provides results very close to traditional DS in terms of weight loss and metabolic effects. It is a very effective method in terms of both providing weight loss and controlling type 2 diabetes and other metabolic diseases. However, since there is less absorption restriction, weight loss may be a little slower than traditional DS.
7. Long-Term Weight Management
- Traditional Duodenal Switch: It is very effective in controlling weight gain in the long term. Patients largely maintain their weight loss, but the severe malabsorption effects of the surgery require lifelong dietary monitoring and nutritional support.
- SADI-S: SADI-S surgery is also successful in controlling weight gain, but because the malabsorption effects are milder, some patients may experience less weight loss or slightly more weight regain in the long term. However, this can be managed with a healthy lifestyle and diet.
