Obesity Reporter

Obesity & Bariatric Guides

Single Anastomosis Duodenal Switch

What is Single Anastomosis Duodenal Switch?

SADi-S, SIPS, Single Loop Duodenal SwitchSingle Anastomosis Duodenal Switch also is known as Single Loop Duodenal Switch (or Single Anastomosis Duodeno–ileal Bypass with Sleeve Gastrectomy SADI-S and SIPS) is a new bariatric surgery procedure used to lose weight. This type of duodenal switch surgery uses a single anastomosis rather than two.

It is a restrictive procedure because it reduces the curvature of a patient’s stomach. However, it also has a malabsorptive function as the common channel of the stomach itself is reduced. The objective of this surgery is to lessen the intestinal loop where nutrients are absorbed into the body. This new surgical procedure is aimed at those suffering from Type II Diabetes. This new surgical procedure was created to have a more above metabolic process that has less of nutritional risk and a safer and easier operation for patients.

The duodenal switch has evolved from the biliopancreatic diversion (BPD), which was primarily a malabsorptive weight loss surgery. BDP is rarely performed now because of malnourishment issues, which were common.

Duodenal Switch works by using two surgical techniques, malabsorptive and restrictive. This surgery is similar to gastric bypass surgery, yet the DS produces more expected weight loss in three different ways.

  1. In a similar fashion to gastric sleeve surgery, 70% of the stomach is cut and permanently removed. This restrictive technique allows patients to feel fuller faster while also reducing ghrelin production.
  2. The malabsorptive procedure is when the large portion of the small intestines is rerouted; this induces fat malabsorption and makes patients absorb roughly 20% of the fat they eat.
  3. It also makes changes to the normal way that bile and digestive juices break down food. This cuts back on how many calories you absorb and contributes to more weight loss.

How it is Performed

The surgery is a simplified 1-loop duodenal switch procedure with a 200-250 common channel. It is said to be minimally-invasive as a laparoscopic or laparotomic duodenal switch surgery. The single anastomosis duodenal bypass with sleeve gastrectomy surgery is a simplified version of the DS procedure that is both safe and quick to perform. It also offers significant results for the treatment of morbid obesity as well as metabolic complications. There is a shorter operation time, a non-opening of the division of bowel and a reduction to just one anastomosis.

During the surgical procedure, a small gastric pouch is created by sectioning the curvature of the stomach (similar to that of the gastric sleeve surgical procedure). The duodenum is then transected while keeping the pylorus intact. From there a duodenum-intestinal anastomosis is performed creating a common channel where nutrients are absorbed to just 8.2 feet long.

Advantages of Single Anastomosis Duodenal Switch

Similar to that of the classic duodenal switch surgery, the Single Anastomosis Duodenal Switch is done to help a patient lose weight successfully. The procedure also helps to improve any comorbidities such as high blood pressure, high cholesterol, sleep apnea and most famously, Type II Diabetes. The main advantage of this surgery compared to the classic version of this bariatric surgery is the single anastomosis. The pylorus itself is preserved, so there are no dumping syndrome instances in patients. Also, the weight loss surgery diet post op is more tolerable for patients resulting in more successful weight loss.

This type of surgery is also very straightforward and easier to perform without any duodenum division. It can be offered to patients as a primary or staged operation for treating morbid obesity. The limb length also can be adjusted and modified as needed according to the patient’s particular body mass index (BMI) or DM status. The procedure also can be reversed or converted to another weight loss surgery if needed and easily. Also, there are no foreign bodies or closed loops involved and the entire GI tract, and bile ducts can be looked at by endoscope if necessary post operation. Researchers also found that by decreasing stomach tube pressure, a nominal rate of staple line leakages has occurred.

Disadvantages of Single Anastomosis Duodenal Switch

Patients with Single Anastomosis Duodenal Switch surgery may need to take vitamin supplements such as Vitamin A, D, E, K and other minerals their entire life. Continuous monitoring must be done to prevent any instances of malnutrition in SADI-S patients. Flatulence, diarrhea, and gallstones are all common with this procedure. Also, the surgical risks are the same in any other weight loss surgeries, but infection, abscess, intestinal perforation, anastomotic leaks, pulmonary embolism (which can lead to bowel obstruction) and venous thrombosis all can occur too.

Study Results

According to a study presented at the 28th Annual Meeting of the American Society for Metabolic and Bariatric Surgery, the procedure is completely safe and has been very successful. The study looked at the weight loss and the metabolic results of 100 consecutively operated patients at a university hospital. A total of 100 patients were performed on and studied. All of those studied had a metabolic disease or morbid obesity. In the first 50 cases, the common channel measured 200 cm, and the length was later changed for the last half of patients to reduce the hypoproteinemia rate.

No mortality or severe complications occurred in any of the 100 patients. The mean excess weight was greater than 95% and was maintained during the entire follow-up period too. Over 90% of the patients experienced remission of Type II Diabetes too. High blood pressure instances were controlled in 98% of the patients with 58% of those experiencing complete remission. Regarding digestive issues, patients experienced on average 2.5 bowel movements each day.


Ultimately single-anastomosis duodenal-ileal bypass with sleeve gastrectomy is a simplified duodenal switch procedure that is both safer and quicker to perform. It offers significant results for the treatment of comorbidities as well as morbid obesity in patients. It has been proven to be effective as well as safe and has countless advantages over other current surgical procedure for the treatment of obesity. However, it is agreed that more experts need to explore this surgical procedure before any solid conclusions can be made on the effectiveness of the method. It is however agreed that initial results are promising.


Duodenal Switch vs SADI-S