What Is SADI-S Surgery? A Guide to Loop Duodenal Switch Weight Loss Surgery
Modified or loop duodenal switch is a more aggressive weight-loss surgery that allows patients to lose around 80% of excess weight and reverse their diabetes.

By Samuel Wasser, MD, Bariatric and General Surgeon, Virtua Complete Weight Management Program
If you’re one of the 40% of adults in the United States who struggle with obesity, your doctor has probably recommended that you make certain lifestyle changes, such as changing your diet, exercising more, or even taking medication.
But for some people, no matter what lifestyle changes you make or how hard you try, it’s difficult to lose weight—and even more difficult to keep it off. If that sounds like you, it may be time to discuss bariatric surgery with your doctor.
What is bariatric surgery?
Bariatric surgery is a type of surgery that makes permanent changes to your stomach or small intestine to help you lose weight. Having bariatric surgery also helps reduce or eliminate high blood pressure, control or reverse type-2 diabetes, and prevent other health problems such as heart attacks and respiratory issues.
There are several bariatric surgery options available, including gastric sleeve surgery, gastric bypass, gastric banding, and duodenal switch.
Modified or loop duodenal switch (SADI-S) is a new minimally invasive procedure that offers exceptional weight-loss results for people who meet the following criteria:
- You have a body mass index (BMI) of more than 50 that puts you at high risk for other obesity-related diseases like type-2 diabetes or heart disease
- You have a BMI of 35-49 AND type-2 diabetes, heart disease or metabolic syndrome (high blood pressure, diabetes, high cholesterol, sleep apnea and increased fat around your waistline)
Here’s what you need to know about the SADI-S procedure, including what it is, how it’s performed, and what to expect.
What is SADI-S weight-loss surgery?
SADI-S—which stands for single anastomosis duodeno-ileostomy with sleeve gastrectomy—is the newest and most aggressive of the bariatric surgeries that Virtua offers. The procedure allows patients to lose around 80% of their excess weight and reverses 95% of cases of type-2 diabetes.
How is SADI-S surgery performed?
SADI-S is a two-step procedure that includes two separate surgeries scheduled a few months apart.
The first procedure is a restrictive surgery known as a gastric-sleeve surgery or sleeve gastrectomy. It’s minimally invasive—using only four to five tiny incisions. During the procedure, the surgeon removes about 80% of the stomach. When finished, the stomach looks like a tube or sleeve that’s about the size of a small banana.
By making your stomach smaller, gastric-sleeve surgery restricts how much food you can eat. It also reduces the production of ghrelin, a hormone that makes you feel hungry.
After the gastric-sleeve procedure is complete, your healthcare team observes you for a few months as you recover from the surgery and adjust to your new diet. After you and your team have decided you’re ready to complete the SADI-S procedure, you’ll be cleared for the second surgery.
The second step is a malabsorption surgery called an intestinal bypass. The procedure bypasses all but 10 feet of your small intestine and strictly limits the amount of calories and nutrients you can absorb from food. Because of this, it’s critically important to take a daily vitamin and protein supplements after this step is complete.
What happens before the SADI-S surgery?
Like all bariatric surgeries, the SADI-S procedure involves a team of doctors, nurses, and registered dietitians who work closely with you to prepare you for surgery and guide you through the healthy lifestyle changes required after surgery.
Before surgery, you’ll need to follow a specific weight-loss diet for about two weeks. Meeting your weight-loss goal before surgery is important as it can shorten the operating time, make the surgery safer, and lower your risk of complications.
What happens after the SADI-S surgery?
After surgery, you’ll need to follow specific diet levels provided by your bariatric surgery team—starting from an all-liquid diet and eventually moving to soft foods. It’s important that you stay well hydrated and get adequate amounts of nutrients, as well as take your daily vitamin and protein supplements.
What are the benefits of the SADI-S surgery?
The SADI-S weight-loss surgery can help you lose a significant amount of weight. It also can reverse type-2 diabetes and control or eliminate other chronic health problems.
Previous versions of this bariatric surgery procedure removed more of the intestine, which made it difficult for patients to get all the nutrients they needed to maintain their health. The SADI-S procedure produces better results and leads to few or no nutrient deficiencies, as long as you continue to take daily supplements and follow the required post-surgery diet.
Who is a candidate for SADI-S surgery?
To be considered a candidate for the SADI-S procedure, your BMI (calculated using your weight and height) must be at or above 50. A BMI of 50 or higher means you are significantly obese and are at high risk of developing health problems associated with obesity, such as heart disease, type-2 diabetes, and other metabolic conditions.
You also may qualify if you have a BMI of 35 to 49 AND metabolic syndrome (high blood pressure, diabetes, high cholesterol, sleep apnea, and increased fat around your waistline).
But, because SADI-S is a type of bariatric surgery that combines restriction and malabsorption, it means that you will have to commit to taking a daily vitamin and other supplements for the rest of your life.
If you don’t meet the criteria—or if you think that you can’t commit to the lifestyle changes required to help you stay healthy after the procedure—the SADI-S procedure may not be right for you.
Why choose Virtua for bariatric surgery?
Virtua is nationally accredited as a Comprehensive Bariatric Surgery Center by the Metabolic and Bariatric Surgery Accreditation Quality Improvement Program. Our bariatric surgeons are dedicated to providing the best possible care and life-lasting results.
Additionally, Virtua is one of the few hospitals in the area to perform the SADI-S procedure laparoscopically, using several small incisions rather than a single large incision in your abdomen. This type of minimally invasive surgery means less blood loss, scarring and pain, and a shorter recovery time when compared to traditional open surgery.
To learn more about bariatric surgery at Virtua or to schedule a consultation with one of our bariatric surgeons, call 888-847-8823.
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