What is Loop Duodenal Switch (SADI-S) Surgery?

SADI-S surgery, or Single Anastomosis Duodenal Switch, also referred to as the Loop Duodenal Switch procedure, is a weight loss surgery that combines features and benefits of gastric sleeve and gastric bypass. The switch is performed in two steps. First, a gastric sleeve is performed. Eighty percent of the stomach is removed, and the remainder is converted into a slender tube. Second, Dr. LeGrand divides the small bowel from the stomach, the duodenum, to create the bypass. Consumed food will then go into the sleeve and then “switched” to the lower part of the small intestine bypassing the initial part of the small intestine. This portion of the surgery is similar to gastric bypass except a more significant length of small intestine is bypassed to create a single connection between the bottom of the sleeve and the small bowel.

Loop Duodenal Switch (SADI-S) Surgery

(Before and After)

How Does Loop Duodenal Switch (SADI-S) Surgery Work?

With the duodenal switch, patients lose more weight and faster than gastric bypass and gastric sleeve procedures. The smaller stomach decreases caloric intake. Bypassing a significant portion of the small intestines reduces food absorption and changes the hormonal balance of the GI tract. Ghrelin (the hunger hormone) decreases along with an increase in insulin sensitivity. Less energy is stored as fat, too. The duodenal switch also changes the types of bacteria that live in the GI tract replacing bad bacteria with good bacteria to promote optimal digestion.

Benefits of Loop Duodenal Switch (SADI-S) Surgery

Weight Loss

Patients can expect to lose 70% to 100% of their excess weight.

Fewer Risks

Decreased chance of experiencing dumping syndrome as compared to gastric bypass.

Improved Health

Up to 95% chance to resolve diabetes.1

Rapid Results

Weight loss can be experienced quite rapidly within the first six months of surgery.

Long-term Success

Long-term success is the highest seen in any bariatric surgery.

Additional Benefits

Up to 75% resolution of both high blood pressure and high cholesterol.

Candidates for Loop Duodenal Switch (SADI-S) Surgery

Candidates for SADI-S surgery are typically individuals who have a BMI of 50 or higher,2 equating to being over 100 lbs. overweight, though not everyone with this BMI is suitable. Suitability depends on a patient’s overall health, evaluated through medical history and possibly additional tests. Candidates often have weight-related health issues like diabetes and a history of unsuccessful weight loss efforts. A commitment to long-term diet maintenance, including pre-and post-surgery dietary habits and guidelines, is crucial. This includes mindful eating, separating food and liquid intake, and avoiding nutritionally poor foods. Psychological readiness is also key, as surgery can have significant psychological effects, and ongoing support is important. Candidates should be willing to commit to regular exercise and lifelong nutritional supplements, including multivitamins, calcium, and vitamin B12, to compensate for reduced food intake and ensure overall health.

Preparing For Loop Duodenal Switch (SADI-S) Surgery

Leading up to surgery, you’ll complete several evaluations and education preparing you for post-op success. You’ll practice new, healthy lifestyle skills early on because it takes time to develop new habits. Your results and success completely depend on your ability to permanently adopt healthy habits.

You may experience weight loss even before surgery because of your lifestyle changes. You should be encouraged by this weight loss and gain confidence in your long-term success. The duodenal switch surgery, as well as support from your medical and personal teams, will help you remain successful.

The Loop Duodenal Switch (SADI-S) Procedure

Dr. LeGrand utilizes a laparoscopic technique for conducting the SADI-S procedure, which is recognized for its minimally invasive nature. This approach typically takes between two to three hours to complete. During the procedure, patients are placed under general anesthesia. Dr. LeGrand makes multiple small cuts in the abdominal area, through which narrow tubes equipped with cameras and miniature surgical instruments are inserted, allowing for the operation to be performed with precision.

SADI-S is then performed in two steps. First, a gastric sleeve is performed. Eighty percent of the stomach is removed, and the remainder is converted into a slender tube. Second, Dr. LeGrand divides the small bowel from the stomach, the duodenum, to create the bypass. Consumed food will then go into the sleeve and then “switched” to the lower part of the small intestine bypassing the initial part of the small intestine. This portion of the surgery is similar to gastric bypass except a more significant length of small intestine is bypassed to create a single connection between the bottom of the sleeve and the small bowel.

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Loop Duodenal Switch (SADI-S) Recovery

Many SADI-S patients are discharged one to three days after surgery. Following your surgery, your initial objectives include frequent walking and practicing breathing exercises using the incentive spirometer provided to you. To prevent blood clots, you will receive anticoagulant medications. Typically, patients can start consuming liquids by mouth several hours post-surgery.

Day 1 | Hospital

Shift entirely from intravenous hydration and medication to taking liquids and pain relievers orally.

Day 2 | Ready For Discharge

While patients are typically ready to leave the hospital the day after surgery, individual recovery varies. Ensure you feel completely at ease before heading home, which might necessitate an additional day in the hospital.

At-Home Recovery

You’ll transition fully to oral medications and fluids as you recover post-hospitalization. Your at-home post-operative routine commences, accommodating your reduced stomach capacity, which significantly restricts your food intake. In the following 1-2 months, you’ll resume the healthy lifestyle and dietary habits, including exercise, that you started before the operation.

A lifelong commitment to a regimen of various vitamins and minerals becomes essential due to your smaller stomach’s limited food capacity, even for nutrient-rich foods. Essential supplements include a multivitamins, calcium, and vitamin B12.

How much does loop duodenal switch surgery cost?

For many of our patients, the cost of loop duodenal switch surgery is covered by their health insurance. There are a number of reasons a patient may pay for loop duodenal switch surgery out-of-pocket: they may not have health insurance or have insufficient coverage, or they may wish to streamline the pre-operative process and avoid waiting periods to have surgery sooner. Regardless of the reason, the self-pay price of loop duodenal switch surgery at Heartland Weight Loss Clinic is $17,995.

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Frequently Asked Questions About SADI-S

How much weight can I expect to lose after SADI-S surgery?

SADI-S typically produces the greatest, and fastest, weight loss when compared to gastric bypass and gastric sleeve surgeries. Patients can expect to lose 70% to 100% of excess body weight. Maintaining weight loss long-term is also more likely with SADI-S. Diabetes is resolved for up to 95% of patients. Sixty-eight to seventy-five percent of patients experience a correction in their blood pressure. High cholesterol is lowered among 70% to 75% of duodenal switch patients.

How is SADI-S surgery different from gastric bypass surgery?

One difference between SADI-S and gastric bypass surgeries is the shape of the new, smaller stomach left behind when the largest portion of the stomach is removed. During gastric bypass, Dr. LeGrand creates a small pouch that bypasses the lower part of the stomach. With SADI-S, the remaining stomach is converted into a slender tube instead of a pouch, more like gastric sleeve surgery.

The second difference between the two procedures is that Dr. LeGrand divides the small bowel from the stomach, the duodenum, to create the duodenal switch bypass. Consumed food will then go into the sleeve and then “switched” to the lower part of the small intestine bypassing the initial part of the small intestine. This portion of the surgery is similar to gastric bypass except a more significant length of small intestine is bypassed to create a single connection between the bottom of the sleeve and the small bowel.

Loop Duodenal Switch (SADI-S)

Surgery (Before and After)

Gastric Bypass Surgery

(Before and After)

When will I begin my new diet before surgery?

Starting two weeks before your surgery, you’ll adopt a stringent diet, limiting calories and carbohydrates while boosting your intake of lean proteins. This nutritional adjustment is aimed at reducing the size of your liver, thus facilitating a smoother transition towards your new lifestyle post-surgery. A large liver can potentially hinder the success of the procedure and increase its risks.

In the final two days leading up to the surgery, your diet will consist exclusively of liquids. This may include options like broth, protein shakes, decaffeinated coffee and tea, and Jell-O. It’s important to steer clear of caffeine, as it might affect the surgical process. Keep in mind that dietary instructions can vary from one patient to another, so it’s essential to follow the specific guidelines provided by Dr. LeGrand.

What’s the difference between SADI-S and the traditional duodenal switch?

The SADI-S procedure differs from the traditional duodenal switch primarily in its surgical configuration. SADI-S involves a single anastomosis, connecting the end of the duodenum directly to the ileum, making it less complex than the classic duodenal switch which features a “Y-shaped” dual anastomosis. This simplification in SADI-S generally leads to a larger portion of the small intestine being bypassed and less operative time and surgical risk, as well as reduced complications associated with postoperative malabsorption.3

What are the side effects and disadvantages of SADI-S surgery?

Dietary Changes

  • Taking regular daily vitamins is necessary to avoid life-threatening vitamin or mineral deficiencies; multi-vitamin/mineral support, additional calcium, additional iron, fat-soluble vitamins (A, D, E, and K), probiotics
  • Additional diet changes may become necessary if a protein deficiency develops
  • Routine blood tests are mandatory to make sure enough protein and supplements are being supplied to the body
  • Routine doctor visits are required and paired with visits with a nutritionist and dietician

Bowel Movements

  • The number of daily bowel movements increased to two to five per day or more
  • Diarrhea and loose stools are not uncommon
  • Foul-smelling stools or flatulence is also more likely
  • Post-op hospital stays range from one to three days, which may be longer than other weight loss procedures

Considering Duodenal Switch Surgery to help achieve your lifestyle goals?


1 IFSO. SINGLE ANASTOMOSIS DUODENAL-ILEAL BYPASS WITH SLEEVE (SADI-S). Available: https://www.ifso.com/single-anastomosis-duodenal-Ileal-bypass-with-sleeve/. Accessed Janauary 17, 2024.
2 Langenbeck’s Archives of Surgery. Single anastomosis duodenal-ileal bypass with sleeve gastrectomy (SADI-S): experience from a high-bariatric volume center. Available: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9399205/. Accessed January 17, 2024.
3 Obesity Surgery. Duodenal Switch vs. Single-Anastomosis Duodenal Switch (SADI-S) for the Treatment of Grade IV Obesity: 5-Year Outcomes of a Multicenter Prospective Cohort Comparative Study. Available: https://pubmed.ncbi.nlm.nih.gov/36282430/. Accessed January 17, 2024.