Stomach Intestinal Pylorus Sparing (SIPS) Weight Loss Surgery

The single-anastomosis duodenal switch, also called stomach intestinal pylorus sparing (SIPS) surgery or the single loop DS, is very similar to the standard duodenal switch operation, except that the small intestine is transected only at one point instead of two. The majority of the most stretchable portion of the stomach is permanently removed (as in a sleeve gastrectomy), but basic stomach function remains the same. In addition, roughly half of the upper small intestine is bypassed, resulting in a moderate decrease in calorie absorption. Weight loss is achieved both through restriction of food consumption and malabsorption, which result in good weight loss maintenance.


As with sleeve gastrectomy surgery, the stretchy upper and outer 85 percent of the stomach is removed leaving a small, tube-shaped stomach. Stomach capacity is reduced from about a quart (1,000 ml) to roughly 4 – 6 ounces (120 – 180 ml). Depending on the size of the tube (bougie) that is created, patients generally report feeling full after eating 4 ­– 6 ounces of solid food.

The important functional elements of the stomach are preserved, including the antrum (the pump that pushes food through the valve at the bottom of the stomach), the pylorus and the nerves that control stomach function. The result is a much smaller stomach that functions similarly to a normal one. Patients are able to enjoy a relatively normal diet and feel satisfied (albeit with much smaller quantities), without experiencing “dumping” syndrome.

The upper small intestine is bypassed, moderately reducing calorie absorption. The duodenum (the first section of the small intestine) is divided just beyond the pylorus and attached to the small intestine approximately 8 – 13 feet (or 250 – 400 cm) from the colon (large intestine). This creates a loop that diverts the food stream from the top half of the small intestine. The top half of the small intestine now carries just digestive (bile and pancreatic) juices and is called the bilio-pancreatic limb (BPL). The segment of the small intestine between the duodenum and the colon where the food and digestive juices mix is referred to as the alimentary limb (AL) / common channel (CC). Absorption of nutrients and calories is determined by the length of the common channel, so a shorter channel helps decrease the chance of weight regain by decreasing calorie absorption.

The removal of the upper and outer stretchable portion of the stomach results in a decrease in ghrelin levels which reduces hunger and appetite. In addition, rerouting the intestine helps bring food to the lowest portion of the small intestine sooner than usual, releasing important appetite-suppressing hormones such as GLP1 and polypeptide YY (PYY). This may explain the superior weight loss, weight maintenance and diabetes resolution associated with this surgery.

Single-Anastomosis Duodenal Switch (SIPS)


Weight Loss

Approximately 75 percent excess weight loss has been reported.1

Improvement / Resolution of Comorbidities

Patients have experienced improvement or resolution of all major comorbidities, including type 2 diabetes, sleep apnea, hypertension and high cholesterol. 2


Because weight loss is achieved through stomach restriction as well as malabsorption, a SIPS bariatric procedure typically provides predictable weight loss with good weight loss maintenance. Patients report experiencing significantly less malabsorptive symptoms because the common channel length is almost twice that of a standard DS.

The risk of “dumping” syndrome is very low. This occurs after a patient (who has had gastric bypass) consumes sugar or carbohydrates, or eats too quickly, and then experiences nausea, cramping, diarrhea, sweating, vomiting and heart palpitations.

In patients who have had a previous Sleeve Gastrectomy who are looking to improve their weight loss outcome , we could add the SIPS as a Sleeve Enhancement Procedure

Medication Tolerance

After a pill-friendly SIPS weight loss procedure, aspirin and other NSAIDS are well tolerated.

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  1. Sánchez-Pernaute A, et al. Single-anastomosis duodenoileal bypass with sleeve gastrectomy: metabolic improvement and weight loss in first 100 patients. Surgery for Obesity and Related Diseases. 2013;9(5):731–735.

  2. Lee W-J, et al. Duodenal–jejunal bypass with sleeve gastrectomy versus the sleeve gastrectomy procedure alone: the role of duodenal exclusion. Surgery for Obesity and Related Diseases. 2015;11(4):765–770.

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