Weight loss surgery is a relatively new discipline that is still evolving. Most significant change in the last 20 years is being able to perform procedures using minimally invasive keyhole (laparoscopic) approach. With the use of laparoscopic method, two established key weight loss surgical procedures are undergoing changes aimed at simplification of technique and reduction of complications while achieving similar or better results.

How it Works

One anastomosis gastric bypass (OAGB) is emerging as an alternative to Roux-en-Y gastric bypass which for many years considered to be the gold standard by many. Single anastomosis duodeno-ileal bypass with sleeve (SADI-S) is coming up in place of Bilio-Pancreatic diversion with duodenal switch.

In both cases simpler modern version has got a single anastomosis (single bowel join) in place of two in the older version making the newer operation easy to perform with less complications. However novel single anastomosis operations are proving to be as effective weight loss and metabolic procedures.

Quick Info

  • SADI-s operations are proving to be as effective weight loss and metabolic procedures.

  • Rearranged SADI-S anatomy also produces a powerful weight loss and metabolic effect due to altered gut hormones.

  • Similar to other gastric bypass procedures, SADI-S is done with key hole access (laparoscopically).

  • SADI-s carries less risk compared to its prototype Duodenal switch operation due to one bowel connection.

SADI-S Diagram

SADI-S (SIPS)

Explainer video taking you through the steps of the procedure.

Further Information

First step in the SADI-S operation is to reduce the stomach capacity from normally a 1500ml sac down to a 200ml tube (sleeve gastrectomy). This results in reduction of the portion size or the restrictive component of the operation. Rearrangement of the small bowel food circuit is to limit the food digestion and absorption to the last 3 meters of the small intestine bypassing roughly half of the small intestinal length (malabsorptive component).

In addition to these obvious effects, rearranged SADI-S anatomy also produces a powerful weight loss and metabolic effect due to altered gut hormones in response to a meal. Gut hormones are a group of chemicals secreted from the gastro intestinal tract which act as signals to control appetite and metabolism and thought to be among key mediators of weight loss after bariatric surgery.

Similar to other gastric bypass procedures, SADI-S is done with key hole access (laparoscopically). If there was a technical difficulty doing the SADI-S in the extreme obese, the intestinal rerouting can be done as a second stage following initial weight loss after sleeve gastrectomy as the first stage. Conversion to SADI-S is also becoming an attractive revisional procedure following weight regain in the long term from a previous sleeve gastrectomy.

SADI-S operation was first reported in medical literature in 2007 and a limited number of surgeons in Australia and world wide have adopted the skills. Although this is no longer considered an experimental procedure there is still a degree of caution due to lack of long term data.

Obesity facts

Acceptable risk profile – As mentioned earlier SADI-s carries less risk compared to its prototype Duodenal switch operation due to one bowel connection. That means less chance of leaking, blockage, bleeding, or internal herniations. However Duodenal switch is a rarely done procedure in a limited specialized centres due to high risks and high need for maintenance.

Less risk of ulcer

Gastric bypass operations with a connection between stomach and intestine have higher risk of developing an ulcer at or near the connection (marginal ulcer). This risk is much less with SADI-S operation. As a result it is considered a safe option for people who smoke or are on anti-inflammatory medication both of which increase ulcer risk.

Highly effective

SADI-s operation generally bypass more intestinal length compared to other types of Gastric bypass procedures and leads to a greater weight loss. As such this strong weight loss operation is a suitable revisional option for weight regain after a previous sleeve gastrectomy.

Best for Diabetes

The best known weight loss operation for resolution of Type 2 Diabetes is the prototype of SADI-S, Duodenal switch. This metabolic benefit is very similar with SADI-S operation.

No long term data

This is a novel operation and currently long term data beyond five years is not available. Until such data is available long term effectiveness and side effects are not fully known.

Leak risk

There are three potential sites of leak in this operation. Stomach tube can have a leak commonly at the upper end of the staple line similar to sleeve gastrectomy. This is usually difficult to manage and slow to heal due to high pressure within the stomach tube forcing fluid (acid and digestive juices) out through the leak site. Intestinal connection is also a rare site of leak. Blind end of the proximal intestine (Duodenum) is a rare site of leak which is very difficult to manage. Duodenal stump leak is a unique risk to this operation.

No ERCP

Tube draining the liver and the pancreas to the intestine (Bile duct) can be accessed at its intestinal end using an endoscopic technique (ERCP). At SADI-S operation intestine is divided before the bile duct entry point preventing this access. The commonest reason for ERCP procedure is to deal with gallstones that slip into the bile duct.

Nutritional deficiency

Duodenal switch (DS) operation did not become a popular operation mainly due to technical difficulty and the long term severe nutritional deficiencies making people very sick. With SADI-S operation length of small bowel available for nutritional absorption is 300cm compared to 80 cm in DS. As a result Nutritional deficiency is less of a problem in SADI-S but still a major long term concern. Published midterm DATA suggest Vitamin A, D, Selenium, Iron and Protein malnutrition are likely.

Diarrhoea

As the length of the intestinal bypass is more with SADI-S ingested meal passes through to the colon quicker and more unabsorbed material are available in the colon. This can lead to lose and frequent stools, a problem that improves with time with gut adaptation. However up to 2% of people can have Diarrhoea and if severe may even require further surgery to reduce the length of intestinal bypass.

No reversal / Difficult to revise

Every weight loss operation comes with an inherent long term need for revision or reversal to address unintended consequences (complication or weight regain). As a major part of the stomach has been removed at this operation and rejoining the intestinal ends are nearly impossible, reversal of SADI-S is not possible. While revision is very difficult and carries significant risks it is possible. Commonest revision procedure involves shortening the intestinal bypass length to treat intractable diarrhoea.