The bypass with sleeve gastrectomy procedure, also known as SADI-S, is a promising bariatric surgery procedure.

SADI-S stands for ‘Single Anastomosis Duodeno–Ileal Bypass with Sleeve Gastrectomy’.

Initial studies indicate it provides greater weight loss than a standard gastric bypass or sleeve gastrectomy without increased complications. SADI-S is being offered to selected patients with full disclosure to enable them to make an informed decision.

How SADI-S works

SADI-S surgery is a modified version of an operation that was developed 30 years ago. It was formally called Biliopancreatic Diversion with Duodenal Switch (BPD-DS). It was more simply known as the duodenal switch.

The SADI-S procedure involves two steps:

  • Step one; The surgeon will perform a sleeve gastrectomy, removing about 80% of the stomach.
  • Step two; The intestine is detached just below the stomach and then reattached to a loop of intestine about 2 metres downstream.

This two-step procedure effectively bypasses food from the metabolically active part of the intestine. This process lessens the total length of the intestinal loop where nutrients are absorbed. This procedure gives you a smaller appetite, restricted meal sizes, and hormonal changes that have a positive effect on metabolism.

What are the potential advantages of the SADI-S procedure?

  • Delivers greater weight loss than a gastric sleeve or standard gastric bypass. This is advantageous for people with a BMI above 50.
  • Provides a more powerful metabolic effect than a sleeve gastrectomy or standard gastric bypass. This is advantageous for people with poorly controlled Type 2 Diabetes.
  • Can be performed on people who have already had a sleeve gastrectomy. This is advantageous for people who experience weight regain or insufficient weight loss.
  • Lowers the risk of diarrhoea and nutritional deficiencies often encountered with a conventional duodenal switch.
  • Compared to a gastric bypass or a duodenal switch, this technique aims to reduce the long-term risk of intestinal obstruction.
  • The pylorus is retained above the connected loop of the small bowel. The pylorus  regulates the rate that food and acid empty from the stomach into the intestines and prevents reflux of bile. This helps to reduce the likelihood of certain problems encountered with gastric bypass surgery. These issues could be: Dumping syndrome, unstable blood sugar fluctuations, food restrictions and intolerance, and marginal ulcers.

What could be potential disadvantages of the SADI-S procedure?

The SADI-S surgical risks are very similar to most other bariatric techniques:

  • Intestinal perforation
  • Anastomotic leaks
  • Infection
  • Abscess
  • Venous thrombosis and pulmonary embolism
  • Chance of bile reflux
  • In the long term it could produce a bowel obstruction

Even though SADI-S is a promising procedure, it is still relatively new compared to other procedures available in bariatric surgery. At present, four published studies are available worldwide totalling 222 patients. Three of the four studies are from a single institution as an ongoing cohort. There is no published data past five years.

What are the results of the SADI-S procedure?

There are still no long term follow up results for large groups of SADI-S patients. However, the current results of this procedure are definitely very good.

The results are from an analysis of 123 patients with an average of 49.4 BMI. These patients underwent the SADI-S procedure between January 2013 and July 2014:

  • 72% excess weight lost at one year
  • No bowel obstructions
  • One marginal ulcer
  • One re-operation

To put this into perspective, prior to this, a group of patients with obesity and a similar BMI range would be expected to have lost:

  • 48% of excess weight following a sleeve gastrectomy
  • 55% of excess weight following a standard gastric bypass, with an expected morbidity of
  • Around 2 bowel obstructions
  • Around 5 marginal ulcers
  • Around 5 re-operations

However, there are questions whether these excellent results will remain constant over time. Whether they will be reproducible by other units and whether larger numbers will reflect the same figures. Other units are also starting to report their experience. Another unit in the US has recently reported their first 100 cases with similar good results.

Ongoing Research

A double-blinded randomised study is currently being conducted in Quebec City, Canada, comparing SADI-S to the Duodenal switch.

Surgeons across the world are following the progress in this field with great interest. It was discussed in depth at the First Duodenal Switch Consensus Conference held in Quebec City, Canada in June 2016.

Take Home Message

It always takes individuals (patients and surgeons) willing to go forth with a fairly new procedure to make progress in medicine.

In terms of bariatric surgery on the Gold Coast, we never offer procedures unless there is sufficient training and research involved. We offer SADI-S to selected patients after full disclosure of the current status of the procedure. All patients are thoroughly assessed on their current health, medical conditions, and weight loss history, etc. Then patients are followed up long-term by a multidisciplinary team with similar protocols as units performing the duodenal switch.