Sleeve gastrectomy is an effective weight-loss operation, but weight regain can occur years later. This does not necessarily mean that the original sleeve has “failed”. Obesity is a chronic disease, and changes in appetite, metabolism, eating behaviour and sleeve anatomy can all contribute to weight recurrence.
Is SASI-S an Option for Weight Regain After Sleeve Gastrectomy?
For selected patients, SASI-S (Single Anastomosis Sleeve–Ileal bypass with Sleeve) can provide renewed and durable weight loss after previous sleeve gastrectomy, while retaining some important advantages of the normal gastrointestinal anatomy.
At Mercy Bariatrics, SASI-S has become an important option in our approach to revisional surgery following sleeve gastrectomy.
Why consider SASI-S after weight regain?
The principle of SASI-S is relatively straightforward. The existing sleeve stomach is retained and a connection is created between the stomach and the ileum further downstream in the small bowel.
Importantly, the normal route through the stomach, pylorus, duodenum and upper small intestine is not divided or completely bypassed. Food can therefore travel by two pathways: through the normal duodenal route and through the new ileal pathway.
This is known as transit bipartition.
Delivering some food more rapidly to the distal small bowel can enhance the hormonal and metabolic signals involved in appetite control and satiety, while food also continues to pass through the normal duodenal pathway.
Because the duodenum and proximal small intestine remain exposed to nutrients, SASI-S may also have nutritional advantages compared with procedures in which these areas are completely bypassed.
Effective additional weight loss
Our own experience has shown substantial renewed weight loss in patients who initially lost weight following sleeve gastrectomy but subsequently regained a significant proportion of it.
The pattern becomes particularly clear when we look at the patient’s entire bariatric journey, beginning with their highest weight before the original sleeve operation.
In our current outcomes series, mean excess weight loss had fallen to approximately 32.5% before SASI-S revision following weight recurrence.
After SASI-S, mean lifetime excess weight loss increased to approximately:
- 79.4% at 10–12 months
- 87.4% at 25–36 months
- approximately 90% in the later follow-up groups
These results suggest that SASI-S can restore a substantial proportion of the weight loss lost after sleeve recurrence.
Our results: the lifetime weight-loss journey
Rather than considering only the kilograms lost after the second operation, we believe it is helpful to look at the patient’s whole weight-loss journey.
The graph below shows mean percentage excess weight loss (%EWL) beginning at the patient’s highest pre-sleeve weight, followed by the initial response to sleeve gastrectomy, subsequent weight regain and then renewed weight loss following SASI-S.
Mercy Bariatrics SASI-S outcomes
The graph demonstrates the characteristic journey:
Highest pre-sleeve weight → sleeve weight loss → weight regain → SASI-S revision → renewed weight loss
The number of patients contributing data at each follow-up point is shown on the graph. As with any clinical series, the number of patients with very long-term follow-up becomes smaller, so later results should be interpreted in that context.
Potential nutritional advantages
One of the features that particularly attracts us to SASI-S is preservation of the normal pathway through the pylorus, duodenum and proximal small intestine.
These areas are important in the absorption of iron, calcium and a range of vitamins and micronutrients.
In procedures such as Roux-en-Y gastric bypass, single-anastomosis gastric bypass and SADI, varying lengths of the proximal intestine are excluded from direct contact with food.
With SASI-S, some food continues to travel through the normal stomach, pylorus and duodenum.
This may reduce the degree of micronutrient malabsorption compared with more completely bypassed gastrointestinal anatomy.
Our own postoperative nutritional experience has been encouraging. Nevertheless, SASI-S remains a metabolic bariatric operation and patients require lifelong nutritional surveillance, blood testing and appropriate supplementation.
A relatively straightforward revision
For many patients, the existing sleeve stomach can be retained. The revisional procedure principally involves creating a single new connection between the stomach and the ileum. Unlike Roux-en-Y gastric bypass, the small intestine does not need to be divided into multiple limbs in the classic SASI-S configuration.
Where appropriate, other anatomical problems can also be addressed during the same operation. These may include:
- enlargement or dilatation of the previous sleeve
- hiatus hernia
- reflux-related anatomical problems.
In our currently analysed revisional series, 46 patients are represented. Of these, 24 underwent concurrent hiatus hernia repair and 11 underwent re-sleeving.
Safety
Revisional bariatric surgery is more complex than a primary bariatric procedure, and no bariatric operation is without risk.
However, in appropriately selected patients and in experienced hands, we have found SASI-S to be a practical and effective revisional procedure with an acceptable safety profile.
Its relative anatomical simplicity is attractive. The existing sleeve remains in place, the small bowel is not divided in the classic SASI-S configuration, and only one new gastrointestinal connection is required.
Potential complications include bleeding, leak, reflux or bile-related symptoms, diarrhoea, nutritional deficiencies and, occasionally, excessive weight loss.
Individual risks and benefits therefore need to be carefully considered before surgery.
Reversibility is an important advantage
Another attractive feature of SASI-S is that the bypass component can potentially be reversed.
Because the normal stomach, pylorus and duodenal pathway remain intact, the stomach-to-ileum connection can potentially be disconnected if circumstances require it.
This may be important in the uncommon situation of significant nutritional problems, excessive weight loss or troublesome gastrointestinal symptoms.
No bariatric operation should be regarded as easily reversible. Nevertheless, maintaining the normal gastrointestinal pathway gives SASI-S an important degree of future flexibility.
Why not convert the sleeve to another type of bypass?
There is no single best treatment for every patient who experiences weight regain after sleeve gastrectomy.
Options may include:
- dietary and behavioural treatment
- GLP-1 and other weight-loss medications
- re-sleeve gastrectomy
- Roux-en-Y gastric bypass
- single-anastomosis gastric bypass
- SADI
- SASI-S
The best approach depends on the reason for the weight regain, reflux symptoms, sleeve anatomy, eating behaviour, previous response to bariatric surgery, nutritional status and the patient’s individual goals.
SASI-S may be particularly attractive when the objective is substantial additional weight loss while maintaining physiological continuity through the pylorus and duodenum.
Is SASI-S right for you?
Not everyone who regains weight after sleeve gastrectomy requires another operation. The first step is to understand why the weight has returned.
At Mercy Bariatrics we assess your original operation, current sleeve anatomy, weight history, reflux symptoms, eating patterns, medical conditions and previous response to treatment.
For some people, medication may be the best next step. For others, an anatomical problem with the sleeve or hiatus may need to be corrected.
For appropriately selected patients, however, our experience suggests that SASI-S can provide powerful renewed weight loss while offering an attractive combination of nutritional preservation, anatomical simplicity, safety and potential reversibility.
Regained weight after sleeve gastrectomy?
If you have previously undergone sleeve gastrectomy and are concerned about weight regain, we can review your individual situation and discuss whether SASI-S, medication or another revisional treatment may be appropriate for you.
Dr Leon Cohen
Bariatric & Metabolic Surgeon
Mercy Bariatrics
Perth, Western Australia
