Confusing SASI with SADI-S can lead to incorrect assumptions about reflux, nutrient absorption, expected outcomes, and reversibility. Always confirm the full procedure name and planned anatomy.
01 — AT A GLANCE
The core differences
| Feature | SASI bypass | SADI-S |
|---|---|---|
| Full name | Single Anastomosis Sleeve Ileal bypass | Single Anastomosis Duodeno-Ileal bypass with Sleeve |
| New connection | Stomach to ileum | Duodenum to ileum |
| Natural pyloric route | Remains available alongside the new route | Pylorus remains functional, then food enters the duodeno-ileal connection |
| Food pathways | Two pathways | One main post-pyloric pathway |
| Bowel division | No complete bowel division for the new connection | Duodenum is divided |
| Evidence and standards | Developing, less standardised | Separate and generally larger procedure-specific evidence base |
02 — SASI
How food travels after SASI
The sleeve-shaped stomach retains its natural pyloric outlet. A second outlet is created by connecting the lower stomach to the ileum. A meal may therefore split between the natural duodenal route and the gastro-ileal route.
03 — SADI-S
How food travels after SADI-S
The sleeve-shaped stomach empties through the pylorus into a short proximal segment of duodenum. That duodenum is divided and connected to the ileum, so food follows the duodeno-ileal route while bile and pancreatic secretions join farther downstream.
04 — CLINICAL MEANING
Why the anatomy matters
Nutrition
Both procedures require long-term nutritional monitoring, but the degree and pattern of malabsorption can differ with anatomy and bowel lengths.
Reflux
Acid and bile reflux questions are procedure-specific. Symptoms, endoscopy, and planned anatomy should be considered rather than relying on the acronym alone.
Revision
Revision options and complexity differ because one procedure uses a gastro-ileal connection and the other divides the duodenum.
Evidence
Outcome rates from a SADI-S study should not be presented as SASI results, or vice versa.
05 — CONSULTATION
Questions that clarify the plan
- Is the planned connection from the stomach or the duodenum?
- Will the bowel or duodenum be divided?
- How much small bowel will remain in the common channel?
- Why does my health profile favour this operation over the other?
- What reflux and nutritional monitoring does this exact procedure require?