Both SADI-S and RYGB are effective bariatric operations designed to promote significant weight loss and improve obesity-related health conditions. While they share common goals, they have distinct differences in terms of benefits, side effects, and potential complications. Understanding these differences can help patients and healthcare providers choose the most suitable procedure.
Benefits of SADI-S Compared to RYGB
- Preservation of the Pylorus
In SADI-S, the pylorus (the valve at the lower end of the stomach) is preserved, which plays a key role in regulating the passage of food from the stomach into the intestines. This natural regulation reduces the risk of dumping syndrome, a condition characterized by symptoms such as nausea, abdominal pain, and diarrhoea due to the rapid passage of undigested food into the small intestine.
RYGB involves dividing the stomach to create a small gastric pouch and rerouting the intestines, bypassing the pylorus, which increases the likelihood of experiencing dumping syndrome.
- Reduced Risk of Marginal Ulcers
In SADI-S, the single anastomosis connects the duodenum (the first part of the small intestine) to the ileum, rather than connecting the intestine directly to the stomach as in RYGB. This anatomical arrangement reduces the risk of developing marginal ulcers, a complication more common in RYGB due to the exposure of the newly created gastric pouch to stomach acid.
Because of the lower risk of ulcer formation, SADI-S patients can safely use nonsteroidal anti-inflammatory drugs (NSAIDs), which are often contraindicated in RYGB due to the heightened risk of ulcers.
- More Effective for High BMI Patients
SADI-S provides a higher degree of malabsorption compared to RYGB, making it particularly suitable for patients with a higher body mass index (BMI). The combination of restriction (from the sleeve gastrectomy) and malabsorption (from the intestinal bypass) enhances weight loss and improves metabolic outcomes more effectively in those requiring significant weight reduction.
RYGB also offers weight loss benefits, but the malabsorptive component is generally less pronounced, which might be less effective for patients with very high BMI or complex metabolic conditions.
- Less Risk of Internal Hernia
SADI-S involves a simpler anatomical rearrangement with only one mesenteric space where the bowel could potentially herniate, whereas RYGB creates two such spaces. This reduces the risk of internal hernia formation, which is a complication more commonly seen after RYGB.
Side Effects of SADI-S Compared to RYGB
- Bile Reflux
SADI-S may predispose patients to bile reflux, a condition where bile flows back into the stomach, causing symptoms such as heartburn or gastritis. This occurs because of the altered anatomical arrangement that allows bile to travel upwards.
In contrast, RYGB tends to improve symptoms of gastro-oesophageal reflux disease (GORD) because the new gastric pouch is disconnected from the bile flow, making it a preferred option for patients with significant reflux symptoms.
- Greater Risk of Malabsorption
While the increased malabsorption seen with SADI-S can lead to greater weight loss, it also raises the risk of nutritional deficiencies. Patients undergoing SADI-S are at a higher risk of deficiencies in essential nutrients like iron, vitamin B12, calcium, and fat-soluble vitamins (A, D, E, K) compared to RYGB patients.
RYGB also involves some degree of malabsorption, but the extent is generally less, leading to a lower risk of severe nutritional deficiencies.
- Diarrhoea and Steatorrhoea
Due to the shorter length of the small intestine available for nutrient absorption in SADI-S, patients may experience diarrhoea or fatty stools (steatorrhoea), especially if they consume high-fat foods. Adherence to dietary recommendations is essential to manage these symptoms.
Although RYGB can also cause changes in bowel habits, including dumping syndrome, the risk of chronic diarrhoea and steatorrhoea is typically lower than with SADI-S.
Complications of SADI-S Compared to RYGB
- Duodenal Stump Blowout (SADI-S Specific)
SADI-S carries a unique risk of duodenal stump blowout, which occurs when there is a leak or rupture at the closed end of the divided duodenum. This serious complication can lead to peritonitis and sepsis, requiring urgent surgical intervention. This complication is not encountered in RYGB since the duodenum is not transected in that procedure.
- Anastomotic Leaks
Both SADI-S and RYGB carry a risk of leaks at the site where the intestines are connected. For SADI-S, this occurs at the anastomosis between the duodenum and the ileum, while in RYGB, it can occur where the small intestine is connected to the new gastric pouch.
Prompt recognition and management of leaks are crucial in both procedures to prevent serious complications such as infection or sepsis.
- Marginal Ulcers (RYGB Specific)
RYGB patients have a higher risk of developing marginal ulcers due to the direct connection of the gastric pouch to the intestines. The exposure to stomach acid can cause ulcer formation at the anastomosis site, especially in patients who smoke or use NSAIDs.
In SADI-S, this risk is significantly reduced because the connection is to the duodenum, where the acidic environment is better tolerated.
- Revisional Surgery Requirements
SADI-S patients may occasionally need conversion to another procedure, such as RYGB or a less extensive bypass, in cases of severe malnutrition, unmanageable diarrhoea, or bile reflux. Similarly, RYGB patients may require revisional surgery due to weight regain or complications like internal hernias.
Both procedures highlight the need for lifelong follow-up and monitoring for nutritional deficiencies and other complications.
Conclusion
SADI-S and RYGB each offer distinct advantages and drawbacks. SADI-S may provide greater weight loss and is better suited for high BMI patients, with a lower risk of dumping syndrome and marginal ulcers. However, it comes with an increased risk of nutritional deficiencies, bile reflux, and unique complications like duodenal stump blowout. On the other hand, RYGB is often preferred for patients with GORD, offering lower risks of bile reflux and nutritional deficiencies but with a higher chance of dumping syndrome and marginal ulcers.
Patients should work closely with their healthcare team to assess which procedure aligns best with their health needs, lifestyle, and weight loss goals.
