The procedure
The single anastomosis gastric bypass is also known as an Omega loop bypass or a “mini” gastric bypass.
Similar to a Roux-en-Y bypass, it begins with creating a smaller stomach pouch. This is done using a stapling device via a laparoscopic (key hole) technique. After the pouch is created, it is joined to the small bowel approximately 2m downstream. Hence the term mini or single loop- as there is only one anastomosis, or join.
The end result is that the digestive fluids from the liver/pancreas and food meet further downstream, and there is a shorter “common channel” for the digestion and absorption of nutrients.

Quick info
- Operating time of approx. 60 to 90 mins
- Average hospital stay of 1 to 4 days
- Average time off work from 2 to 4 weeks
- Procedure is technically reversible
- Weight loss surgery financing plans available
How it works
The gastric bypass works in several ways. Like many bariatric procedures, the newly created stomach pouch is smaller and able to hold less food. This means fewer calories are ingested. Additionally, the food does not come into contact with the first portion of the small bowel and this results in decreased absorption. Most importantly, the modification of the food course through the gastrointestinal tract has a profound effect to decrease hunger, increase fullness, and allow the body to reach and maintain a healthy weight.
The impact on hormones and metabolic health often results in improvement of adult-onset diabetes even before significant weight loss has occurred.
Advantages
- Effective for remission of obesity-associated conditions- especially Type II Diabetes
- Reliable and long-lasting weight loss
- Avoiding risk of internal hernia/obstruction that can be seen in Roux-en-Y
Disadvantages
- Ongoing need for vitamin supplementation
- Risk of ulceration- especially if continued NSAID or tobacco use
- May cause “dumping syndrome”, a feeling of sickness after eating or drinking, especially sweets
BMI CALCULATOR
BMI can be a useful starting measure to identify your weight classification and risk of comorbidities.
BMI is not relevant if you are under 18 years or pregnant.
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