Single anastamosis bypass (also known as mini-bypass or omega-loop bypass) is a variation on the traditional 'roux en y' gastric bypass. The variation has designed to decrease the rate of internal hernia (3-5% lifetime risk after 'roux en y' bypass) and the rate of complications after surgery (one surgical join required and not two). It appears to give similar weight loss and health benefits to the traditional 'roux en y' gastric bypass, but does have a 10-20% rate of bile reflux (reflux that isn't as easily treated with tablets).
In gastric bypass two things are done to cause weight loss. Firstly a small pouch is created at the upper part of your stomach. This has the effect of decreasing the amount of food you can eat in a meal. Secondly, your small bowel is joined to the pouch. This decreases the amount of time food will spend in contact with both the bowel, and also the enzymes that help digestion and absorption in your bowel. It also alters the way your body processes food, sugars, carbohydrates and hormones associated with feelings of fullness , also helping with long term weight loss.
A single anastamosis gastric bypass is performed as a laparoscopic (key-hole) operation through 5 small incisions. Firstly, the pouch is made using a stapling device. Secondly the small bowel joined with a single join to the pouch. After this is done a test is performed to ensure the join is watertight. You should expect to spend 1-2 nights in hospital after your operation.
Longer term you must avoid all anti-inflammatory tablets and smoking. Using anti-inflammatory tablets or smoking even years after your surgery can cause significant ulcers and other problems.