Mini-Gastric Bypass

There are a few very similar operations with different names: Mini-Gastric Bypass (MGB), and One Anastomosis Gastric Bypass (OAGB), which are now accepted as basically the same thing and the names can be used interchangeably.

This is basically a newer version of the RYGB operation which is gaining in popularity because it is simpler, quicker, associated with lower complication rates and appears to be just as effective. I prefer the term OAGB but many patients like calling this the MGB. It has been around since the 1990s but has only become popular over the last 10 years or so. However, in that time thousands of patients have undergone this operation and it is now accepted as a non-experimental variant. Again this is performed laparoscopically but not usually written with an L.

It is very similar to the traditional RYGB. But it is a simpler procedure with a shorter operating time. The key difference is that this technique involves only one join of the bowel (anastomosis) rather than two. This join is between the stomach and the small bowel, whereas the standard Roux-en-Y Gastric Bypass has another join between two loops of small bowel. In simple terms having one less join reduces the risk of the procedure as the joins are often the site of complications such as bleeding and leak. The operation is another 'keyhole' or laparoscopic surgery which uses 5 small holes to complete. It is a great primary operation but I also use this as a revision procedure for patients who have had a failed previous surgery such as a gastric band.

It works in the same way as a RYGB. There is a degree of restriction, as instead of eating into your stomach which can easily hold 1.5l of food or fluid, you eat into a smaller gastric 'pouch' which is again surgically constructed with our special staplers. This has a volume of only 50-200ml and around 1.5m of bowel is ‘bypassed’ so the malabsorptive effects are almost identical to the RYGB as the food travels into the small bowel further down the road than previously. This is the 'bypass' component and means that you do not absorb all the calories in your food. Finally, there are a number of hormone changes as a result of the diversion of food and the stapling of the gastric pouch which reduces your hunger and increases the feeling of fullness after eating only small amounts.

· Moderately small meals & less hunger

· Feel fuller quicker and stay fuller for longer

· Lose 30% of total body weight 

· Significant effects on co-morbidities (possibly even better than a RYGB): resolution of type 2 diabetes, improvement in hypertension, reduce sleep apnoea etc.

· Reversible (although a major operation to do so)

· Technically easier than a RYGB and only one join to have problems with

· Internal hernia rates extremely low

· Technically more difficult than a LSG

· Not technically possible in very high BMI patients (BMI>60kg/m2)

· Complications possible such as leaks and bleeds – see following section

· No access to the duodenum with a gastroscope due to the bypassed bowel

· Daily vitamin/mineral supplements for life

· Annual blood tests required

· Dumping syndrome when eating high carbohydrate meals

· Ulcers can form at the join between the gastric pouch and the bowel

· Bile reflux and biliary gastritis