One anastomosis gastric bypass (mini gastric bypass)

The mini gastric bypass is a variant of the classic Roux-en-Y gastric bypass. In this operation, a long narrow gastric pouch is created which is connected to a long small-intestine loop so that the large remnant stomach is bypassed. The new connection between the gastric pouch and the intestine allows the gastric juices to mix with the food. Digestion therefore only takes place after the entire section of small intestine has been passed through. The large remnant stomach is preserved, so this procedure, unlike the sleeve gastrectomy, is reversible.

The procedure is performed by keyhole surgery (laparoscopy) or with the robot.

The mini bypass has a restrictive as well as a malabsorptive and a hormonal effect. The amount of food one can eat during a meal is greatly limited without a feeling of hunger in return. In addition, the absorption of fats is reduced. Eating high-calorie food, in particular sugars, can give an unpleasant feeling. This is called dumping syndrome. It can be accompanied by palpitations, sweating, dizziness and nausea. It keeps the patient away from eating sugars and can therefore contribute to better eating habits after the operation.

Difference from the Roux-en-Y gastric bypass

The major advantage of this procedure compared to the Roux-en-Y gastric bypass is that only 1 connection (anastomosis) has to be made instead of two as with the Roux-en-Y gastric bypass.

In addition, studies show that the weight loss at very high BMIs is even better after a mini gastric bypass than after a Roux-en-Y gastric bypass. The chance that diabetes mellitus disappears after the operation is also greater. However, a disadvantage is that after a mini bypass the bile can flow back directly into the gastric pouch and oesophagus, which can cause reflux complaints.

Patients undergoing this procedure are usually admitted on the day of the procedure. A few hours after the operation, the patient may already drink a few sips of water and carefully get out of bed. The next day, a liquid diet can be started and the patient may go home again. The length of the hospital stay can of course vary depending on the clinical circumstances.

Results

Studies show that after a mini gastric bypass, patients can expect a loss of 80% of their excess weight. The weight loss usually occurs in the first 12-18 months after the procedure, the majority of it during the first 6 months. These values can vary from patient to patient and depend on lifestyle, age, adherence to the post-operative guidelines, comorbidity and genetic predisposition.

A mini gastric bypass not only leads to substantial weight loss but also has a very beneficial effect on comorbidity. Diseases such as diabetes, sleep apnoea and high blood pressure can improve considerably or even disappear as a result of this procedure.

Complications

Every operation can be accompanied by complications. People who are overweight have a greater chance of complications than people of a normal weight. There are standard post-operative complications that can occur after any operation, such as bleeding, infection, abscess formation, incisional hernia, thrombosis of the leg or a pulmonary embolism.

The most common risks directly associated with a mini gastric bypass are:

• Stomach ulcer (greatly increased risk in smokers).
• Vitamin or iron deficiency (supplements will be prescribed for this).
• Hair loss (this is caused by the weight loss and is temporary. The hair loss remains limited and the hair grows back completely).
• Dumping (mainly caused by eating sugars, which is strongly discouraged after a procedure).
• Internal herniation (to reduce this risk, at Obesity Clinic Dendermonde the spaces that arise after a bypass are closed).
• Chronic unexplained abdominal pain.
• Leakage or bleeding along the staple line.
• The remnant stomach is difficult to reach after the operation for any possible future examinations.