Gastric bypass

In the USA, gastric bypass surgery is standard and is meanwhile also being performed quite frequently in Europe.

Surgical technique

In this type of surgery the upper portion of the stomach is first divided off, creating a small upper pouch. The remaining part of the stomach is retained in the body. The gastric juice generated here is released into the duodenum, as usual.  

Then, the upper part of the small intestine is divided off. The length of the small intestine from the stomach to the line of division is approx. 50 cm and is referred to as the biliary limb, as this part of the intestinal tract transports e.g. the bile. The portion of the intestinal tract behind the division is now anastomosed to the stomach pouch. This limb is referred to as the alimentary limb, as the food eaten passes through the oesophagus, into the stomach pouch and from there to the alimentary limb, which has a length of 140-200 cm. The biliary limb is anastomosed to the alimentary limb at the end of the alimentary limb so that the digestion enzymes are now added to the further joint part of the intestinal tract.

The operation is performed laparoscopically, generally using five, sometimes six tiny incisions.

How does gastric bypass surgery work?

Gastric bypass works due to three effects. First, stomach size is reduced significantly during surgery, as a result of which only a small amount of food can be ingested. Second, the part of the stomach in which the appetite stimulating hormone ghrelin is produce is bypassed, so that only very low hormone levels are present and hunger is inhibited in patients. Third, the lower portion of the stomach and the upper loops of the small intestine no longer participate in the absorption of calories from food. This results in a significant reduction of calorie intake. Additionally, a dumping feeling can occur if sweet foods pass into the small intestine too fast. This aids a healthier food intake through conditioning.

A reduction of approx. 70-80% of the excess weight is to be expected. Due to the fact that the upper part of the small intestine is bypassed, substances that are usually absorbed here must be supplemented in the form of tablets. This so-called supplementation generally covers vitamin B12, iron, calcium and folic acid.

In contrast to gastric band surgery or sleeve gastrectomy, this operation is a complex procedure. However, this type of surgery generally also results in the highest loss of weight.

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