Medical instrument

Gastric bypass

Mixed technique. Reduces the stomach and manipulates the intestine to limit fat and sugar absorption

Gastric by-pass is a bariatric surgery procedure to correct morbid obesity. It is a mixed technique, as it reduces stomach capacity to favour prompt satiety, and manipulates digestion to limit the absorption of calories in the form of sugars or fats.

It is a complex operation because of the characteristics of obese patients and should only be performed by expert surgeons in hospitals with the best facilities and equipment. There is a 3-5% risk of haemorrhage, infections, pulmonary embolism or suture failure. The choice of specialist team and clinic is fundamental for minimising possible complications.

How is the operation performed?

By laparoscopy, with small incisions and without the need to open, the general surgeon divides the stomach, creating a small reservoir. The patient feels satiated early and reduces his or her appetite. This surgery also excludes a part of the small intestine, manipulating the route that food follows and shortening digestion. It thus reduces absorption of food, especially sugars and fats.

Who can be a candidate for this surgery?

With a BMI of more than 35, any patient is a candidate for this surgery, although other factors are studied before establishing the treatment. Gastric bypass cannot be performed on patients with severe cardiac disease or mental and cognitive problems that prevent them from understanding the surgery and committing to changing their habits. This treatment is also contraindicated in some patients with eating disorders.

What happens after the operation?

Although each patient evolves differently, bypass surgery requires around 3 days of hospitalisation. After two weeks the patient can return to work and continue with his or her normal activities. A gentle, controlled and progressive return to sport is recommended, and sport can be practised normally after 3 or 4 months.

The diet will be prescribed by a doctor. Patients can usually ingest liquids the day after the operation and progressively add other foodstuffs. After 3 or 4 months, patients start a normal diet under specialist supervision.

The most immediate benefits are found in the first month, with control of diabetes and sleep apnoea, the main disorders associated to morbid obesity. The patient notices a better quality of life in the first few weeks, sleeping better and ceasing to need insulin.

Weight loss is fast during the first six months, representing 60-70% of the total target. Weight reduction then becomes slower and stops after 12 or 18 months, when the patient reaches his or her definitive weight.

Like other bariatric surgery procedures, bypass is indirect surgery. The technique in itself does not solve the problem, but helps the patient to lose weight. Patients themselves have to manage their condition and actively participate in its cure.

How is bypass different than other bariatric surgery techniques?

Unlike purely restrictive techniques that limit stomach capacity without affecting food absorption, a gastric bypass shortens the route that food follows, thus limiting the absorption of calories in the form of fats or sugars.

Although this surgery is very effective for losing weight, its main disadvantage is related to the poor absorption of some basic elements such as some vitamins, iron or calcium. Patients have to take supplements for the rest of their lives in order to prevent some nutritional deficiencies.

Some patients also present other side effects such as diarrhoea or Dumping Syndrome, one of the most common after a bypass, characterised by the onset of discomfort after eating in the form of tremors, dizziness and general malaise.