Duodenal switch surgery – how does it work?

Duodenal switch surgery works by reducing stomach size at the same time as reducing the length of the digestive tract. The overall effect is to make it difficult to eat large amounts and food, particularly fat, is not absorbed into the blood as well as before. You cannot absorb as many calories from the food you do eat but the operation also changes the level of hormones that are released from the bowel and stomach. This makes you feel less hungry – so that you also eat less. Weight loss is therefore very fast and duodenal switch surgery is an effective procedure for the very obese.

This article on duodenal switch surgery is by Kathryn Senior, a freelance journalist who writes health, medical, biological, and pharmaceutical articles for national and international journals, newsletters and web sites.

What are the advantages and disadvantages of duodenal switch surgery?

As with any surgical procedure, duodenal switch surgery is not without its risks as well as its benefits.

Advantages of duodenal switch surgery:

• Weight loss: You can expect to lose 75 to 80% of your excess weight in the months following duodenal switch surgery. This can have a big impact on weight-associated health risks, e.g. type II diabetes, hypertension, raised cholesterol and sleep apnoea. You also tend to lose weight more quickly than with other obesity surgery procedures.

• Convenience: The duodenal switch procedure keeps your pyloric valve intact. This allows food to pass from the stomach into the small bowel in very small quantities and at a softer consistency. Your body will therefore absorb many nutrients normally, including protein, calcium, iron and vitamin B12. This can be impaired in other gastric bypass procedures. You should also find that you are able to eat more normal meals than with standard gastric bypass. ‘Dumping syndrome' is also less common with duodenal switch surgery. Caused when food passes too quickly into the small intestine, this can make you feel very ill and can be a problem with standard gastric bypass surgery. The operation can be done in two separate phases to lessen the risks.

  Disadvantages of duodenal switch surgery:

• Duodenal switch is a major operation that can only ever be partially reversed.

• Poor absorption of food afterwards may cause long-term diarrhoea.

• You have to follow a quite restricted diet following surgery.

• You will need regular blood tests and vitamin supplements following the operation.

• You have to attend follow up appointments for the rest of your life.

Is duodenal switch surgery suitable for me?

The criteria used by the National Institute of Health and Clinical Excellence (NICE) to determine whether you are eligible for surgical intervention are:

• Are you classified as obese?

• Does your obesity cause you problems?

• Have you tried hard to lose weight using conventional treatments?

The most suitable type of surgery depends on several factors, including your body mass index (BMI). Duodenal switch surgery is generally used in people with a BMI of more than 50 kg/m².

The surgical team will also take other factors into account, including:

• Your age/gender/ethnic background.

• Your history of weight gain/weight loss.

• Whether you have other illnesses such as type II diabetes, hypertension, sleep apnoea, arthritis, and asthma.

• If you have medical/genetic reasons that make you gain weight.

• If you are taking any medication.

How is duodenal switch surgery performed?

The first part of duodenal switch surgery, known as a sleeve gastrectomy, involves removing ¾ of the stomach. The stomach that is left is made into a narrow tube. The second part , the distal bypass, rearranges the small intestine so that calories and some nutrients can’t be absorbed as well After around 12 to 18 months, your stomach will expand to hold a small to near-normal sized meal, but the changes to the intestines will remain intact so that you can maintain your new, lower weight. 

You will usually need to stay in hospital for 4 to 6 days following duodenal switch surgery.

What are the risks with duodenal switch surgery?

Duodenal switch surgery may cause slightly more of the side effects commonly affect all distal bypass patients - including smelly wind, diarrhoea, vitamin/mineral deficiencies or protein-calorie malnutrition. These problems generally clear up within six months of surgery and you can manage them by being careful about what you eat and by taking activated charcoal tablets. 

After duodenal switch surgery, there is usually a period of ‘intestinal adaptation’, during which there may be frequent loose bowel motions (up to 10 to 15 times a day). This may persist for several months and in some case, you might find this carries on permanently.

Lifestyle changes following duodenal switch surgery

You will definitely need to adjust your diet following surgery but not quite so much as with gastric bypass surgery. You will need to eat far less fat - because fat absorption does not start until later in your new digestive tract, eating high fat foods causes undigested fat to pass through – making the usual side effects much worse. The poor food absorption that follows duodenal switch surgery also means that you take in less protein and less of the important vitamins and minerals such as vitamins A, D E and K, iron and zinc. You therefore also need to eat a diet that is high in protein, as well as taking vitamin and mineral supplements for the rest of your life.

Profile of the author

Dr Kathryn Senior is an acclaimed medical journalist who has written over 500 feature articles for leading international journals within The Lancet group. As Senior Writer at Freelance Copy she produces high quality scientific and medical content for websites and printed publications for companies and organisations in the health, medical and pharmaceutical sectors.

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