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The duodenal switch procedure combines restrictive and malabsorption elements to achieve and maintain the best-reported long-term percentage of excess weight-loss among modern weight-loss surgery procedures.  It works because fat absorption occurs only in the common tract so by reducing its length, less fat absorption can occur.

The procedure
The restrictive part of the operation involves removing ¾ of the stomach along the greater curve of the stomach, leaving the stomach in the form of a narrow tube (known as a sleeve gastrectomy).  This effectively restricts the stomach capacity without affecting its function.

The second part of the procedure, known as a distal bypass, rearranges the small intestine to separate the flow of food from the flow of bile and pancreatic juices to inhibit the absorption of calories and some nutrients.  The small bowel is divided near its middle and the distal part (the alimentary limb) is joined to part of the divided duodenum (just beyond the pylorus, stomach outlet).  The other part (biliary limb) of the divided small bowel is joined to the distal bowel about 125cm from the ileocaecal valve (junction of the small and large bowel).  Further down the digestive tract, these divided intestinal paths are rejoined; food and digestive juices begin to mix, and limited fat absorption occurs in the common tract (125cm) as the food continues on its path towards the large intestine.

Recovery
You will usually need to stay in hospital for four to six days.  Following surgery, you will need to take daily multi-vitamins, vitamin D, extra calcium and iron.  It is generally recommended that you consume extra potein early on as well, around 90 rather than 60 grams of protein each day.  Common sources of protein are lean meats, poultry, fish, eggs, cheeses, yoghurt, legumes and nuts.  Protein is also available in the form of liquid concentrates, powders and bars at most health food stores.  If you follow these simple guidelines, malnourishment is very unlikely to occur.

The stomach will eventually (after 12-18 months or so) expand to hold a small to near-normal sized meal, with weight loss being maintained by the malabsorption component of the procedure. 

The risks
Of all the weight-loss procedures, duodenal switch is associated with the greatest weight loss.  However, there are also higher risks from the operation itself and of side effects.   For this reason the duodenal switch procedure is generally reserved for Super Obese patients and should be considered very carefully first.

In general, a shorter common tract and reduced absorption of nutrients and fats after a distal bypass, means that people might experience more of the side effects that can affect all distal bypass patients (eg smelly gas, diarrhoea, vitamin, iron and calcium deficiencies or protein-calorie malnutrition).  Problems with loose stools and bad-smelling flatulence can be minimised by avoiding high-fat foods and taking chewable Bismuth Subgallate tablets or activated charcoal tablets, and these problem generally improve and resolve within six months of surgery. 

The advantages
The duodenal switch procedure keeps the pyloric valve intact.  This eliminates the possibility of dumping syndrome (nausea, vomiting, cramps and palpitations), marginal ulcers, stomal strictures and blockages, all of which can occur after other gastric bypass procedures.  It also means that food is able to pass into the small bowel from the stomach in very small quantities and a softer consistency.  As a result this enables more normal absorption of many nutrients including protein, calcium, iron and vitamin B12 than is seen after other gastric bypass procedures. 

The beauty of this operation is that the operation can be performed in two stages to reduce the risks of surgery, especially in patients with a very high Body Mass Index (BMI) or with risk factors.  First, the sleeve gastrectomy is performed which may reduce excess weight by about 30% alone.  The next stage of the operation (malabsorption) is performed six to 18 months later by which time the patient will be much fitter.  Shorter operation times and low leakage rates help reduce the risks to a minimum.

Next steps
A free consultation is available with our Consultant Bariatric Surgeon.  This is an opportunity to discuss all the options, your suitability for treatment and the procedure itself.  To make an appointment please call us on 020 8936 1201.