The Modified BPD/Duodenal Switch procedure combines restrictive and malabsorptive elements to achieve and maintain the best-reported long-term percentage of excess weight loss among modern weight-loss surgery procedures.
The Restrictive Component (Sleeve Gastrectomy) This stage 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. This effectively restricts the stomach capacity without affecting its function.
The Malabsorptive Component (distal bypass) The small bowel is divided near its middle and the distal divided small bowel (alimentary limb) is joined to the proximal divided duodenum (just beyond the pylorus, stomach outlet). The proximal part of the divided small bowel (biliary limb) is joined to the distal bowel about 125cm from the ileocaecal valve (junction of the small and large bowel). Thus the malabsorptive component of the DS procedure rearranges the small intestine to separate the flow of food from the flow of bile and pancreatic juices. This inhibits the absorption of calories and some nutrients. 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.
How Duodenal Switch works Sugars, protein and nutrients are absorbed to a limited degree in the food tract. Fat absorption occurs only in the common tract. Therefore, the shorter the common tract, the less fat absorption can occur.
Advantages The Duodenal Switch procedure keeps the pyloric valve intact. This eliminates the possibility of dumping syndrome, marginal ulcers, stomal strictures and blockages, all of which can occur after other gastric bypass procedures. The preservation of the pylorus means the food is allowed in very small quantities into the small bowel from the stomach and that too in a softer consistency. As a result the Duodenal Switch procedure enables more normal absorption of many nutrients including protein, calcium iron and vitamin B12 than is seen after gastric bypass procedures. 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 beauty of this operation is that the operation could be performed in 2 stages to reduce the risks of surgery, especially in patients with very high Body Mass Index (BMI) ie. Super Obese or with risk factors. First, sleeve gastrectomy is performed; this may reduce the excess weight by about 30%. The next stage of the operation (malabsorption) is performed 6 – 18 months later; patient is much fitter at this stage. Shorter operation times and low leakage rates help reduce the risks to a minimum.
Disadvantages In general, a shorter common tract means that patients might experience more of the side effects that can affect all distal bypass patients (eg smelly gas, diarrhoea, vitamin, iron & calcium deficiencies, protein calorie malnutrition). You will also may have the complications mentioned in risks section. Also there are higher risks from operation itself. One has to consider this operation very carefully; this is the reason it is generally reserved for Super Obese.
Problem with foul gas and loose bowels Because of the reduced absorption of nutrients and fats after a distal gastric bypass, patients can experience loose stools and bad-smelling flatulence but this problem generally improves and resolves itself within 6 months after surgery. This doesn’t just affect duodenal switch patients -- it can affect anyone who undergoes a distal bypass. There are several remedies that you can use to minimize the problem:
1. Avoid high-fat foods. This is probably the most effective way to combat the problem.
2. Taking chewable Bismuth Subgallate tablets/Activated charcoal tablets. Activated charcoal may absorb other medicines.
Diet You will need to take daily multivitamins, vitamin D, extra calcium and iron. Extra protein is sometimes recommended early on, just after surgery. Your doctor can check your bloods. If you follow these simple guidelines, mal-nourishment is very unlikely to occur. It is generally recommended that you consume 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. These items boost your protein intake.
