These operations are the most complex and serious among bariatric procedures. They are both ancient (more than 25 years) and 'modern' because they have been refreshed and are still very much disputed among the bariatric surgical community, for instance in the US. In this first newsletter, we shall examine the general principles, then we'll focus on the technical aspects, and finally underline the results and long-term surveillance.

The bilio-pancreatic bypass was born in 1979 owing to the Italian surgeon Nicola Scopinaro. Its aim was to create malabsorbtion, but in a much better way than the pure intestinal diversions that were used at this time, and created multiple deficiencies with sometimes dreadful consequences. This operation combines a gastric restriction (partial gastrectomy) and a malabsorbtion: ingested food will be in contact with the bilio-pancreatic secretions only in a limited portion of the digestive tract (small bowel). The name of bilio-pancreatic diversion must then be understood as a much less efficient digestion of fat-food within the small intestine. The most important issue (and the most dangerous), is the fact that other nutriments are ill-absorbed, such as: calcium, vitamins from group B and D, proteins, oligo-elements, etc. A very strict surveillance is therefore necessary, particularly during the first post-operative year, with regular blood samples analysis.

Supplements should be routinely prescribed: iron, vitamin B1, B6, B12 and D, calcium... Patients must comply by strict rules and may be affected by bothering side-effects (rarely life-threatening), such as soiling, diarrhoea, malnutrition. On the other hand, this operation achieves the best results in bariatric surgery in terms of weight-loss, with permanent effects over the time, as opposed to the regular (standard) gastric bypass or the laparoscopic gastric banding. Italian series have more than 10 years follow-up and good results, and show a fair digestive comfort: there is indeed little or no food restriction in the long run.

There are three typical variations: the regular (original) BPD that entails a partial gastrectomy, the duodenal switch that entails a sleeve gastrectomy (see previous chapter), and an hybrid operation that is popular in the US (long limb gastric bypass). Despite their seriousness and the potential complications, these operations are still favoured and debated owing to the fact that a large portion of morbidly obese patients are yet resistant to other typical procedures and eventually fail to achieve a sustained weight-loss after 5 years, particularly those who have a BMI over 50 or 60. An ongoing dispute...