i HAD to go look. here's what i found. the term is pancreaticoduodenectomy - and it refers to taking out large parts [or all of!] the pancreas and the duodenum [the part of the small intesting that attaches to the stomach]. the 'bulbus preserving' refers to keeping the pyloric valve at the bottom of the stomach. in older forms of this operation, the pyloric valve was removed. this newer form keeps it.
and, as we all know, the pyloric valve is responsible for releasing the stomach contents slowly. in gastric bypass, the pyloric valve is removed. in other forms of WLS, like the gastric sleeve, duodenal switch, and lapband, it's not removed.
there are several reasons for this surgery, like chronic pancreatitis and pancreas cancer. in both diseases, weight loss even before the surgery is common, but apparently there are real problems afterwards. why? well, the pancreas makes lots of digestive enzymes. if it's not working right [pancreatitis/cancer] or GONE [like after surgery], it's real hard to digest things, and little is absorbed.
large weight loss - i saw numbers of anywhere from 10 to 40 kg, which amounts to about 20 to close to 90 pounds, and about 4-7% of total body weight.
weight loss due to malnutrition seems to be related to the inability to eat or digest protein. people have been surviving primarily on carbs, and they've had long-term problems. there's been some interest in supplementation, but the jury is still out on that one.
sooooo, it seems as if this isn't really a good idea for weight loss - pancreatitis is serious, and the post-op nutrition issues are severe and medicine isn't quite sure how to cope with them.
here's some reading - some more technical than others. hope this helps!!!
http://www.redorbit.com/news/display...ource=r_health
http://www.joplink.net/prev/200601/01.html
http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_docsum