Scopinaro and biliarypancreatic diversion

The late Nicola Scopinaro was an interesting chap. I came across him while reading about the use of the biliarypancreatic diversion (BPD) operation for the management of obesity and diabetes. He developed the operation in the 1970s and produced a string of publications about it over around 40 years. He died in 2020.

I can appreciate his practical abilities. In an obituary a friend describes how, during a parachute malfunction in the 1970s, Scopinaro spent his time during the descent in working out how to best position himself on impact to minimise the probability of any of the 13 fractures he sustained leading to a penetrating injury of his abdominal or thoracic viscera, or brain. He survived, hitting the ground at ~100kph. So he can work things out. An impressively pragmatic person.

His operation works.

If anyone wants the details there is always Scopinaro's comprehensive (and possibly mildly biased) review from the early days here:

Biliopancreatic diversion

but the core is that it pretty well always works and while there can be catastrophic problems these can be relatively simply managed. Inject B vitamins sooner rather than later if your patient's brain malfunctions and perform revision surgery to increase the protein absorption section if they develop protein malnutrition. And a few others. All in the paper.

Here's what the operation does.

If that's not clear we can analyse it in a little more detail. Most of the small intestine is separated from the stomach and is simply left in place to act as a conduit for bile salts and pancreatic juices to be transferred to the far end of the small intestine. We can remove this conduit from the diagram and replace it with the large red arrow like this:

The last 250cm of the small intestine is plumbed directly to a truncated stomach and functions to absorb glucose and sucrose (using the brush border sucrase enzyme), highlighted in blue below:

The conduit provided by the rest of the small intestine delivers the bile salts and pancreatic secretions to the last 50cm of small intestine. This 50cm section is the only section of the gut which is able to digest starch, fat and protein, that's the region highlighted in red:

Under these condition it is impossible to overfeed using anything containing starch, fat or protein. People with this alteration to their digestive system usually eat around 3000kcal/d, with just under half of the food eaten going down the loo.

If you make them over-eat to a total of ~5000kcal/d by adding an extra 2000kcal of fat/starch there is absolutely no change to their weight over 15 days. I prefer not to think about the resulting changes to their already execrable lower bowel function during this period.

Here are the weight loss data from a case series who had a milder version of the above procedure. Roughly 70% loss initial excess weight (IEW) maintained for longer than 18 years:

The full operation as described above gives more like an 80% permanent loss of IEW.

You can develop all sorts of ideas about how this operation works physiologically, what bypassing the bulk of the small intestine does to GPL-1, GIP, vagal sectioning, endocananbinoids etc etc but the bottom line is that Scopinaro was a pragmatic surgeon and what he means by satiety and appetite may not be quite the same as I do.

Which puts us in a position to think about Tataranni's paper comparing BPD patients with normal weight people as regards insulin sensitivity and RQ. And maybe basal metabolic rate.

Peter