Idiopathic recurrent pancreatitis: the ERCP luddites are at the door.

When I was in high school, atomic physics was easy: there were nuclei with protons and neutrons, surrounded by clouds of whirling electrons. At least, that's what it said in Volume 10 of Professor Jardine's ghastly high school text, Physics Is Fun. But not only was the "Bohr atom" as taught to many of us in the 1960s a gross simplification, it was downright wrong. Atomic physics is now a bewildering landscape filled with particles of every imaginable color and flavor. Although gravity steadfastly defies incorporation into a modern Theory of Everything (TOE) (the theory formerly known as Grand Unification), physicists now have a pretty clear picture of the nature of matter. When I was a gastroenterology fellow in the early 1980s, sphincter of Oddi manometry (SOM) was in the Bohr atom state: primordial, mysterious, and with its own Uncertainty Principle (the uncertainty was what it really meant). Heisenberg said that you can know the position of an electron, or its momentum, but not both, at any point in time. The very act of measuring these properties changes the result. SOM can irrevocably change a patient's condition by leading to sphincterotomy (for high pressure) or by causing pancreatitis, an unwanted, unpleasant, and sometimes dangerous complication. The Milwaukee (Geenen-Hogan) Classification of sphincter of Oddi dysfunction (SOD) was the Bohr Atom of the late 1980s, a convenient, best-guess approach to a very difficult problem. More than a decade and many, many studies later we are faced with a confusing array of conflicting data. Rather than the physicists' comforting Theory of Everything, gastroenterologists have lots of theories but still only a rudimentary understanding of what causes idiopathic recurrent pancreatitis. We are told that many patients with sphincter of Oddi dysfunction also have abnormal pancreatic sphincters (1). Our cherished belief that cutting the biliary or pancreatic sphincter—an action associated with very real risk—terminates its existence as a functional muscle is apparently wrong; repeat manometry can and frequently does show persisting high pressure. The biliary sphincter seems to be asymmetric (2), possibly as a result of the septum between the biliary and pancreatic ducts, which means that accurate pressure measurements may be dependent on the fortuitous conjunction of catheter ports and squeezing muscle. Those of us who perform these studies wonder how to interpret high pressure in only one lead. No two centers seem to perform SOM in exactly the same way, making comparisons between studies difficult if not meaningless. As someone who performs biliary and pancreatic manometry on a regular basis, I am less sure now than I ever was of being able to predict the result of sphincterotomy performed to treat biliary pain or recurrent pancreatitis, especially in those with type III SOD. Although never a manometry enthusiast, I find it increasingly difficult to know what we are measuring. Can we do without SOM? I know several technically excellent ERCP endoscopists who cut every suspect biliary and pancreatic sphincter they come across, without prior manometry. They argue that as the risk of pancreatitis is increased when SOM is performed, they would rather take their chances with a complication of sphincterotomy, which they believe will deal with the problem (biliary microlithasis, SOD, recurrent pancreatitis) in the majority of cases. All endoscopists who perform SOM know the agony of giving a patient who has a normal study bad pancreatitis. It is worst of all possible worlds: negative data, no treatment, and an ugly complication that may keep the patient in the hospital for weeks or months. Would that we could replace manometry by a less invasive (or preferably noninvasive) radiological test of biliary and pancreatic secretion. A radionuclide hepatobiliary scan with time measured from the appearance of tracer at the liver hilum to its delivery into the duodenum has been touted as a possible alternative to SOM (3). However, solid data that this technique is comparable to SOM in sensitivity and specificity are lacking.