Biliopancreatic reflux-pathophysiology and clinical implications.

The common bile duct and the main pancreatic duct open into the duodenum, where they frequently form a common channel. The sphincter of Oddi is located at the distal end of the pancreatic and bile ducts; it regulates the outflow of bile and pancreatic juice. In patients with a pancreaticobiliary maljunction, the action of the sphincter does not functionally affect the junction. Therefore, in these patients, two-way regurgitation (pancreatobiliary and biliopancreatic reflux) occurs. This results in various pathological conditions of the biliary tract and the pancreas. Biliopancreatic reflux could be confirmed by: operative or postoperative T-tube cholangiography; CT combined with drip infusion cholangiography; histological detection of gallbladder cancer cells in the main pancreatic duct; and reflux of bile on the cut surface of the pancreas. Biliopancreatic reflux occurs frequently in patients with a long common channel. Although the true prevalence, degree, and pathophysiology of biliopancreatic reflux remain unclear, biliopancreatic reflux is related to the occurrence of acute pancreatitis. Obstruction of a long common channel easily causes bile flow into the pancreas. Even if no obstruction is present, biliopancreatic reflux can still result in acute pancreatitis in some cases.