Sphincter of Oddi dysfunction (SOD) was defined according following Classification. Biliary type I SOD was defined as biliary-type abdominal pain, liver enzyme elevation, and common bile duct dilation > 9mm. Biliary type II SOD was defined as biliary-type abdominal pain and either abnormal liver enzymes or a dilated bile duct. Biliary type III SOD was defined as biliary-type pain without any other objective findings. Pancreatic type I SOD was defined as pancreatic-type pain and a dilated pancreatic duct and elevated pancreatic enzymes, or recurrent acute pancreatitis. Type II pancreatic SOD was defined as pancreatic-type pain and a dilated pancreatic duct or elevated pancreatic enzymes. Type III pancreatic SOD was defined as pancreatic-type pain alone.