Distal common bile duct obstruction: an experimental study in monkeys.

Biliary obstruction was accomplished by surgically occluding the distal common bile duct in seven rhesus monkeys. Ultrasound scanning at 24-hour intervals showed that dilation of the common bile duct and gallbladder occurred before elevation of bilirubin or development of jaundice. The bile ducts expanded centrifugally from the obstructing point, with dilation of the intrahepatic ducts occurring several days after the onset of obstruction. After surgical release of the obstruction, the biliary ducts contracted centripetally, with the common bile duct requiring 30-50 days to return to normal size.