Expandable biliary endoprosthesis: an experimental study.

Expandable stents constructed of stainless-steel wire were inserted in the extrahepatic bile ducts of five animals to determine the effect of the endoprosthesis on the ductal wall. The stents were left in place 4-23 weeks, at which time the bile ducts were inspected. The bile ducts remained patent in all animals. Relatively mild reactive inflammatory changes observed in the wall of the bile ducts were more pronounced in animals with stents in place for the longest periods. A relatively small-caliber catheter (9 French) was necessary for the introduction of the stent, which acquired a much larger diameter once it was released from the catheter. This study suggests that expandable wire stents could be safely used to relieve biliary obstruction.