Bacterial biofilm and clogging of biliary stents.

Endoscopic biliary stenting has become a standard palliative treatment for obstructive jaundice due to malignancies of the pancreas and the hepatobiliary system. Despite the high initial success rate in achieving biliary drainage, durable endoscopic stenting has been limited by the clogging of biliary stents, usually after 4-5 months, due to formation of an adherent bacterial biofilm. Various methods have been investigated for the prevention of bacterial adhesion and prolongation of stent patency. These include: 1) prophylactic use of antimicrobial agents and bile salts; 2) testing of new stent material and new designs for these biliary stents; and 3) the recent introduction of self-expandable metal stents. Each method has its own merits as well as specific problems. This article reviews the pathogenesis of biofilm formation on the biliary stents and the latest status of research in avoiding the problem of stent occlusion.