Biliary self-expandable metal stents

Abstract

Endoscopic biliary drainage is the treatment of choice for palliation of malignant biliary obstruction, particularly in patients with a high operative risk or in cases with inoperable tumor. It is less invasive than surgical bypass and has a lower complication rate than percutaneous transhepatic cholangiography. Various stents including plastic stents of different configurations and uncovered, partially covered, or fully covered metal stents are available which can be used for this purpose. Self-expandable metal stents (SEMS) were introduced to overcome the problem of early clogging of plastic stents. The larger-diameter and self-expandable mesh structure of SEMS reduce the incidence of sludge occlusion and migration. However, the disadvantage of the uncovered SEMS is occlusion due to tumor ingrowth or tissue hyperplasia through the stent mesh, and the impossibility of removal. The covered metallic stents were developed to overcome tissue ingrowth and the other disadvantages of uncovered SEMS. Removable fully covered SEMS are being used for treatment of benign biliary strictures. The precise applications and patient selection for each of these stents are still a matter of considerable research and debate. All available biliary metal stents are effective, but definitive data favoring one stent over another are currently lacking. This chapter gives an overview of the some of the biliary SEMS which are commercially available.