Authors: Byoung Wook Bang Seok Jeong Don Haeng Lee Jung Il Lee Se Chul Lee SungGwon Kang
Publish Date: 2011/11/19
Volume: 57, Issue: 4, Pages: 1056-1063
Abstract
Covered biliary metal stents have been introduced for the purpose of overcoming tumor ingrowth and treatment of benign biliary stricture The aim of this study was to evaluate the biodurability of three commercially available biliary metal stent covering materials ePTFE expanded polytetrafluoroethylene silicone and polyurethane in a bile flow phantomBy operation of a peristaltic pump human bile was circulated continuously in an experimental perfusion system containing covered metal stents Each stent was removed respectively 1 2 4 and 6 months after bile exposure We performed a gross inspection of the covered stents The covering membrane was detached from the stent and observed by scanning electron microscopy SEM Finally we measured tensile and tear strength of the membranesBilestaining of the membrane showed gradual progression after bile exposure however progress was the fastest in ePTFE SEM examination showed that the polyurethane surface was smooth and the silicone surface was relatively smooth However ePTFE had a rough and uneven surface After bile exposure there were no significant changes in polyurethane and silicone however biofilms and microcracks were observed in ePTFE In contrast to a gradual decrease of tensile/tear strength of polyurethane and silicone those of ePTFE showed a rapid reduction despite of the strongest baseline tensile and tear strengthePTFE tended to form biofilms more frequently than polyurethane and silicone during bile exposure ePTFE seemed to be less durable than silicone and polyurethane however as clinically applicable material because of strong absolute tensile/tear strengths
Keywords: