A Comparative Study on the Efficacy of Covered Metal Stent and Plastic Stent in Malignant Biliary Obstruction

Kim, Jun Hwan; Jang, Byung Ik; Kim, Tae Nyeun; Chung, Moon Kwan

Abstract

BACKGROUND/AIMS
Insertion of self-expanding metallic stents (SEMS) has become an established option for the palliation of malignant biliary obstruction (MBO). However, stent occlusion by tumor ingrowth is still an unsolved problem. To overcome this problem, membrane-covered SEMSs have been developed. The purpose of this study was to compare the effectiveness of membrane-covered SEMS versus plastic stent in the treatment of MBO.
METHODS
Between Jan 2001 and Jul 2002, 57 patients with unresectable MBO who initially had plastic stents inserted were randomized to receive either plastic stent and membrane-covered SEMSs after initial plastic stent failure.
RESULTS
Placement of either plastic stents or membrane-covered SEMs was successful in all patients. Mean patency duration of stents were significantly longer in membrane-covered SEMS group (189 days) than in plastic stent group (82 days) (p=0.01). The causes of stent failure were occlusion in 10 cases and migration in 1 case in membrane-covered SEMS group. Of these occluded 10 cases, tumor ingrowth was noted in 7, tumor overgrowth in 2, and biliary incrustation in 1.
CONCLUSIONS
Membrane-covered SEMS has a longer patency than plastic stent. However, new membrane covering material is needed to prevent tumor ingrowth more effectively.