Multicenter randomized trial of the spiral Z-stent compared with the Wallstent for malignant biliary obstruction.

Background: The industry standard since 1990 for self-expanding biliary metallic stents has been the Wallstent. In 1998 the Spiral Z-stent was released. This randomized trial compared the Z-stent with the Wallstent in the treatment of malignant biliary obstruction.