Abstract

Background
/Aims: In order to provide a complete ob- stacle to tumoral growth, we designed a new self- expandible metal stent fully covered with polyurethane membrane. The purpose cf the study was to compare the safety and effectiveness of a new membrane-covered Niti-S stent versus conventional uncovered Wallstent. Methods: In a prospective trial, 59 patients with malignant extrahepatic biliary obstruction received either a newly developed covered metal stent (Niti-S stent, 30 cases) or an uncovered metal stent (Wallstent, 29 cases) by the endoscopic trans-papillary route. Results: Effective biliary decompression was achieved in all patients initially, and short-term results were similar in both groups. Stent failure was observed in 4 of the 30 patients (13%) after a median period of 165 days in the Niti-S group and in 8 of the 29 patients (28%) after a median period of 152 days in the Wallstent group. The reasons of stent failure were occlusion (n=3) and migration (n=l) in the covered Niti-S stent group and occlusion (n=8) in uncovered Wallstent group. According to the Kaplan-Meier life table analysis, the patency rates after 90, 180, and 360 days were 100%, 90%, and 74% in covered Niti-S stent group and 100%, 73%, and 61% in uncovered Wallstent group respectively. The occluded membrane-covered Niti-S stent was easily removed endoscopically and a new Niti-S stent was reinserted in one patient. Conclusions: The new, membrane-covered Niti-S stent has a lower stent failure rate and a tendency toward long-term patency rate compared to uncovered Wallstent. The covering may effectively prevent tumor ingrowth and it is sometimes possible to remove an occluded Niti-S stent. (Korean J Gastrointest Endosc 2001;23:93-99)

• Keywords: 악성 담관협착 , 막을 부착한 Niti - S 스텐트 , 막을 부착하지 않은 Wallstent , Malignant biliary obstruction , Membrane - covered Niti - S stent , Uncovered Wallstent