A Novel, Fully Covered Laser-Cut Nitinol Stent with Antimigration Properties for Nonresectable Distal Malignant Biliary Obstruction: A Multicenter Feasibility Study

Abstract

Background/AimsStent migration occurs frequently, but the prevention of complications resulting from covered self-expandable metal stents (C-SEMSs) remains unresolved. We prospectively assessed a newly developed C-SEMS, a modified covered Zeo stent (m-CZS), in terms of its antimigration effect.MethodsBetween February 2010 and January 2011, an m-CZS was inserted into 42 patients (31 initial drainage cases and 11 reintervention cases) at a tertiary referral center and three affiliated hospitals. The laser-cut stent was flared for 1.5 cm at both ends, with a 1 cm raised bank located 1 cm in from each flared end. The main outcome of this study was the rate of stent migration, and secondary outcomes were the rate of recurrent biliary obstruction (RBO), the time to RBO, the frequencies of complications, and overall survival.ResultsOf the 31 patients with initial drainage, stent migration occurred in four (12.9%, 95% confidence interval, 5.1% to 29.0%), with a mean time of 131 days. RBO occurred in 18 (58%), with a median time to RBO of 107 days. Following previous C-SEMS migration, seven of 10 patients (70%) did not experience m-CZS migration until death.Conclusionsm-CZSs with antimigration properties effectively, although not completely, prevented stent migration after stent insertion.

Pilot study of a novel, large‐bore, fully covered self‐expandable metallic stent for unresectable distal biliary malignancies

“…In addition, because stent migration of our novel stent was observed in three (8%) patients, which is the same as the rate observed for the partially covered WallFlex stents (8%) in our WATCH study, the anti‐migration system of the present FCSEMS‐12 does not appear to be sufficient to prevent stent migration. In previous studies of CSEMS migration, the flared ends and banked features of the CSEMS were not found to significantly prevent stent migration . However, in a study using different types of FCSEMS with anchoring flaps for benign biliary strictures, stent migration was not noted over a period of 6 months, and the FCSEMS removal rate was 100% .…”

“…In previous studies of CSEMS migration, the flared ends and banked features of the CSEMS were not found to significantly prevent stent migration. 20,24,25 However, in a study using different types of FCSEMS with anchoring flaps for benign biliary strictures, stent migration was not noted over a period of 6 months, and the FCSEMS removal rate was 100%. 24 Additionally, CSEMS with low RF have been associated with migration.…”

Percutaneous Management of Malignant Biliary Strictures: Current Status and Future Directions

“…Isayama et al described a modified Zeo stent with flared ends which effectively, though not completely, prevented stent migration. 38 A randomized trial with 120 patients showed an increased stent patency with antimigration covered stent compared to uncovered stents (187 vs. 132 days). 39 Published studies demonstrate conflicting evidence as to whether CSEMS increase stent patency.…”

Endoscopic ultrasonography‐guided choledochoduodenostomy using a newly designed laser‐cut metal stent: Feasibility study in a porcine model

“…2,13,14 To reduce stent migration, covered stents have been equipped with various mechanical, antimigration properties, including different stent frameworks, different membrane materials, high radial force (RF), different flare structures, and inclusion of an anchoring flap. [15][16][17] Stent flare structure and low RF have been associated directly with stent migration. 8,16,18 RF is the radially outward expanding force that maintains luminal patency at the stricture following stent deployment.…”