Removal of Duckbill‐type laser‐cut anti‐reflux metal stents: Clinical evaluation and in vitro study

Abstract

Objectives Duckbill‐type metal stent (DMS) was the first laser‐cut biliary metal stent with an anti‐reflux valve. Removal of DMS is believed to be difficult and relevant reports are scarce. This study aims to investigate the feasibility of DMS removal. Methods We retrospectively analyzed patients who underwent DMS removal between June 2019 and March 2022 to evaluate success rates and factors affecting outcomes. In addition, six different methods of DMS removal were reproduced in vitro, varying removal devices, angle of applied force, and grasped location. Extraction resistance, the distance of forceps stroke, and stent length after removal were compared. Results Forty patients were enrolled, and DMS removal was successful in 31 cases (78%). No adverse events were observed. Tumor ingrowth was evident in 78% (7/9) of failed cases. Patients receiving biliary metal stents for the first time (naïve cases), long indwelling time, longer stent, and stent tearing during removal were associated with unsuccessful stent removal. In the in vitro study, a larger force was required to remove the stent at an extraction angle of 120° than at 0°. Among cases in which force was applied at 120°, the load tended to be lower when rat‐tooth forceps were applied horizontally across the stent. Conclusions Stent removal was possible in a majority of cases. Deployment of additional stents inside DMS may be preferable to forceful removal in the presence of factors associated with difficult stent removals, such as tumor ingrowth, naïve cases, longer stents, long indwelling time, and stent tearing during removal.

Successful removal of a biliary metal stent using the stent-in-stent-in-stent technique

“…Successful removal of both uncovered [1,2] and covered SEMSs [3] has been reported using the stent-in-stent technique. The duckbill-type stent is a novel covered SEMS with an antireflux valve [4]. The removal of this kind of SEMS can be difficult [4,5].…”

“…The duckbill-type stent is a novel covered SEMS with an antireflux valve [4]. The removal of this kind of SEMS can be difficult [4,5]. When the stent-in-stent technique proves unsuccessful, the addition of a third stent may facilitate removal.…”