Application of the "covered-stent-in-uncovered-stent" technique for easy and safe removal of embedded biliary uncovered SEMS with tissue ingrowth.

self-expandable metal stents (uSEMS) is regarded as difficult or even impossible when the duration of indwell exceeds a couple of weeks, because of the ingrowth of tissue [1–3]. The presence of diffuse and severe ingrowth is the main feature limiting SEMS removal [1]. In the esophagus, placement of a self-expanding plastic stent (SEPS) inside the SEMS has been shown to induce pressure necrosis of this tissue hyperplasia, allowing subsequent removal of the stent [4]. We applied this technique in a 58-year-old patient with a history of alcohol abuse, obstructive jaundice, and suspected malignancy, in whom an uSEMS 10mm wide and 6 cm long (Wallflex; Boston Scientific, Natick, Massachusetts, USA) had been mistakenly inserted more than 1 year before. The patient had experienced recurrent cholangitis due to stent obstruction caused by tissue ingrowth. Stent removal was therefore considered, but was unsuccessful using conventional maneuvers. A covered SEMS (Wallflex) was then placed inside the uSEMS (●" Figs. 1, 2). The patient developed acute cholecystitis and a liver abscess, needing percutaneous drainage and prolonged antibiotherapy. Four weeks later, after resolution of the sepsis, removal of both stents was reattempted but failed due to persistent tissue ingrowth. A new covered SEMS was inserted for another 4-week period. Endoscopic retrograde cholangiopancreatography showed spontaneous migration of the covered stent and disappearance of the tissue hyperplasia, except at the distal end of the metal stent (●" Fig. 3). Removal of the uncovered stent was, however, easy using a rat-tooth forceps (●" Fig. 4). Damage to the bile duct was checked using SpyGlass (Boston Scientific), which showed permeability and no residual stricture (●" Fig. 5). Removal of biliary uncovered SEMS is less successful than removal of covered stents (0–38% vs. 92%). We previously reported on piecemeal extraction of double uncovered Wallstents in a laborious procedure [5]. More recently we applied the “covered-stent-in-uncovered-stent” technique described for removal of esophageal SEMS in the biliary tree and showed that a period of 6–8 weeks might be appropriate for successful and less time-consuming removal.