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

Abstract
Removal of embedded biliary uncovered 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 ] [ 2 ] [ 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 10 mm 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 ]). Fig. 1 Endoscopic view of the placement of a covered self-expandable metallic stent (SEMS) inside the uncovered SEMS. Fig. 2 Fluoroscopic view of both covered and uncovered stents in the common bile duct. 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 ]). Fig. 3 Disappearance of tissue ingrowth shown by common bile duct opacification. Removal of the uncovered stent was, however, easy using a rat-tooth forceps ([ Fig. 4 ]). Fig. 4 Extraction of the uncovered SEMS with a rat-tooth forceps. Damage to the bile duct was checked using SpyGlass (Boston Scientific), which showed permeability and no residual stricture ([ Fig. 5 ]). Fig. 5 SpyGlass cholangioscopy showing permeability of the common bile duct and absence of damage after removal of the stent. 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. Competing interests: None Endoscopy_UCTN_Code_TTT_1AR_2AZ