An “uncovered stent-in-covered stent” technique combined with electrohydraulic lithotripsy for the removal of a displaced type B (metal) bile duct stent stone complex

A stent–stone complex is a rare long-term complication of forgotten biliary stenting,[ 1​ ] and forcible extraction of the complex carries risks of ductal injury and perforation.[ 2​ ] However, for the B-type (metal) bile duct stent–stone complex, the removal process is extremely difficult. Therefore, we describe a novel approach combining an uncovered stent-in-covered stent technique with electrohydraulic lithotripsy (EHL) to remove a displaced metal stent–stone complex ([ Video 1 ]). Video 1 An “uncovered stent-in-covered stent” technique combined with electrohydraulic lithotripsy for the removal of a displaced type B (metal) bile duct stent stone complex. Download Video A 69-year-old woman with a covered biliary stent placed 1 year ago for bile duct stenosis presented with jaundice in the urine, poor appetite, and skin itching. Computed tomography revealed progressive intrahepatic ductal dilatation, prompting endoscopic retrograde cholangiopancreatography for stent removal ( Fig. 1 ). Fig. 1 The CT scan of the upper abdomen indicating significant dilation of the bile duct, forming a bile duct–stent complex (white arrow). The endoscopy revealed that the stent head protrudes slightly beyond the duodenal papilla. The foreign object forceps repeatedly attempted to remove it but failed. The cutting knife guided catheter repeatedly inserted but failed to reach the distal bile duct. Under the direct vision of the biliary scope, it was observed that the stent was filled with inhomogeneous stones. EHL was used to remove the stones within the stent. However, the attempt to remove the stent failed again. Therefore, an 8 mm×6 cm metal bare stent was placed under the guidance of the catheter ([ Fig. 2 ]). One week later, the foreign object forceps successfully removed the internal stent, and then the external stent was pulled into the duodenal lumen, and a snare was used to capture and completely remove it. Repeat endoscopy showed no injury. Cholangiography confirmed a patent duct with mild mid-segment narrowing ([ Fig. 3 ]). Fig. 2 ( a ) The head end of the metal covered stent protrudes slightly at the duodenal papilla and is difficult to remove. ( b ) Under oral cholangioscopy, it was observed that the stent was filled with calculi and lithotripsy with electrohydraulic energy was performed. ( c ) The placement of a bare metal stent within the metal covered stent. ( d ) The cholangiography indicates that the metal uncovered stent has been successfully implanted. Fig. 3 ( a ) The foreign object forceps removed the internal stent (white arrow), and the snare removed the external covered stent (yellow arrow). ( b ) The cholangiography indicates that the bile duct is unobstructed. Unlike the conventional covered stent-in-covered stent approach, our temporary “uncovered stent-in-covered stent” technique harnesses the continuous radial force and open-cell mesh of the uncovered stent. The mesh actively interlocks with the stone complex, transmits the radial force through its interstices to break it down, and markedly increases friction to prevent stent slippage. A short 1-week dwell time allows atraumatic retrieval together with the old covered stent, effectively avoiding bile duct injury while being more economical. Endoscopy_UCTN_Code_TTT_1AR_2AZ Publication History Received: 15 March 2026 Accepted after revision: 01 June 2026 Article published online: 29 July 2026 © 2026. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/). Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany