Gel immersion electrohydraulic lithotripsy for gallbladder stones through a lumen-apposing metal stent

Peroral cholecystoscopy through a lumen-apposing metal stent (LAMS) after endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) enables the direct visualization and lithotripsy of gallbladder stones [ 1 ] [ 2 ]. However, saline irrigation may fail to achieve complete stone submersion because of rapid outflow through the large-caliber LAMS [ 3 ]. Gel immersion endoscopy maintains a clear visual field with lower intraluminal pressure than saline [ 4 ] and has been applied for bile duct lithotripsy [ 5 ], but not yet reported for gallbladder stones. A 78-year-old woman, a poor surgical candidate, presented with acute cholecystitis caused by a 15-mm stone impacted in the gallbladder neck ([ Fig. 1 ]). EUS-GBD was performed using a 10-mm Hot AXIOS stent (Boston Scientific, Marlborough, MA, USA; [ Fig. 2 ]). Acute cholecystitis resolved promptly. Fig. 1 Contrast-enhanced computed tomography at the time of diagnosis of acute cholecystitis. a An axial view showing gallbladder distension, wall thickening, and pericholecystic inflammation (yellow arrowheads). b A coronal view demonstrating a 15-mm stone impacted in the gallbladder neck (yellow circle). Fig. 2 Endoscopic ultrasound-guided gallbladder drainage (EUS-GBD) for acute cholecystitis. a An endoscopic view after lumen-apposing metal stent (LAMS) deployment, showing drainage of purulent bile (blue arrowheads). b A fluoroscopic image confirming the placement of the LAMS from the duodenal bulb to the gallbladder (blue circle). Ten days later, peroral cholecystoscopy was performed using an ultrathin endoscope (GIF-1200N; Olympus, Tokyo, Japan). Gel immersion electrohydraulic lithotripsy (EHL) was performed using Viscoclear (Otsuka Pharmaceutical Factory, Tokushima, Japan), an electrolyte-free gel with viscoelastic properties compatible with electrosurgical procedures [ 4 ]. The gel was injected through the working channel. Despite the large-caliber LAMS, 10 mL per injection sufficed to submerge the stone and provide excellent visualization during EHL ([ Fig. 3 ]). The viscosity minimized fragment dispersion and maintained a clear field ([ Video 1 ]). The gel was easily removed by aspiration and saline flushing. Complete stone clearance was achieved using a Memory Basket Eight Wire (Cook Medical, Bloomington, IN, USA), with a total gel volume of less than 100 mL ([ Fig. 4 ]). In larger gallbladders, excess gel would naturally drain through the LAMS. Other gels with similar properties may be applicable. Fig. 3 Endoscopic views during gel immersion electrohydraulic lithotripsy (EHL) via the lumen-apposing metal stent (LAMS) using an ultrathin endoscope. a Complete stone submersion is achieved with a small volume of gel despite the large-caliber LAMS. b Stone fragmentation is performed using EHL. Download Video Gel immersion electrohydraulic lithotripsy for gallbladder stones through a lumen-apposing metal stent.Video 1 Fig. 4 Endoscopic views during stone extraction and final inspection under gel immersion. a Stone fragments are retrieved using an 8-wire basket. b Final cholecystoscopy under gel immersion confirms complete stone clearance. The low-pressure environment provided by gel immersion was considered advantageous for the fragile gallbladder wall following acute inflammation. The patient recovered without complications. This is the first report of gel immersion EHL through a LAMS for gallbladder stone removal, effectively overcoming the limitations of saline irrigation. Endoscopy_UCTN_Code_CCL_1AZ_2AD Endoscopy_UCTN_Code_CPL_1AK_2AF Endoscopy_UCTN_Code_TTT_1AR_2AH Endoscopy_UCTN_Code_TTT_1AR_2AL Publication History Article published online: 28 January 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