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.

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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.

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Contributorsʼ Statement

Kiyoyuki Kobayashi: Conceptualization, Project administration, Writing – original draft. Takako Nomura: Data curation, Validation. Maki Ayaki: Data curation. Daisuke Namima: Data curation, Visualization. Hironobu Suto: Data curation, Investigation. Hideki Kamada: Data curation, Validation. Hideki Kobara: Project administration, Supervision, Writing – review & editing.

Conflict of Interest

The authors declare that they have no conflict of interest.

Acknowledgement

Division of Innovative Medicine for Hepatobiliary and Pancreatology is an endowment department, supported with an unrestricted grant from HITO Medical Center. We would like to thank Editage (www.editage.jp) for English language editing.

• References

• 1 Chan SM, Teoh AYB, Yip HC. et al. Feasibility of per-oral cholecystoscopy and advanced gallbladder interventions after EUS-guided gallbladder stenting (with video). Gastrointest Endosc 2017; 85: 1225-1232
• 2 Campbell C, Pawa R. Definitive nonsurgical management of stump cholecystitis with EUS-guided lumen-apposing metal stent placement and electrohydraulic lithotripsy. VideoGIE 2023; 8: 203-205
• 3 Vara-Luiz F, Mendes I, Nunes G. et al. Endoscopic ultrasound-guided cholecystoduodenostomy followed by stone clearance using electrohydraulic and mechanical lithotripsy in a frail patient with acute cholecystitis. Endoscopy 2024; 56: E1006-E1007
• 4 Yano T, Takezawa T, Hashimoto K. et al. Gel immersion endoscopy: Innovation in securing the visual field – Clinical experience with 265 consecutive procedures. Endosc Int Open 2021; 9: E1123-E1127
• 5 Miyano A, Ogura T, Okuda A. et al. Gel-immersion electrohydraulic lithotripsy during digital single-operator cholangioscopy is helpful when bleeding occurs. Endoscopy 2023; 55: E98-E99

Publication History

Article published online:
28 January 2026