Electrohydraulic Lithotripsy for Difficult Common Bile Duct Stones

Efficacy

When performed under direct cholangioscopic visualization after failure of standard extraction methods, electrohydraulic lithotripsy (EHL) achieves stone clearance in 73‑97 % of cases. 1
Single‑operator cholangioscopy‑guided intraductal EHL also yields stone clearance rates of 73‑97 %. 2
Both EHL and laser lithotripsy, when applied under cholangioscopic guidance, provide comparable high clearance rates of 73‑97 %. 3

EHL is indicated after failure of conventional stone extraction techniques (e.g., mechanical lithotripsy, endoscopic papillary balloon dilation with prior sphincterotomy). 1
Specifically, failure of endoscopic papillary balloon dilation with prior sphincterotomy constitutes a clear indication for EHL. 4

The single‑operator cholangioscopy (SOC) platform—exemplified by the SpyGlass system (introduced 2006, digital version 2015)—allows a disposable cholangioscope with fiber‑optic or digital visualization to be passed through the duodenoscope for EHL. 5

Insert the cholangioscope through the duodenoscope to obtain direct visualization of the bile duct. 4
Position the EHL probe under direct vision and aim it precisely at the target stone. 1
Deliver a high‑voltage spark to generate hydraulic shock waves that fragment the stone into removable pieces. 3

The overall complication profile of cholangioscopy‑guided EHL is comparable to conventional ERCP. 2
Post‑procedure cholangitis occurs in up to 9 % of patients; prophylactic antibiotics are recommended to mitigate this risk. 1
Blind instrumentation of the bile duct carries a high risk of perforation and subsequent stricture formation; therefore, cholangioscopic (choledochoscopic) exploration should be used whenever feasible. 4

Cholangioscopy‑assisted lithotripsy (EHL or laser) should be employed when standard techniques such as mechanical lithotripsy or EPBD with prior sphincterotomy have failed. 3
In the small subset of patients in whom EHL and other advanced endoscopic methods are unsuccessful, percutaneous stone extraction or open duct exploration become necessary alternatives. 6

Continuous cholangioscopic visualization during energy delivery is required to ensure safety and precise targeting of the stone fragments. 7, 8, 9, 10
Direct visualization is mandatory; performing blind instrumentation of the bile duct markedly increases the risk of perforation and subsequent stricture formation. 9
Direct cholangioscopic guidance is essential for both safety and accurate targeting throughout the fragmentation process. 7, 8, 9, 10
Careful positioning of the EHL probe (within ~1 mm of the stone surface) is necessary to avoid ductal injury from the hydraulic shock wave. 7, 8

Electrohydraulic lithotripsy should be employed after failure of standard extraction techniques such as mechanical lithotripsy, endoscopic papillary balloon dilation, and prior sphincterotomy. 7, 9, 10
Stone clearance rates of 73 %–97 % are achievable when EHL is performed under cholangioscopic guidance. 7, 9, 10
Single‑operator cholangioscopy platforms (e.g., SpyGlass) enable EHL delivery through the duodenoscope, facilitating the procedure. 7, 8, 9, 10

Current guidelines do not specify universal voltage or joule settings for EHL; energy delivery must be individualized. 7, 8, 9, 10

Post‑procedure cholangitis occurs in up to 9 % of patients; prophylactic antibiotics are recommended. 7, 9
Overall complication rates are comparable to conventional ERCP when EHL is performed under direct cholangioscopic vision. 7, 9
Complications can be minimized by never advancing the probe blindly and maintaining continuous visualization throughout the procedure. 9

When performed under cholangioscopic guidance, both laser lithotripsy and EHL achieve the guideline‑cited stone‑clearance range of 73 %–97 %. 7, 9, 10