Extracorporeal shock wave lithotripsy with pancreatic stent prevents spontaneous clearance of stone

Extracorporeal shock wave lithotripsy (ESWL) is currently the first-line treatment for pancreatic stones larger than 5 mm. However, it remains unclear whether the presence of a preexisting pancreatic stent during ESWL influences the procedure's efficacy or complication rate. This study aims to evaluate whether the stent should be removed prior to ESWL.

All consecutive patients who underwent ESWL between March 2011 and March 2020, with a history of pancreatic stent placement within the two years preceding ESWL, were included in the study. Based on the presence or absence of an indwelling pancreatic stent during the ESWL procedure, the patients were categorized into two groups: the stent group and the non-stent group. The primary outcome assessed was the rate of spontaneous stone clearance following ESWL. The secondary outcome included number of ESWL shock waves and post-ESWL complications.

A total of 704 patients were initially enrolled. After exclusions, 117 patients in the non-stent group and 200 in the stent group were included in the final analysis. The rate of spontaneous stone clearance was significantly higher in the non-stent group than in the stent group (64.1% vs. 28.5%; p < 0.001). However, no significant differences were observed between the two groups in the number of shock waves required for successful stone fragmentation (7475.0 ± 3508.7 vs. 7777.8 ± 3908.7; p = 0.478), nor in the overall incidence of post-ESWL complications (5.5% vs. 7.7%; p = 0.439).

The presence of a pancreatic stent is associated with reduced rates of spontaneous stone clearance but does not significantly affect the incidence of ESWL-related complications. Therefore, proactive removal of the stent prior to ESWL may be considered.