Pancreatic extracorporeal shockwave lithotripsy (ESWL) is the first-line therapy for pancreatic stone larger than 5mm. Whether a preexisting pancreatic stent during ESWL have an impact on efficacy and complications of ESWL has not been investigated. We aimed to determine whether the stent should be removed before ESWL.

All consecutive patients who underwent ESWL from March 2011 to March 2020 with a history of pancreatic stent placement within two years before ESWL were included. According to whether the pancreatic stent was in place during ESWL, patients were further divided into the stent group and the non-stent group. The primary outcome was the rate of spontaneous stone clearance after ESWL. The secondary outcome included number of ESWL shock waves and post-ESWL complications.

A total of 704 patients were initially included. After exclusions, 117 patients in the non-stent group and 200 patients in the stent group were finally studied. A significantly higher rate of spontaneous stone clearance was achieved in the non-stent group compared with the stent group (64.1% vs. 28.5%; P<0.001). No significant difference was found in number of shock waves to achieve successful stone fragmentation between the stent group and the non-stent group (7475.0±3508.7 vs. 7777.8±3908.7; P=0.478). The overall post-ESWL complication rate did not significantly differ between two groups (5.5% vs. 7.7%; P=0.439).

Pancreatic stent prevents the spontaneous clearance of stone and does not reduce complications of ESWL. Active stent removal is recommended before ESWL.