Predictors of Treatment Outcomes and Technical Limitations of POPS-guided Electrohydraulic Lithotripsy for Pancreatic Duct Stones

Purpose The optimal endoscopic approach for pancreatic duct stones in chronic pancreatitis remains unclear, particularly regarding the selection between extracorporeal shock wave lithotripsy (ESWL) and peroral pancreatoscopy-guided electrohydraulic lithotripsy (POPS-EHL). This study aimed to evaluate the efficacy and limitations of POPS-EHL and to identify pre-procedural predictors of incomplete fragmentation. Methods We retrospectively analyzed patients who underwent POPS-assisted treatment for pancreatic duct stones at a tertiary center between 2017 and 2025. Clinical outcomes, adverse events, and factors associated with incomplete EHL were assessed, and multivariate logistic regression was used to identify independent predictors of EHL failure. Results POPS insertion was feasible in 47 of 52 patients (90.4%), and 34 proceeded to POPS-EHL. Complete fragmentation without the need for ESWL was achieved in 67.6% (23/34), whereas 32.4% (11/34) required ESWL because of incomplete fragmentation. Stones requiring ESWL had significantly higher CT attenuation and larger size than those successfully fragmented. Multivariate analysis identified CT attenuation > 2,050 HU (OR 8.92; 95% CI 1.78–44.6; p = 0.007) and diameter > 12.8 mm (OR 6.45; 95% CI 1.41–29.6; p = 0.016) as independent predictors of incomplete EHL. Adverse events were limited to mild or moderate pancreatitis. Conclusion POPS-EHL is an effective option for selected patients with chronic pancreatitis. However, stones with CT attenuation exceeding 2,050 HU or a diameter greater than 12.8 mm carry a markedly higher risk of incomplete fragmentation. Incorporating these CT-based thresholds into pre-procedural planning may help guide the choice between POPS-EHL and ESWL and ultimately improve procedural efficiency and clinical outcomes.