Extracorporeal shock wave lithotripsy is a safe and effective treatment for pancreatic stones coexisting with pancreatic pseudocysts

Background and Aims: We aimed to investigate outcomes of pancreatic extracorporeal shock wave lithotripsy (P-ESWL) for the removal of large pancreatic stones coexisting with pancreatic pseudocysts (PPCs) in chronic pancreatitis (CP). Methods: This is a prospective study performed in CP patients with at least 1 stone (>= 5 mm). Patients were divided into the PPC group (stones coexisting with PPCs) or the control group (stones alone). Patients were initially subjected to successive P-ESWL treatments, followed by ERCP. Primary outcomes were P-ESWL adverse events, and secondary outcomes were stone clearance, long-term pain relief, improved quality-of-life scores, and PPC regression. Results: A total of 849 patients (59 in the PPC group and 790 in the control group) was subjected to P-ESWL between March 2011 and October 2013. Occurrences of P-ESWL adverse events were similar between the PPC group and the control group (11.86% vs 12.41%, P = .940). After the treatment of initial P-ESWL combined with ERCP, the complete, partial, and nonclearance of stones occurred in 67.24%, 20.69%, and 12.07%, respectively, of patients in PPC group, with no significant difference from the control group (complete, partial, and nonclearance: 83.17%, 10.40%, and 11.39%, respectively; P = .106). Fifty-five of 59 patients (93.22%) with PPCs were followed for a median period of 21.9 months (range, 12.0-45.1). PPCs disappeared in 56.36% (31/55) and 76.36% (42/55) of patients after 3 months and 1 year of follow-up visits, respectively. Moreover, complete and partial pain relief were achieved in 63.64% (35/55) and 25.45% (14/55) of patients, respectively. The scores for quality of life (P < .001), physical health (P < .001), and weight loss (P < .001) improved. Conclusions: In our multispecialty tertiary center, initial P-ESWL followed by ERCP was safe in patients with coexisting pancreatic stones and PPCs and effective for stone clearance, main pancreatic duct drainage, and pain relief.