Predictors of Prolonged Treatment Duration: Laser and/or Extracorporeal Shock Wave Lithotripsy of the Pancreatic Stones

Abstract

We reported single-session endoscopic treatment of the pancreatic stones using pancreatoscopic laser lithotripsy (PSLL) in a selected patient group (Hirai T. Endoscopy 2004; 36: 212-6). But the other many patients undergo extracorporeal shock wave lithotripsy (ESWL) in subsequent sessions, and need a long treatment period. This study investigated the predictors of prolonged treatment duration using PSLL and/or ESWL of the pancreatic stones. Methods: Sixty-two consecutive patients with symptoms who received PSLL and/or ESWL of pancreatic stones in our institute were included in this study. We excluded the patients who underwent only simple basket lithotomy. PSLL was selected for the first-choice treatment only for patients without sever stricture of the main pancreatic duct. Consequently, fifteen patients underwent only PSLL, 25 patients underwent PSLL and ESWL, and 22 patients underwent only ESWL. The clinical end point was defined as sufficient patency of the main pancreatic duct and without large stones in the main pancreatic duct. At 2 months from beginning of therapy, the patients did not get to the clinical end point were defined as prolonged treatment group. Various predictors, including size, location, number of stones, stone developing into branch ducts or not, therapeutic methods, cause of chronic pancreatitis, and sex were analyzed in relation to the prolonged treatment duration. Multivariate logistic regression analysis was performed to determine the significance of various predictive variables. The continuous variables were compared by the Student t-test. Results: The symptoms of all patients were disappeared or decreased after treatment. The prolonged group included 27 (43.5%) patients. Stone developing into branch ducts was only significant factor that predicted prolonged (more than 2 months) treatment duration (p=0.0001). Mean treatment periods of the patients with stones developing into branch ducts or not were 77.9 ± 14.6: 28.4 ± 42.1 days (p<0.0001), respectively. Finally 56 patients (90.3%) got clinical end point, mean treatment duration of all patients was 48.7 ± 37.9 days, and mean size of the stones was 14.6 ± 6.7 mm. Conclusions: Our laser and/or extracorporeal shock wave lithotripsy of the pancreatic stones achieves high cure rate and disappearance or decrease of symptoms. The only significant factor that prolongs treatment duration is stone developing into branch ducts.