Purpose: To evaluate the effectiveness and the prognostic factors of the bladder stones (BS) treatment by means of extracorporeal shock wave lythotripsy (ESWL).
Methods: 183 patients with BS treated using ESWL were retrospectively analysed. Independent variables were: gender, age, obstruction, BS size, BS number and amount of waves. Dependent variable was total BS resolution. Statistical analysis was provided by Cox's regression multivariate analysis, Kaplan-Meier analysis and the t Student test.
Results: Total effectiveness of the treatment was 73%. Initial BS size was the only prognostic factor on multivariate analysis (p = 0.0035) with smaller stones obtaining the best results (log rank p = 0.00001): 92% of effectiveness in BS smaller than 1 cm2, 73% in 1-2 cm2, 57% in 2-3 cm2 and 42% in larger than 3 cm2. BS mean size decreased 2 cm2 after the first ESWL (p = 0.00001).
Conclusions: Initial BS size was the only prognostic factor of resolution. Total effectiveness was 73% and it highly increased in BS smaller than 2 cm2.