RESUMO
OBJECTIVE: To assess the safety of increasing the number of waves per session in the treatment of urolithiasis using extracorporeal lithotripsy. MATERIAL AND METHODS: Prospective, comparative, nonrandomized parallel study of patients with renoureteral lithiasis and an indication for extracorporeal lithotripsy who were consecutively enrolled between 2009 and 2010. We compared group I (160 patients) treated on schedule with a standard number of waves/session (mean 2858,3±302,8) using a Dornier lithotripter U/15/50 against group II (172 patients) treated with an expanded number of waves/session (mean, 6728,9±889,6) using a Siemens Modularis lithotripter. The study variables were age, sex, location, stone size, number of waves/session and total number of waves to resolution, stone-free rate (SFR) and rate of complications (Clavien-Dindo classification). Student's t-test and the chi-squared test were employed for the statistical analysis. RESULTS: The total rate of complications was 11.9% and 10.46% for groups I and II, respectively (P=.39). All complications were minor (Clavien-Dindo grade I). The most common complications were colic pain and hematuria in groups I and II, respectively, with a similar treatment intolerance rate (P>.05). The total number of waves necessary was lower in group II than in group I (P=.001), with SFRs of 96.5% and 71.5%, respectively (P=.001). CONCLUSION: Treatment with an expanded number of waves per session in extracorporeal lithotripsy does not increase the rate of complications or their severity. However, it could increase the overall effectiveness of the treatment.