The Effect of Shock Wave Rate on the Outcome of Shock Wave Lithotripsy: A Meta-Analysis

Purpose: Although experimental evidence suggests that the rate of shock wave delivery can affect the outcome of shock wave lithotripsy, clinical studies produce conflicting results. We performed a systematic review and meta-analysis to define the effect of shock wave rate on the outcome of shock wave lithotripsy. Materials and Methods: A search of MEDLINE and EMBASE was performed and all randomized controlled trials comparing SWL treatment at 60 shocks per minute to 120 shocks per minute were included in the analysis. Data from 4 trials (589 patients) were pooled. The primary outcome measure was treatment outcome (success, failure), as defined by the authors of the source studies. The difference in the proportion of patients with a successful treatment outcome was compared between the 60 and 120 shocks per minute groups as a risk difference, and risk differences were pooled across the 4 trials with a fixed effects model. Results: Patients treated at a rate of 60 shocks per minute had a significantly greater likelihood of a successful treatment (risk difference 10.2, 95% CI 3.7-16.8, p = 0.002). Conclusions: Our meta-analysis suggests that patients treated at a rate of 60 shocks per minute have a significantly greater likelihood of a successful treatment outcome than patients treated at a rate of 120 shocks per minute.