Optimal shock wave rate for shock wave lithotripsy in urolithiasis treatment: a prospective randomized study

We aimed to compare the effects of a fast shock wave rate (120 shocks per minute) and a slow shock wave rate (60 shocks per minute) on the shock wave lithotripsy (SWL) success rate, patient's pain tolerance, and complications.

A total of 165 patients with radiopaque renal pelvis or upper ureter stones were included in the study. Patients were classified by use of a random numbers table. Group I (81 patients) received 60 shock waves per minute and group II (84 patients) received 120 shock waves per minute. For each session, the success rate, pain measurement, and complication rate were recorded.

No statistically significant differences were observed in the patients according to age, sex, body mass index, stone size, side, location, total energy level, or number of shocks. The success rate of the first session was greater in group I than in group II (p=0.002). The visual analogue pain scale was lower in group I than in group II (p=0.001). The total number of sessions to success and the complication rate were significantly lower in group I than in group II (p=0.001).

The success rate of SWL is dependent on the interval between the shock waves. If the time between the shock waves is short, the rate of lithotripsy success decreases, and the pain measurement score and complications increase. We conclude slow SWL is the optimal shock wave rate.