Ultraslow versus slow-rate shockwave lithotripsy in the management of renal stone: A randomized controlled trial

This study aimed to evaluate the efficacy of ultraslow shockwave (SW) lithotripsy compared with slow-rate SW lithotripsy (SWL) in the management of renal stones using a common power ramping protocol.

This randomized trial enrolled patients with solitary renal calculus ≤2 cms between December 2021 and February 2024. Ultraslow lithotripsy (40 patients) was applied at a rate of 30 shocks per minute and slowrate lithotripsy (40 patients) was applied at a rate of 60 shocks per minute. Common power ramping protocol was followed for both the groups. Up to a maximum of three sessions were carried out with follow-up at 3 months after the last session. The primary outcome was the stone-free rate.

The overall stone-free rate (SFR) was 77.5% in the ultraslow arm and 72.5% in the slow-rate arm (P = 0.60). Ultraslow group attained a higher SFR after the first session (37.5% vs. 20%; P = 0.07) with significantly lesser number of shocks (1300 vs. 1500; P < 0.01). Complications were only mild and similar between both the groups (P = 0.06), with a longer treatment duration in the ultraslow group (100 min vs. 50 min; P < 0.01).

In the setting of an electromagnetic lithotripter with a common ramping protocol and equal energy SWs, both ultraslow and slowrate SWL achieved a comparable overall stone-free rate with a similar safety profile. Higher number of patients in the ultraslow arm, almost double that of the slow arm, attained stone-free status after the first session itself with significantly fewer shocks.