Rethinking high-frequency lithotripsy: a review by EAU endourology group

To evaluate the current evidence comparing high-frequency (HF) (> 20 Hz) versus low-frequency (LF) (≤ 20 Hz) laser lithotripsy in patients undergoing flexible and/or rigid ureteroscopy for renal and ureteral stones, with focus on stone-free rate (SFR), operative outcomes, and safety profiles.

A systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A search was conducted on MEDLINE and EMBASE databases through October 2025 for randomized controlled trials (RCT), prospective comparative studies, and single-arm studies involving patients undergoing ureteroscopic laser lithotripsy with holmium: yttrium aluminum-garnet (Ho: YAG), thulium fiber lasers (TFL), and pulsed Thulium: YAG (p-Tm: YAG) lasers. Primary outcomes included SFR, and secondary outcomes included operative duration, energy utilization, and complications.

Twenty-two studies encompassing 2,059 patients were included. SFR demonstrated substantial overlap between LF (67-100%) and HF (77-100%) groups. Operative times ranged from 24.7 to 96.6 min for LF and 19.9-90 min for HF settings. Energy consumption (J/mm³) showed similar ranges: 8.7-29.03 J/mm³ for LF and 1.6-27.9 J/mm³ for HF groups. Overall complication rates remained low (4-21%). Notably, studies using TFL combining HF with high-power (HP) settings for renal stones reported elevated ureteral injury rates (3.1-4.4%). Infectious complications demonstrated frequency-dependent patterns, with HF, HP Ho: YAG settings showing UTI/sepsis rates up to 2.9% in patients with large stones. Bleeding complications appeared more strongly associated with laser technology than frequency settings, with intra-op bleeding occurring more with use of Ho: YAG laser and post-op hematuria occurring more with TFL use.

HF and LF settings achieved comparable SFR and operative times. The overall incidence of ureteral injury across both frequency ranges was low. However, higher instances of ureteral injury and infection were observed in studies where HF settings were used in combination with HP. Bleeding complications were found to be related to laser technology rather than frequency.