Optimization of Thulium Fiber Laser Lithotripsy Efficacy Based on Multidimensional Parameter Combination Strategies

This study marks the first systematic evaluation of how various parameter combinations in domestic thulium fiber lasers (TFLs) influence the efficacy of urinary stone lithotripsy.

By establishing a multiparameter decoupling experimental platform, this study enabled the systematic combination of peak power (Ppeak), average power (AP), and pulse energy (Ep) at varying levels, allowing for a comprehensive evaluation of how different parameter configurations of TFLs influence fragmentation efficiency, dusting efficiency, thermal effects, and stone retropulsion. All experiments were independently repeated at least three times. Under fixed Ep and AP, comparisons between different Ppeak levels were performed using independent-samples t tests. Under fixed Ppeak, two-way analysis of variance was applied to assess the main effects of Ep and AP and their interaction. Data are presented as mean ± SD, with statistical significance defined as p < 0.05.

At fixed Ep and AP, increasing Ppeak markedly increased TFLs' fragmentation efficiency, dusting efficiency, yet left the thermal effects statistically unchanged. At lower AP (20 W) and Ep (<0.2 J), high Ppeak significantly improved fragmentation and dusting efficiency (all p ≤ 0.001). However, the increase in stone retropulsion was not statistically significant (all p ≥ 0.051). At higher AP (40 W), the beneficial effects of increasing Ppeak on fragmentation and dusting efficiency were markedly attenuated (all p ≥ 0.053). This study was strictly limited to in vitro conditions. Although the observed parameter effects are mechanistically informative, they generate hypotheses rather than clinical implications.

Higher Ppeak with lower AP and Ep can improve fragmentation and dusting efficiency while minimizing thermal damage. Conversely, lower Ppeak with higher AP and Ep can reduce stone retropulsion while maintaining fragmentation and dusting efficiency. This study was a purely in vitro experiment. The innovative multiparameter combination optimization strategy provides theoretical support and research directions for future clinical studies, generating hypotheses for subsequent precise and personalized treatment of patients with urinary stones in different anatomical locations, rather than constituting a protocol directly applicable to clinical practice.