RIRS outcomes of conventional and pulse-modulated Ho:YAG lasers versus thulium fiber laser: a multinomial matching analysis.

To compare the impact of conventional Ho:YAG, pulse-modulated Ho:YAG, and thulium fiber laser (TFL) on surgical outcomes in patients undergoing retrograde intrarenal surgery (RIRS) for renal stones using a propensity score–matched design. We retrospectively reviewed 1,039 adults who underwent RIRS for renal stones between 1 January 2022 and 1 June 2025 at a center; 755 patients met the inclusion criteria. Patients were categorized by laser type: Group 1, conventional 30 W Ho:YAG; Group 2, pulse-modulated 65 W Ho:YAG; Group 3, 60 W TFL. Demographic variables, stone characteristics, laser-on time, operative time, total energy use, need for auxiliary procedures, complications, and stone-free rate (SFR) after the first session were recorded. To minimize baseline imbalances, three-arm 1:1:1 nearest-neighbor propensity score matching based on multinomial logistic regression was performed using age, sex, BMI, side, stone location, total stone burden, and HU as covariates, yielding 513 matched patients (171 per group). Both multivariable logistic regression analysis and effect size analysis were performed. Before and after matching, demographic features and stone characteristics were comparable across groups. In both the crude and matched cohorts, TFL (Group 3) was associated with shorter laser-on and operative times and lower total energy consumption than Ho:YAG groups. SFR, the need for auxiliary procedures, and complication rates did not differ among the three groups. In the multivariable logistic regression analysis, no independent predictive factor affecting SFR was identified. However, TFL demonstrated medium-to-large effect sizes on operative parameters. In RIRS for renal stones, TFL enables more efficient lithotripsy than conventional and pulse-modulated Ho:YAG lasers, with shorter laser-on and operative times and reduced energy use, while maintaining similar SFR and complication rates. TFL is a safe and effective alternative to Ho:YAG-based lithotripsy.