Comparison of TFL and high-power Ho: YAG lasers with multiple pulse modulations: an in vitro study

To compare the stone ablation volume (AV) achieved by thulium fiber laser (TFL) and high-power Holmium: YAG (Ho: YAG) lasers with MOSES™, Virtual Basket™ (VB™), Vapor Tunnel™ (VT™), and Magneto pulse-modulation technologies in an artificial stone model.

BegoStone phantoms (15:6 "powder-to-water" ratio) were used. A motorized arm applied the laser at a constant speed (0.7 mm/s). Laser settings included 1.5 J × 5 Hz, 1 J × 20 Hz, and 0.3 J × 50 Hz, with five 21-mm cuts per setting. AV was calculated from width and depth measurements using an optical microscope. ANOVA was performed.

Among 750 measurements, TFL-200 μm achieved the highest AV in most settings. At 1.5 J x 5 Hz, TFL-200 μm (15.9 mm³) significantly outperformed MOSES™ (LP: 11 mm³, SP: 10.4 mm³, MD: 9.7 mm³) and Magneto (9.1 mm³) (p < 0.05). At 1 J × 20 Hz, TFL-200 μm (21.2 mm³) exceeded all technologies (p < 0.001). At 0.3 J x 50 Hz, TFL-200 μm (8.9 mm³) outperformed MOSES™ MD (3.8 mm³) and Magneto (4.9 mm³), p < 0.05. TFL-150 μm showed comparable AV to Ho: YAG lasers across settings, except at 1 J x 20 Hz, where it was lower than TFL-200 μm and CyberHo150 SP and VT™ (p < 0.05), primarily due to lower depth of fissure (DOF) while width of fissure (WOF) remained comparable. At 0.3 J × 50 Hz, TFL-150 μm (6.7 mm³) demonstrated lower AV than CyberHo150 SP (10.9 mm³; p = 0.003), but higher AV than MOSES™ MD (3.8 mm³; p = 0.034).

TFL-200 μm achieved higher AV than Ho: YAG in most settings, but statistical significance was observed in one-third of comparisons. TFL-150 μm demonstrated similar AV to Ho: YAG, except in cases where Ho: YAG had higher DOF. TFL-150 μm has known advantages in terms of irrigation, visibility, ureteroscope tip deflection, and potential for miniaturization of flexible ureteroscopy devices and aspiration methods, supporting its potential applicability for dusting strategies while maintaining comparable AV.