To compare in vitro the ablation rates of p-Tm:YAG, TFL and Ho:YAG against synthetic and human stones.
p-Tm:YAG, TFL and Low-Power (LP) Ho:YAG were compared using 270 μm core-diameter laser fibres (CDF); experiments with 200 μm(p-Tm:YAG) and 150 μm-CDF (TFL) were also included. A continuous laser emission was applied through a spiral trajectory for 20 seconds with the laser fibre tip in contact with synthetic hard (HSP) and soft stone phantoms (SSP) submerged in saline. "Dusting" settings for p-Tm:YAG(0,6 J-20 Hz-Flex Long Pulse), TFL(0,5 J-30 Hz-Short Pulse) and Ho:YAG(0,5 J-30 Hz-Long Pulse) and "Fragmentation" settings for p-Tm:YAG(1 J-15 Hz-Captive), TFL(1 J-15 Hz-Short Pulse) and Ho:YAG(1 J-15 Hz-Long Pulse) were analysed. Then, experiments for human calcium oxalate monohydrate (COM), uric acid (UA) and cystine (CYS) stones were performed with single laser pulses at 0.6 J, 0.8 J and 1.0 J for p-Tm:YAG (Captive Fragmenting mode), TFL (Short Pulse) and Ho:YAG (Long Pulse). Synthetic and human stone samples were dried before three-dimensional scanning to measure ablation rates (ARs) and ablation volume per pulse (AVP).
For synthetic stones with 270 μm-CDF, the p-Tm:YAG and TFL presented similar ARs, except in Fragmentation against HSP (95,1 ± 13,6vs67 ± 14 p = 0,02, respectively). Both p-Tm:YAG and TFL achieved higher ARs than Ho:YAG in all settings. p-Tm:YAG-200 μm-CDF and TFL-150 μm-CDF presented similar ARs, except in Fragmentation against HSP(78,4 ± 8vs42,5 ± 2,6 mm3/min,p = 0,0002). Both p-Tm:YAG-200 μm-CDF and TFL-150 μm-CDF presented at least 50% higher ARs than 270 μm-Ho:YAG. For human stones with COM, TFL exhibited higher AVP compared to p-Tm:YAG and Ho:YAG across all pulse energies (258,2 ± 213vs81,7 ± 31,9vs41,5 ± 25,4 μm3 p = 0,01, respectively). Against UA, Ho:YAG demonstrated higher AVP compared to TFL and p-Tm:YAG (355,2 ± 161vs99,8 ± 76,7vs292,9 ± 203,1 μm3 p = 0,0005, respectively). For CYS, Ho:YAG presented higher AVP but without significance (99,8 ± 76,7 vs 49,3 ± 36,3 vs 38,8 ± 12,2 μm3, p = 0,09).
p-Tm:YAG and TFL achieved higher ARs than LP-Ho:YAG against synthetic stones in vitro. For human stones, TFL achieved the highest AVP against COM while LP-Ho:YAG delivered higher AVPs against UA and CYS, for which TFL performed worst.
BJUI compass. 2025 Aug 18*** epublish ***
Frédéric Panthier, Alba Sierra, Etienne Xavier Keller, Marie Chicaud, Eugenio Ventimiglia, Jia-Lun Kwok, Vincent De Coninck, Mariela Corrales, Michel Daudon, Cyril Gorny, Steeve Doizi, Laurent Berthe, Daron Smith, Olivier Traxer
Sorbonne University GRC Urolithiasis no. 20, Tenon Hospital Paris France., Progressive Endourological Association for Research and Leading Solutions (PEARLS) Paris France., PIMM UMR 8006 CNRS-Arts et Métiers ParisTech Paris France., Department of Urology Westmoreland Street Hospital, UCLH NHS Foundation Trust London UK.