Thermal Injury and Laser Efficiency with Holmium YAG and Thulium Fiber Laser-An In Vitro Study

Alba Sierra; Mariela Corrales; Merkourios Kolvatzis; Frederic Panthier; Adrià Piñero; Olivier Traxer

doi:10.1089/end.2022.0216

Thermal Injury and Laser Efficiency with Holmium YAG and Thulium Fiber Laser-An In Vitro Study

J Endourol. 2022 Dec;36(12):1599-1606. doi: 10.1089/end.2022.0216.

Authors

Alba Sierra^{1

2}, Mariela Corrales^{1

2}, Merkourios Kolvatzis^{1

2}, Frederic Panthier^{1

2}, Adrià Piñero^{1

2}, Olivier Traxer^{1

2}

Affiliations

¹ Sorbonne University, GRC Urolithiasis No. 20, Tenon Hospital, Paris, France.
² Department of Urology, AP-HP, Sorbonne University, Tenon Hospital, Paris, France.

PMID: 35793107
DOI: 10.1089/end.2022.0216

Abstract

Objective: To evaluate using an inanimate model the thermal injury and laser efficiency on high frequency, high energy, and its combination in hands of junior and experienced urologists during holmium YAG (Ho:YAG) and Thulium fiber laser (TFL) lithotripsy. Methods: A Cyber: Ho 150 WTM and Fiber Dust TFL (Quanta System) with 200 μm core-diameter laser fibers (LF) were used in a saline in vitro ureteral model. Each participant (five junior and five experienced urologists) performed 32 sessions of 5-minute lasering (125 mm³ phantom BegoStones™), comparing four modes (3 J/5 Hz [1.5 W], 0.3 J/20 Hz [6 W], 1.2 J/5 Hz [6 W], and 1.2 J/20 Hz [24 W]). Transparent tip and cleaved LF, and digital and fiberoptic ureteroscopes were also compared. Ureteral damage was classified in a scale (0-5) according to the burns and holes seen in the ureteral model's surface. Results: High-power (HP) setting (24 W) was associated with higher delivered energy and higher ablation rates (ARs) in both lasers (p < 0.001). For the same power setting (6 W), there was no difference in delivered energy or stone ARs. Regardless the settings, a higher AR was observed with TFL than with Ho:YAG (0.5Δ mg/s ± 0.33 vs 0.39 Δmg/s ± 0.31, p = 0.002) laser. Higher mean AR was found with cleaved tip vs transparent tip (p = 0.03) in TFL. For both lasers, higher ureteral damage was observed in the 24 W group (p = 0.006) and in the junior urologists (p = 0.03). Between 6 W groups, different types of lesions were found and junior urologist have more lesions when high frequency was used, for both Ho:YAG (p = 0.05) and TFL (p = 0.04). Conclusion: More stone ARs and reduced operative time are observed in HP settings; however, more ureteral thermic-related damage is produced. When comparing the same power, higher energy or frequency does not modify the AR. Nonetheless, more ureteral thermic-related thermal damage is observed in high-frequency settings in unexperienced hands.

Keywords: Thulium fiber laser; holmium YAG; laser efficiency; laser settings; thermal damage; urinary stones.

MeSH terms

Fiber Optic Technology
Holmium*
Humans
Lasers
Research Design
Thulium*

Substances

Thulium
Holmium