Comparison of Holmium:YAG and Thulium Fiber Lasers on the Risk of Laser Fiber Fracture

• Main Authors: Audrey Uzan, Paul Chiron, Frédéric Panthier, Mattieu Haddad, Laurent Berthe, Olivier Traxer, Steeve Doizi
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Journal of Clinical Medicine
• Subjects: Ho:YAG laser; thulium fiber laser; laser fiber; lithotripsy; urolithiasis; ureteroscopy
• Online Access: https://www.mdpi.com/2077-0383/10/13/2960

Objectives: To compare the risk of laser fiber fracture between Ho:YAG laser and Thulium Fiber Laser (TFL) with different laser fiber diameters, laser settings, and fiber bending radii. METHODS: Lengths of 200, 272, and 365 μm single use fibers were used with a 30 W Ho:YAG laser and a 50 W Super Pulsed TFL. Laser fibers of 150 µm length were also tested with the TFL only. Five different increasingly smaller bend radii were tested: 1, 0.9, 0.75, 0.6, and 0.45 cm. A total of 13 different laser settings were tested for the Ho:YAG laser: six fragmentation settings with a short pulse duration, and seven dusting settings with a long pulse duration. A total of 33 different laser settings were tested for the TFL. Three laser settings were common two both lasers: 0.5 J × 12 Hz, 0.8 J × 8 Hz, 2 J × 3 Hz. The laser was activated for 5 min or until fiber fracture. Each measurement was performed ten times. Results: While fiber failures occurred with all fiber diameters with Ho:YAG laser, none were reported with TFL. Identified risk factors of fiber fracture with the Ho:YAG laser were short pulse and high energy for the 365 µm fibers (<i>p</i> = 0.041), but not for the 200 and 272 µm fibers (<i>p</i> = 1 and <i>p</i> = 0.43, respectively). High frequency was not a risk factor of fiber fracture. Fiber diameter also seemed to be a risk factor of fracture. The 200 µm fibers broke more frequently than the 272 and 365 µm ones (<i>p</i> = 0.039). There was a trend for a higher number of fractures with the 365 µm fibers compared to the 272 µm ones, these occurring at a larger bend radius, but this difference was not significant. Conclusion: TFL appears to be a safer laser regarding the risk of fiber fracture than Ho:YAG when used with fibers in a deflected position.