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Thulium fiber laser lithotripsy in an in vitro ureter model.
J Biomed Opt 2014; 19(12):128001JB

Abstract

Using a validated in vitro ureter model for laser lithotripsy, the performance of an experimental thulium fiber laser (TFL) was studied and compared to the clinical gold standard holmium:YAG laser. The holmium laser (λ = 2120 nm) was operated with standard parameters of 600 mJ, 350 μs, 6 Hz, and 270-μm-core optical fiber. The TFL (λ=1908 nm) was operated with 35 mJ, 500 μs, 150 to 500 Hz, and a 100-μm-core fiber. Urinary stones (60% calcium oxalate monohydrate/40% calcium phosphate) of uniform mass and diameter (4 to 5 mm) were laser ablated with fibers through a flexible video-ureteroscope under saline irrigation with flow rates of 22.7 and 13.7 ml/ min for the TFL and holmium laser, respectively. The temperature 3 mm from the tube's center and 1 mm above the mesh sieve was measured by a thermocouple and recorded throughout each experiment for both lasers. Total laser and operation times were recorded once all stone fragments passed through a 1.5-mm sieve. The holmium laser time measured 167±41 s (n=12). TFL times measured 111±49, 39±11, and 23±4 s, for pulse rates of 150, 300, and 500 Hz, respectively (n=12 each). Mean peak saline irrigation temperatures reached 24±1°C for holmium, and 33±3°C, 33±7°C, and 39±6°C, for TFL at pulse rates of 150, 300, and 500 Hz, respectively. To avoid thermal buildup and provide a sufficient safety margin, TFL lithotripsy should be performed with pulse rates below 500 Hz and/or increased saline irrigation rates. The TFL rapidly fragmented kidney stones due in part to its high pulse rate, high power density, high average power, and observation of reduced stone retropulsion and may provide a clinical alternative to the conventional holmium laser for lithotripsy.

Authors+Show Affiliations

University of North Carolina at Charlotte, Department of Physics and Optical Science, 9201 University City Avenue, Charlotte, North Carolina 28223-0001, United States.University of North Carolina at Charlotte, Department of Physics and Optical Science, 9201 University City Avenue, Charlotte, North Carolina 28223-0001, United States.McKay Department of Urology, Carolinas Medical Center, 1024 Edgehill Road South, Charlotte, North Carolina 28207, United States.University of North Carolina at Charlotte, Department of Physics and Optical Science, 9201 University City Avenue, Charlotte, North Carolina 28223-0001, United StatesbMcKay Department of Urology, Carolinas Medical Center, 1024 Edgehill Road South, Charlot.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

25518001

Citation

Hardy, Luke A., et al. "Thulium Fiber Laser Lithotripsy in an in Vitro Ureter Model." Journal of Biomedical Optics, vol. 19, no. 12, 2014, p. 128001.
Hardy LA, Wilson CR, Irby PB, et al. Thulium fiber laser lithotripsy in an in vitro ureter model. J Biomed Opt. 2014;19(12):128001.
Hardy, L. A., Wilson, C. R., Irby, P. B., & Fried, N. M. (2014). Thulium fiber laser lithotripsy in an in vitro ureter model. Journal of Biomedical Optics, 19(12), p. 128001. doi:10.1117/1.JBO.19.12.128001.
Hardy LA, et al. Thulium Fiber Laser Lithotripsy in an in Vitro Ureter Model. J Biomed Opt. 2014;19(12):128001. PubMed PMID: 25518001.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Thulium fiber laser lithotripsy in an in vitro ureter model. AU - Hardy,Luke A, AU - Wilson,Christopher R, AU - Irby,Pierce B, AU - Fried,Nathaniel M, PY - 2014/09/12/received PY - 2014/11/12/accepted PY - 2014/12/18/entrez PY - 2014/12/18/pubmed PY - 2015/8/1/medline SP - 128001 EP - 128001 JF - Journal of biomedical optics JO - J Biomed Opt VL - 19 IS - 12 N2 - Using a validated in vitro ureter model for laser lithotripsy, the performance of an experimental thulium fiber laser (TFL) was studied and compared to the clinical gold standard holmium:YAG laser. The holmium laser (λ = 2120 nm) was operated with standard parameters of 600 mJ, 350 μs, 6 Hz, and 270-μm-core optical fiber. The TFL (λ=1908 nm) was operated with 35 mJ, 500 μs, 150 to 500 Hz, and a 100-μm-core fiber. Urinary stones (60% calcium oxalate monohydrate/40% calcium phosphate) of uniform mass and diameter (4 to 5 mm) were laser ablated with fibers through a flexible video-ureteroscope under saline irrigation with flow rates of 22.7 and 13.7 ml/ min for the TFL and holmium laser, respectively. The temperature 3 mm from the tube's center and 1 mm above the mesh sieve was measured by a thermocouple and recorded throughout each experiment for both lasers. Total laser and operation times were recorded once all stone fragments passed through a 1.5-mm sieve. The holmium laser time measured 167±41 s (n=12). TFL times measured 111±49, 39±11, and 23±4 s, for pulse rates of 150, 300, and 500 Hz, respectively (n=12 each). Mean peak saline irrigation temperatures reached 24±1°C for holmium, and 33±3°C, 33±7°C, and 39±6°C, for TFL at pulse rates of 150, 300, and 500 Hz, respectively. To avoid thermal buildup and provide a sufficient safety margin, TFL lithotripsy should be performed with pulse rates below 500 Hz and/or increased saline irrigation rates. The TFL rapidly fragmented kidney stones due in part to its high pulse rate, high power density, high average power, and observation of reduced stone retropulsion and may provide a clinical alternative to the conventional holmium laser for lithotripsy. SN - 1560-2281 UR - https://www.unboundmedicine.com/medline/citation/25518001/Thulium_fiber_laser_lithotripsy_in_an_in_vitro_ureter_model_ L2 - https://doi.org/10.1117/1.JBO.19.12.128001 DB - PRIME DP - Unbound Medicine ER -