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Thermal Response to High-Power Holmium Laser Lithotripsy.
J Endourol 2017; 31(12):1308-1312JE

Abstract

OBJECTIVES

The aim of this study was to investigate "caliceal" fluid temperature changes during holmium laser activation/lithotripsy using settings up to 40 W power output with different irrigation flow rates.

MATERIALS AND METHODS

The experimental system consisted of a glass test tube (diameter 10 mm/length 75 mm) filled with deionized water, to mimic a calix. Real-time temperature was recorded using a thermocouple (Physitemp, NJ) positioned 5 mm from the bottom of the tube. A 200 μm laser fiber (Flexiva; Boston Scientific, MA) was introduced through the working channel of a disposable ureteroscope (LithoVue; Boston Scientific) and the laser fiber tip was positioned 15 mm above the bottom of the test tube. Deionized water irrigation (room temperature) through the working channel of the ureteroscope was delivered at flow rates of 0, 7-8, 14-15, and 38-40 mL/minute. A 120-W holmium laser (pulse 120; Lumenis, CA) was used. The following settings were explored: 0.5 J × 10 Hz, 1.0 J × 10 Hz, 0.5 J × 20 Hz, 1.0 J × 20 Hz, 0.5 J × 40 Hz, 1.0 J × 40 Hz, and 0.5 J × 80 Hz. During each experiment, the laser was activated continuously for 60 seconds.

RESULTS

Temperature increased with increasing laser power output and decreasing irrigation flow rate. The highest temperature, 70.3°C (standard deviation 2.7), occurred with laser setting of 1.0 J × 40 Hz and no irrigation after 60 seconds of continuous laser firing. None of the tested laser settings and irrigation parameters produced temperature exceeding 51°C when activated for only 10 seconds of continuous laser firing.

CONCLUSION

High-power holmium settings fired in long bursts with low irrigation flow rates can generate high fluid temperatures in a laboratory "caliceal" model. Awareness of this risk allows urologist to implement a variety of techniques (higher irrigation flow rates, intermittent laser activation, and potentially cooled irrigation fluid) to control and mitigate thermal effects during holmium laser lithotripsy.

Authors+Show Affiliations

1 Division of Endourology, Department of Urology, University of Michigan , Ann Arbor, Michigan.1 Division of Endourology, Department of Urology, University of Michigan , Ann Arbor, Michigan.2 Department of Biomedical Engineering, University of Michigan , Ann Arbor, Michigan.1 Division of Endourology, Department of Urology, University of Michigan , Ann Arbor, Michigan. 2 Department of Biomedical Engineering, University of Michigan , Ann Arbor, Michigan.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

29048216

Citation

Aldoukhi, Ali H., et al. "Thermal Response to High-Power Holmium Laser Lithotripsy." Journal of Endourology, vol. 31, no. 12, 2017, pp. 1308-1312.
Aldoukhi AH, Ghani KR, Hall TL, et al. Thermal Response to High-Power Holmium Laser Lithotripsy. J Endourol. 2017;31(12):1308-1312.
Aldoukhi, A. H., Ghani, K. R., Hall, T. L., & Roberts, W. W. (2017). Thermal Response to High-Power Holmium Laser Lithotripsy. Journal of Endourology, 31(12), pp. 1308-1312. doi:10.1089/end.2017.0679.
Aldoukhi AH, et al. Thermal Response to High-Power Holmium Laser Lithotripsy. J Endourol. 2017;31(12):1308-1312. PubMed PMID: 29048216.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Thermal Response to High-Power Holmium Laser Lithotripsy. AU - Aldoukhi,Ali H, AU - Ghani,Khurshid R, AU - Hall,Timothy L, AU - Roberts,William W, Y1 - 2017/11/17/ PY - 2017/10/20/pubmed PY - 2018/7/4/medline PY - 2017/10/20/entrez KW - holmium laser KW - lithotripsy KW - temperature KW - ureteroscopy SP - 1308 EP - 1312 JF - Journal of endourology JO - J. Endourol. VL - 31 IS - 12 N2 - OBJECTIVES: The aim of this study was to investigate "caliceal" fluid temperature changes during holmium laser activation/lithotripsy using settings up to 40 W power output with different irrigation flow rates. MATERIALS AND METHODS: The experimental system consisted of a glass test tube (diameter 10 mm/length 75 mm) filled with deionized water, to mimic a calix. Real-time temperature was recorded using a thermocouple (Physitemp, NJ) positioned 5 mm from the bottom of the tube. A 200 μm laser fiber (Flexiva; Boston Scientific, MA) was introduced through the working channel of a disposable ureteroscope (LithoVue; Boston Scientific) and the laser fiber tip was positioned 15 mm above the bottom of the test tube. Deionized water irrigation (room temperature) through the working channel of the ureteroscope was delivered at flow rates of 0, 7-8, 14-15, and 38-40 mL/minute. A 120-W holmium laser (pulse 120; Lumenis, CA) was used. The following settings were explored: 0.5 J × 10 Hz, 1.0 J × 10 Hz, 0.5 J × 20 Hz, 1.0 J × 20 Hz, 0.5 J × 40 Hz, 1.0 J × 40 Hz, and 0.5 J × 80 Hz. During each experiment, the laser was activated continuously for 60 seconds. RESULTS: Temperature increased with increasing laser power output and decreasing irrigation flow rate. The highest temperature, 70.3°C (standard deviation 2.7), occurred with laser setting of 1.0 J × 40 Hz and no irrigation after 60 seconds of continuous laser firing. None of the tested laser settings and irrigation parameters produced temperature exceeding 51°C when activated for only 10 seconds of continuous laser firing. CONCLUSION: High-power holmium settings fired in long bursts with low irrigation flow rates can generate high fluid temperatures in a laboratory "caliceal" model. Awareness of this risk allows urologist to implement a variety of techniques (higher irrigation flow rates, intermittent laser activation, and potentially cooled irrigation fluid) to control and mitigate thermal effects during holmium laser lithotripsy. SN - 1557-900X UR - https://www.unboundmedicine.com/medline/citation/29048216/Thermal_Response_to_High_Power_Holmium_Laser_Lithotripsy_ L2 - https://www.liebertpub.com/doi/full/10.1089/end.2017.0679?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -