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Optimal power settings for Holmium:YAG lithotripsy.
J Urol. 2012 Mar; 187(3):914-9.JU

Abstract

PURPOSE

We determined the optimal Ho:YAG lithotripsy power settings to achieve maximal fragmentation, minimal fragment size and minimal retropulsion.

MATERIALS AND METHODS

Stone phantoms were irradiated in water with a Ho:YAG laser using a 365 μm optical fiber. Six distinct power settings were tested, including 0.2 to 2.0 J and 10 to 40 Hz. For all cohorts 500 J total radiant energy were delivered. A seventh cohort (0.2 J 40 Hz) was tested post hoc to a total energy of 1,250 J. Two experimental conditions were tested, including with and without phantom stabilization. Total fragmentation, fragment size and retropulsion were characterized. In mechanism experiments using human calculi we measured crater volume by optical coherence tomography and pressure transients by needle hydrophone across similar power settings.

RESULTS

Without stabilization increased pulse energy settings produced increased total fragmentation and increased retropulsion (each p <0.0001). Fragment size was smallest for the 0.2 J cohorts (p <0.02). With stabilization increased pulse energy settings produced increased total fragmentation and increased retropulsion but also increased fragment size (each p <0.0001). Craters remained symmetrical and volume increased as pulse energy increased. Pressure transients remained modest at less than 30 bars even at 2.0 J pulse energy.

CONCLUSIONS

Holmium:YAG lithotripsy varies as pulse energy settings vary. At low pulse energy (0.2 J) less fragmentation and retropulsion occur and small fragments are produced. At high pulse energy (2.0 J) more fragmentation and retropulsion occur with larger fragments. Anti-retropulsion devices produce more efficient lithotripsy, particularly at high pulse energy. Optimal lithotripsy laser dosimetry depends on the desired outcome.

Authors+Show Affiliations

Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia, Canada.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

22264464

Citation

Sea, Jason, et al. "Optimal Power Settings for Holmium:YAG Lithotripsy." The Journal of Urology, vol. 187, no. 3, 2012, pp. 914-9.
Sea J, Jonat LM, Chew BH, et al. Optimal power settings for Holmium:YAG lithotripsy. J Urol. 2012;187(3):914-9.
Sea, J., Jonat, L. M., Chew, B. H., Qiu, J., Wang, B., Hoopman, J., Milner, T., & Teichman, J. M. (2012). Optimal power settings for Holmium:YAG lithotripsy. The Journal of Urology, 187(3), 914-9. https://doi.org/10.1016/j.juro.2011.10.147
Sea J, et al. Optimal Power Settings for Holmium:YAG Lithotripsy. J Urol. 2012;187(3):914-9. PubMed PMID: 22264464.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Optimal power settings for Holmium:YAG lithotripsy. AU - Sea,Jason, AU - Jonat,Lee M, AU - Chew,Ben H, AU - Qiu,Jinze, AU - Wang,Bingqing, AU - Hoopman,John, AU - Milner,Thomas, AU - Teichman,Joel M H, Y1 - 2012/01/20/ PY - 2011/06/30/received PY - 2012/1/24/entrez PY - 2012/1/24/pubmed PY - 2012/4/4/medline SP - 914 EP - 9 JF - The Journal of urology JO - J. Urol. VL - 187 IS - 3 N2 - PURPOSE: We determined the optimal Ho:YAG lithotripsy power settings to achieve maximal fragmentation, minimal fragment size and minimal retropulsion. MATERIALS AND METHODS: Stone phantoms were irradiated in water with a Ho:YAG laser using a 365 μm optical fiber. Six distinct power settings were tested, including 0.2 to 2.0 J and 10 to 40 Hz. For all cohorts 500 J total radiant energy were delivered. A seventh cohort (0.2 J 40 Hz) was tested post hoc to a total energy of 1,250 J. Two experimental conditions were tested, including with and without phantom stabilization. Total fragmentation, fragment size and retropulsion were characterized. In mechanism experiments using human calculi we measured crater volume by optical coherence tomography and pressure transients by needle hydrophone across similar power settings. RESULTS: Without stabilization increased pulse energy settings produced increased total fragmentation and increased retropulsion (each p <0.0001). Fragment size was smallest for the 0.2 J cohorts (p <0.02). With stabilization increased pulse energy settings produced increased total fragmentation and increased retropulsion but also increased fragment size (each p <0.0001). Craters remained symmetrical and volume increased as pulse energy increased. Pressure transients remained modest at less than 30 bars even at 2.0 J pulse energy. CONCLUSIONS: Holmium:YAG lithotripsy varies as pulse energy settings vary. At low pulse energy (0.2 J) less fragmentation and retropulsion occur and small fragments are produced. At high pulse energy (2.0 J) more fragmentation and retropulsion occur with larger fragments. Anti-retropulsion devices produce more efficient lithotripsy, particularly at high pulse energy. Optimal lithotripsy laser dosimetry depends on the desired outcome. SN - 1527-3792 UR - https://www.unboundmedicine.com/medline/citation/22264464/Optimal_power_settings_for_Holmium:YAG_lithotripsy_ L2 - https://www.jurology.com/doi/full/10.1016/j.juro.2011.10.147?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -