Skip to main content
SpringerLink
Log in

Laser operator duty cycle effect on temperature and thermal dose: in-vitro study

  • Original Article
  • Published:
World Journal of Urology Aims and scope Submit manuscript

Abstract

Purpose

High-power laser lithotripsy can elevate temperature within the urinary collecting system and increase risk of thermal injury. Temperature elevation is dependent on power settings and operator duty cycle (ODC)—the percentage of time the laser pedal is depressed. The objective of this study was to quantify temperature and thermal dose resulting from laser activation at different ODC in an in-vitro model.

Methods

Holmium laser energy (1800 J) was delivered at 30 W (0.5 J × 60 Hz) to a fluid filled glass bulb. Room temperature irrigation was applied at 8 ml/min. ODC was evaluated in 10% increments from 50–100%. Bulb fluid temperature was recorded and thermal dose calculated. Time to reach threshold of thermal injury and maximal allowable energy were also determined at each ODC.

Results

Upon laser activation, there was an immediate rise in fluid temperature with a “saw-tooth” oscillation superimposed on the curves for 50–90% ODC corresponding to periodic activation of the laser. Higher ODC resulted in greater maximum temperature and thermal dose, with ODC ≥ 70% exceeding threshold. Use of 50% compared to 60% ODC resulted in a tenfold increase in time required to reach threshold of thermal injury and an eightfold increase in maximal allowable energy.

Conclusions

Laser activation at higher ODC produced greater fluid temperature and thermal dose. Time to threshold of thermal injury and maximal allowable energy were dramatically higher for 50% compared to 60% ODC at high-power settings. Proper management of laser ODC can enhance patient safety and optimize stone treatment.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3

Similar content being viewed by others

References

  1. Dauw CA, Simeon L, Alruwaily AF, Sanguedolce F, Hollingsworth JM, Roberts WW, Faerber G, Wolf JS, Ghani KR (2015) Contemporary practice patterns of flexible ureteroscopy for treating renal stones: results of a worldwide survey. J Endourol 29:1221–1230. https://doi.org/10.1089/end.2015.0260

    Article  PubMed  Google Scholar 

  2. Molina WR, Silva IN, Donalisio Da Silva R, Gustafson D, Sehrt D, Kim FJ (2015) Influence of saline on temperature profile of laser lithotripsy activation. J Endourol 29(2):235–239. https://doi.org/10.1089/end.2014.0305

    Article  PubMed  PubMed Central  Google Scholar 

  3. Aldoukhi AH, Ghani KR, Hall TL, Roberts WW (2017) Thermal response to high-power holmium laser lithotripsy. J Endourol 31(12):1308–1312. https://doi.org/10.1089/end.2017.0679

    Article  PubMed  Google Scholar 

  4. Wollin DA, Carlos EC, Tom WR, Simmons WN, Preminger GM, Lipkin ME (2018) Effect of laser settings and irrigation rates on ureteral temperature during holmium laser lithotripsy, an in vitro model. J Endourol 32(1):59–63. https://doi.org/10.1089/end.2017.0658

    Article  PubMed  Google Scholar 

  5. Sourial MW, Ebel J, Francois N, Box GN, Knudsen BE (2018) Holmium-YAG laser: Impact of pulse energy and frequency on local fluid temperature in an in-vitro obstructed kidney calyx model. J Biomed Opt 23(10):1. https://doi.org/10.1117/1.jbo.23.10.105002

    Article  CAS  PubMed  Google Scholar 

  6. Hein S, Petzold R, Schoenthaler M, Wetterauer U, Miernik A (2018) Thermal effects of Ho:YAG laser lithotripsy: real-time evaluation in an in vitro model. World J Urol 36(9):1469–1475. https://doi.org/10.1007/s00345-018-2303-x

    Article  CAS  PubMed  Google Scholar 

  7. Winship B, Wollin D, Carlos E, Peters C, Li J, Terry R, Boydston K, Preminger GM, Lipkin M (2019) The rise and fall of high temperatures during Ureteroscopic Holmium laser lithotripsy. J Endourol 33(10):794–799. https://doi.org/10.1089/end.2019.0084

    Article  PubMed  Google Scholar 

  8. Hein S, Petzold R, Suarez-Ibarrola R, Müller PF, Schoenthaler M, Miernik A (2020) Thermal effects of Ho:YAG laser lithotripsy during retrograde intrarenal surgery and percutaneous nephrolithotomy in an ex vivo porcine kidney model. World J Urol 38(3):753–760. https://doi.org/10.1007/s00345-019-02808-5

    Article  PubMed  Google Scholar 

  9. Aldoukhi AH, Hall TL, Ghani KR, Maxwell AD, MacConaghy B, Roberts WW (2018) Caliceal fluid temperature during high-power Holmium laser lithotripsy in an in vivo Porcine model. J Endourol 32(8):724–729. https://doi.org/10.1089/end.2018.0395

    Article  PubMed  PubMed Central  Google Scholar 

  10. Maxwell AD, MacConaghy B, Harper JD, Aldoukhi AH, Hall TL, Roberts WW (2019) Simulation of laser lithotripsy-induced heating in the urinary tract. J Endourol 33(2):113–119. https://doi.org/10.1089/end.2018.0395

    Article  PubMed  PubMed Central  Google Scholar 

  11. William JG, Goldsmith L, Moulton DE, Waters SL, Turney BW (2021) A temperature model for laser lithotripsy. World J Urol 39:1707–1716. https://doi.org/10.1007/s00345-020-03357-y

    Article  Google Scholar 

  12. Class 2 Device Recall Olympus. U.S. Food and Drug Administration (FDA). Initiated June 30, 2021. https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfRes/res.cfm?id=188172. Accessed Aug 24, 2021.

  13. Aldoukhi AH, Dau JJ, Majdalany SE, Hall TL, Ghani KR, Hollingsworth JM, Ambani SN, Dauw CA, Roberts WW (2021) Patterns of laser activation during ureteroscopic lithotripsy: effects on caliceal fluid temperature and thermal dose. J Endourol 35(8):1217–1222. https://doi.org/10.1089/end.2020.1067

    Article  PubMed  Google Scholar 

  14. Sapareto SA, Dewey WC (1984) Thermal dose determination in cancer therapy. Int J Radiat Oncol Biol Phys 10(6):787–800. https://doi.org/10.1016/0360-3016(84)90379-1

    Article  CAS  PubMed  Google Scholar 

  15. Yarmolenko PS, Moon EJ, Landon C, Manzoor A, Hochman DW, Viglianti BL, Dewhirst, (2011) Thresholds for thermal damage to normal tissues: an update. Int J Hyperth 27(4):320–343. https://doi.org/10.3109/02656736.2010.534527

    Article  Google Scholar 

  16. Khajeh NR, Hall TL, Ghani KR, Roberts WW (2021) Pelvicalyceal volume and fluid temperature elevation during laser lithotripsy. J Endourol. https://doi.org/10.1089/end.2021.0383

    Article  Google Scholar 

  17. Aldoukhi AH, Black K, Hall TL, Ghani KR, Maxwell AD, MacConaghy B, Roberts WW (2020) Defining thermal safe laser lithotripsy power and irrigation parameters: in vitro model. J Endourol 34(1):76–81. https://doi.org/10.1089/end.2019.0499

    Article  PubMed  Google Scholar 

  18. Dau JJ, Hall TL, Maxwell AD, Ghani KR, Roberts WW (2021) Effect of chilled irrigation on Caliceal fluid temperature and time to thermal injury threshold during laser lithotripsy in vitro model. J Endourol 35(5):700–705. https://doi.org/10.1089/end.2020.0896

    Article  PubMed  Google Scholar 

  19. Dau JJ, Khajeh NR, Hall TL, Roberts WW (2021) Chilled irrigation for control of temperature elevation during ureteroscopic laser lithotripsy: in vivo porcine model. J Endourol. https://doi.org/10.1089/end.2021.0537

    Article  PubMed  Google Scholar 

Download references

Funding

Funding provided through a research grant from Boston Scientific Corporation.

Author information

Authors and Affiliations

  1. Department of Urology, University of Michigan, Medical Science I, 1137 Catherine Street, 4432, Ann Arbor, MI, 48109-5330, USA

    Marne M. Louters, Julie J. Dau, Khurshid R. Ghani & William W. Roberts

  2. Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA

    Timothy L. Hall & William W. Roberts

Authors
  1. Marne M. Louters
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Julie J. Dau
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Timothy L. Hall
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Khurshid R. Ghani
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. William W. Roberts
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

MM Louters: data collection and analysis, manuscript writing. WW Roberts: project development and management, data analysis, manuscript editing KR Ghani: manuscript editing. JJ Dau: manuscript editing. TL Hall: manuscript editing.

Corresponding author

Correspondence to Marne M. Louters.

Ethics declarations

Conflict of interest

WW Roberts has a consulting relationship with Boston Scientific. KR Ghani has consulting relationships with Boston Scientific, Lumenis, Olympus, Coloplast, and Karl Storz. MM Louters, JJ Dau, and TL Hall have no relevant financial or non-financial interests to disclose.

Ethical approval

This was an in-vitro study that did not require ethics approval.

Informed consent

This was an in-vitro study that did not include human participation. Informed consent was not required.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Below is the link to the electronic supplementary material.

Supplementary file1 (PDF 380 KB)

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Louters, M.M., Dau, J.J., Hall, T.L. et al. Laser operator duty cycle effect on temperature and thermal dose: in-vitro study. World J Urol 40, 1575–1580 (2022). https://doi.org/10.1007/s00345-022-03967-8

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00345-022-03967-8

Keywords

Search

Navigation