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World Journal of Urology

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01-09-2018 | Original Article

Thermal effects of Ho: YAG laser lithotripsy: real-time evaluation in an in vitro model

Authors: Simon Hein, Ralf Petzold, Martin Schoenthaler, Ulrich Wetterauer, Arkadiusz Miernik

Published in: World Journal of Urology | Issue 9/2018

Abstract

Purpose

To evaluate the thermal effect of Ho:YAG laser lithotripsy in a standardized in vitro model via real-time temperature measurement.

Methods

Our model comprised a 20 ml test tube simulating the renal pelvis that was immersed in a 37 °C water bath. Two different laser fibers [FlexiFib (15–45 W), RigiFib 1000 (45–100 W), LISA laser products OHG, Katlenburg-Lindau, Germany] were placed in the test tube. An Ho:YAG 100 W laser was used in all experiments (LISA). Each experiment involved 120 s of continuous laser application, and was repeated five times. Different laser settings (high vs. low frequency, high vs. low energy, and long vs. short pulse duration), irrigation rates (0 up to 100 ml/min, realized by several pumps), and human calcium oxalate stone samples were analyzed. Temperature data were acquired by a real-time data logger with thermocouples (PICO Technology, Cambridgeshire, UK). Real-time measurements were assessed using MatLab^®.

Results

Laser application with no irrigation results in a rapid increase in temperature up to ∆28 K, rising to 68 °C at 100 W. Low irrigation rates yield significantly higher temperature outcomes. Higher irrigation rates result immediately in a lower temperature rise. High irrigation rates of 100 ml/min result in a temperature rise of 5 K at the highest laser power setting (100 W).

Conclusions

Ho:YAG laser lithotripsy might be safe provided that there is sufficient irrigation. However, high power and low irrigation resulted in potentially tissue-damaging temperatures. Laser devices should, therefore, always be applied in conjunction with continuous, closely monitored irrigation whenever performing Ho:YAG laser lithotripsy.

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Title: Thermal effects of Ho: YAG laser lithotripsy: real-time evaluation in an in vitro model
Authors: Simon Hein
Ralf Petzold
Martin Schoenthaler
Ulrich Wetterauer
Arkadiusz Miernik
Publication date: 01-09-2018
Publisher: Springer Berlin Heidelberg
Published in: World Journal of Urology / Issue 9/2018
Print ISSN: 0724-4983
Electronic ISSN: 1433-8726
DOI: https://doi.org/10.1007/s00345-018-2303-x

Keynote webinar | Spotlight on medication adherence

Springer Medicine

Thermal effects of Ho: YAG laser lithotripsy: real-time evaluation in an in vitro model

Abstract

Purpose

Methods

Results

Conclusions

Keynote webinar | Spotlight on medication adherence

Springer Medicine

Abstract

Purpose

Methods

Results

Conclusions

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