Thermal Safety Boundaries for Laser Power and Irrigation Rate During Ureteroscopy: In-Vivo Porcine Assessment with a Ho:YAG Laser.

Document Type

Article

Publication Date

7-21-2023

Publication Title

Urology

Abstract

OBJECTIVE: To map thermal safety boundaries during ureteroscopy with laser activation in two in-vivo porcine subjects to better understand the interplay between laser power, irrigation rate, and fluid temperature in the collecting system.

METHODS: Ureteroscopy was performed in two in-vivo porcine subjects with a prototype ureteroscope containing a thermocouple at its tip. Up to 6 trials of 60 seconds laser activation were carried out at each selected power setting and irrigation rate. Thermal dose was calculated for each trial, and laser power-irrigation rate parameter pairs were categorized based on number of trials that exceeded a thermal dose of 120 equivalent minutes.

RESULTS: The collecting fluid temperature was increased with greater laser power and slower irrigation rate. In the first porcine subject, 25 W of laser power could safely be applied if irrigation was at least 15 ml/min, and 48 W with at least 30 ml /min. Intermediate values followed a linear curve between these bounds. For the second subject, where the calyx appeared larger, 15 W laser power required 9 ml/min irrigation, 48 W required 24 ml/min, and intermediate points also followed a near-linear curve.

CONCLUSIONS: This study validates previous bench research and provides a conceptual framework for selection of safe laser lithotripsy settings and irrigation rates during ureteroscopy with laser lithotripsy. Additionally, it provides insight and guidance for future development of thermal mitigation strategies and devices.

Volume

S0090-4295

Issue

23

First Page

00632-5

DOI

10.1016/j.urology.2023.07.014

ISSN

1527-9995

PubMed ID

37482102

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