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Pulsed Thulium:YAG Laser - What Is the Lithotripsy Ablation Efficiency for Stone Dust from Human Urinary Stones? Results from an in Vitro PEARLS Study - Beyond the Abstract

The novel pulsed Thulium: YAG (p-Tm: YAG) is a promising laser and has been shown to dust all prevailing human urinary stone compositions.1 However, available in vitro and in vivo studies had not provided efficiency data on its applicability to differing stone composition types. The authors thus sought to investigate the unexplored question of ablation efficiency with the p-Tm: YAG for stone dust from human urinary stones.

The study found that ablation seems equally efficient with calcium oxalate monohydrate (COM) or uric acid (UA) stones, which is a new insight since COM is generally considered as more resilient to lithotripsy.

Beyond the results, through the course of the study, the authors were excited to find fresh perspectives on reporting laser performance:

We applied a unique methodology with a study setup that allowed for selecting ablated stone mass with particle size ≤ 250 µm, meeting an evaluated stone dust definition.2 Additionally, with measured ablated stone weight, we used known stone density values to calculate the estimated ablated volume. Surprisingly, a higher weight may not equate to a higher estimated volume, highlighting a limitation of weight measurements for in vitro laser performance studies.

It is of great interest that in reporting performance metrics for the p-Tm: YAG, we realised that there is no standardized terminology for reporting ablated volume relating to energy or time. This pivotal discovery thus led us to conduct a published systematic review on laser performance volume metrics together with a proposal for standardized terminology in reporting laser ablation efficiency, laser ablation speed, and laser energy consumption.3

Written by: Jia-Lun Kwok, MBBS, FRCS1,2 & Etienne Xavier Keller, MD, FEBU1

  1. Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
  2. Department of Urology, Tan Tock Seng Hospital, Singapore, Singapore
References:

  1. Kwok J-L, Ventimiglia E, De Coninck V, Corrales M, Sierra A, Panthier F, et al. Pulsed thulium: YAG laser—ready to dust all urinary stone composition types? Results from a PEARLS analysis. World Journal of Urology. 2023.
  2. Keller EX, De Coninck V, Doizi S, Daudon M, Traxer O. What is the exact definition of stone dust? An in vitro evaluation. World Journal of Urology. 2021;39(1):187-94.
  3. Kwok J-L, De Coninck V, Ventimiglia E, Panthier F, Corrales M, Sierra A, et al. Laser Ablation Efficiency, Laser Ablation Speed, and Laser Energy Consumption During Lithotripsy: What Are They and How Are They Defined? A Systematic Review and Proposal for a Standardized Terminology. European Urology Focus. 2023.
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