Proximal fiber tip damage during Holmium: YAG and thulium fiber laser ablation of kidney stones

Christopher R. Wilson, Luke A. Hardy, Pierce B. Irby, Nathaniel M. Fried

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The Thulium fiber laser (TFL) is being studied as an alternative to Holmium:YAG laser for lithotripsy. TFL beam originates within an 18-μm-core thulium doped silica fiber, and its near single mode, Gaussian beam profile enables transmission of higher laser power through smaller fibers than possible during Holmium laser lithotripsy. This study examines whether TFL beam profile also reduces proximal fiber tip damage compared to Holmium laser multimodal beam. TFL beam at wavelength of 1908 nm was coupled into 105-μm-core silica fibers, with 35-mJ energy, 500-μs pulse duration, and pulse rates of 50-500 Hz. For each pulse rate, 500,000 pulses were delivered. Magnified images of proximal fiber surfaces were taken before and after each trial. For comparison, 20 single-use, 270-μm-core fibers were collected after clinical Holmium laser lithotripsy procedures using standard settings (600 mJ, 350 μs, 6 Hz). Total laser energy, number of laser pulses, and laser irradiation time were recorded, and fibers were rated for damage. For TFL studies, output power was stable, and no proximal fiber damage was observed after delivery of 500,000 pulses at settings up to 35 mJ, 500 Hz, and 17.5 W average power. In contrast, confocal microscopy images of fiber tips after Holmium lithotripsy showed proximal fiber tip degradation in all 20 fibers. The proximal fiber tip of a 105-μm-core fiber transmitted 17.5 W of TFL power without degradation, compared to degradation of 270-μm-core fibers after transmission of 3.6 W of Holmium laser power. The smaller and more uniform TFL beam profile may improve fiber lifetime, and potentially reduce costs for the surgical disposables as well.

Original languageEnglish (US)
Title of host publicationPhotonic Therapeutics and Diagnostics XII
PublisherSPIE
Volume9689
ISBN (Electronic)9781628419245
DOIs
Publication statusPublished - 2016
Externally publishedYes
EventPhotonic Therapeutics and Diagnostics XII - San Francisco, United States
Duration: Feb 13 2016Feb 14 2016

Other

OtherPhotonic Therapeutics and Diagnostics XII
CountryUnited States
CitySan Francisco
Period2/13/162/14/16

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Keywords

  • ablation
  • damage
  • fiber
  • holmium
  • kidney stones
  • lithotripsy
  • proximal
  • thulium

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Radiology Nuclear Medicine and imaging

Cite this

Wilson, C. R., Hardy, L. A., Irby, P. B., & Fried, N. M. (2016). Proximal fiber tip damage during Holmium: YAG and thulium fiber laser ablation of kidney stones. In Photonic Therapeutics and Diagnostics XII (Vol. 9689). [96891Q] SPIE. https://doi.org/10.1117/12.2207895