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World Journal of Urology

, Volume 37, Issue 9, pp 1933–1939 | Cite as

Ho:YAG laser lithotripsy in non-contact mode: optimization of fiber to stone working distance to improve ablation efficiency

  • Vincent De Coninck
  • Etienne Xavier Keller
  • Paul Chiron
  • Laurian Dragos
  • Esteban Emiliani
  • Steeve Doizi
  • Laurent Berthe
  • Olivier TraxerEmail author
Original Article

Abstract

Purpose

To evaluate how variable working distances between the laser fiber and the stone influence ablation volume.

Methods

A laser fiber was fixed on a robotic arm perpendicular to an artificial stone. A single laser pulse was triggered at different working distances (0–2.0 mm in 0.2 mm increments) between the distal fiber tip and the stone. To achieve a measurable impact, pulse energy was set to 2 and 3 J, with either short or long pulse duration. Ablation volume was calculated with an optical microscope. Experiments were repeated five times for each setting.

Results

Highest ablation volume was observed with a long pulse of 3 J at a working distance of 0.4 mm between the laser fiber and the stone surface (p value < 0.05). At 2 J, the highest ablation volume was noticed with a short pulse in contact mode. However, ablation volume of the latter was not significantly greater than with a long pulse of 2 J at a working distance of 0.4 mm (p value > 0.05). Compared to lithotripsy in contact mode, triggering a single long pulse at 0.4 mm increased ablation volume by 81% (p value = 0.016) at 2 J and by 89% (p value = 0.034) at 3 J.

Conclusions

For Ho:YAG laser lithotripsy, ablation volume may be higher in non-contact mode using long pulses, rather than in direct contact to the stone. Findings of the current study support the need of further studies of lithotripsy in non-contact mode.

Keywords

Distance Ho:YAG Laser Nephrolithiasis Non-contact 

Abbreviation

Ho:YAG

Holmium:yttrium–aluminum–garnet

Notes

Acknowledgements

We would like to express our greatest appreciation to Prof. Gregory Altshuler, Prof. Nathaniel M. Fried and Viktoriya Vinnichenko for their valuable suggestions and proofreading of this article.

Author contributions

VDC: protocol/project development, data collection or management, data analysis, manuscript writing/editing. EXK: protocol/project development, data collection or management, data analysis, manuscript writing/editing. PC: protocol/project development, data collection or management, data analysis. LD: protocol/project development. EE: protocol/project development. SD: protocol/project development, data analysis. LB: protocol/project development, data analysis. OT: protocol/project development, data collection or management, data analysis, manuscript writing/editing.

Funding

Prof. Olivier Traxer is a consultant for Coloplast, Rocamed, Olympus, EMS and Boston Scientific. Dr. Steeve Doizi is a consultant for Coloplast. Dr. Vincent De Coninck is supported by the EUSP scholarship from the European Association of Urology and by a grant from the Belgische Vereniging voor Urologie (BVU). Dr. Etienne Xavier Keller is supported by a Travel Grant from the University Hospital Zurich and by a grant from the Kurt and Senta Herrmann Foundation.

Compliance with ethical standards

Ethical statement

We did not perform research involving human participants and/or animals.

Supplementary material

Supplementary material 1 (MP4 1604 KB)

Supplementary material 2 (MP4 1890 KB)

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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Sorbonne Université, GRC n°20, Groupe de Recherche Clinique Sur La Lithiase UrinaireParisFrance
  2. 2.Department of UrologyAZ KlinaBrasschaatBelgium
  3. 3.Department of UrologyUniversity Hospital Zurich, University of ZurichZurichSwitzerland
  4. 4.Department of UrologyUniversity of Medicine and Pharmacy “Victor Babes” TimişoaraTimisoaraRomania
  5. 5.Fundació Puigvert, Department of UrologyUniversidad Autonoma de BarcelonaBarcelonaSpain
  6. 6.Process and Engineering in Mechanics and Materials Laboratory (PIMM), UMR CNRS/ENSAMParisFrance

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