Basic Science: Stones

Moderated Poster Session

MP2-13 - Effects of Wavelength and Pulse Shape on Stone Fragmentation Rate of Laser Lithotripter Devices

Thursday, September 20
4:00 PM - 6:00 PM
Location: Room 242B

Introduction & Objective : Pulsed Ho:YAG lasers are the energy source of choice for endoscopic treatment of urolithiasis. Pulse frequency and pulse energy were the most investigated parameters to improve efficiency of such lasers. However, newer research focusses on the influence of pulse width and pulse shape. Aim of our study was to compare the efficiency of stone dusting of pulsed 2.1 µm Ho:YAG lasers and a pulsed 1.94 µm Thulium-fibre laser (TFL) with identical pulse energy, pulse frequency, and average power settings.


Methods : The laser systems tested were the Lumenis Versa Pulse Power Suite P 100 (Ho short pulse), the Lumenis Pulse 120H (Ho long pulse) and a commercially not available prototype of a pulsed TFL (Fig.1, left to right). The lasers were tested at 0.2 J and 40 Hz (average power of 8-W). Pulse energies and pulse shapes were measured. Subsequently, efficiency of stone ablation (ablation speed) was compared in vitro on human COM, COM-phosphate, and Uric Acid stones for the three lasers. The in vitro experimental setup included a specially designed cuvette with several levels of metallic meshes allowing for precise quantification of size distribution of stone fragments. 


Results : The pulse widths (range in ms) of all three lasers are shown in Fig. 1 below. The following values of the peak power were derived from the pulse shape and pulse energy measurements: P100: 1650-W, P120: 1040-W, TFL: 660-W. The measured values of stone ablation speed (in dusting mode, i.e. fragments < 1mm) are summarized in Fig.2.


Conclusions : The new pulsed TFL shows a clearly defined pulse width with a large area under the curve. This in combination with the wavelength superior in terms of water absorption leads to better efficiency of stone fragmentation in dusting mode.

Christopher Netsch

Consultant
Asklepios Klinik Barmbek, Abteilung für Urologie

Dr. med. Dr. habil. Christopher Netsch, MD, FEBU is an Assistant Professor of Urology at the Semmelweis University of Budapest/Hungary. He received his medical degree from the University of Mainz/Germany. His training in urology was conducted at the Inselspital Bern/Switzerland, Städtisches Klinikum Karlsruhe/Germany and at the Asklepios Klinik Barmbek/Germany. After his board certification in 2011 (Hamburg/Germany), Dr. Netsch became a consultant urologist at the Asklepios Klinik Barmbek/Germany. Dr. Netsch completed his Endourology Fellowship at the Asklepios Klinik Barmbek in 2012. He was also qualified as a Fellow of the European Board of Urology (FEBU) in 2015.
Dr. Netsch`s research focuses on urolithiasis and minimally-invasive therapies for BPH. He has authored or co-authored over 70 peer-reviewed journal articles and numerous book chapters. He was awarded with the Mauermayer award of the German Society of Urology (DGU) in 2013 and the Hans Marberger award of the European Association of Urology (EAU) in 2014. He is currently an editorial consultant for the World Journal of Urology.
Dr. Netsch is a member of the DGU Urolithiasis Guidelines committee. He is also an active member of numerous national and international societies such as the DGU, EAU, and the Endourological Society. He is also a member of the DGU working group in Endourology and the EAU section of Uro-Technology (ESUT): Lower Tract Section.

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    Benedikt Becker

    Resident
    Asklepios Klinik Barmbek, Department of Urology

    Dr. Becker is a resident of urology in the urological department of the Asklepios Hospital Barmbek in Hamburg, Germany. He studied in Giessen and Lübeck (both Germany). His main scientific interest is the broad spectrum of endourology, especially laser treatment of benign prostatic obstruction. He is an active member of the German Society of Urology (DGU), the German Society of Residents in Urology (GeSRU), and the Endourological Society (WCE). At this time, he is participating in the Two Year fellowship program in Endourology/Stone Surgery.

    Presentation(s):

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      Mark Taratkin

      Researcher
      Institute for Urology, Sechenov University

      Researcher at the Institute for Urology and Reproductive health, Sechenov University.
      Head of the laser technology lab.

      Presentation(s):

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        Dmitry Enikeev

        Deputy Director for Science
        Institute for Urology and Reproductive health, Sechenov University

        Deputy Director for Science, Institute for Urology and Reproductive health, Sechenov University

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          Petr Glybochko

          Director
          RI for Uronephrology, Sechenov University

          Presentation(s):

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            Leonid Rapoport

            Deputy Director
            RI for Uronephrology, Sechenov University

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              Andreas J. Gross

              Head of Department
              Asklepios Klinik Barmbek, Abteilung für Urologie

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