Category: Basic Science: Stones

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

Thu, Sep 20
4:00 PM - 6:00 PM

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
Hamburg, Hamburg, Germany

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.

Benedikt Becker

Resident
Asklepios Klinik Barmbek, Department of Urology
Hamburg, Hamburg, Germany

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.

Mark Taratkin

Researcher
Institute for Urology, Sechenov University
Moscow, Moskva, Russia

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

Dmitry Enikeev

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

Surgical experience:
Experienced in TURP (>300 surgeries).
Experienced in upper urinary tract endosurgery (PCNL >200, RIRS >200).

2008-Present: Multiple upper and lower urinary tract surgeries;
2011-Present: HoLEP (400 surgeries);
2011-Present: En-bloc enucleation of bladder tumor (50 surgeries);
2016-Present: ThuLEP (>400 surgeries);
2016-Present: Thulium en-bloc enucleation of bladder tumor (>80 surgeries);
2016-Present: Brachytherapy (>40 surgeries); prostate cryoablation (70 surgeries), renal cancer cryoablation (30 surgeries);
Apr 2017-Present: Irreversible electroporation (10 surgeries);
Apr 2017-Present: MR-fusion prostate biopsy (80 procedures).

Petr Glybochko

Director
RI for Uronephrology, Sechenov University
Moscow, Moskva, Russia

Leonid Rapoport

Deputy Director
RI for Uronephrology, Sechenov University
Moscow, Moskva, Russia

Andreas J. Gross

Head of Department
Asklepios Klinik Barmbek, Abteilung für Urologie
Hamburg, Hamburg, Germany