Category: Clinical Stones: Equipment (stents, lasers, guidewires, sheaths)

MP27-18 - Moses and the Stone: In vitro Comparison of a Novel Laser Technology to Short and Long Pulse in a Stone Dusting Model

Sun, Sep 23
10:00 AM - 12:00 PM

Introduction & Objective :

Moses technology is a novel Holmium:YAG laser pulse delivery system designed to minimize urinary stone retropulsion and improve stone fragmentation even when the laser is not in contact with the stone. Our aim was to assess the ablation efficiency of Moses technology in laser lithotripsy using an in vitro "dusting model" of stone comminution.


Methods :

All tests were conducted using a Lumenis Pulse 120H Holmium:YAG laser with a 365µm Moses fiber. "Hard" (15:3) and "soft" (15:6) Begostones mimicking calcium oxalate monohydrate and calcium oxalate dihydrate stones, respectively, were used.  To assess comminution efficiency and fiber tip degradation a dusting model was employed: the laser tip was moved by a 3-dimensional positioning system in a spiral motion across a flat Begostone surface submerged in water. Comminution efficiency was measured as the loss of stone mass after 4kJ of energy delivery. Fiber tip degradation was measured at 1kJ intervals. Comparative trials at short pulse, long pulse, Moses-contact and Moses-distance settings were completed with the laser tip positioned at 0, 1, and 2mm distances from the stone surface at energy settings of 0.4J delivered at 70Hz. Each pulse type was tested 4 times on each stone type.


Results :

In our dusting model, comminution was significantly greater the closer the laser tip was to the stone surface.  On hard stones, pulse type did not have a significant impact on stone comminution at any distance. On soft stones at 0mm, Moses-contact produced the greatest amount of comminution, significantly greater than long pulse (p<0.05) and trending toward significance relative to short pulse. At 1mm, Moses-distance produced significantly greater comminution than all other settings (p=0.025) and was as effective as long or short pulse at 0mm (Figure).  Fiber tip degradation was minimal and there was no significant difference between any laser settings.


Conclusions :

In an in vitro dusting model, the novel Moses Holmium:YAG laser technology provides greater comminution of soft stones when in contact with the stone surface and enables effective comminution at 1mm from the stone surface. Further clinical studies are warranted to assess the clinical utility of this new technology.

Brenton B. Winship

Endourology Fellow
Duke University Medical Center, Division of Urology
Durham, North Carolina

Daniel Wollin

Durham, North Carolina

Evan Carlos

Durham, North Carolina

Jingqiu Li

Singapore, Not Applicable, Singapore

Chloe Peters

Durham, North Carolina

Russell S. Terry

Endourology Fellow
Duke University Medical Center, Division of Urology
Durham, North Carolina

Fellow in Endourology, Metabolic Stone Disease, Laparoscopy, and Robotic Surgery
Division of Urologic Surgery
Duke University Medical Center

W. Neal Simmons

Durham, North Carolina

Charles D. Scales

Associate Professor
Duke University Medical Center, Division of Urology
Durham, North Carolina

Charles D. Scales, Jr., MD MSHS is Associate Professor of Surgery (Urology) and Population Health at Duke University School of Medicine and Vice Chief for Quality Improvement and Patient Safety in the Division of Urologic Surgery. He completed medical school and residency training in urology at Duke University Medical Center. After residency, Dr. Scales completed the Robert Wood Johnson Foundation Clinical Scholars Program at UCLA, where he received advanced training in health services research, health policy, and quality of care.

Dr. Scales has a strong interest in education, having previously served on the ACGME Review Committee for Urology and as a member of the ACGME Board of Directors. He currently leads a course in quality improvement and data analytics in the Masters of Management in Clinical Informatics program at the Duke University School of Medicine.

From the research perspective, Dr. Scales has a longstanding interest in the epidemiology of and patient care for urinary stone disease. Recent studies have redefined the burden of urinary stone disease in the United States, compared the effectiveness of dominant stone removal technologies, and identified new opportunities for improving patient-centered and policy-relevant outcomes, such as unplanned care after procedural interventions. His research and perspective on urinary stone disease has been highlighted in U.S. News & World Report, Reuters, NPR, and the Wall Street Journal, among other media outlets.

As a result of these investigations, he has an appointment at the Duke Clinical Research Institute where he leads a diverse health services and clinical research program. He has received research support from the National Institute of Aging, the American Geriatrics Society, and philanthropic funding, among other sources. Currently, Dr. Scales is the Principal Investigator for the Scientific Data and Research Center for the NIDDK Urinary Stone Disease Research Network (U01).

Michael Ferrandino

Assoc Professor of Urology Surgery
Duke University Medical Center
Durham, North Carolina

Dr. Michael Ferrandino is Director of Minimally Invasive Surgery for the Division of Urology at Duke University Medical Center in Durham, NC. He is an Associate Professor of Urologic Surgery. His area of expertise and is minimally invasive surgical approaches to benign and malignant urologic disease. He received his medical degree in 2001 from NYU School of Medicine. In 2007 he completed his urology residency at SUNY Downstate Medical Center and went on to an Endourologic Fellowship at Duke University Medical Center. He joined the faculty after fellowship and has continued to grow the field of minimally invasive surgery throughout his tenure. He serves as the Associate Residency Program Director and the Vice Chief of Education for the Division of Urology.

Glenn M. Preminger

Duke University Medical Center, Division of Urology
Durham, North Carolina

Michael E. Lipkin

Associate Professor Urology
Duke University Medical Center, Division of Urology
Durham, North Carolina