Dr. Winshop and team performed their experiment using a Lumenis Pulse 120H Holmium:YAG laser with a 365µm Moses fiber on hard and soft Begostones. The laser fiber was held steady by a a 3-dimensional positioning system that moved in a spiral motion across a flat Begostone surface submerged in water as seen below.
Comminution efficiency and fiber tip degradation were recorded. The team measured comminution efficiency as the loss of stone mass after 4kJ of energy delivery while fiber tip degradation was measured at 1kJ intervals. Tests were done with the laser fiber tip positioned at 0, 1 and 2mm from the stone surface. The laser was set to 0.4J at 70Hz.
After analysis, they found that there was no significant difference in fiber tip degradation across all groups. For comminution efficiency, they found that it was significantly greater at smaller laser fiber tip distances. However, for hard stones pulse type did not impact comminution at 0, 1, or 2 mm distances. For soft stones, the greatest comminution was at 0 mm and was just as effective at 1mm.
Dr. Winshop concludes that in an in vitro model, the Moses 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.
Presented by: Brenton Winship, Endourology Fellow, Duke University Medical Center, Division of Urology, Durham, North Carolina
Co-Authors: Daniel Wollin1, Evan Carlos1, Jingqiu Li2, Chloe Peters1, Endourology Fellow Russell Terry1, W. Neal Simmons1, Associate Professor Charles Scales1, Associate Professor Michael Ferrandino1, Glenn Peminger1, Associate Professor Michael Lipkin1
1. Duke University Medical Center, Division of Urology, Durham, North Carolina
2. Singapore, Singapore
Written by: Renai Yoon, medical writer for UroToday.com at the 36th World Congress of Endourology (WCE) and SWL - September 20-23, 2018 Paris, France