AUA 2019: The Impact of Laser Pulse Parameters on Popcorn Lithotripsy

Chicago, IL ( Dr. Russel Terry and his colleagues investigated the use of Moses technology and its efficiency on popcorn lithotripsy through studying pulse length and pulse type. Dr. Terry notes that there is already previous literature about the effects of moderate energy and high frequency improved the efficiency of popcorn lithotripsy. They characterized popcorn lithotripsy as non-contact, continuous laser discharge. It should be noted that there are continuous improvements to laser systems, allowing them to become more precise and powerful.

In their model, they used BegoStone fragments of either “hard” or “soft” stone composition with sizes ranging from two to four millimeter. A laser fired at the stones vertically for two minutes with constant irrigation at varying pulse types and pulse lengths. The four different measured variables being tested were short pulse, long pulse, Moses contact, and Moses distance.

For the hard stone composition, Dr. Terry found that at 0.5J/70Hz, short pulse and Moses distance settings ablated significantly more than any of the other pulse length and pulse type. The results for the soft stone model yielded significantly more stone ablation at the 0.5J/70Hz and the 0.5J/40Hz energy and frequency level with a short pulse and Moses distance setting. In both situations, significantly more stone was ablated at the 0.5J/70Hz than at any of the other settings.

In conclusion, Dr. Terry found that efficiency on popcorn lithotripsy the best conditions are short pulse and Moses distance at moderate energy and high frequency.

Presented by: Russel Terry, MD, Duke University Medical Center, and Durham VA Health Care System, Durham, North Carolina

Written by: Joshua Tran, (Department of Urology, University of California-Irvine) medical writer for at the American Urological Association's 2019 Annual Meeting (AUA 2019), May 3 – 6, 2019 in Chicago, Illinois