1284 In Vitro Evaluation of Optimal Device Settings for the Swiss Lithoclast Trilogy Lithotripter
C O Connor, L Lyons, D Hennessey- Surgery
Abstract
Aim
The LithoClast Trilogy Lithotripter is the latest generation lithotripter. It has four modifiable settings for stone fragmentation - Impact (0-100%), frequency (0-12Hz), ultrasound (0-100%) and suction (0-100%). The configuration for different stone types is unknown. We aim to determine the optimal settings for four stone types.
Method
Calcium oxalate, calcium phosphate, uric acid and struvite 2cm3 phantoms were created using Begostone. Ultrasound and suction were kept constant at 100% and 40%. Impact and frequency were adjusted for a combination of 10 settings and repeated N = 3. Drill speed and fragment size were calculated using 34mm probes.
Results
One hundred percent impact and frequency of 12 Hz resulted in the fastest clearance times of Struvite phantom stones, mean 83 seconds. For uric acid stone phantoms, impact of 30% and a frequency of 4 Hz was the fastest setting for stone clearance, mean 83 seconds. Calcium phosphate phantom stones were treated fastest at an impact of 30% and frequency of 4Hz (mean 217 seconds). The fastest clearance rate for calcium oxalate stone phantoms was at an impact of 30% and a frequency of 12Hz (mean 204 seconds). The slowest rate of calcium oxalate stone phantom clearance was an impact of 60% and 8Hz (mean 269 seconds).
Conclusions
Stone clearance rates, drill speeds and average fragment sizes were calculated for the most commonly occurring stones using the Swiss Lithoclast Trilogy lithotripter. The results indicate that harder stone phantoms may fragment more efficiently at lower device settings.