An ex-vivo assessment of a new single probe triple modality (Trilogy) lithotripter

Abstract

Introduction and objectives: This Swiss LithoClast® Trilogy lithotrite is a new lithotrite for percutaneous nephrolithotomy (PCNL). It has four modifiable settings; impact, frequency, ultrasound and suction. We aim to determine the optimal device settings for the fastest stone clearance. Materials and methods: Kidney stone phantoms were made with Begostone in a powder to water ratio (15:3–15:6). Complete stone clearance (seconds) was calculated and impact and frequency were adjusted and repeated N = 3. Intra renal pressure (IRP) was then measured in a porcine kidney model. Results: Stone phantoms with physical properties similar to struvite were cleared best with 100% impact and frequency of 12 Hz. Both uric acid stone phantoms and calcium phosphate stone phantoms were cleared most efficiently with an impact of 30% and a frequency of 4 Hz. The mean time to clear uric acid stone phantoms was 83 s versus 217 s for calcium phosphate stone phantoms. Similarly, for calcium oxalate stone phantoms, an impact of 30% and a frequency of 4 Hz was associated with the fastest clearance time, mean 204 s. However, the differences between 4, 8 and 12 Hz were not statistically significant. At a suction level of 60% or higher, IRP became negative. Conclusion: These results indicate that stone phantoms of hard kidney stones are cleared more efficiently at lower impact and frequency settings. With regard to suction, a setting of ≤ 50% appears to be the optimal setting.