Pulsed thulium:YAG laser-ready to dust all urinary stone composition types? Results from a PEARLS analysis.

ABSTRACT

PURPOSE: To evaluate whether stone dust can be obtained from all prevailing stone composition types using the novel pulsed thuliumYAG (p-TmYAG), including analysis of stone particle size after lithotripsy. METHODS: Human urinary stones of 7 different compositions were subjected to in vitro lithotripsy using a p-TmYAG laser with 270 µm silica core fibers (Thulio®, Dornier MedTech GmbH®, Wessling, Germany). A cumulative energy of 1000 J was applied to each stone using one of three laser settings 0.1 J × 100 Hz, 0.4 J × 25 Hz and 2.0 J × 5 Hz (average power 10 W). After lithotripsy, larger remnant fragments were separated from stone dust using a previously described method depending on the floating ability of dust particles. Fragments and dust samples were then passed through laboratory sieves to evaluate stone particle count according to a semiquantitative analysis relying on a previous definition of stone dust (i.e., stone particles ≤ 250 µm). RESULTS: The p-TmYAG laser was able to produce stone dust from lithotripsy up to measured smallest mesh size of 63 µm in all seven stone composition types. Notably, all dust samples from all seven stone types and with all three laser settings had high counts of particles in the size range agreeing with the definition stone dust, i.e., ≤ 250 µm. CONCLUSION: This is the first study in the literature proving the p-TmYAG laser capable of dusting all prevailing human urinary stone compositions, with production of dust particles ≤ 250 µm. These findings are pivotal for the broader future implementation of the p-TmYAG in clinical routine.