Improving environmental and stone factors toward a more realistic in vitro lithotripsy model

Abstract

To improve in vitro lithotripsy models, we investigated the effects of multiple experimental variables on stone fragmentation. We performed timed burst wave lithotripsy (BWL) and shock wave lithotripsy (SWL) exposures in a water tank with the following variable parameters: water gas content (60, 30, and 15% O2), temperature (20 and 37°C), stone holder degree of enclosure (open wire basket, polyvinyl chloride (PVC) open-ended gel, and similar material anatomically accurate artificial kidney), and stone type (Begostone at 2 mixture ratios, calcite, calcium oxalate monohydrate (COM), and uric acid). At least 3 stones were treated for each condition, with fragmentation defined as percent stone mass <2 mm. Begostone (2:1 powder:water ratio) treated with BWL at 20°C vs. 37°C showed 75±13% vs. 62±6% breakage, respectively. Using the same stone type, gas concentrations of 60, 30, and 15% O2 showed breakage of 23±4%, 55±8%, and 82±16%, respectively. More enclosed kidney phantoms showed decreasing lithotripsy efficacy of 94±11%, 64±21%, and 13±2% breakage in basket, PVC, and anatomic phantoms, respectively. 2:1 Begostone most closely mimicked COM stone breakage. SWL exposures produced similar trends. This work indicates the importance of controlling multiple variables during in vitro lithotripsy experiments. [Work supported by NIH P01 DK043881 and K01 DK104854.]To improve in vitro lithotripsy models, we investigated the effects of multiple experimental variables on stone fragmentation. We performed timed burst wave lithotripsy (BWL) and shock wave lithotripsy (SWL) exposures in a water tank with the following variable parameters: water gas content (60, 30, and 15% O2), temperature (20 and 37°C), stone holder degree of enclosure (open wire basket, polyvinyl chloride (PVC) open-ended gel, and similar material anatomically accurate artificial kidney), and stone type (Begostone at 2 mixture ratios, calcite, calcium oxalate monohydrate (COM), and uric acid). At least 3 stones were treated for each condition, with fragmentation defined as percent stone mass <2 mm. Begostone (2:1 powder:water ratio) treated with BWL at 20°C vs. 37°C showed 75±13% vs. 62±6% breakage, respectively. Using the same stone type, gas concentrations of 60, 30, and 15% O2 showed breakage of 23±4%, 55±8%, and 82±16%, respectively. More enclosed kidney phantoms showed decreasing lithotripsy effic...