Simulation of ventilatory-induced stone movement and its effect on stone fracture during extracorporeal shock wave lithotripsy.

Because ventilation influences renal movement, we investigated the effect of stone motion on the efficiency of extracorporeal shock-wave lithotripsy (ESWL). Comparisons of the rates of fragmentation of an experimental model of renal calculi were made between simulated high-frequency jet ventilation at 100 breaths/min. with four-mm. stone movement as measured from the fluoroscope screen, conventional mechanical ventilation at 10 breaths/min. with 32-mm. stone movement as measured from the fluoroscope screen, and a static control. Fragmentation did not differ significantly between high-frequency jet ventilation and no ventilation (static control), but was significantly greater with high-frequency jet ventilation than with conventional ventilation.