In vitro calcium oxalate lithotripsy: comparison of Dornier HM3 and Siemens Lithostar

In vitro lithotripsy of round calcium oxalate stones retrieved from a patient at pyelolithotomy was used to compare the Dornier HM3 and Siemens Lithostar lithotripters. Similar stones were subjected to the same number of shock waves at similar kilovoltages and shock wave frequencies, and percent fragmentation was calculated. The numbers of shock waves required to fragment similar stones completely at the same kilovoltages were determined. Using 50 shock waves at less than 16 kV, the Siemens Lithostar produced little fragmentation of like stones, while at 16 kV and above, the Lithostar and the Dornier HM3 yielded similar stone fragmentation. The number of shock waves required to obtain complete fragmentation was similar for the HM3 and the Lithostar at greater than 16 kV. Using energy levels less than 16 kV, the HM3 needed markedly fewer shock waves to achieve fragmentation, although complete fragmentation could be accomplished with the Lithostar.