Piezoelectric shockwave lithotripters: differences in fragmentation efficiency in vitro

In a comparative assessment of the stone fragmentation efficacy of different piezoelectric lithotripters 72 human gallstones consisting of 24 sets of 3 stones each were disintegrated in vitro using the Piezolith 2300, the EDAP LT.01, and the Therasonic. On the basis of the maximum diameter the calculi were divided into group A (6-15 mm; n = 3 x 16) and group B (16-25 mm; n = 3 x 8) and were treated by using the maximum energy setting of each lithotripter (Piezolith 2300: setting 4, high power; EDAP LT.01: 95%; Therasonic: setting 7). Shockwave application was terminated when the residual fragments measured < or = 4 mm or after a total number of 6000 pulses. With the Piezolith 2300 all calculi could be disintegrated into fragments < or = 4 mm. In contrast, fragmentation was not successful, even after 6000 applied pulses, in the case of 2 and 6 stones when using EDAP LT.01 and the Therasonic lithotripters, respectively. With the remaining concrements of group A (n = 3 x 11) the fragmentation end point was achieved after a lower number of pulses when the Piezolith 2300 (median, 250 pulses; range, 50-500 pulses) was used than with the EDAP LT.01 (1000; 150-2500; p < 0.01) and the Therasonic lithotripters (2750; 750-5500; p < 0.01). Similar results were obtained for group B (n = 3 x 6): the Piezolith 2300 required fewer pulses (200; 100-1250) than the EDAP LT.01 (1000; 500-1000; p < 0.05) and the Therasonic (2000, 500-4000; p < 0.05) units.(ABSTRACT TRUNCATED AT 250 WORDS)