Piezoelectric Shockwave Lithotripters: Differences in Fragmentation Efficiency in Vitro

Abstract

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 × 16) and group B (16–25 mm; n = 3 × 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 ≤4 mm or after a total number of 6000 pulses. With the Piezolith 2300 all calculi could be disintegrated into fragments ≤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 × 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 × 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. Lithotripters based on the piezoelectric Shockwave principle show differences in fragmentation efficacy. The Piezolith 2300 system proved to be more effective in disintegrating human gallstones in vitro than the other two piezoelectric generators tested.

Key Words:

• Gallstones
• in vitro fragmentation
• piezoelectric lithotripsy
• Shockwave lithotripsy