Dual pulse shock wave lithotripsy: in vitro and in vivo study.
OBJECTIVE
We evaluated the performance of a novel dual pulse lithotriptor for extracorporeal lithotripsy.


METHODS
A piezoelectric lithotriptor was modified to produce pairs of successive (tandem) shock waves. Four kidney stone models were exposed in vitro to 500 single shock waves with a standard lithotriptor. Another set of stones was exposed 1 at a time to 250 pairs of shock waves with the tandem lithotriptor. The time delay between the first and second shock waves was increased in steps of 50 microseconds between 100 and 600 microseconds. Four stones were used per delay, ie 44 phantoms were fractured with the tandem system. Rabbits were used in vivo to demonstrate that the novel device does not produce more tissue trauma. Five rabbits were exposed to shock waves generated by the new device, 5 were treated with the standard system and 5 served as the sham treated group. Renal damage caused by the 2 systems was compared 1 week after shock wave application.


RESULTS
Enhanced fragmentation efficiency was achieved at a delay of 250 microseconds. In vivo results indicate that the dual pulse shock wave generator does not produce more kidney tissue damage.


CONCLUSIONS
Tandem lithotriptors may improve the quality and rate of stone comminution without increasing tissue damage. The device enhances cavitation induced damage to kidney stones. Extensive in vivo experiments will be important to evaluate the new design.
Loske
Achim M
AM
Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, A.P. 1-1010, 76000 Querétaro, Querétaro, México. loske@fata.unam.mx
Fernández
Francisco
F
Zendejas
Horacio
H
Paredes
Miguel
M
Castaño-Tostado
Eduardo
E
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006470:Hemorrhage / Q000473:pathology / Q000628:therapy; D019220:High-Energy Shock Waves; D007669:Kidney Calculi / Q000473:pathology / Q000628:therapy; D007684:Kidney Tubules / Q000473:pathology; D008096:Lithotripsy; D011817:Rabbits; D013997:Time Factors; D016896:Treatment Outcome