Pressure-release versus rigid reflector for extracorporeal shockwave lithotripsy.
OBJECTIVE
To evaluate the advantages and disadvantages of using a pressure-release reflector instead of a rigid reflector to concentrate shockwaves for extracorporeal shockwave lithotripsy (SWL).


METHODS
As in all electrohydraulic lithotripters, shockwaves were generated by electrical breakdown of water between two electrodes, located at the focus (F1) closest to a paraellipsoidal reflector. A pressure-release reflector, made out of polyurethane foam, was constructed and tested on a research lithotripter using kidney stone models. Fragmentation data and pressure measurements were compared with those of a conventional rigid reflector tested on the same device.


RESULTS
The weight of stone model fragments remaining after shockwave exposure was less with the pressure-release reflector after screening through a 3.0 x 3.0-mm mesh. The residual fragment weight was less with the rigid reflector using 1.0 x 1.0- and 0.6 x 0.6-mm meshes.


CONCLUSIONS
Pressure-release reflectors may maintain acceptable stone fragmentation while offering improved patient safety and should be considered for SWL.
Centro de Física Applicada y Technología Avanzada, UNAM, Querétaro, Mexico. loske@fisica.unam.mx
Achim M
AM
Loske
Fernando E
FE
Prieto
D004867:Equipment Design; D006801:Humans; D007669:Kidney Calculi / Q000628:therapy*; D008096:Lithotripsy / Q000295:instrumentation*; D008954:Models, Biological