Engineering Better Lithotripters

Although shock wave lithotripsy (SWL) remains an excellent non-invasive method for active removal of stones from the ureter and kidney, its popularity has decreased during recent years and the arguments for choosing endoscopic procedures rather than the only non-invasive surgical procedure are usually based on the opinion that SWL results are inferior to those obtained with endoscopic methods. It is considered that slow technical progress has not sufficiently met the requirements of disintegration, reduced need of repeated treatments, shorter treatment duration and less negative effects on tissues. This article summarises some recently published articles that address these problems and have the aim of improving the function of lithotripters. Modification of the shock wave geometry, elimination or control of cavitation bubbles, and different techniques of disintegration studied in in vitro and in animal experiments suggest several possible future directions that might provide a basis for development of a new "gold standard" lithotripter.