Analysis of stone trajectory during laser lithotripsy: an in vitro study

Stone retropulsion is an inevitable side effect of laser lithotripsy. It is generally considered undesirable but can also be beneficial in techniques such as "popdusting". It is often described by a single parameter such as a distance moved, which might not correlate with the degree to which retropulsion interferes with clinical use. We report on a novel method of measuring retropulsion in vitro using high-speed video photography to describe the stone trajectory across multiple parameters, and present results from a range of laser systems. Describing the nature of this movement may help explain how some types of retropulsion are considered clinically disruptive and others are not.