In Vitro Model of Shock Wave Lithotripsy (SWL) Produces Stone Breakage Equivalent to that Seen In Vivo

摘要

Although in vitro model systems are used frequently in lithotripsy research, few attempts have been made to compare in vitro results directly with those in vivo. To determine if in vitro stone fragmentation correlates with that in vivo, gypsum stones were exposed to SWL in two systems: In vivo, stones were placed into pig kidneys and exposed to SW's in an unmodified Dornier HM3 lithotripter. 400 SW's (20 kV) were delivered at two rates. In vitro, stones were placed on plastic mesh inside a polypropylene tube, and exposed to SW's in an HM3-like research lithotripter. At 0.5 Hz, SW's in vitro yielded 280+-34% breakage (increase in surface area, n=8), while in vivo breakage was 327+-26% (n=6). At 2 Hz, in vitro breakage was 101+-16% (n=20), while in vivo was 134+-47% (n=7). Statistically, in vitro and in vivo effects did not differ, while the effect of SW rate was significant in both. Thus, with the in vitro system and lithotripters used here, both absolute stone breakage and rate effects were similar to what was observed in vivo.