Comparative Evaluation of Inertial Forces Generated by Ultrasonic Lithotriptors

摘要

Percutaneous nephrolithotomy has become the standard of care for large renal calculi requiring surgical removal. Ultrasonic intracorporeal lithotriptors are used to fragment and evacuate the calculi. Numerous commercially available systems exist. While previous study has demonstrated differing performance characteristics of the various systems, a standardized testing modality does not exist. In addition, ultrasonic lithotriptor efficiency is thought to deteriorate over time, but an objective measurement technique has not been reported. Rather, subjective performance of the ultrasound during surgical procedures is used to gauge the effectiveness of the instrument.rnIn this study we test the performance of two commercially available ultrasonic lithotriptors, the Lithoclast Select (Boston Scientific, Natick, MA) and Cyberwand (Gyrus ACMI, Southborough, MA). The Lithoclast Select combines pneumatic and ultrasonic lithotripsy in one handpiece but only the ultrasonic component was evaluated in this study. The Cyberwand combines two concentric ultrasound probes into a single handpiece. Several recent studies have shown the clinical effectiveness of the Lithoclast Ultra for PCNL. The Cyberwand has been shown during in vitro testing to be an efficient lithotrite.rnG-force is the measurement of as objects acceleration relative to free-fall and is measured by the unit g. One g is equal to the standard of gravity which is 9.806 m/s2. In this study we measured the g-forces generated by the ultrasonic lithotriptors to determine if there was a difference in the forces generated by the devices.