Assessment of Tissue Damage from Ultrasonic, Pneumatic and Combination Lithotripsy

Abstract

Objective: To conduct a comparative evaluation of ultrasonic, pneumatic, and dual ultrasonic lithotripsy to predict the safety of probes on urinary tract tissue. Methods: Lithotriptors (medical device used to breakup kidney stones) tested were the Swiss Lithoclast Ultra (ultrasonic only - US, and ultrasonic-pneumatic combination US+P), and the Gyrus ACMI Cyberwand (dual ultrasonic). Fresh porcine ureters, bladders, and renal pelvis tissues were used for testing. A hands-free set up was used with each probe to vertically apply no pressure, 400 g, or 700 g of pressure for a duration of 3 seconds, 5 seconds or 180 seconds. Repetitive testing of each tissue/pressure/time combination was performed, for a total of 351 trials. Conclusion: All devices afforded a level of safety at tissue durations typical of inadvertent intraoperative contact (3-5 seconds), though the Lithoclast US-only was superior with regard to perforation for all tissue types. Overall, very similar results were observed between the Lithoclast US+P and Cyberwand.