Preliminary results of the initial human clinical trial of focused ultrasound to reposition kidney stones

Methods There are three arms of the study: de novo stones, postlithotripsy fragments, and large stones within the preoperative setting. A pain questionnaire is completed immediately prior to and following propulsion. A maximum of 40 push attempts are administered on either low (50 V) or high (90 V) power settings. Movement is classified as no motion, movement with rollback (2-3 mm), or movement to a new location (> 3 mm) (Table 1). Results and conclusions Eight subjects have been enrolled and undergone ultrasonic propulsion to date. None of the subjects reported pain associated with the treatment. Subjects did report a mild warming of the skin with high (90 V) power pushes; no sensation was reported with low (50 V) power pushes. A summary of push movement results is provided in Table 1. Stones were visualized and repositioned in all subjects. One subject in the post-lithotripsy arm passed two small stones immediately following treatment. At least three post-lithotripsy subjects reported passage of multiple small fragments within two weeks of treatment. In five subjects, ultrasonic propulsion identified a collection of stones previously characterized as a single stone on KUB and ultrasound. Pre-operatively, one of two 7 mm stones was move before surgery. In surgery, it appeared one stone was firmly attached to Randall’s