Randomized controlled, multicentre clinical trial comparing a dual-probe ultrasonic lithotrite with a single-probe lithotrite for percutaneous nephrolithotomy

Study Type - Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Studies have indicated that not all ultrasonic lithotripters are created equal when it comes to efficiency of stone fragmentation and removal. To improve the efficiency of stone fragmentation and removal, combination pneumatic and ultrasonic devices have been developed. This study demonstrates that one available combination device, the Cyberwand, did not decrease the time to removal of the target stone nor did it increase the stone free rate compared to a standard ultrasonic lithotripter. OBJECTIVES To compare the Cyberwand (Gyrus/ACMI, Southborough, MA, USA), a dual-probe ultrasonic lithotrite, with a single-probe ultrasonic lithotrite. The Cyberwand incorporates coaxial high- and low-frequency ultrasonic probes that work synergistically. PATIENTS AND METHODS An institutional review board-approved, multicentre, randomized controlled trial to compare the Cyberwand to the Olympus LUS-II (Olympus America, Inc., Melville, NY, USA) single-probe lithotrite was performed. Patients undergoing a percutaneous nephrolithotomy (PCNL) with a target stone >2 cm in diameter were eligible for the study. The primary outcome was the time to removal of the targeted stone. RESULTS A total of 57 PCNLs were performed after randomization: 25 Cyberwand and 32 LUS-II. There was no difference (P > 0.05) observed between the two devices for target stone surface area (Cyberwand 526.6 cm ³ vs LUS-II 540.1 cm ³), time to clearance of target stone (Cyberwand 15.8 min vs LUS-II 14.2 min) and target stone clearance rate (Cyberwand 61.9 mm ²/min vs LUS-II 75.8 mm ²/min). Of the patients with stone analysis, hard stones (calcium oxalate monohydrate, brushite and cystine) were noted in 14 (56.0%) of the 25 Cyberwand and 18 (62.1%) of the 29 LUS-II patients. Fifteen of the 25 (60.0%) Cyberwand and 20 of the 32 (62.5%) LUS-II patients were stone-free after the initial PCNL. Those patients not rendered stone-free went on to receive a secondary PCNL. Device malfunction occurred in eight of 25(32.0%) Cyberwand and five of 32 (15.6%) LUS II patients. Complications were similar in both treatment groups. CONCLUSION No appreciable difference between the dual-probe Cyberwand and the standard ultrasonic Olympus LUS-II lithotrites can be identified.