In Vitro Assessment of a Novel Dual Probe Ultrasonic Intracorporeal Lithotriptor

Purpose

The Cyberwand (Cybersonics, Erie, Pennsylvania) is a novel intracorporeal lithotrite that uses coaxial ultrasonic elements operating at 2 frequencies. We compared this device to the LithoClast® Ultra, which we previously noted is the most efficient commercially available intracorporeal lithotripsy device.

Materials and Methods

An in vitro test system was used to assess the efficiency of stone penetration for the Cyberwand and the LithoClast Ultra. The devices were mounted upright with the probe tip up in a modified irrigation sheath. A gypsum artificial stone was centered on the probe tip and a mass was placed atop the stone to provide a constant force. The manufacturer recommended setting was selected for the Cyberwand, while for the LithoClast Ultra a pneumatic frequency of 12 Hz with an ultrasonic power setting of 100% was selected, representing optimal settings in previous in vitro tests. The time required for complete stone penetration was measured. Differences in mean stone penetration times were compared using ANOVA.

Results

Mean ± SD penetration time for the Cyberwand was significantly shorter than for the LithoClast Ultra (4.8 ± 0.6 vs 8.1 ± 0.6 seconds, p <0.0001). Neither device showed any difficulties with overheating, occlusion or another malfunction.

Conclusions

Initial assessment using our hands-free in vitro test system, in which stone penetration time is not affected by operator bias, suggests that the Cyberwand is an efficient lithotrite. These promising results justify in vivo testing.

Key Words: kidney, kidney calculi, lithotripsy, nephrostomy, percutaneous