BigPatents India

A percutaneous surgical instrument (10) for de-bulking calculi or drilling bone includes an actuator (12) for generating vibrations at ultrasonic frequencies and a horn (22) coupled to said actuator for amplifying the actuator vibration. A fixed probe (32) is attached to said horn for engaging the calculi and introducing the ultrasonic frequencies thereto. A floating probe (44) is disposed concentric to and over said fixed probe and slidable thereover. A free mass (56) is disposed between the horn and the floating probe for oscillating therebetween, in response to actuator vibration, for causing low frequency impact with the calculi. (FIG. - 1)