An ultrasonic medical treatment device has a casing, an elongate probe, a transducer assembly, a sheath and at least one electrode member. The probe is mounted to and extends from the casing and has an axis and a free end serving as an operative tip. The transducer assembly is mounted to the casing and is operatively connected to the probe for generating vibrations of at least one ultrasonic frequency in the probe. The sheath surrounds the probe. The electrode member is connectable to an RF voltage source and is mounted at least indirectly to the casing so as to permit relative motion between the electrode member and the probe.