Ultrasonic surgical tool system including a tip capable of simultaneous longitudinal and torsional movement and a console capable of applying a drive signal to the tip so the tip engages in substantially torsional oscillations

An ultrasonic tool system comprising:

• an ultrasonic handpiece including:
• at least one driver that, in response to application of an AC drive signal, cyclically expands and contracts, and
• a tip including opposed proximal and distal ends, the proximal end of the tip being coupled to the at least one driver so that the expansions and contractions of the at least one driver cause longitudinal vibrations at the proximal end of the tip, and a feature between the proximal and distal ends of the tip that converts the longitudinal vibrations present at the proximal end of the tip to vibrations at the distal end of the tip having a longitudinal component and a torsional component;
• and
• a control console for vibrating the tip of the ultrasonic handpiece, the control console configured to:
• generate the AC drive signal that is applied to the at least one driver of the ultrasonic handpiece, the AC drive signal having a variable frequency, and
• set the frequency of the AC drive signal to a frequency between resonant frequencies of first and second adjacent mechanical resonant modes of the ultrasonic handpiece, the set frequency corresponding to first vibrations in the tip associated with the first mechanical resonant mode and second vibrations in the tip associated the second mechanical resonant mode, each of the first and second vibrations having a longitudinal component and a torsional component, the longitudinal component of the first vibrations at least partially cancelling out the longitudinal component of the second vibrations.