Banko Anton, Kelman Charles D: Material removal apparatus and method employing high frequency vibrations. Cavitron Corporation, June 29, 1971: US3589363 (450 worldwide citation)

An instrument for breaking apart and removal of unwanted material, especially suitable for surgical operations such cataract removal, including a handheld instrument having an operative tip vibrating at a frequency in the ultrasonic range with an amplitude controllable up to several thousandths of a ...