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AssigneeRadley Scientific Limited
InventorsMichael John Radley Young, Stephen Michael Radley Young, Michael James Ede
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A torsional-mode ultrasonic vibration generator is manufactured with longitudinal slots extending along its horn which damp unwanted vibrational modes and allow it to be made significantly smaller than previous apparatus. The torsional-mode ultrasonic generator is operable with a suite of surgical tools, to perform portions of an orthopaedic arthroplasty revision procedure. Three of the tools are for removing bone cement from within a bone cavity on a prosthesis cemented into the bone cavity. Three other tools are for separating an uncemented prosthesis from ingrown bone by cutting the bone between the prosthesis and walls of the bone cavity. The seventh tool is provided with sensors to determine a separation between a bone-cutting tool head and a metal prosthesis, feedback from the sensors being used to control servo motors of an articulated mounting for the seventh tool, to maintain the separation at a desirable value.
Apparatus to generate torsional-mode ultrasonic vibrations, adapted for use with ultrasonically-vibratable surgical tools, comprising conversion horn means having a frustoconical horn portion extending away therefrom and defining a longitudinal axis of the apparatus, and two axial mode ultrasonic transducer stacks, each comprising a plurality of piezo-electric ceramic elements disposed on a common axis, wherein said transducer stacks are mounted to the conversion horn means at respective points on opposite sides of the longitudinal axis and spaced equally therefrom, with the common axes of the transducer stacks each extending substantially perpendicularly to the longitudinal axis but offset therefrom and each extending parallel to the other, whereby motion of the transducer stacks exerts a rotational moment about the longitudinal axis, and wherein at least one elongate slot means extends longitudinally along a conical surface of the frustoconical horn portion.
Dependencies are inferred from the claim text.