Orthosonics Limited

General Dispensing Systems Limited

Other

Sra Developments Limited

Michael J Young

Brian R Bradnock

The apparatus for removal of bone-cement comprises means to generate an ultrasonic signal and a tool element including an elongate stem (1) to transmit the signal to a distal end:. A plurality of spoke members (3), preferably four or eight, extend radially from adjacent the distal end to connect with an annular member (2) surrounding and spaced from the distal end. A plurality of openings (4) are each defined by the stem (1), the annular member (2) and two of the spokes (3). The annular member (2) is provided with a distally facing cutting edge. The spokes (3) are so configured as to transmit to and allow axial movement of the annular member (2) with respect to the stem (1), with an enhanced displacement relative to that of the stem (1).

Apparatus for removal of plastics cement

An elongate tool bit is disclosed for ultrasonic excitation to remove plastics cement around a prosthetic implant in bone, as in a hip-joint replacement procedure. The tool bit features a stem portion with a distal-end claw formation, in the nature of a proximally open cup, having a convexly rounded distal end, with longitudinal apertures that provide through-passage for proximally directed flow of melted plastic. When the claw formation is driven via longitudinal vibration of the stem, cement melts at and near the convex distal end of the claw formation, and melted plastic passes through the apertures in the proximal direction to accumulate within and proximally of the claw formation. The claw formation features a relatively sharp proximally facing lip, thereby permitting the distal end of the tool to additionally serve an ultrasonic scraper function against the imbedded outer surface of the stud part of an appliance which requires replacement; alternatively, the tool can be used to ultrasonically remove plastics cement from the embedment of a distal fragment of a prosthetic appliance which has been broken, thereby aiding a procedure to remove the embedded fragment.

Tool bit for use in ultrasonic removal of plastics embedment of an

In a preferred embodiment, the invention provides a plurality of spaced ultrasonic piezoelectric transducers, which may be so fixed to and around an afflicted area of a patient as to enable their sequential or interlaced excitation, whereby the afflicted area of the patient can be excited from different aspects, so that ultrasonic energy is not permitted to enter the body from any single point on a continuous-wave basis. Each transducer delivers its ultrasonic energy via a body of material having a wave impedance that substantially matches the wave impedance of human soft tissue, thereby avoiding or minimizing the annoyance of a mismatched entry into the patient's body. The net result is for the patient to derive the therapeutic benefits of a moving applicator, without any physical displacement of one with respect to any other of the plural spaced transducers. Various embodiments and an illustrative plurality of different excitation sequences are described.

Ultrasonic therapeutic system

A relatively massive annular body is driven in radial-mode resonant oscillation by an ultrasonic driver that is fixed to the periphery of the annular body, with the axis of its ultrasonic drive oriented for intersection with the central axis of the annular body. A selected chucking device within the bore of the annular body is adapted to engage part of a prosthetic device, to which the resonant oscillation is imparted, for melting bone cement and for severing bony ingrowth into the prosthetic, thus permitting immediate retraction of the prosthetic from its pre-existing implantation in a living bone.

Means for removal of osteal prostheses

An apparatus producing an aperture through a workpiece of brittle material such as ceramic or glass which includes a piezo electric transducer to generate longitudinal vibrations at a frequency within the range 20-40 kHz, and transmit the vibrations to a tip adapted to contact the workpiece. Additionally a motor generates small amplitude movements of the tip at a frequency in the range of 10-100 Hz in a plane transverse to the direction of the longitudinal vibrations.

Apparatus for making an aperture in a tile

The apparatus comprises a piezoelectric vibrator adapted to generate ultrasonic energy which is transmitted through an output section 1 to a plastics head 6. The shape of the head 6 may be varied to suit whichever part of a body on which it is to be used. The material and shape of the head 6 is chosen to allow accurate control of frequency and amplitude of the ultrasonic energy. The preferred ultrasonic frequency is in the range of 20-120 kHz.

Apparatus for ultrasonic therapeutic treatment

Method for removal of osteal prostheses

A tool for use in removing plastics material from a hole comprises a work surface adapted to contact the material. A piezo-electric transducer is operatively connected through a work horn and causes the work surface to vibrate ultrasonically and thereby to heat locally the plastics material. A cavity is adapted to receive heated plastics material. The cavity has communication with a working zone adjacent the work surface. The work surface comprises an elongate boring member and rearwardly thereof a substantially annular cutting edge; the working zone communicates with the cavity via apertures disposed between the boring member and the annular cutting edge.

Tool for removal of plastics material

A method of cutting a brittle workpiece comprises applying to the surface of the workpiece a pointed tool, applying high frequency vibrations in a longitudinal direction to the tool, and moving the tool along a line to be cut of the workpiece while applying substantially steady longitudinally directed pressure to the tool. Stress is thereby applied to the workpiece as a combination of short impulses and steady direct stress and the breaking stress of the material would be attained coincident with the peak oscillatory stress. Crack propagation would therefore proceed by a series of stepwise fractures induced by successive cyclic stress peaks, resulting ultimately in the separation of the workpiece into two pieces. An apparatus for carrying out the method comprises a piezoelectric ceramic transducer to generate ultrasonic vibrations, a tip to be applied to the workpiece and having a hardness greater than that of the workpiece, with a tuned horn or the like being utilized to convey the ultrasonic vibrational energy to the tip.

Cutting brittle materials

A piezo electric ceramic transducer 1, a coupling horn 2 and a work surface 11 are connected a work horn 3. The work surface is ultrasonically vibrated and heats locally plastics material, causing it to flow through holes 12 in the work surface 11 to a space behind. The material can be removed when the tool is removed from the hole. The tool is particularly useful old cement from bones when revising a joint prosthesis.

Infuser

There is disclosed a control valve having an inlet 24, an outlet 26 connected a a valve cavity 23. The valve includes an armature 31 of a solenoid 32, movement of which opens a valve seal 28 seated in valve seat 27. A piezoceramic transducer 21 transmits ultrasonic vibrations through a tapering output section 22 to the valve cavity, whereby cavitation is induced in liquid therin to cause cleaning of the surfaces.

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Ashburton, United Kingdom

Michael J Young