Surgery – Surgically implanted vibratory hearing aid
Reexamination Certificate
2000-05-30
2001-09-25
Lacyk, John P. (Department: 3736)
Surgery
Surgically implanted vibratory hearing aid
Reexamination Certificate
active
06293903
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus and method for supportably mounting an implantable hearing aid device to a patient's skull, and more particularly, to a mounting apparatus and method that provides enhanced stability, mounting-position flexibility and/or ease-of-installation advantages.
BACKGROUND OF THE INVENTION
A number of different types of implantable hearing devices have been proposed. By way of primary example, such devices include those which utilize electromechanical or piezoelectric transducers for stimulation of the ossicular chain (see, e.g., U.S. Pat. No. 5,702,342), and those which utilize excitor coils to electromagnetically stimulate magnets affixed above to a bone in the middle ear (see, e.g., U.S. Pat. No. 5,897,486). Additional implantable approaches employ piezoelectric transducers to stimulate the ossicular chain.
In most instances, hearing aid devices of the above-noted nature entail supportably mounting at least a portion of a middle ear actuator to a patient's skull, wherein the supported portion is positioned in an opening surgically defined in the skull. Most typically, the supported portion is at least partially located within the mastoid process and requires stable and reliable placement. However, desirable locations for skull interconnection may be limited and can vary significantly from patient-to-patient, thereby adding to implant procedure complexity. In this regard, the required time associated with mounting during implant procedures is of growing concern given the high costs associated with surgical facility usage and the baseline objective of making implantable hearing aid devices an affordable option for the hearing impaired.
SUMMARY OF THE INVENTION
In view of the foregoing, a primary objective of the present invention is to provide an apparatus and method for implantable hearing aid device mounting that provides positioning-flexibility and enhanced stability.
A further primary objective of the present invention is to provide an apparatus and method for implantable hearing aid device mounting that can be implemented with reduced installation time and attendant cost relative to many current mounting devices/methods.
The above objectives and additional advantages may be realized by the inventive apparatus and method disclosed herein. The apparatus comprises a support member adapted to support an implantable hearing aid device within a patient's skull. The apparatus further includes a plurality of mounting legs (e.g., two or more) interconnected to and extending laterally away from the support member in a corresponding plurality of differing directions. Each of the plurality of mounting legs includes at least one mounting aperture for selectively receiving a skull attachment device therethrough.
In one aspect of the invention, the mounting legs may be disposed to radiate from a top end of the support member and may be spaced (e.g., equally) within a predetermined arc of &bgr;° thereabout. For example, in one arrangement four mounting legs may be equally-spaced about an arc of 180°, wherein adjacent legs form 60° angles within the 180° arc. In another arrangement, three mounting legs may be spaced about a 180° arc, wherein adjacent legs define 90° angles therebetween. Additional combinations comprising two or more legs and varying radiating orientations will be apparent to those skilled in the art.
As may be appreciated, the provision of a plurality of mounting legs which laterally extend from a support member in a plurality of differing directions disposes the mounting apertures of the different mounting legs in radially offset positions from each other, thereby yielding enhanced positioning options for skull interconnection. Further, and in another aspect of the invention, at least one of the plurality of mounting legs, and preferably each of the mounting legs, may comprise a plurality of mounting apertures which are radially offset from each other. Additionally, it is preferable for each mounting leg to include at least two mounting apertures that are located at differing lateral distances from the support member.
In an additional inventive aspect, it may be preferable for the mounting legs to adjoin a top end of the support member in a substantially planar adjoinment region, and for the support member (e.g., a center axis thereof) to be disposed at an acute angle &thgr;° relative to the substantially planar adjoinment region. Preferably, the acute angle &thgr;° may be advantageously established at between about 20° to 70°. By way of example, alternative embodiments may be provided with &bgr;° established at differing angles (e.g., 35° and 55°) to provide medical personnel with mounting apparatus options to address differing patient skull configurations.
In yet another aspect of the invention, the mounting legs may be disposed to radiate from a substantially planar support member adjoinment region in different directions within a first arc of &bgr;°, while the support member may be disposed to extend from the adjoinment region within a non-overlapping second arc of 360°−&bgr;°. For example, in a top or plan view, the mounting legs may be provided to linearly radiate in different directions within a predetermined arc of &bgr;° (e.g., 180°) about the adjoinment region, while the support member itself linearly radiates in yet another different direction outside of the predetermined arc of &bgr;°.
In a further aspect of the present invention, the plurality of mounting legs may be integrally formed with the support member. In this regard, the mounting legs and support member may comprise a material selected from a group consisting of: titanium (e.g., grade 1, grade 2 or commercially pure titanium), stainless steel, or plastic. Further, the surfaces of the mounting legs and/or support member may be finished to selectively promote or retard tissue and/or bone attachment. By way of example, where the mounting legs and/or support member are of metal construction, the surfaces may be roughened (e.g., grit-blasted) to enhance tissue attachment. Conversely, the surfaces may be chemically treated (e.g., with paclitaxal) to frustrate tissue attachment.
In a related aspect of the present invention the mounting legs may be adjoined to the support member in a fashion to render them bendable along their respective adjoinment regions within a predetermined angular range. Preferably, the predetermined angular range may be about ±30°. Such bendability allows the mounting legs to be pivoted (e.g., downwardly) to facilitate flush engagement with the curved contours of a patient's skull. Further, it may be preferable for the mounting legs to be frangible upon severe bending for selective removal.
In two exemplary embodiments of the inventive apparatus three or four mounting legs integrally adjoin and extend laterally from a top end of a cylindrical support member. In a top view, the mounting legs and support member each radiate away from the top end of the support member in different directions. Each mounting leg is of a Y-shaped configuration with its base adjoining the support member. Three apertures are disposed at the distal end of each mounting leg so that each of the three apertures are radially offset and one of the apertures is located at a different lateral distance than the other two apertures relative to the top end of the support member. In the three mounting leg embodiment, the support member is disposed at a first acute angle relative to a planar support member/mounting leg adjoinment region, and in the four mounting leg embodiment the support member is disposed at a second acute angle relative to a planar mounting leg/support member adjoinment region, the first acute angle (e.g., 55°) being greater than the second acute angle (e.g., 35°).
In the two noted embodiments, the cylindrical support member may be sized so as to permit passage of at least a portion of an implantable middle ear actuator therethrough, wherein a top end portion of the hearing aid device being may be supportably
Kasic, II James Frank
Miller Douglas Alan
Slattery, III William Howard
Lacyk John P.
Marsh & Fischmann & Breyfogle LLP
Otologics LLC
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