Prosthesis (i.e. – artificial body members) – parts thereof – or ai – Implantable prosthesis
Reexamination Certificate
1998-12-11
2001-01-23
Milano, Michael J. (Department: 3738)
Prosthesis (i.e., artificial body members), parts thereof, or ai
Implantable prosthesis
C623S017190
Reexamination Certificate
active
06176879
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a medical implant which is suitable for implantation in an artificial bone bed on the mastoid region of the skull having a hermetically sealed housing in which an electronic component and optionally, other components or modules are accommodated.
2. Description of the Related Art
Implants of this general type are known in the art as exemplified by U.S. Pat. No. 5,411,467 to Hortmann et al. and by the published German patent application No. DE 39 18 329 A1. Such implants are surgically imbedded in the bony area of the skull behind the ear which is known as the mastoid. An artificial bone bed can be created in the mastoid to receive the housing of the implant. The designs of these implant housings are difficult in that there are severe size limitations. One major design limitation lies in the fact that the size of the bone bed must be kept as small as possible. Another limitation lies in the fact that the depth of the bone bed must be kept as shallow as possible. On the other hand, any projection of the housing above the outside edge of the bone bed would result in bulging of the skin above the housing which would not be desirable since one of the goals and benefits of such implants is to make the implants and the aiding devices inconspicuous. Of course, this design difficulty is exacerbated when the medical implant requires a volumetrically large housing. This can arise when the implant's electronics or other components are relatively large and complex such as a power supply unit or components thereof
In known implantable cochlea implants such as Nucleus 22 and Nucleus 24 Cochlea Implant System from Firma Cochlear AG, a receiver/stimulator electronic module is accommodated in a titanium housing which includes a silastic jacket. The silastic jacket forms a thin, flexible silastic flap (for example, 2.5 mm thick) which extends away from one side of the titanium housing and holds a receiving antenna coil together with a magnet. During the implantation, only the titanium housing is inserted into the bone bed while the thin flexible flap holding the antenna coil and/or magnet is placed on the outside of the bone bed. This flexible flap is then covered by the skin. The flexible silastic flap however, does not provide a hermetically air-tight sealing of the components enclosed therein. Although flexibility of the flap allows it to conform to the curved shape of the skull, there is a danger of breakage in the connections between the components held in the silastic flap and the components located in the titanium housing. Moreover, because the thickness of the flap is limited so that the skin over the flap does not disruptively bulge, this also severely limits the size of the implant components and the type of components which can be held within the flexible silastic flap.
SUMMARY OF THE INVENTION
A primary object of the present invention is to devise a medical implant with a housing which maximizes the volume available in the housing for holding implant components.
Another object of the present invention is to provide a medical implant with a housing that minimizes any protrusion beyond the artificial bone bed in the mastoid of the skull such that bulges in the skin can also be minimized.
These objects are achieved in the present invention by providing a medical implant suitable for implantation in an artificial bone bed formed on the mastoid region of the skull which includes a hermetically sealed housing in which electronic implant and implant components may be accommodated where the housing includes at least one bend in at least one plane. The bend is dimensioned such that a tangential line extending from a bottom portion of one housing end forms an angle with a tangent extending from the other housing end.
Preferably, the implant housing in accordance with the present invention includes a bend in the middle third region or roughly in the middle half region of the housing. The angle formed by the tangents may be between 5 degrees and 25 degrees. More preferably, the angle formed by the tangents may be between 7 to 15 degrees. An angle of approximately 10 degrees has proven especially favorable. Furthermore, in accordance with another embodiment of the present invention, the implant housing may include multiple bends on a single plane.
In another embodiment of the present invention, the largest dimension of the housing, which is generally the length of the housing, is between 30 mm to 55 mm and more preferably, is between 38 mm to 50 mm. In many applications, the direction of the bend in the housing would run perpendicular to this largest dimension. The smallest dimension of the housing which is generally the thickness of the housing, is preferably between 4 mm to 8 mm.
The housing is also preferably made rigid such as shown in U.S. Pat. No. 4,991,582 to Byers et al. thereby reducing mechanical stresses on the components housed therein and on the electrical connections. In this regard, a portion of the housing can be made from a ceramic. The housing can also include multiple portions such as a ceramic housing portion and a metal housing portion. This housing design would result in a housing which is at least partially transparent to electrical, magnetic and electromagnetic fields. This is important if, for example, the housing is to accommodate an energy and/or data receiving antenna and/or a data transmitting antenna, or an antenna used for receiving and transmitting data as well as for receiving energy, particularly energy used to directly operate the medical implant and/or to recharge a trancutaneously rechargeable power supply unit of the medical implant. But as evident to those skilled in the art, the housing can also be made from a metal depending on the special design and application of the implant and the housing.
In one embodiment of a housing with a ceramic housing portion and a metal housing portion, the bend is advantageously placed in the vicinity of where the ceramic housing portion joins with the metal housing portion. This embodiment is especially adaptable for containing a power supply unit, particularly a trancutaneously rechargeable power supply unit, or at least a component thereof, in one housing portion and an electronic component in the other housing portion.
For example, the present implant housing can be used effectively in totally or partially implantable hearing aid systems, especially in such systems that actively stimulate the inner ear through mechanical or electrical stimulation. These types of hearing aids are known in the art as exemplified in U.S. Pat. No. 5,411,467 to Hortmann et al., U.S. Pat. No. 5,279,292 to Baumann et al. and U.S. Pat. No. 4,419,995 to Hochmair et al. These types of hearing aids are further exemplified in the German patent DE 39 40 632 C1, and the German patent applications, DE 39 18 329 A1, and DE 196 38 159.2 and its related U.S. Pat. No. 5,814,095 commonly assigned to the present applicant.
Although the above discussion focused on the present invention's application in hearing said systems, the invention is in no way limited thereto. The present invention may also be used in the like manner for any other implants. Of course, the above discussed embodiment of the present invention is especially applicable for implantation in the mastoid region of the skull. Other examples of these implants include tinnitus suppression systems, drug pumps and retinal stimulators and others.
The preferred embodiments of the present invention are set forth in detail below together attached drawings.
REFERENCES:
patent: 2495476 (1950-01-01), Posen
patent: 3798390 (1974-03-01), Gage
patent: 4419995 (1983-12-01), Hochmair et al.
patent: 4991582 (1991-02-01), Byers et al.
patent: 5271397 (1993-12-01), Seligman
patent: 5279292 (1994-01-01), Baumann et al.
patent: 5411467 (1995-05-01), Hortmann et al.
patent: 5645586 (1997-07-01), Meltzer
patent: 5724431 (1998-03-01), Rieter
patent: 5792208 (1998-08-01), Gray
patent: 5814095 (1998-09-01), M{umlaut over (u)}ller et
Lehner Rolf Martin
Leysieffer Hans
M{umlaut over (u)}ller Dieter
Reischl Gabriele E.
Implex Aktienegesellschaft Hearing Technology
Milano Michael J.
Nixon & Peabody LLP
Safran David S.
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