U.S. patent number RE33,170 [Application Number 06/811,019] was granted by the patent office on 1990-02-27 for surgically implantable disconnect device.
This patent grant is currently assigned to The Regents of the University of California. Invention is credited to Charles L. Byers.
United States Patent |
RE33,170 |
Byers |
February 27, 1990 |
Surgically implantable disconnect device
Abstract
A surgically implantable connector for a transcutaneous driving
system comprised of a case having a base and a lid which are shaped
to provide a cavity between them with a first elastomeric pad for
supporting a first set of electrical contacts in the cavity which
contacts mate with a second set of electrical contacts carried by
the lid, a second elastomeric pad for supporting a third set of
electrical contacts inbetween the lid and the first pad and which
mate with the first or the second set of electrical contacts, means
for electrically connecting the firs set of electrical contacts to
an implantable electrode, means for electrically connecting the
second set of electrical contacts to the driving system and means
for electrically connecting the third set of electrical contacts to
a percutaneous plug.
Inventors: |
Byers; Charles L. (Vacaville,
CA) |
Assignee: |
The Regents of the University of
California (Berkeley, CA)
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Family
ID: |
27001645 |
Appl.
No.: |
06/811,019 |
Filed: |
December 18, 1985 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
Reissue of: |
362344 |
Mar 26, 1982 |
04495917 |
Jan 29, 1985 |
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Current U.S.
Class: |
607/57;
128/903 |
Current CPC
Class: |
A61F
2/18 (20130101); A61F 2250/0001 (20130101) |
Current International
Class: |
A61F
2/02 (20060101); A61F 2/18 (20060101); A61N
001/04 () |
Field of
Search: |
;128/419P,419R,419F,419G,746,642,419PG,903 ;179/17R,17BC,17FD ;3/1
;339/116C,17F |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"Electrocardial RF Pacemaker"; Barr et al, 5-67. .
"Bone Plating", Down Bros. et al. .
"Gold Dot--A Non-Connector . . . ", Wittmann, Hughes Aircraft Co.
.
"Metal-Elastomeric Display Connectors", L. S. Buchoff, Proceedings
of SID, vol. 21/2, 1980. .
"Recent Developments . . . ", C. L. Byers. .
"Cochlear Implant Prostheses: Strategies and Progress", Merzenich
et al, 6-5-81, Pergamon Press..
|
Primary Examiner: Coven; Edward M.
Attorney, Agent or Firm: Phillips, Moore, Lempio &
Finley
Government Interests
The invention described herein was made in the course of work under
a grant or award from the Department of Health and Human Services.
Claims
What is claimed is:
1. A connector comprising a case, including a base member and a
lid, the base member and lid being shaped to provide a cavity
between them, a first contact pad of elastomeric material, a first
set of electrical contacts embedded in the first contact pad, the
contact pad being dimensioned to fit within the cavity, the contact
pad being interposed between the lid and the base member, a second
set of electrical contacts .[.carried by the lid.]. within the
cavity, means for providing separate electrical connections through
the case to the first and second sets of electrical contacts, and
means for pressing the lid against the base member and the contact
pad to exert a predetermined pressure on the pad, causing it to
form a fluid tight seal around the first and second sets of
electrical contacts, some of which are thereby placed in electrical
contact with each other.Iadd., one of the first and second sets of
electrical contacts being comprised of partially flattened metallic
spheres.Iaddend..
2. A connector as recited in claim 1 wherein the case is
cylindrical and the first and second sets of electrical contact are
each arranged in corresponding radial patterns.
3. A connector as recited in claim 1 wherein the first contact pad
is comprised of silicone rubber reinforced with a mesh.
4. A connector as recited in claim 1 further comprising a second
contact pad having a third set of electrical contacts arranged in a
pattern to mate with the first set of electrical contacts, the
second contact pad being made of an elastomeric material which is
dimensioned to fit within the cavity, means for providing separate
electrical connections through the case to the third set of
electrical contacts, and wherein the second contact pad is
interposed between the lid and the first contact pad.
5. A connector as recited in claim 4 wherein the second contact pad
includes a fourth set of electrical contacts arranged in a pattern
to mate with the second set of electrical contacts and means for
providing separate electrical connections through the case to the
fourth set of electrical contacts. .[.6. A connector as recited in
claims 1, 4 or 5 wherein one of the sets of electrical contacts are
comprised of partially
flattened metallic spheres..]. 7. A connector as recited in claims
4 or 5 wherein the second contact pad is made of silicone rubber
reinforced by
mesh. 8. A connector as recited in claims 1 or 4 wherein the case
is made
of titanium. 9. In combination, a connector comprising a case,
including a base member and a lid, the base member and lid being
shaped to provide a cavity between them, a first contact pad of
elastomeric material, a first set of electrical contacts embedded
in the first contact pad, the contact pad being dimensioned to fit
within the cavity, the contact pad being interposed between the lid
and the base member, a second set of electrical contacts .[.carried
by the lid.]. within the cavity, means for providing separate
electrical connections through the case to the first and second
sets of electrical contacts, means for pressing the lid against the
base member and the contact pad to exert a predetermined pressure
on the pad, causing it to form a fluid tight seal around the first
and second sets of electrical contacts, some of which are thereby
placed in electrical contact with each other, a second contact pad
having a third set of electrical contacts arranged in a pattern to
mate with the first set of electrical contacts, the second contact
pad being made of an elastomeric material which is dimensioned to
fit within the cavity, means for providing separate electrical
connections through the case to the third set of electrical
conacts, wherein the second contact pad is interposed between the
lid and the first contact pad, a transcutaneous driving circuit
receiver for a cochlear stimulating protheses, a cochlear
stimulating electrode, a percutaneous plug, and wherein the driving
circuit receiver is housed in the lid, and further including means
for electrically connecting the second set of electrical contacts
to the driving circuit receiver, means for electrically connecting
the first set of electrical contacts to the cochlear stimulating
electrode, and means for electrically connecting the percutaneous
plug to the third set of
electrical contacts. 10. The combination as recited in claim 9
wherein the second contact pad includes a fourth set of electrical
contacts arranged in a pattern to mate with the second set of
electrical contacts and further comprising means for electrically
connecting the percutaneous plug to the fourth set of electrical
contacts and means for providing separate electrical connections
through the case to the fourth set of electrical
contacts. 11. A connector as recited in claim 1 wherein the means
for providing separate electrical connections through the case
comprises electrical feedthroughs which pass through bores in the
lid, bushings of elastomeric material surrounding the feedthroughs
in the bores, and wherein the bushings, when the lid and base
member are pressed together, are placed under pressure to form
fluid tight seals around the
feedthroughs. 12. A connector as recited in claim 1 or claim 11
wherein the base member is provided with a circumferential ridge,
the lid is provided with a corresponding circumferential groove to
mate with the base member ridge, an antennae coil disposed within
the groove, an elastomeric material which pots the antennae coil in
the groove, and further wherein the lid is provided with a second
cavity for housing electronic circuitry, feedthrough means for
electrically connecting the antennae to the electronic circuitry,
and elastomeric bushings surrounding the feedthrough means,
whereby, when the lid and base member are pressed together, a
predetermined pressure is exerted on the elastomeric bushings
through the elastomeric potting material in the groove to form a
liquid tight seal
around the feedthroughs. .Iadd.13. In a cochlear implant prosthesis
including an implantable disconnect means for transmitting an
electrical signal to at least one electrode implantable in the
cochlea of a human ear, said disconnect means comprising
a base member,
a lid,
means for pressing said lid against said base member under a
predetermined pressure to form a closed casing,
first electrical contact means mounted in said casing for
transmitting said electrical signal to said electrode,
second electrical contact means mounted in said casing for
receiving said electrical signal and transmitting it to said first
electrical contact means,
elastomeric gasket means mounted in said casing for electrically
isolating and forming a fluid tight seal around said first and
second electrical contact means when said lid is pressed against
said base member under said predetermined pressure, and
means mounted in said casing for receiving an external signal and
for communicating said electrical signal to said second contact
means in
response to said external signal. .Iaddend. .Iadd.14. The cochlear
implant prosthesis of claim 13 wherein said base member and said
lid are shaped to provide a cavity therebetween, said gasket means
disposed in said cavity. .Iaddend. .Iadd.15. The cochlear implant
prosthesis of claim 13 wherein said first electrical contact means
is mounted on an inner side of said base and said second electrical
contact means is mounted in said gasket means and is maintained in
direct contact with said first electrical contact means by said
predetermined pressure. .Iaddend. .Iadd.16. The cochlear implant
prosthesis of claim 15 further comprising third electrical contact
means mounted on an inner side of said lid and maintained in direct
contact with said second electrical contact means. .Iaddend.
.Iadd.17. The cochlear implant prosthesis of claim 16 further
comprising cable means for connecting said first electrical contact
means to said electrode, said cable means extending through said
case. .Iaddend.
.Iadd.18. The cochlear implant prosthesis of claim 13 wherein said
first and second electrical contact means comprise a plurality of
circumferentially spaced first and second sets of contacts,
respectively, and wherein the contacts of said first set of
contacts are each maintained in electrical contact with a
respective one of the contacts of said second set of contacts under
said predetermined pressure. .Iaddend. .Iadd.19. The cochlear
implant prosthesis of claim 18 wherein each of said first and
second sets of contacts comprises radially spaced inner and outer
sets of contacts. .Iaddend. .Iadd.20. The cochlear implant
prosthesis of claim 18 wherein said gasket means comprises an
elastomeric first gasket mounted on an inner side of said base,
said first set of contacts embedded in said first gasket. .Iaddend.
.Iadd.21. The cochlear implant prosthesis of claim 20 wherein said
gasket means further comprises an elastomeric second gasket mounted
between said first gasket and said lid, said second set of contacts
embedded in said second gasket. .Iaddend. .Iadd.22. The cochlear
implant prosthesis of claim 18 further comprising a plurality of
electrodes embedded in an elastomeric material to form an electrode
array adapted to be implantable in the cochlea of a human ear and
cable means for connecting said electrodes to said first set of
contacts, said cable
means extending through said case. .Iaddend. .Iadd.23. A connector
comprising a case, including a base member and a lid, the base
member and lid being shaped to provide a cavity between them, a
first contact pad of elastomeric material, a first set of
electrical contacts embedded in the first contact pad, the contact
pad being interposed between the lid and the base member, a second
set of electrical contacts within the cavity, means for providing
separate electrical connections through the case to the first and
second sets of electrical contacts, means for pressing the lid
against the base member and the contact pad to exert a
predetermined pressure on the pad, causing it to form a fluid tight
seal around the first and second sets of electrical contacts, some
of which are thereby placed in electrical contact with each other,
a second contact pad having a third set of electrical contacts
arranged in a pattern to mate with the first set of electrical
contacts, the second contact pad being made of elastomeric material
which is dimensioned to fit within the cavity, and means for
providing separate electrical connections through the case to the
third set of electrical contacts, and wherein the second contact
paid is interposed between the lid and the first contact pad.
.Iaddend. .Iadd.24. In a cochlear implant prosthesis including an
implantable disconnect means for transmitting an electrical signal
to at least one electrode implantable in the cochlea of a human
ear, said disconnect means comprising
a base member,
a lid,
means for pressing said lid against said base member under a
predetermined pressure to form a closed casing,
first electrical contact means mounted in said casing for
transmitting said electrical signal to said electrode,
second electrical contact means mounted in said casing for
receiving said electrical signal and transmitting it to said first
electrical contact means,
elastomeric gasket means mounted in said casing for electrically
isolating and forming a fluid tight seal around said first and
second electrical contact means when said lid is pressed against
said base member under said predetermined pressure, said first and
second electrical contact means comprising a plurality of
circumferentially spaced first and second sets of contacts,
respectively, and wherein the contacts of said first set of
contacts are each maintained in electrical contact with a
respective one of the contacts of said second set of contacts under
said predetermined pressure. .Iaddend.
Description
BACKGROUND OF THE INVENTION
This invention relates to an electrical connector and more
particularly one for use in the human body.
In cochlear stimulating prostheses systems an electrical connector
is often placed between the stimulating electrode and the driving
component of the prosthesis to allow the driving component to be
removed, replaced, or converted to another driving system, without
disturbing the electrode itself. This connection and disconnection
can be done by either mounting the connector in a channel through
the skin (referred to as a percutaneous plug) or by implanting the
connector beneath the skin (referred to as a surgical
disconnect).
Percutaneous plugs seem to have a limited rather than a permanent
life span of usefulness due to the ever present threat of infection
through the open skin, and a tendency of the epithelium to bridge
beneath such a foreign body and to eject it. Further, a
percutaneous plug will usually never be considered in a
transcutaneous driving system which emphasizes a fully implanted
radio frequency or ultra sonic receiver. In such systems the
receiver is implanted under the skin and receives signals from a
transmitter located outside of the human body. The transmitter is
of course, connected to a transducer and amplifier to convert audio
signals into either radio signals or ultra sonic signals which are
transmitted through the patient's skin to be detected by a receiver
or a transducer connected to an amplifier within the patient's
body.
From an engineering standpoint, the surgical disconnect presents
unique problems. It must be small yet still easily manipulated by a
gloved surgeon. It must be rugged, biologically inert, and should
function reliably in a very hostile environment through multiple
disconnection and reconnection cycles. For multi-channel systems it
must carry fifteen to twenty leads or more.
Pin-type connectors have been succesfully adapted in prior art
surgical disconnects for cochlear implant systems. There are,
however, some disadvantages with such pin-type connectors. Such
connectors involve the use of non-biocompatible metal like
beryllium copper. Such copper pins are isolated by gold plate in
the expoxy connector housing but some small risk remains. The need
to weld or solder the leads to the electrode also adds a potential
failure site to the device. And finally, there is a constant desire
to reduce the size of any implant.
Still another serious problem is to electrically isolate each of
the contacts in the disconnect and prevent water vapor or liquid
from causing a short circuit between them.
SUMMARY OF THE INVENTION
The above and other disadvantages of prior art implantable
connectors are overcome by the present invention of a connector
comprising a case, including a base member and a lid which are
shaped to form a cavity between them, a first contact pad of
elastomeric material, a first set of electrical contacts imbedded
in the first contact pad, and with the first contact pad being
dimensioned to fit within the cavity. Either the lid or the base
member has a portion which is dimensioned to fit within the cavity.
The lid has a second set of electrical contacts which are located
on one wall of the cavity. Separate electrical connections are made
through the case to the first and second sets of electrical
contacts.
Means are provided in the form of a screw for pressing the lid
against the base member and the contact pad to exert a
predetermined pressure on the pad, thereby causing it to form a
fluid tight seal around the first and second sets of electrical
contacts, some of which are thereby placed in electrical contact
with each other. The first set of electrical contacts are
electrically connected to the intra-cochlear electrode. The second
set of electrical contacts are connected to the driving system
which, in the preferred embodiment, is housed in the case lid.
In the preferred embodiment a second contact pad is also provided
which has a third set of electrical contacts arranged in a pattern
to mate with the first set of electrical contacts. The second
contact pad is also made of elastomeric material and is dimensioned
to fit within the cavity. The third set of electrical contacts are
connected through the case to a percutaneous connector. This second
contact pad is interposed between the first contact pad and the lid
so that when the lid and base member are forced together the third
set of electrical contacts will be placed against the first set of
electrical contacts. A fluid tight seal is thereby effected between
the first and third sets of electrical contacts, some of which are
also electrically connected together.
There are several advantages to the contact pad approach. By the
configuration of the first, second, and third electrical contacts
any combination of connections between the individual electrodes
can be made. Furthermore the combination of electrodes can be
relatively easily changed by simply changing the lid of the
disconnect or by changing the contact pads.
In the embodiment in which a second contact pad is provided,
patient testing can now be done in a form which was not previously
possible. This second or interface pad carries leads to and from a
percutaneous plug through which multi-channel information can be
input and both the electrode array and the driving system can be
monitored. This plug need only be utilized by the research staff in
the hospital facility conducting the tests. While away from the
facility the patient wears a radio frequency or ultra sonic
transmitter connected to an audio transducer and amplifier system.
Thus the risk of damage to the plug or infection at the side is
reduced through reduced and closely monitored handling of the
percutaneous plug. Also, the percutaneous plug site is sufficiently
distant from the implanted disconnect that any infection there
would not threaten the implanted connector site. At the end of the
test series or at the first indications of infection the
percutaneous plug can be removed along with its electrical contact
pad and the patient will retain the transcutaneous driving system.
If indicated by the test series, the lid and the receiving unit in
it can be replaced with one which is reconfigured to stimulate a
more optimal combination of electrodes.
It is therefore an object of the present invention to provide an
implantable disconnect which provides an easily manipulated fluid
tight seal between electrical contacts.
It is still another object of the invention to provide an
implantable disconnect made of biocompatible materials.
It is still another object of the invention to provide a disconnect
which allows easy interconnections between an implanted electronic
driving circuit, a percutaneous connector and an implanted
electrode.
The foregoing and other objectives, features and advantages of the
invention will be more readily understood upon consideration of the
following detailed description of certain preferred embodiments of
the invention, taken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded, perspective view of a surgical disconnect
according to one embodiment of the invention together with the
components of a cochlear stimulating prosthesis;
FIG. 2 is an enlarged, vertical, sectional view of a first
electrical contact pad taken generally along the line 2--2 in FIG.
1;
FIG. 3 is an enlarged, vertical, sectional view of an interface
electrical contact pad taken generally along the line 3--3 in FIG.
1;
FIGS. 4a and 4b are enlarged vertical, sectional views illustrating
one method of assembly of the embodiment depicted in FIG. 1;
FIGS. 5a and 5b are enlarged vertical, sectional views illustrating
a second method of assembly of the embodiment depicted in FIG. 1
when an interface pad is utilized;
FIG. 6 is an enlarged, vertical, sectional view of a second
embodiment of the invention; and
FIG. 7 is an enlarged, vertical, sectional view of a third
embodiment of the invention.
DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS
Referring now more particularly to FIG. 1 an implantable disconnect
10 according to the invention is illustrated in exploded form. The
disconnect is comprised of a casing made up of a hollow base member
12 and a lid 14. The base member 12 is in the form of a cylinder
and has a cavity 16 therein. The base member 12 is intended to be
cemented into a surgically created recess in a bone of the patient,
such as the skull. Lid 14 is also in the form of a cylinder and has
a reduced diameter section 18 which is dimensioned to fit within
the cavity 16 of the base member 12. The lid and the base member
are made of a biocompatible material such as titanium.
A first electrical contact pad 20, made of elastomeric material is
dimensioned to fit within the cavity 16. The pad 20 carries a first
set of electrical contacts 22 embedded in it. The contacts are
arranged in a radial pattern about a hypothetical axis of
revolution which passes through the entire disconnect 10.
Referring more particularly to FIG. 2 it can be seen that the pad
20 is made of a silicone rubber material reinforced with a first
layer of fine dacron mesh 24 followed by an unreinforced layer of
silicone rubber 26 and then followed by a second dacron mesh layer
28 which is more loosely woven than the layer 24. Finally an
unreinforced layer 30 is the topmost layer as viewed in FIG. 2.
The contacts 22 are formed by melting the free ends of
platinum-iridium wires to form essentially uniform spheres. These
spheres are then embedded in the matrix of silicone rubber
reinforced mesh of the pad 20 in a radially spaced pattern. The
other ends of the wires are gathered together to form a cable 32
which connects the first set of contacts 22 to an intracochlear
electrode 34. Thus there are no welds or solder joints needed to
connect the cable wires to the contacts of the disconnect.
The cable 32 passes through an aperture 36 in the base member 12 so
that the pad 20 and contacts 22 assume a fixed orientation with
respect to the lid 14 and base member 12. The lid 14 is aligned
with the base 12 and the pad 20 by a protrusion 38 on the lid 14
which mates with the aperture 36.
A second set of electrical contacts 40 is positioned on a layer of
elastomeric material 41 on the underside of the reduced diameter
section 18 of the lid 14. These contacts are arranged in a pattern
to mate with some or all of the first set of contacts 22, as will
be described in greater detail hereinafter.
An interface contact pad 42, which is also dimensioned to fit
within the cavity 16, is positioned between the first pad 20 and
the reduced diameter section 18 of the lid 14. The pad 42 is also
constructed of an elastomeric material such as silicone rubber and
carries a third set of electrical contacts 44 (not shown in FIG. 1)
which protrude from the underside of the pad 42 as viewed in FIG.
1.
As is more clearly shown in FIG. 3, these contacts 44 are also
melted balls on the ends of platinum-iridium wires which have been
flattened slightly to ensure good contact with complementary
contacts 22 of the pad 20. The contacts 44 are arranged in a radial
pattern about the hypothetical axis of revolution of the disconnect
10 and are embedded in the pad 42. The pad 42 is comprised of a
layer of silicone rubber with intermediate layers of fine dacron
mesh 46. The interface pad also carries a fourth set of electrical
contacts 48 on its upper surface as viewed in FIGS. 1 and 3. The
contacts 48 are also arranged in a radial pattern about the
hypothetical axis of revolution and, like and contacts 44 and 22,
are formed by melting the ends of platinum-iridium wires to form
spheres of uniform diameter.
The contacts 44 are arranged in a pattern to mate with some or all
of the contacts 22 of pad 20. The contacts 48 are arranged to mate
with some or all of the contacts 40 of the lid 14. All of the
contacts 44 and 48 are separately connected by means of a cable
bundle 50 of platinum-iridium wires to a percutaneous plug 52.
The entire assembly 10 is held together by means of a screw 53
which passes through a hole 15 in the lid 14 along the hypothetical
axis of revolution and threadably engages in the base member 12.
When the screw 53 is tightened the lid 14 is pressed down on the
pads 42 and 20 to cause them to deform, the electrical contacts to
mate, and the elastomeric material on the layer 41 and the pads 20
and 42 to form fluid tight seals around the contacts 22,44 and
48.
The lid 14 is hollow and contains a receiver/driver circuit 55
(shown in FIG. 4A). In the preferred embodiment the receiver/driver
55 is part of a transcutaneous driving system of a cochlear
stimulating prostheses. The entire disconnect 10 along with the
receiver/driver 55 is positioned near the surface of the skin so
that when the antenna or ultrasonic transducer 54, which is
connected via a cable 56 to a transmitter unit 58 is placed over
the disconnect 10 on the surface of the skin, the receiver/driver
55 will detect the appropriate signal and convert it into
electrical signals which are transmitted through the contacts 40,
48, 44 and 22 to the intracochlear electrode 34. At this point it
should be mentioned that the disconnect 10 is also intended to
operate without the presence of the second contact pad 42 as will
be explained in greater detail hereinafter. In such cases the
electrical signals would be transmitted directly from the contacts
40 to the contacts 22.
In the embodiment depicted in FIG. 1, however, which illustrates
the research mode of the disconnect 10, the signals derived from
the contacts 40 pass through the cable 50 to the percutaneous
connector 52. They can then be monitored by researchers through the
connector 52 or, in other cases, the signals can be directed back
through the cable 50 via connections made at the plug 52 to pass on
through the contacts 44 and 22 to the intracochlear electrode 34.
Thus the researcher can control what connections are made to the
intracochlear electrode as well as monitor the signals through the
percutaneous connector 52.
While the patient is away from the research facility he or she
relies solely on the transmitter 58; the plug 52 would not be
utilized or handled. Thus the risk of damage to the plug or
infection at that site is reduced through reduced and closely
monitored handling of the plug 52. Also the plug site 52 is
sufficiently distant from the site of the disconnect 10 that any
infection at the plug site would not threaten the connector site.
At the end of the test series or at the first indications of
infection, the percutaneous plug 52 can be surgically removed along
with its interface pad 42 and the patient will then retain the
transcutaneous driving system. Also, if indicated by the test
series, the lid 14 along with the transcutaneous receiver therein,
could be replaced with one which is reconfigured to stimulate a
more optimal combination of electrodes in the intracochlear
electrode 34.
Referring now more particularly to FIGS. 4a and 4b the assembly of
the disconnect 10 is shown when the interface pad 42 is removed.
Under these circumstances the electrical contacts 40 mate directly
with the first set of contacts 22 when the screw 53 is threadably
engaged in the base member 12 to clamp the lid 14 down against the
pad 20.
Referring now more particularly to FIGS. 5a and 5b the assembly of
the disconnect 10 is illustrated when the interface pad 42 is
present. Under these circumstances the contacts 40 only mate with
the contacts 48 and the contacts 44 of the interface pad mate with
the contacts 22 of the first contact pad. In both cases the
tightening of the screw 53 in the base member 12 causes the lid 14
to press the pads 20 and 42 against the base member 12 with a
predetermined pressure sufficient to effect the fluid tight seal
among the various electrical contacts.
Referring now more particularly to FIG. 6 an alternative embodiment
of the invention is illustrated. In this embodiment a disconnect 60
is made of a base member 62 and a lid 63. The base member 62 is
essentially a flat plate with sloping side edges which is cemented
in a surgically created cavity in the bone 64 of a patient by means
of a surgical adhesive or cement 66. The base member 62 is provided
with a groove 68 which receives the bottom edge 70 of the lid 63.
The lid 63 is constructed to have the shape of an H in vertical
cross-section to thereby create a cavity 72 between the lid 70 and
the base 62.
It is into this cavity 72 that the electrical contact pads 20 and
42 are placed in the same manner as in the embodiment of FIG. 1.
Similarly the second set of electrical contacts 40 are placed on
the bottom surface of the lid 70, that is at the top of the cavity
72 to mate with the electrical contacts 48 or 22, depending on
whether the second contact pad 42 is in place.
The screw 53 is threadably received in a recess 74 in the base
member 62 to hold the lid 70 against the base member 62 and to
exert the predetermined pressure on the pads 20 and 42 as in the
embodiment in FIG. 1. The groove 68 is of sufficient depth to allow
such pressure to be exerted by the screw 53.
The upper portion of the lid 70 contains a second cavity 76 into
which the electronic receiving circuitry is installed. This cavity
76 is covered by a second lid 78 which can be cemented in a sealed
relationship to the lid 70 to make a fluid tight seal. An antenna
coil 80 can be mounted around the outside upper edge of the lid 70
and connected through the lid to electronic circuitry 82 within the
cavity 76. The disconnect 60 is preferably cylindrical however it
can take other shapes in other embodiments.
Referring now more particularly to FIG. 7, still another embodiment
of the invention is illustrated. In this embodiment the junction of
the antennae coil wires to the input feedthroughs to the
electronics receivers is sealed in the same manner as the
electrical contacts in the contact pads. It has been found that
potting around the weld site with an elastomer is not sufficient,
since the water vapor, which can pass through the elastomer,
condenses on the weld (or solder) joint. When the elastomer is
placed under pressure, however, it will prevent condensation as
long as the matrix is reasonably free of voids. In this embodiment,
the elastomer potted around the input feedthroughs is put under
pressure by the side walls of the connector base when the connector
is closed.
Thus, the disconnect depicted in FIG. 7 comprises a base member 92
and lid member 90. The base member 92 is provided with a cavity
portion which houses the pads 20, 40 and 42 as in the embodiments
previously discussed herein. The lid 90 is provided with a cavity
which contains the electronics 82 for the receiver. The electronics
82 are connected by means of feedthrough contacts 102, sealed by
elastomeric potting material 100 in the bottom of the lid 90, to
contact the pads 42 as in the previously described embodiments.
The base member 92 is also provided with a circumferential ridge
106 which mates with a corresponding circumferential groove 108 in
the lid 90. Within the groove 108 is placed the antennae coil 94.
It is connected by means of the feedthrough 96 to the electronics
82. The antennae 94 is potted in an elastomeric material 104 of the
type previously described. When a bolt (not shown) is passed
through the lid 90 and screwed into the base 92, thereby forcing
the lid 90 down on to the base 92, the contact pad 42 and the
elastomeric material 104 are pressed up against the elastomeric
feedthrough bushings 98 and 100 to effect a fluid tight seal around
the feedthroughs.
The silicone rubber utilized in the preferred embodiment is type
MDX4-4210 Silastic.RTM. brand silicone subdermal implant material.
Silastic.RTM. is a registered trademark of The Dow Chemical Company
for its series of unvulcanized organopolysiloxane elastomers.
The discount has heretofore been described only in reference to a
hearing prothesis. It should be apparent, however, that the
disconnect according to the invention has a far broader
application. It is also suitable for use with brain stimulators,
nerve stimulators and heart pacemakers, for example.
The terms and expressions which have been employed here are used as
terms of description and not of limitations, and there is no
intention, in the use of such terms and expressions, of excluding
equivalents of the features shown and described, or portions
thereof, it being recognized that various modifications are
possible within the scope of the invention claimed.
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