U.S. patent application number 13/342536 was filed with the patent office on 2012-04-26 for implantable electrode with variable mechanical modulation wiring.
This patent application is currently assigned to MED-EL ELEKTROMEDIZINISCHE GERAETE GMBH. Invention is credited to Fabrice Beal, Claude Jolly, Stefan Nielsen.
Application Number | 20120101559 13/342536 |
Document ID | / |
Family ID | 42340744 |
Filed Date | 2012-04-26 |
United States Patent
Application |
20120101559 |
Kind Code |
A1 |
Jolly; Claude ; et
al. |
April 26, 2012 |
Implantable Electrode with Variable Mechanical Modulation
Wiring
Abstract
A cochlear implant electrode is described. A basal electrode
lead carries electrical stimulation signals from an implant housing
to a cochleostomy opening, and a portion of the electrode lead has
a periodically recurring lead shape. An apical electrode array at
the cochleostomy end of the electrode lead passes into a cochlea
scala and includes electrode contacts for applying the electrical
stimulation signals to target neural tissue. A portion of the
electrode array has a periodically recurring array shape different
from the lead shape.
Inventors: |
Jolly; Claude; (Innsbruck,
AT) ; Nielsen; Stefan; (Innsbruck, AT) ; Beal;
Fabrice; (Mutters, AT) |
Assignee: |
MED-EL ELEKTROMEDIZINISCHE GERAETE
GMBH
Innsbruck
AT
|
Family ID: |
42340744 |
Appl. No.: |
13/342536 |
Filed: |
January 3, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12700988 |
Feb 5, 2010 |
8112161 |
|
|
13342536 |
|
|
|
|
61150496 |
Feb 6, 2009 |
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Current U.S.
Class: |
607/137 |
Current CPC
Class: |
A61N 1/0541
20130101 |
Class at
Publication: |
607/137 |
International
Class: |
A61F 11/04 20060101
A61F011/04; A61N 1/05 20060101 A61N001/05 |
Claims
1. A cochlear implant electrode comprising: an extra-cochlear
electrode lead containing a plurality of electrode wires for
carrying electrical stimulation signals from an implant housing to
a cochleostomy opening; an intra-cochlear electrode array
containing the plurality of electrode wires and passing from the
cochleostomy opening into a cochlea scala and terminating in a
plurality of electrode contacts for applying the electrical
stimulation signals to target neural tissue; and an impact
reinforcement element around a portion of the electrode lead for
resisting effects of an external impact.
2. A cochlear implant electrode according to claim 1, wherein a
polymer material is used for the impact reinforcement element.
3. A cochlear implant electrode according to claim 1, wherein a
metallic material is used for the impact reinforcement element.
4. A cochlear implant electrode according to claim 1, wherein the
impact reinforcement element forms a helical spring shape.
5. A cochlear implant electrode according to claim 4, wherein round
wire material is used for the impact reinforcement element.
6. A cochlear implant electrode according to claim 4, wherein
ribbon wire material is used for the impact reinforcement
element.
7. A cochlear implant electrode according to claim 1, wherein the
impact reinforcement element forms a tubular shape.
8. A cochlear implant electrode according to claim 7, wherein the
impact reinforcement element includes a pattern of slits for
controlling mechanical properties of the impact reinforcement
element.
9. A cochlear implant electrode according to claim 1, wherein the
impact reinforcement element is embedded in the body of the
electrode lead.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of U.S. patent
application Ser. No. 12/700,988 filed Feb. 5, 2010, which in turn
claims priority from U.S. Provisional Patent Application
61/150,496, filed Feb. 6, 2009; both of which are incorporated
herein by reference in their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to medical implants, and more
specifically to a stimulation electrode used in cochlear implant
systems.
BACKGROUND ART
[0003] Implantable multi-channel electrodes for neuro-stimulation
or neuro-modulation need to be mechanically robust, and yet
flexible and of small size to be inserted into body cavities such
as the human cochlea, or to be inserted into a body organ such as
the brain. Typically, the wires in most implant electrodes have a
homogenous shape from one end to the other: either generally
straight, repeating coiled loops, or recurring wave shapes. In
environments where the implanted electrodes continuously move
relative to the surrounding tissues, matching the mechanical
properties of the electrodes to the properties of the surrounding
tissues is important for avoiding adverse biological reactions and
massive scar tissue generation.
[0004] Implant electrodes are being developed for insertion ever
more deeply into body cavities of progressively more complex shape.
So an implant electrode should have non-uniform and non-homogeneous
mechanical properties (e.g., bending and flexing) to accommodate
the tortuous path that it must take, and also for maintaining
biological compatibility with the surrounding tissue. There may be
some parts of an implant electrode that need to be highly resistant
to micro-movement (e.g., the portion of a cochlear implant
electrode which lies immediately under the skin on the skull).
Other portions of the implant electrode may need to be very
bendable to accommodate a convoluted insertion path (e.g., the
portion of a cochlear implant electrode that goes into the
cochlea). Some portions of the implant electrode may be exposed to
occasional impact force and so may need to be very resistant to
external impact (e.g., portions of a cochlear implant electrode
under the skin on the skull).
[0005] Some compromise in these factors must be achieved in
circumstances where high flexibility is needed but space is very
limited (e.g. as in the cochlea). Electrode structures that are
highly resistant to micro-movements tend to occupy relatively more
space, whereas electrode structures that are small in size tend to
be relatively rigid. Presently, as the number of electrode
stimulation channels increases, the number of corresponding
metallic wires in the electrodes also increases. That in turn
causes the implant electrodes to become increasingly rigid.
[0006] As used herein, the term "electrode array" refers to the
apical end section of the implant electrode that penetrates into a
cochlea scala of the inner ear. An electrode array has multiple
electrode contacts on or slightly recessed below its outer surface
for applying one or more electrical stimulation signals to target
audio neural tissue. An "electrode lead" refers to the basal
portion of the implant electrode that goes from the implant housing
to the electrode array. It usually has no contacts except perhaps a
ground electrode and it encloses connecting wires delivering the
electrical stimulation signals to the electrode contacts on the
electrode array. The term "electrode" refers to the entire implant
electrode from end to end, that is, the combination of the
electrode array and the electrode lead.
SUMMARY OF THE INVENTION
[0007] Embodiments of the present invention are directed to a
cochlear implant electrode. An extra-cochlear electrode lead
contains electrode wires for carrying electrical stimulation
signals from an implant housing to a cochleostomy opening. An
intra-cochlear electrode array containing the electrode wires
passes from the cochleostomy opening into a cochlea scala and
terminates in electrode contacts for applying the electrical
stimulation signals to target neural tissue. One or more of the
electrode wires in the electrode lead has an associated lead shape
and one or more of the electrode wires in the electrode array has
an associated array shape which is different from the lead shape.
The array shape may differ in amplitude from the lead shape, for
example, the lead shape may have a larger amplitude than the array
shape. The shapes may include a smoothly varying wave that repeats
and/or a sequence of coiled loops.
[0008] In some embodiments, the one or more electrode wires in the
electrode lead may include a portion without the lead shape, for
example, there may be a portion having the lead shape on each side
of the portion without the lead shape. Similarly, the one or more
electrode wires in the electrode array may include a portion
without the array shape, for example, a portion having the array
shape on each side of the portion without the array shape. The
portion of the one or more electrode wires in the electrode array
without the array shape may be rigid for pushing the electrode
array into the cochlea scala. The one or more electrode wires in
the electrode lead having the lead shape also may include a portion
having a different second lead shape that periodically recurs. In
addition or alternatively, the one or more electrode wires in the
electrode array may have multiple different array shapes.
[0009] Some embodiments may also include an impact reinforcement
element around a portion of the electrode lead for resisting
effects of an external impact. The impact reinforcement element may
be a polymer and/or metallic material. The electrode lead or the
electrode array may include a portion with an elliptical
cross-section. At least one of the shapes may include a smoothly
varying wave that repeats and/or a sequence of coiled loops.
[0010] Embodiments of the present invention also include a cochlear
implant electrode having an extra-cochlear electrode lead
containing electrode wires for carrying electrical stimulation
signals from an implant housing to a cochleostomy opening. An
intra-cochlear electrode array contains the electrode wires and
passes from the cochleostomy opening into a cochlea scala and
terminates in electrode contacts for applying the electrical
stimulation signals to target neural tissue. And an impact
reinforcement element surrounds a portion of the electrode lead for
resisting effects of an external impact.
[0011] In further such specific embodiments, a polymer and/or
metallic material may be used for the impact reinforcement element.
The impact reinforcement element may form a helical spring shape,
for example from round or ribbon wire material. The impact
reinforcement element may form a tubular shape and may include a
pattern of slits for controlling mechanical properties of the
impact reinforcement element. In addition or alternatively, the
impact reinforcement element may be embedded in the body of the
electrode lead.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 shows an example of an implant electrode according to
one specific embodiment of the present invention.
[0013] FIG. 2 shows a portion of another implant electrode
according to one embodiment of the present invention.
[0014] FIG. 3 shows the principle of another embodiment of an
implant electrode.
[0015] FIG. 4 shows an example of another implant electrode
according to an embodiment of the present invention.
[0016] FIG. 5A-D shows example photographs of impact reinforcement
elements in the form of helical springs according to embodiments of
the present invention.
[0017] FIG. 6A-C shows examples of impact reinforcement elements in
the form of tubular structures with different patterns of slits
according to various specific embodiments of the present
invention.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0018] Various embodiments of the present invention are directed to
an implant electrode that can accommodate the different and
potentially contradictory mechanical and physical requirements
along its length. Some regions may provide improved resistance to
micro-movements, some regions may have improved impact resistance,
and other regions may have extra flexibility. The entire implant
electrode still satisfies overall limitations such as required size
so that it can best accomplish its intended use.
[0019] FIG. 1 shows one specific embodiment of an implant electrode
100 having an extra-cochlear electrode lead 101 portion containing
multiple electrode wires 104 that carry electrical stimulation
signals from an implant housing 102 to a cochleostomy opening 103.
An intra-cochlear electrode array 105 portion also contains the
electrode wires 104 and passes from the cochleostomy opening 103
into a cochlea scala and terminates in electrode contacts 106 for
applying the electrical stimulation signals to target neural
tissue. One or more of the electrode wires 104 in the electrode
lead 101 portion have an associated lead shape, and one or more of
the electrode wires 104 in the electrode array 105 portion have an
associated array shape which is different from the lead shape. For
example, the array shape in FIG. 1 is a sequence of smoothly
varying waves that allow the array to be highly flexible yet having
minimum cross-sectional dimensions to aid in atraumatic insertion
into the cochlea scala. The lead shape, though, is a series of
looped coils that are resistant to micro-movement which can lead to
fracture of the electrode wires 104 in the middle ear and on the
skull.
[0020] Although FIG. 1 shows that all the electrode wires 104 in
each portion have the same shape, in other specific embodiments,
that may not necessarily be the case, and all the electrode wires
104 may not necessarily have the same shape and structure at the
same place. Some electrode wires 104 may be shaped and others not,
and in each portion, some electrode wires 104 may have one shape
and other electrode wires 104 may have another shape. Some or all
of one or more of the electrode wires 104 may have an elliptical
cross-section, while other electrode wires 104 may have a circular
cross-section. Thus, the shape and size of each individual
electrode wire 104 is a subject for individual selection.
[0021] FIG. 2 shows a portion of another implant electrode 200 in
which the electrode wires in the electrode lead 201 portion include
an unshaped lead portion 202 having lead shaped portions 203 on
each side. In this case, the lead shaped portions 203 both have the
same shape, a large amplitude series of waves which provide
resistance to repeated micro-movements or elongation for the
section of the electrode lead 201 that is against the skull and/or
in the middle ear. In other specific embodiments, the lead shaped
portions 203 may have different shapes and/or sizes. Similarly, the
electrode wires in the electrode array 205 include an unshaped
array portion 206 having array shaped portions 207 on each side. In
this case, the array shaped portions 207 both have the same shape,
a small sequence of repeating loops which provide maximum
flexibility for insertion into the cochlea scala, while the
unshaped array portion 206 is rigid for pushing the electrode array
205 into the cochlea scala. In other specific embodiments, the
array shaped portions 207 may have different shapes and/or
sizes.
[0022] FIG. 3 shows the principle of another embodiment of an
implant electrode 300. An extra-cochlear electrode lead 301 has
multiple electrode wires 302 for carrying electrical stimulation
signals from an implant housing to a cochleostomy opening. A lead
portion of at least one electrode wire 302 has an associated lead
shape, in this case, large recurring triangular waves. An
intra-cochlear electrode array 305 at the cochleostomy end of the
electrode lead passes into a cochlea scala and includes multiple
electrode contacts 306 connected to the electrode wires 301 for
applying the electrical stimulation signals to target neural
tissue. An array portion of at least one electrode wire 302 has an
associated array shape different from the lead shape, in this case,
more smaller-size triangular waves.
[0023] FIG. 4 shows an example of another embodiment of an implant
electrode 400 wherein the natural relaxed state of the electrode is
relatively straight, but within a main electrode body made of a
resilient silastic material is an electrode lead 401 portion having
one or more electrode wires with an associated lead shape (in this
case, two large waves that resist micro-movement of the electrode
400), while one or more electrode wires in an electrode array 405
portion has its own associated array shape (in this case, many
smaller waves). The silastic body around the electrode lead 401
acts as an impact reinforcement element for resisting effects of an
external impact. In other embodiments, such an impact reinforcement
element may be made of an appropriate polymer and/or metallic
material.
[0024] FIG. 5A-D shows example photographs of impact reinforcement
elements in the form of helical springs according to embodiments of
the present invention. Helical spring 501 in FIG. 5A is made from
round wire, whereas the helical spring 502 if formed from ribbon
wire. Characteristics such as the wire material, size, spring
diameter, and spring pitch can be controlled to achieve desired
mechanical properties. The impact reinforcement around a portion of
the electrode lead may be embedded in the main electrode body (as
shown, for example, in FIG. 5B and C), or it may be external to it
(for example, as in FIG. 5D).
[0025] FIG. 6A-C shows examples of impact reinforcement elements in
the form of tubular structures with different patterns of slits
according to various specific embodiments of the present invention.
The number, size, and relative arrangement of the slits may be
controlled to achieve desired mechanical properties such as bend
radius and direction and impact resistance.
[0026] Although various exemplary embodiments of the invention have
been disclosed, it should be apparent to those skilled in the art
that various changes and modifications can be made which will
achieve some of the advantages of the invention without departing
from the true scope of the invention.
* * * * *