U.S. patent application number 15/634057 was filed with the patent office on 2018-05-03 for nerve cuff electrodes fabricated using over-molded lcp substrates.
This patent application is currently assigned to THE ALFRED E. MANN FOUNDATION FOR SCIENTIFIC RESEARCH. The applicant listed for this patent is THE ALFRED E. MANN FOUNDATION FOR SCIENTIFIC RESEARCH. Invention is credited to Brian R. Dearden, Morten Hansen, Boon Khai Ng, Siegmar Schmidt.
Application Number | 20180117312 15/634057 |
Document ID | / |
Family ID | 59285395 |
Filed Date | 2018-05-03 |
United States Patent
Application |
20180117312 |
Kind Code |
A1 |
Schmidt; Siegmar ; et
al. |
May 3, 2018 |
NERVE CUFF ELECTRODES FABRICATED USING OVER-MOLDED LCP
SUBSTRATES
Abstract
An electrode lead may comprise a flexible circuit that includes
a planar dielectric substrate including an elongated lead substrate
portion having opposing ends, an electrode carrying substrate
portion disposed on one end of the lead substrate portion, and a
connector substrate portion disposed on the other end of the lead
substrate portion, wherein the lead substrate portion is pre-shaped
into a three-dimensional structure. The flexible circuit may
further include an electrically conductive trace extending from the
connector substrate portion to the electrode carrying substrate
portion, a first window formed in the connector substrate portion
to expose the electrically conductive trace to form a connector
pad, and a second window formed in the electrode carrying substrate
portion to expose the electrically conductive trace to form an
electrode pad. The electrode lead may further comprise a lead
connector that incorporates the connector substrate portion.
Inventors: |
Schmidt; Siegmar; (Simi
Valley, CA) ; Ng; Boon Khai; (La Crescenta, CA)
; Dearden; Brian R.; (Pasadena, CA) ; Hansen;
Morten; (Welwyn, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THE ALFRED E. MANN FOUNDATION FOR SCIENTIFIC RESEARCH |
Valencia |
CA |
US |
|
|
Assignee: |
THE ALFRED E. MANN FOUNDATION FOR
SCIENTIFIC RESEARCH
Valencia
CA
|
Family ID: |
59285395 |
Appl. No.: |
15/634057 |
Filed: |
June 27, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62415028 |
Oct 31, 2016 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61N 1/3605 20130101;
A61N 1/0558 20130101; A61N 1/375 20130101; A61B 5/0488 20130101;
A61N 1/0556 20130101; A61N 1/3752 20130101 |
International
Class: |
A61N 1/05 20060101
A61N001/05; A61N 1/375 20060101 A61N001/375 |
Claims
1. An electrode lead, comprising: an elongated planar lead body
pre-shaped into a three-dimensional structure; a lead connector
disposed at a proximal end of the lead body; an electrode carrying
structure disposed at a distal end of the lead body; at least one
connector contact carried by the lead connector; at least one
electrode contact carried by the electrode carrying structure; and
at least one electrical conductor extending through the lead body
between the at least one connector contact and the at least one
electrode contact.
2. The electrode lead of claim 1, wherein the three-dimensional
structure is a helical structure.
3. The electrode lead of claim 1, wherein the three-dimensional
structure is a sigmoid structure.
4. The electrode lead of claim 1, wherein the electrode carrying
structure is planar.
5. The electrode lead of claim 4, wherein the electrode carrying
structure comprises a biologically compatible, elastic,
electrically insulative cuff body affixed to the distal end of the
lead body, the cuff body configured for being circumferentially
disposed around a nerve, wherein the at least one electrode contact
is affixed to the cuff body.
6. The electrode lead of claim 5, wherein the at least one
electrode contact is configured for being on an inner surface of
the cuff body when circumferentially disposed around a nerve.
7. The electrode lead of claim 4, wherein the electrode carrying
structure comprises a biologically compatible, elastic,
electrically insulative paddle body affixed to the distal end of
the lead body.
8. The electrode lead of claim 1, wherein the lead body comprises
an outer layer of insulative material composed of one of silicone,
polyurethane, polyether polyurethane, polycarbonate polyurethane,
parylene, perfluoroalkoxy alkanes (PFA), and
polytetrafluoroethylene (PTFE).
9. The electrode lead of claim 1, wherein the lead body comprises a
planar dielectric substrate.
10. The electrode lead of claim 9, wherein the planar dielectric
substrate is composed of liquid crystal polymer (LCP).
11. The electrode lead of claim 9, wherein each of the at least one
electrical conductor is an electrically conductive trace embedded
within the planar dielectric substrate.
12. The electrode lead of claim 1, wherein the at least one
electrode contact comprises three electrode contacts in a tripolar
electrode arrangement.
13. The electrode lead of claim 1, wherein the lead connector is
configured for being inserted into a corresponding connector of a
neurostimulator.
14. A flexible circuit, comprising: a planar dielectric substrate
including an elongated lead substrate portion having opposing ends,
an electrode carrying substrate portion disposed on one end of the
lead substrate portion, and a connector substrate portion disposed
on the other end of the lead substrate portion, wherein the lead
substrate portion is pre-shaped into a three-dimensional structure;
an electrically conductive trace extending from the connector
substrate portion to the electrode carrying substrate portion; a
first window formed in the connector substrate portion to expose
the electrically conductive trace to form a connector pad; and a
second window formed in the electrode carrying substrate portion to
expose the electrically conductive trace to form an electrode
pad.
15. The flexible circuit of claim 14, wherein the three-dimensional
structure is a helical structure.
16. The flexible circuit of claim 14, wherein the three-dimensional
structure is a sigmoid structure.
17. The flexible circuit of claim 14, wherein the electrode
carrying substrate portion is an enlarged cuff substrate portion
pre-shaped into a cuff sized for being circumferentially disposed
around a nerve.
18. The flexible circuit of claim 17, wherein the cuff substrate
portion is rectangular.
19. The flexible circuit of claim 17, wherein the electrode pad is
configured for facing a nerve when the cuff substrate portion is
circumferentially disposed around a nerve.
20. The flexible circuit of claim 14, wherein the electrode
carrying substrate portion is an enlarged paddle substrate
portion.
21. The flexible circuit of claim 14, further comprising an outer
layer of insulative material disposed over the planar dielectric
substrate, the insulative material composed of one of silicone,
polyurethane, polyether polyurethane, polycarbonate polyurethane,
parylene, perfluoroalkoxy alkanes (PFA), and
polytetrafluoroethylene (PTFE).
22. The flexible circuit of claim 14, wherein the planar dielectric
substrate is composed of liquid crystal polymer (LCP).
23.-256. (canceled)
Description
RELATED APPLICATION
[0001] This application is a continuation of co-pending U.S.
Provisional Patent Application Ser. No. 62/415,028, filed Oct. 31,
2016, which is expressly incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention generally relates to implantable
neurostimulation leads, and specifically relates to implantable
nerve cuff electrodes that can be used to stimulate nerves.
BACKGROUND OF THE INVENTION
[0003] Nerve cuff electrodes are conventionally manufactured using
implantable grade silicone or, in some cases, polyurethane. Nerve
cuff electrodes generally comprise a lead body, a connector
proximally located on the lead body, a cuff body distally located
on the lead body, electrode contacts placed on the inner surface of
the cuff body, and electrical conductors extending from the cuff
body through the lead body to the connector. The method of making
these nerve cuffs electrodes is typically time consuming, since the
conductors and electrode contacts in the cuff body are overmolded
using molds. The electrode contacts must be connected to the ends
of the conductors using a mechanical crimp or welded together. The
cuff body is conventionally formed by injection molding the
silicone over the conductors and part of the electrode contact. The
lead body that contains the conductors is overmolded with
insulative material such as silicone or polyurethane. This entire
process for making a nerve cuff electrode is time and labor
intensive and therefore adds to the final cost of the finished lead
with nerve cuff electrode.
[0004] It is desirable to make nerve cuff electrodes that would be
less labor intensive and easier to make. The substrate material
used to make the nerve cuff electrode should be inert in biological
environments, and mechanically flexible, substantially impermeable
to moisture, oxygen, and other gases and liquids, be relatively low
cost, and have suitable dielectric properties. A new class of
material, known as thermoplastic liquid crystal polymers (LCP),
satisfies these unique combination of properties, and is well
suited for cuff electrodes as a substrate on which the electrical
circuitry is disposed. LCPs offer the additional advantage of
precision molding and being amenable to photolithography and
thin-film deposition of electrical circuitry, which can greatly
reduce the time and labor to manufacture the cuff electrode.
[0005] The planarity of the LCP substrates provides various
opportunities for incorporating beneficial features that are not
otherwise available to conventional lead structures. However, due
to its planar nature, the use of LCP as a substrate in nerve cuff
electrodes, and medical leads in general, provides several
challenges. First, as discussed above, it is important that medical
leads be flexible in all planes, especially when implanted in
regions of the body prone to extensive movement, such as the neck
region, of a patient. Although an LCP substrate may be flexible in
one plane perpendicular to its surface, the same LCP substrate may
be somewhat rigid in the plane along its surface. Second, the lead
ports for conventional neurostimulation devices are generally
cylindrical, thereby making the mechanical and electrical
transition from planar LCP-based leads to such neurostimulation
devices particularly challenging. Third, because the edges of LCP
substrates tend to be sharp, such LCP substrates may need to be
over-molded with a softer material, such as silicone. However,
because there are only two sides of the LCP substrate on which the
silicone can be adhered to, the silicone may be prone to
delamination from the LCP substrate. Additionally, for the same
reason, electrodes disposed on one of these planar surfaces of the
LCP substrate may also be prone to delamination from the LCP
substrate.
[0006] There, thus, remains a need for providing improvements to
medical leads, such as nerve cuff electrodes, that utilize planar
dielectric substrates, such as LCP, on which electrical circuitry
is disposed.
SUMMARY OF THE INVENTION
[0007] In accordance with the present inventions, electrode leads
are provided. Such electrode leads may comprise an elongated lead
body, a lead connector disposed at a proximal end of the lead body
(e.g., one that can be inserted into a corresponding connector of a
neurostimulator), an electrode carrying structure disposed at a
distal end of the lead body, at least one connector contact carried
by the lead connector, at least one electrode contact (e.g., three
electrode contacts in a tripolar electrode arrangement) carried by
the electrode carrying structure, and at least one electrical
conductor extending through the lead body between the at least one
connector contact and the at least one electrode contact.
[0008] In one embodiment, the lead body, electrode carrying
structure, and/or lead connector are planar. In this case, the lead
body, electrode carrying structure, and/or lead connector may
comprise a planar dielectric substrate (e.g., liquid crystal
polymer (LCP)). As one example, the electrode carrying structure
may comprise a biologically compatible, elastic, electrically
insulative cuff body affixed to the distal end of the lead body,
and being configured for being circumferentially disposed around a
nerve. The electrode contact(s) may be configured for being on an
inner surface of the cuff body when circumferentially disposed
around a nerve. As another example, the electrode carrying
structure may comprise a biologically compatible, elastic,
electrically insulative paddle body affixed to the distal end of
the lead body. Such lead bodies may comprise an outer layer of
insulative material composed of one of silicone, polyurethane,
polyether polyurethane, polycarbonate polyurethane, parylene,
perfluoroalkoxy alkanes (PFA), and polytetrafluoroethylene
(PTFE).
[0009] In accordance with the present inventions, flexible circuits
are also provided. Such flexible circuits may comprise a planar
dielectric substrate (e.g., liquid crystal polymer (LCP)) including
an elongated lead substrate portion having opposing ends, an
electrode carrying substrate portion disposed on one end of the
lead substrate portion, and a connector substrate portion disposed
on the other end of the lead substrate portion. Such flexible
circuits may also comprise an electrically conductive trace
extending from the connector substrate portion to the electrode
carrying substrate portion, at least a first window is formed in
the connector substrate portion to expose the electrically
conductive trace to form a connector pad, and at least a second
window is formed in the electrode carrying substrate portion to
expose the electrically conductive trace to form an electrode
pad.
[0010] In one embodiment, the electrode carrying substrate portion
is an enlarged cuff substrate portion pre-shaped into a cuff sized
for being circumferentially disposed around a nerve. The cuff
substrate portion may be, e.g., rectangular. The electrode pad may,
e.g., be configured for facing a nerve when the cuff substrate
portion is circumferentially disposed around a nerve. In another
embodiment, the electrode carrying substrate portion is an enlarged
paddle substrate portion. Such flexible circuits may further
comprise an outer layer of insulative material (e.g., one of
silicone, polyurethane, polyether polyurethane, polycarbonate
polyurethane, parylene, perfluoroalkoxy alkanes (PFA), and
polytetrafluoroethylene (PTFE)) disposed over the planar dielectric
substrate.
[0011] In accordance with the present inventions, lead connectors
(e.g., those that can be inserted into corresponding connectors of
neurostimulators) are also provided. Such lead connectors may
comprise a planar dielectric connector substrate (e.g., one
composed of liquid crystal polymer (LCP)), and at least one
connector pad carried by the connector substrate. Such lead
connectors may further comprise at least one electrically
conductive trace disposed within the connector substrate, and at
least one window formed in the connector substrate to expose the
electrically conductive trace(s) to form the connector pad(s).
[0012] In accordance with a first aspect of the present inventions,
the elongated planar lead body of an electrode lead or the lead
substrate portion of a flexible circuit is pre-shaped into a
three-dimensional structure (e.g., a helical structure or a sigmoid
structure).
[0013] In accordance with a second aspect of the present
inventions, the elongated planar lead body of an electrode lead has
at least one slit to form a plurality of planar strands, in which
case, electrical conductors will extend within the plurality of
strands between the connector contact(s) and the electrode
contact(s). In one embodiment, the slit(s) may extend through the
distal end of the lead body, such that the planar strands have
loose ends. The planar strands may be pre-shaped into
three-dimensional structures (e.g., helical structures, which may
form a co-helical structure, or sigmoid structures). Electrode
contacts may be respectively affixed to the loose ends of the
planar strands. In another embodiment, the slit(s) may not extend
through either the proximal end or the distal end of the lead body,
such that both ends of the lead body are intact. The slit(s) may
comprise a plurality of collinear slits, such that the lead body is
intact between the collinear slits.
[0014] Similarly, the lead substrate portion of a flexible circuit
has at least one slit to form a plurality of planar strands, in
which case, the electrically conductive traces respectively extend
through the planar strands. In one embodiment, the slit(s) may
extend through one end of the lead substrate portion, such that the
planar strands have loose ends. In this case, a plurality of
electrode carrying substrate portions may be respectively disposed
on the loose ends of the planar strands, with the second plurality
of windows being respectively formed in the electrode carrying
substrate portions. The planar strands may be pre-shaped into
three-dimensional structures (e.g., helical structures, which may
form a co-helical structure, or sigmoid structures). In another
embodiment, the slit(s) may not extend through either of the
opposing ends of the lead substrate portion, such that both ends of
the lead substrate portion are intact. In this case, a single
electrode carrying substrate portion may be disposed at the one end
of the lead substrate portion. The slit(s) may comprise a plurality
of collinear slits, such that the lead substrate portion is intact
between the collinear slits.
[0015] In accordance with a third aspect of the present inventions,
a plurality of first windows are formed in one of the connector
substrate portion and the electrode carrying substrate portion to
expose the electrically conductive trace to form a respective
connector pad or electrode pad, such that the respective connector
pad or electrode pad has a peripheral region and an interior region
embedded within the planar dielectric substrate. In one embodiment,
the interior region is smaller than the size of each of the first
windows.
[0016] In accordance with a fourth aspect of the present
inventions, the periphery of the planar electrode carrying
structure of an electrode lead has a plurality of open slots (e.g.,
a slotted hole, a rounded slot, or a slotted "T"), and an outer
layer of insulative material covers the electrode carrying
structure over the open slots. Similarly, periphery of the
electrode carrying structure of a flexible circuit has a plurality
of open slots (e.g., a slotted hole, a rounded slot, or a slotted
"T"), and an outer layer of insulative material covering the
electrode carrying substrate portion over the open slots.
[0017] In accordance with a fifth aspect of the present inventions,
an electrode lead comprises an elongated planar main lead body
having a proximal end and a distal end, and an elongated planar
branch lead body extending from the main lead body between the
proximal end and distal end. In this case, the lead connector
disposed at the proximal end of the main lead body, the electrode
carrying structure is disposed at the distal end of the main lead
body, a plurality of connector contacts are carried by the lead
connector, at least one first electrode contact is carried by the
electrode carrying structure, at least one second electrode contact
is carried by the branch lead body, and a plurality of electrical
conductors extend through the main lead body between the plurality
of connector contacts and the plurality of electrode contacts. In
embodiment, the branch lead body has a barb.
[0018] Similarly, the planar dielectric substrate of a flexible
circuit includes an elongated main lead substrate portion having
opposing ends, at least one electrode carrying substrate portion
disposed on one end of the main lead substrate portion, a connector
substrate portion disposed on the other end of the main lead
substrate portion, and an elongated branch lead substrate portion
extending from the main lead substrate portion between the opposing
ends. In this case, the flexible circuit may comprise a first
electrically conductive trace extending from the connector
substrate portion to the electrode carrying substrate portion, a
second electrically conductive trace extending from the connector
substrate portion to the branch lead substrate portion, first and
second windows formed in the connector substrate portion to expose
the first and second electrically conductive traces to respectively
form first and second connector pads, a third window formed in the
electrode carrying portion to expose the first electrically
conductive trace to form a first electrode pad, and a fourth window
formed in the branch lead substrate portion to expose the second
electrically conductive trace to form a second electrode pad. In
one embodiment, the elongated branch lead substrate portion has a
barb.
[0019] In accordance with a sixth aspect of the present inventions,
an electrode lead comprises a plurality of biologically compatible,
elastic, electrically insulative cuff bodies affixed to the distal
end of the lead body. In this case, the electrode lead comprises a
plurality of connector contacts carried by the lead connector, a
plurality of electrode contacts respectively carried by the
plurality of cuff bodies, and a plurality of electrical conductors
extending within the lead body between the plurality of connector
contacts and the plurality of electrode contacts. The lead body may
be divided into proximal lead body portion and a distal lead body
portion, the cuff bodies may comprise a proximal cuff body and a
distal cuff body, the proximal lead body portion may extend between
the lead connector and the proximal cuff body, and the distal lead
body portion may extend between the proximal cuff body and the
distal cuff body.
[0020] Similarly, a flexible circuit comprises first and second
enlarged cuff substrate portions disposed on one end of the lead
substrate portion. In this case, the flexible circuit comprise
first and second electrically conductive traces respectively
extending from the connector substrate portion to the first and
second cuff substrate portions, first and second windows formed in
the connector substrate portion to expose the first and second
electrically conductive traces to respectively form first and
second connector pads, and third and fourth windows formed in the
first and second cuff substrate portions to expose the first and
second electrically conductive traces to respectively form first
and second electrode pads. The lead substrate portion may be
divided into a first lead substrate portion and a second lead
substrate portion, the first lead substrate portion may extend
between the connector substrate portion and first cuff substrate
portion, and the second lead substrate portion may extend between
the first cuff substrate portion and the second cuff substrate
portion.
[0021] In accordance with an eighth aspect of the present
inventions, the cuff body is pre-shaped to curve in two orthogonal
directions, such that the cuff body has a bi-stable structure. The
cuff body may be configured between an unfurled stable state and a
furled stable state. Similarly, the enlarged cuff substrate portion
of a flexible circuit is pre-shaped to curve in two orthogonal
directions, such that the cuff substrate portion has a bi-stable
structure. The cuff substrate portion may be configured for being
configured between an unfurled stable state and a furled stable
state.
[0022] In accordance with an eighth aspect of the present
inventions, the lead connector of an electrode lead includes a
rigid cylindrical rod having an outer surface on which the
connector substrate is affixed, such that connector contact(s)
faces outward away from the cylindrical rod. The connector
substrate may be pre-shaped to conform to the outer surface of the
cylindrical rod. Similarly, an electrode lead may include the
flexible circuit, and the rigid cylindrical rod on which the
connector substrate portion of the flexible circuit is affixed,
such that the connector pad faces outward away from the cylindrical
rod to form a lead connector contact. The connector substrate may
be pre-shaped to conform to the outer surface of the cylindrical
rod. Similarly, a lead connector may comprise a rigid cylindrical
rod on which the connector substrate is affixed, such that the
connector pad(s) faces outward away from the cylindrical rod to
form the lead connector contact. The connector substrate may be
pre-shaped to conform to the outer surface of the cylindrical
rod.
[0023] In accordance with a ninth aspect of the present invention,
the lead connector of an electrode lead comprises at least one
rigid connector contact having an arcuate surface affixed to the
connector substrate and electrically coupled respectively to the
connector pad(s), and a cylindrical, rigid, electrical insulator at
least partially encapsulating the connector substrate and the
connector contact(s), such that only the arcuate surface of each of
the connector contact(s) is exposed. Similarly, the electrode lead
may comprise a connector contact having an arcuate surface affixed
to the connector substrate portion of the flexible circuit and
electrically coupled respectively to the connector pad, and a
cylindrical, rigid, electrical insulator at least partially
encapsulating the connector substrate portion and the connector
contact, such that only the arcuate surface of the connector
contact is exposed. Similarly, a lead connector may comprise at
least one rigid connector contact having an arcuate surface affixed
to the connector substrate and electrically coupled respectively to
the at least one connector pad, and a cylindrical, rigid,
electrical insulator at least partially encapsulating the connector
substrate and the at least one connector contact, such that only
the arcuate surface of each of the at least one connector contact
is exposed.
[0024] The electrical insulator may be composed of, e.g., epoxy or
polyurethane. The arcuate surface of each of the connector
contact(s) may conform with an outer surface of the electrical
insulator. In one embodiment, each of the connector contact(s) has
an arc length of 180 degrees or less. In another embodiment, each
of the connector contact(s) has an arc length greater than 180
degrees. Each of the connector contact(s) may be, e.g., disk-shaped
or half-moon shaped. Each of the connector contact(s) may have a
notch in which the connector substrate is disposed.
[0025] In accordance with a tenth aspect of the present invention,
the lead connector of an electrode lead comprises a cylindrical
connector portion having at least one connector contact, at least
one wire respectively coupled between the connector pad(s) and the
connector contact(s), and a cylindrical, rigid, electrical
insulator encapsulating the connector substrate. Similarly, an
electrode lead may comprise a cylindrical connector portion having
a connector contact, at least one wire coupled between the
connector pad and the connector contact, and a cylindrical, rigid,
electrical insulator encapsulating the connector substrate portion
of a flexible circuit. Similarly, a lead connector may comprise a
cylindrical connector portion having at least one connector
contact, at least one wire respectively coupled between the
connector pad(s) and the connector contact(s), and a cylindrical,
rigid, electrical insulator encapsulating the connector substrate
portion. The electrical insulator may be composed of, e.g., epoxy
or polyurethane. In one embodiment, each of the connector
contact(s) is a ring contact. In another embodiment, the wire(s)
extends longitudinally along the cylindrical connector portion from
the connector contact(s) out of a distal face of the cylindrical
connector portion.
[0026] Other and further aspects and features of the invention will
be evident from reading the following detailed description of the
preferred embodiments, which are intended to illustrate, not limit,
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The drawings illustrate the design and utility of preferred
embodiments of the present invention, in which similar elements are
referred to by common reference numerals. In order to better
appreciate how the above-recited and other advantages and objects
of the present inventions are obtained, a more particular
description of the present inventions briefly described above will
be rendered by reference to specific embodiments thereof, which are
illustrated in the accompanying drawings. Understanding that these
drawings depict only typical embodiments of the invention and are
not therefore to be considered limiting of its scope, the invention
will be described and explained with additional specificity and
detail through the use of the accompanying drawings in which:
[0028] FIG. 1 is a perspective view of an electrode lead
constructed in accordance with one embodiment of the present
invention, wherein a cuff body of the electrode lead is
particularly shown disposed on a nerve;
[0029] FIG. 2 is a plan view of a cuff electrode of the electrode
lead of FIG. 1, which can be rolled up and circumferentially
disposed around a nerve;
[0030] FIG. 3 is a cross-sectional view of the cuff electrode of
FIG. 2, taken along the line 3-3;
[0031] FIG. 4 is a perspective view of one embodiment of a flexible
circuit that can form a portion of the electrode lead of FIG.
1;
[0032] FIG. 5 is a plan view of the flexible circuit of FIG. 4;
[0033] FIG. 6a is a cross-sectional view of the flexible circuit
showing one embodiment of an arrangement of electrically conductive
traces, taken along the line 6a-6a;
[0034] FIG. 6b is a cross-sectional view of the flexible circuit
showing one embodiment of an arrangement of electrically conductive
traces, taken along the line 6b-6b;
[0035] FIG. 7a is a plan view of one connector pad or electrode pad
of the flexible circuit of FIG. 5, wherein no portion of the
connector pad or electrode pad is embedded within a planar
dielectric substrate;
[0036] FIG. 7b is a plan view of one connector pad or electrode pad
of the flexible circuit of FIG. 5, wherein the peripheral region of
the connector pad or electrode pad is embedded within a planar
dielectric substrate;
[0037] FIG. 7c is a plan view of one connector pad or electrode pad
of the flexible circuit of FIG. 5, wherein the peripheral region
and interior region of the connector pad or electrode pad is
embedded within a planar dielectric substrate;
[0038] FIG. 8a is a cross-sectional view of the connector pad or
electrode pad of FIG. 7a;
[0039] FIG. 8b is a cross-sectional view of the connector pad or
electrode pad of FIG. 7b;
[0040] FIG. 8c is a cross-sectional view of the connector pad or
electrode pad of FIG. 7c;
[0041] FIG. 9 is a perspective view of one embodiment of a cuff
substrate portion that includes the flexible circuit of FIG. 5,
particularly showing an elastic layer disposed over the cuff
substrate portion;
[0042] FIG. 10 is a cross-sectional view of the cuff substrate
portion of FIG. 9, taken along the line 10-10;
[0043] FIG. 11 is a plan view of one embodiment of a cuff substrate
portion of the flexible circuit of FIG. 5, particularly showing an
anti-inflammatory coating disposed over the cuff substrate
portion;
[0044] FIG. 12a is one embodiment of an open slot formed in the
cuff substrate portion of FIG. 9;
[0045] FIG. 12b is another embodiment of an open slot formed in the
cuff substrate portion of FIG. 9;
[0046] FIG. 12c is still another embodiment of an open slot formed
in the cuff substrate portion of FIG. 9;
[0047] FIG. 13a is a perspective view of the cuff substrate portion
of the FIG. 9 in an unfurled stable configuration;
[0048] FIG. 13b is a perspective view of the cuff substrate portion
of the FIG. 9 in a furled stable configuration;
[0049] FIG. 14 is a plan view of another embodiment of a flexible
circuit that can be used to manufacture the electrode lead of FIG.
1;
[0050] FIG. 15 is a perspective view of a flexible circuit that may
be part of a cuff body of an electrode lead constructed in
accordance with another embodiment of the present invention;
[0051] FIG. 16 is a perspective view of a flexible circuit that may
be part of a cuff body of an electrode lead constructed in
accordance with still another embodiment of the present
invention;
[0052] FIG. 17 is a perspective view of an electrode lead
constructed in accordance with yet another embodiment of the
present invention, wherein a cuff body of the electrode lead is
particularly shown disposed on a nerve;
[0053] FIG. 18 is a plan view of one embodiment of a flexible
circuit that forms a portion of the electrode lead of FIG. 17;
[0054] FIG. 19 is a perspective view of an electrode lead
constructed in accordance with yet another embodiment of the
present invention, wherein two cuff bodies of the electrode lead
are particularly shown disposed on two nerves;
[0055] FIG. 20 is a plan view of one embodiment of a flexible
circuit that forms a portion of the electrode lead of FIG. 19;
[0056] FIG. 21a is a plan view of one embodiment of a lead body of
the electrode lead of FIG. 1;
[0057] FIG. 21b is a plan view of another embodiment of a lead body
of the electrode lead of FIG. 1;
[0058] FIG. 21c is a plan view of the lead body of FIG. 21b with an
additional insulating tube;
[0059] FIG. 21d is a plan view of still another embodiment of a
lead body of the electrode lead of FIG. 1;
[0060] FIG. 21e is a plan view of yet another embodiment of a lead
body of the electrode lead of FIG. 1;
[0061] FIG. 21f is a plan view of yet another embodiment of a lead
body of the electrode lead of FIG. 1;
[0062] FIG. 21g is a plan view of the lead body of FIG. 21f with an
additional insulating tube;
[0063] FIG. 21h is a plan view of yet another embodiment of a lead
body of the electrode lead of FIG. 1;
[0064] FIG. 21i is a plan view of the lead body of FIG. 21h with an
additional insulating tube;
[0065] FIG. 22 is a perspective view of a connector substrate
portion of the flexible circuit of FIG. 4;
[0066] FIG. 23 is a perspective view of one embodiment of a lead
connector of the electrode lead of FIG. 1 that can be formed from
the connector substrate portion of FIG. 22;
[0067] FIG. 24 is a perspective view of a connector substrate
portion of the flexible circuit of FIG. 4;
[0068] FIG. 25 is a perspective view of one embodiment of a rigid
arcuate connector contact;
[0069] FIG. 26 is a perspective view of an assembly consisting of
connector contacts of FIG. 25 affixed to the connector substrate
portion of FIG. 24;
[0070] FIG. 27 is a perspective view of another embodiment of a
lead connector of the electrode lead of FIG. 1 that can be formed
from the assembly of FIG. 26;
[0071] FIG. 28 is a perspective view of a connector substrate
portion of the flexible circuit of FIG. 4;
[0072] FIG. 29 is a perspective view of another embodiment of a
rigid arcuate connector contact;
[0073] FIG. 30 is a perspective view of an assembly consisting of
connector contacts of FIG. 29 affixed to the connector substrate
portion of FIG. 28;
[0074] FIG. 31 is a perspective view of another embodiment of a
lead connector of the electrode lead of FIG. 1 that can be formed
from the assembly of FIG. 30;
[0075] FIG. 32 is a perspective view of an assembly of a
conventional cylindrical connector portion affixed to a connector
substrate portion of the flexible circuit of FIG. 4;
[0076] FIG. 33 is a perspective view of another embodiment of a
lead connector of the electrode lead of FIG. 1 that can be formed
from the assembly of FIG. 32; and
[0077] FIG. 34 is a flow diagram illustrating one method of
constructing an electrode lead in accordance with various
embodiments of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0078] Referring first to FIGS. 1-3, an electrode lead 10
constructed in accordance with one embodiment of the present
inventions will now be described. The electrode lead 10 may be used
for any medical treatment where it is desired to stimulate a nerve
and/or record physiological signals from a nerve or surrounding
tissue.
[0079] The electrode lead 10 generally comprises an elongated
planar lead body 12 having a proximal end 14 and a distal end 16, a
lead connector 18 affixed to the proximal end 14 of the lead body
12, at least one lead connector contact 20 (two shown) disposed on
the lead connector 18, a planar electrode carrying structure 22
affixed to the distal end 16 of the lead body 12, at least one
electrode contact 24 (three shown in phantom in FIG. 1) disposed on
the electrode carrying structure 22, and at least one electrical
conductor 26 (two shown) extending through the lead body 12 between
the lead connector contacts 20 and the electrode contacts 24. For
the purposes of this specification, "planar" means having a
two-dimensional characteristic, with the thickness of the body
being much less than the width of the body. For example, the width
of the body may be greater than ten times, greater than fifty
times, or even greater than one hundred times the width of the
body.
[0080] In the illustrated embodiment, the electrode carrying
structure 22 takes the form of a cuff body 22 that can be
circumferentially disposed around tissue, e.g., a nerve 28, such
that the electrode contacts 24 are disposed on an inner surface of
the cuff body 22 in contact with the nerve 28. In alternative
embodiments, the electrode carrying structure 22 can be any
structure suitable for carrying the electrode contacts 24, e.g., a
paddle or even the distal end of the lead body 12.
[0081] In the illustrated embodiment, the electrode contacts 24 can
be in the form of a guarded tripolar electrode arrangement (e.g.,
anode-cathode-anode) that can be used for purposes of stimulating
the nerve 28. Two of the outer electrode contacts 24 (the anodes)
can be ganged together and coupled to one of the lead connector
contacts 18 via an electrical conductor 26, and the remaining
electrode contact 24 (the middle cathode) may be coupled to the
other lead connector contact 18 via the other electrical conductor
26. It should be appreciated that, alternatively, the number of
electrode contacts 24, lead connector contacts 18, and electrical
conductors 26 can be identical, such that electrode contacts 24 may
be energized independently of each other.
[0082] The cuff body 22 is relatively thin, e.g., having a
thickness less than 1 mm, and preferably less than 0.5 mm, so that
the cuff body 22 may be easily disposed around in conformance with
the nerve 28. The cuff body 22 takes the form of a planar sheet (as
best shown in FIG. 2) that can be rolled up on itself to be
circumferentially disposed around the nerve 28 (as best shown in
FIG. 1). The electrode lead 10 may comprise a strap and buckle
arrangement, along with a locking mechanism, that tightens and
secures the cuff body 22 around the nerve 28, as described in U.S.
Provisional Patent Application Ser. No. 62/500,080, entitled "Nerve
Cuff Electrode Locking Mechanism," which is expressly incorporated
herein by reference.
[0083] To this end, the lead connector 18 (which is a male
connector in the illustrated embodiment) can be inserted into a
corresponding female connector 32 of a neurostimulation device 30,
which supplies electrical pulses to the electrode contacts 24 of
the electrode lead 10 in accordance with a stimulation regimen. In
embodiments described herein, the female connector 32 of the
neurostimulation device 30 is conventional in nature. For example,
the female connector 32 may take the form of an in-line connector,
such as a Bal Seal.RTM. connector.
[0084] Recording electrode contacts can also be connected to the
neurostimulation device 30 to provide sensed physiological signals
(e.g., electromyogram (EMG) signals) to the neurostimulation device
30, and thus, in an alternative embodiment, the electrode contacts
24 of the electrode lead 10 may serve as recording electrodes.
Alternatively, the recording electrode may be on a separate lead
body, which is connected to the neurostimulation device 30.
[0085] In the illustrated embodiment, the electrode lead 10 is
formed, at least partially, from an easily manufacturable flexible
circuit 34, as best illustrated in FIGS. 4 and 5. To this end, the
flexible circuit 34 comprises a planar dielectric substrate 36,
which in the illustrated embodiment, is composed of liquid crystal
polymer (LCP). LCP is inert in biological environments and is
substantially impermeable to moisture, oxygen, and other gases and
liquids. LCP is low cost and light weight, and can be precision
molded and sealed using conventional thermoplastic welding
techniques to create a substantially impermeable seal. Polyimide
may alternatively be used for the planar dielectric substrate 12.
However, LCP has one-tenth of the moisture uptake, and
advantageously is compatible with both semiconductor processes and
layer-to-layer lamination by fusion bonding of multiple LCP sheets
with heat and pressure without the use of adhesives.
[0086] The planar dielectric substrate 36 generally includes an
elongated lead substrate portion 38 that forms the lead body 12 of
the electrode lead 10. The lead substrate portion 38 has one end 40
corresponding to the proximal end 14 of the lead body 12, and an
opposing end 42 corresponding to the distal end 16 of the lead body
12. The planar dielectric substrate 36 further includes a connector
substrate portion 44 disposed at the one end 40 of the lead
substrate portion 38, and an enlarged cuff substrate portion 46
disposed at the other end 42 of the lead substrate portion 38. The
connector substrate portion 44 forms at least a portion of the
connector 18 of the electrode lead 10 (shown in FIG. 1), and the
cuff substrate portion 46 forms the cuff body 22 of the electrode
lead 10 (shown in FIG. 1). In the illustrated embodiment, the
connector substrate portion 44 and cuff substrate portion 46 are
rectangular in nature.
[0087] The flexible circuit 34 further comprises electrically
conductive traces 48 embedded within the planar dielectric
substrate 36, and extend from the connector substrate portion 44 to
the enlarged cuff substrate portion 46. The electrically conductive
traces 48 may be composed of a suitable electrically conductive and
biocompatible material, such as gold, or 90/10 or 80/20
Platinum-Iridium alloy.
[0088] The flexible circuit 34 further comprises windows 50 formed
in the planar dielectric substrate 36, and in particular, in the
connector substrate portion 44 and the cuff substrate portion 46,
that respectively exposes portions of the electrically conductive
traces 48 to form connector pads 52 and electrode pads 54. As will
be described in further detail below, the connector pads 52 may be
used as the lead connector contacts 20 themselves or may be used to
connect the electrically conductive traces 48 to the lead connector
contacts 20. In the illustrated embodiments described herein, the
electrode pads 54 are used as the electrode contacts 24 themselves,
although in alternative embodiments, the electrode contacts 24 may
be separate and distinct from the electrode pads 54 and may, thus,
be coupled to the electrode pads 54. The unexposed portions of the
electrically conductive traces 48 form the electrical conductors 26
of the electrode lead 10 (shown in FIG. 1).
[0089] The electrically conductive traces 48 may be disposed in the
planar dielectric substrate 36 side-by-side in a single layer, as
illustrated in FIG. 6a, or as stacked multiple layers, as
illustrated in FIG. 6b. As illustrated in FIGS. 4 and 5, the
portions of the electrically conductive traces 48 that form the
connector pads 52 and electrode pads 54 are many times larger in
terms of surface area than the portions of the electrically
conductive traces 48 that form the electrical conductors 26.
[0090] In one embodiment illustrated in FIGS. 7a and 8a, each
connector pad 52 or electrode pad 54 is not interlocked in place by
the edges 56 of the respective window 50, such that no portion of
the connector pad 52 or electrode pad 54 is embedded in the planar
dielectric substrate 36. In this case, the size and geometry of the
window 50 will be the same size and geometry as the respective
connector pad 52 or electrode pad 54.
[0091] In another embodiment illustrated in FIGS. 7b and 8b, each
connector pad 52 or electrode pad 54 is interlocked in place by the
edges 56 of the respective window 50, such that only the peripheral
region 58 of the connector pad 52 or electrode pad 54 is embedded
in the planar dielectric substrate 36. In this case, the size of
the window 50 will be smaller than the size of the respective
connector pad 52 or electrode pad 54. It can be appreciated that
because the overlapping edges 56 of the window 50 lock the
respective connector pad 52 or electrode pad 54 in place,
delamination of the respective terminal 20 or electrode pad 54 from
the planar dielectric substrate 26, that may otherwise be initiated
at the edges 60 of the connector pad 52 or electrode pad 54, is
prevented or at least minimized.
[0092] In still another embodiment illustrated in FIGS. 7c and 8c,
each connector pad 52 or electrode pad 54 is interlocked in place
by the edges 56 of the multiple respective windows 50 (in this
case, two windows), such that a peripheral region 58 and additional
interior regions 62 (in this case, one portion) of the connector
pad 52 or electrode pad 54 are embedded in the planar dielectric
substrate 36. In this case, the sizes of the windows 50 will be
less than half the size of the respective connector pad 52 or
electrode pad 54. The interior regions 62 that are embedded in the
planar dielectric substrate 36 are smaller than the size of the
windows 50, such that the respective connector pad 52 or electrode
pad 54 electrically functions as a single connector pad 52 or
electrode pad 54. It can be appreciated that because planar
dielectric substrate 36 locks the respective connector pad 52 or
electrode pad 54 at the interior regions 62 in addition to the
peripheral region 58, delamination of the respective terminal 20 or
electrode pad 54 from the planar dielectric substrate 26, that may
otherwise be initiated at the edges 60 or interior region 62 of the
connector pad 52 or electrode 24, is further prevented or
minimized.
[0093] As best illustrated in FIGS. 9 and 10, the flexible circuit
34 may further comprise one or more layers of an elastic,
electrically insulative, biocompatible, material 64, such as, e.g.,
silicone, polyurethane, polyether polyurethane, polycarbonate
polyurethane, parylene, perfluoroalkoxy alkanes (PFA), and
polytetrafluoroethylene (PTFE), disposed over the cuff substrate
portion 46 of the planar dielectric substrate 36. The elastic layer
64 allows implantation of the completed electrode lead 10 within a
patient without cutting surrounding tissue, which may otherwise
occur due to the sharp edges of the planar dielectric substrate 36.
As illustrated in FIG. 11, the flexible circuit 34 may optionally
comprise an anti-inflammatory coating 66 (represented by the hashed
lines) disposed over or as part of the cuff substrate portion 46.
The anti-inflammatory coating 66 releases an anti-inflammatory
drug, such as a steroid dexamethasone, into surrounding tissue over
time, thereby providing therapeutic effects following implantation
of the electrode lead 10 by reducing subsequent nerve inflammation
and swelling. Notably, the windows 50 described above will not only
be formed through the planar dielectric substrate 36, but will be
formed through the elastic layer 64 and optional anti-inflammatory
coating 66, to form the connector pads 52 and electrode pads
54.
[0094] The electrode lead 10 may further comprise a plurality of
open slots 68 disposed along the periphery of the cuff body 22 to
facilitate the anchoring of the elastic layer 64 to the cuff
substrate portion 46 of the planar dielectric substrate 36. That
is, the elastic layers 64 on both sides of the cuff substrate
portion 46 interlocks with each other through the open slots 68.
Furthermore, the shape and size of the open slots 68 can be
selected to influence the rigidity (i.e., the curling stiffness) of
the cuff body 22. That is, as the number of open slots 68 or the
size of the open slots increases, the rigidity of the cuff body 22
will decrease. As examples, the open slots 68 may take the form of
slotted holes 68a (FIG. 12a), rounded slots 68b (FIG. 12b), or a
slotted "Ts" 68c (FIG. 12c).
[0095] Referring now to FIGS. 13a and 13b, the cuff body 22, and in
the illustrated embodiment the cuff substrate portion 46 of the
flexible circuit 34, may be pre-shaped to curve in two orthogonal
directions (in this case, pre-shaped to curve along a lateral axis
69a in FIG. 13a, and pre-shaped to curve along a longitudinal axis
69b in FIG. 13b), such that the cuff body 22 has a bi-stable
structure. For example, the cuff body 22 may be configured between
in an unfurled stable configuration (FIG. 13a), which facilitates
handling and placement of the cuff body 22 underneath the nerve 28,
and a furled stable configuration (FIG. 13b), which facilitates
placement of the cuff body 22 around the nerve 28. When the cuff
body 22 is in the unfurled state, in the absence of external force,
the lateral curve provides an additional bending stiffness in the
cuff body 22 that overcomes the bending force imposed on the cuff
body 22 by the longitudinal curve, such that the cuff body 22 is
maintained in the unfurled state. However, when a torqueing force
is applied to the cuff body 22 along the longitudinal axis 69b, the
additional ending stiffness in the cuff body 22 provided by the
lateral curve can be overcome, such that the cuff body 22 is placed
into the furled stable state by the bending force imposed on the
cuff body 22 by the longitudinal curve.
[0096] Although the connector substrate portion 44 and the cuff
substrate portion 46 are illustrated in FIGS. 4 and 5 as being
oriented perpendicularly to the lead substrate portion 38, an
alternative embodiment of a flexible circuit 34a may be identical
to the flexible circuit 34 described in FIGS. 4 and 5, with the
exception that the connector substrate portion 44 and the cuff
substrate portion 46 may be oriented obliquely to the lead
substrate portion 38, as illustrated in FIG. 14. This arrangement
facilitates the coiling of the lead body 12 into an actual coil
configuration, so that the cuff body 22 can be positioned
perpendicularly to the lead body 12. If the cuff substrate portion
46 is oriented perpendicularly to the connector substrate portion
44 before it is coiled, the final position of the cuff body 22 will
be skewed and will not be perpendicular to the coiled lead body
12.
[0097] In the embodiment of the electrode lead 10 illustrated in
FIG. 1, only electrode contacts 24 that serve as stimulation
electrodes are described. An alternative embodiment of an electrode
lead 10a may be identical to the electrode lead 10 illustrated in
FIG. 1, with the exception that recording electrode contacts 24'
are located on the outer surface of the cuff body 22 when
circumferentially disposed around a nerve (not shown), as
illustrated in FIG. 15. In this case, additional connector contacts
(not shown) may be located on the lead connector (not shown) for
electrically coupling to the additional electrode contacts 24'.
Notably, the cuff body 22 of the electrode lead 10a may be
circumferentially disposed around a nerve, and therefore, the
recording electrode contacts 24' may be used to sense EMG signals
in muscle surrounding the nerve, while the stimulation electrode
contacts 24 are used to stimulate the nerve.
[0098] In another alternative embodiment of an electrode lead 10b,
as illustrated in FIG. 15, the stimulation electrode contacts 24
can be located on the outer surface of the cuff body 22, and the
recording electrode contacts 24' can be located on the inner
surface of the cuff body 22. In the same manner that the
stimulating electrode contacts 24 are provided in the flexible
circuit 34 illustrated in FIGS. 4 and 5, the recording electrode
contacts 24' illustrated in FIGS. 15 and 16 can be provided by
forming windows 50' in the planar dielectric substrate 26, and in
particular the cuff substrate portion 46, to expose portions of
electrically conductive traces 48' to form electrode pads 54'
corresponding to the recording electrode contacts 24'.
[0099] Referring to FIG. 17, an alternative embodiment of an
electrode lead 10c is similar to the electrode lead 10 illustrated
in FIG. 1, with the exception that the electrode lead 10c comprises
a branch lead body 12' extending from the lead body 12 (as the main
lead body 12), at least one additional connector contact 20' (two
shown) disposed on the lead connector 18, at least one additional
electrode contact 24' (two shown) disposed on the branch lead body
12', and at least one electrical conductor 26' (two shown)
extending through the main lead body 12 and branch lead body 12'
between the additional lead connector contacts 20' and the
additional electrode contacts 24'.
[0100] The electrode lead 10c further comprises a barb 70 formed at
the end of the branch lead body 12', which can be used to anchor
the branch lead body 12' and the corresponding electrode contacts
24' to muscle remotely located from the nerve 28. Notably,
anchoring of the branch lead body 12' to the muscle will occur as
tissue grows and envelopes around the barb 70, and thus, the barb
70 need not be rigid. The electrode contacts 24' may be used as
sensors to detect physiological signals, such as EMG signals, in
the muscle in which the branch lead body 12' is anchored via the
barb 70.
[0101] In this embodiment, the electrode lead 10c will be formed,
at least partially, from a flexible circuit 34b that is similar to
the flexible circuit 34, with the exception that the planar
dielectric substrate 26 includes an additional elongated branch
lead substrate portion 38' extending from the lead substrate
portion 38 (as the main lead substrate portion), as illustrated in
FIG. 18. The flexible circuit 34b comprises additional electrically
conductive traces 48' embedded within the planar dielectric
substrate 36 and extending from the connector substrate portion 44
to the branch lead substrate portion 68. The flexible circuit 34b
further comprises windows 50' formed through the planar dielectric
substrate 36, and in particular, in the connector substrate portion
44 and the branch lead substrate portion 12', that respectively
exposes portions of the electrically conductive traces 48' to form
the two additional connector pads 52' and the two additional
electrode pads 54'.
[0102] As will be described in further detail below, the connector
pads 52' may be used as the lead connector contacts 20' themselves
or may be used to connect the electrically conductive traces 48' to
the lead connector contacts 20'. In the illustrated embodiments
described herein, the electrode pads 54' are used as the electrode
contacts 24' themselves, although in alternative embodiments, the
electrode contacts 24' are distinct from the electrode pads 54' and
may be coupled to the electrode pads 54'. The unexposed portions of
the electrically conductive traces 48' form the electrical
conductors 26'. The distal end of the branch lead substrate portion
68 will be shaped into the form of the barb 70.
[0103] Referring to FIG. 19, an alternative embodiment of an
electrode lead 10d is similar to the electrode lead 10c illustrated
in FIG. 17, with the exception that the electrode lead 10d
comprises a proximal cuff body 22a in addition to a distal cuff
body 22b, at least one additional connector contact 20 (four total
connector contacts 20 shown) disposed on the lead connector 18, at
least one additional electrode contact 24 (four electrode contacts
24 shown) disposed on the proximal cuff body 22a and distal cuff
body 22b, and at least one electrical conductor 26 (four total
electrical conductors 26 shown) extending through the main lead
body 12 between the lead connector contacts 20 and the electrode
contacts 24. The proximal cuff body 22a is located along the lead
body 12 between the lead connector 18 and the distal cuff body
22b.
[0104] The lead body 12 may be divided into a proximal lead body
portion 12(1) extending between the lead connector 18 and the
proximal cuff body 22a, and a distal lead body portion 12(2)
extending between the proximal cuff body 22a and the distal cuff
body 22b. The lengths of the lead body portions 12(1), 12(2) may be
configured for allowing the cuff bodies 22a, 22b to be placed
around bilateral sections of the same nerve, such as, e.g., the
hypoglossal nerve in the neck, and the branch lead body 12' may be
anchored into muscle, such that the electrode contacts 24' can
detect the patency of the upper airway. Specifically, the electrode
contacts 24' may be positioned, such that it can detect EMG signals
on the genioglossus muscle or other upper airway muscles.
[0105] In the illustrated embodiment, the branch lead body 12' is
located between the lead connector 18 and the proximal cuff body
22a, although in alternative embodiments, the branch lead body 12'
may be located between the proximal cuff body 22a and the distal
cuff body 22b. In still another embodiment, the electrode lead 10c
may not have the branch lead body 12'. Although the electrode lead
10c is illustrated with only two cuff bodies 22a, 22b, the
electrode lead 10c may alternatively include more than two cuff
bodies. In alternative embodiments, the lead body 12 may be split
into plurality distal ends on which cuff bodies 22 may be
disposed.
[0106] In this embodiment, the lead body 12c will be formed, at
least partially, from a flexible circuit 34c that is similar to the
flexible circuit 34b, with the exception that the planar dielectric
substrate 26 includes a first enlarged cuff substrate portion 46a
in addition to the second cuff substrate portion 46b, as
illustrated in FIG. 20. The first cuff substrate portion 46a is
located along the lead substrate portion 38 between the second cuff
substrate portion 46b and the branch lead substrate portion 38'.
Thus, the lead substrate portion 38 can be divided into a first
elongated lead substrate portion 38a that extends between the
connector substrate portion 44 and the first cuff substrate portion
46', and a second elongated lead substrate portion 38b that extends
between the first cuff substrate portion 46' and the second cuff
substrate portion 46. In the alternative embodiment where the
branch lead body 12' is located between the first cuff body 22a and
the second cuff body 22b, the branch lead substrate portion 38' may
likewise be located between the first cuff substrate portion 46a
and the second cuff substrate portion 46b.
[0107] The flexible circuit 34c comprises electrically conductive
traces 48 embedded within the planar dielectric substrate 36 and
extending from the connector substrate portion 44 to the first and
second cuff substrate portions 46a, 46b. The flexible circuit 34c
further comprises windows 50 formed through the planar dielectric
substrate 36, and in particular, in the connector substrate portion
44 and the first and second cuff substrate portions 46a, 46b, that
respectively expose portions of the electrically conductive traces
48 to form four connector pads 52 and four additional electrode
pads 54.
[0108] As will be described in further detail below, the connector
pads 52 may be used as the lead connector contacts 20 themselves or
may be used to connect the electrically conductive traces 48 to the
lead connector contacts 20. In the illustrated embodiments
described herein, the electrode pads 54 are used as the electrode
contacts 24 themselves, although in alternative embodiments, the
electrode contacts 24 are distinct from the electrode pads 54 and
may be coupled to the electrode pads 54. The unexposed portions of
the electrically conductive traces 48 form the electrical
conductors 26.
[0109] The lead bodies 12 in the electrodes leads 10 described
above may be variously configured, depending on the flexibility
requirements of the particular application of the electrode lead
10. If minimal lateral flexibility is required, a lead body 12a,
which is planar by virtue of the lead substrate portion 38 of the
planar dielectric substrate 36 from which it is composed, may
remain flat and straight, as illustrated in FIG. 21a. Notably, LCP
is relatively inflexible, and thus, the lead 12a illustrated in
FIG. 20a will not flex along the plane of the lead 12a.
[0110] If additional lateral flexibility is required, the lead
substrate portion 38 of the planar dielectric substrate 36 can be
pre-shaped into a three-dimensional structure that increases the
flexibility of the lead substrate portion 38 in the plane of the
dielectric substrate 36. As one example, the three-dimensional
structure may be a helical structure that forms a lead body 12b, as
illustrated in FIG. 21b. Thus, the helical structure provides the
lead body 12b with a wider range of movement in all three
dimensions relative to the lead body 12a. The lead body 12b may
further comprise an outer layer of insulative material 72 disposed
over the helical structure, as illustrated in FIG. 21c. The
insulative material 72 may be composed of one of silicone,
polyurethane, polyether polyurethane, polycarbonate polyurethane,
parylene, perfluoroalkoxy alkanes (PFA), and
polytetrafluoroethylene (PTFE). In the illustrated embodiment, the
insulative material 72 takes the form of tubing composed of a soft
polymer, such as, e.g., silicone, over the helical structure. The
soft polymer tubing 72 may prevent the sharp edges of the lead
substrate portion 38 of the planar dielectric substrate 26 from
injuring the living tissue adjacent the electrode lead 10.
[0111] Alternatively, if additional lateral flexibility is
required, the lead substrate portion 38 of the planar dielectric
substrate 36 may have at least one slit 74 (only one shown) formed
between the electrically conductive traces 48, thereby forming a
lead body 12c having a plurality of planar strands 76 (only two
shown), as illustrated in FIG. 21d. As there shown, the slit 74
extends through the one end of the lead substrate portion 38 (and
in this case, the distal end of the lead body 12c), such that an
end portion 78 of the lead substrate portion 38 remain intact, and
the planar strands 76 have loose ends. In this case, multiple cuff
bodies 22 (not shown) can be respectively disposed on the loose
ends of the planar strands 76. Alternatively, the slits 74 may not
extend through either end of the lead substrate portion 38, such
that both end portions 78a, 78b of the lead substrate portion 38
remains intact, thereby forming a lead body 12d, as illustrated in
FIG. 21e. The slits 74 may be collinear in nature, such that the
lead substrate portion 38 remains intact between the collinear
slits 74. Thus, the slits 74 intermittently extend along the length
of the lead substrate portion 38, such that planar strands 76
periodically split from each other and then join back to together
at points along the length of the lead substrate portion 38.
[0112] Because the widths of the planar strands 76 in the lead
bodies 12c, 12d of FIGS. 21d and 21e are smaller than the lead
substrate portion 38 and that the planar strands 76 can move
relative to each other, the entireties of the lead bodies 12 are
afforded a wider range of movement in all three dimensions relative
to a single wider intact lead body 12a. In the case where the
planar strands 76 of the lead body 12 have loose ends, as
illustrated in FIG. 21d, the planar strands 76 may be pre-shaped
into a co-helical structure (i.e., the helical structures are
interleaved with each other) to form a lead body 12e, as
illustrated in FIG. 21f. The lead body 12e may further comprise a
tube 72 composed of a soft polymer, such as, e.g., silicone, over
the co-helical structure, as illustrated in FIG. 21g.
[0113] Alternatively, if additional lateral flexibility is
required, the lead substrate portion 38 of the planar dielectric
substrate 36 may be pre-shaped into a sigmoid structure to form a
lead body 12f, as illustrated in FIG. 21h. Like the helical
structure described above, the sigmoid structure provides the lead
body 12f with a wider range of movement. The lead body 12f may
further comprise a tube 72 composed of a soft polymer, such as,
e.g., silicone, over the sigmoid structure, as illustrated in FIG.
21i.
[0114] As briefly discussed above, the female connector 32 of the
neurostimulation device 30 (shown in FIG. 1) is conventional in
nature, and thus, it is desirable that the lead connector 18 be
compatible with the connector 32 of the neurostimulation device 30.
This requires that the lead connector 18 be cylindrical in nature,
and that the connector contacts 20 be disposed around the
circumference of the lead connector 18, such that when inserted
into the connector 32 of the neurostimulation device 30 electrical
connection between the electronics of the neurostimulation device
30 and the electrode contact 24 be created. However, because the
connector substrate portions 44 of the flexible circuits 34
described herein are planar in nature, without significant
modification, the flexible circuits 34 will not be compatible with
conventional connectors 32.
[0115] To this end, one embodiment of a lead connector 18a
comprises the connector substrate portion 44 and connector pads 52
of the flexible circuit 34 described above, and a rigid cylindrical
rod 80 having an outer surface on which the connector substrate
portion 44 is affixed, as illustrated in FIGS. 22 and 23. The
cylindrical rod 80 is sized to firmly fit within the female
connector 32 of the neurostimulation device 30. The cylindrical rod
80 can be composed of any suitable material (e.g., stainless steel,
polyurethane, or epoxy) that has the necessary column strength to
allow the lead connector 18a to be inserted into the connector 32
of the neurostimulation device 30.
[0116] The connector substrate portion 44 may be thermoformed into
the shape of the outer surface of the cylindrical rod 80 and
affixed to the outer surface of the cylindrical rod 80 using
suitable means, such as bonding, although in alternative
embodiments, the connector substrate portion 44 may be affixed to
the outer surface of the cylindrical rod 80 without thermoforming.
The connector pads 52 of the flexible circuit 34 face outward away
from the cylindrical rod 80 when the connector substrate portion 44
is affixed to the outer surface of the cylindrical rod 80. In this
manner, the connector pads 52 will be exposed and will serve as the
connector contacts 20 when the lead connector 18a is inserted into
the connector 32 of the neurostimulation device 30.
[0117] Referring to FIGS. 24-27, another embodiment of a lead
connector 18b comprises the connector substrate portion 44 and
connector pads 52 of the flexible circuit 34 described above, at
least one rigid arcuate connector contact 82a (two shown) affixed
to the connector substrate portion 44 and electrically coupled
respectively to the connector pads 52, and a generally cylindrical,
rigid, electrical insulator 84 encapsulating the connector
substrate portion 44 between and adjacent the connector contacts
82a, such that only the arcuate surfaces of the connector contacts
82a are exposed. In this manner, the connector contacts 82a will be
exposed for electrical connection to the circuitry of the
neurostimulation device 30 when the lead connector 18a is inserted
into the connector 32 of the neurostimulation device 30. The
electrical insulator 84 may be composed of a suitable material that
can be over-molded over the connector substrate portion 44 and
connector contacts 82a, such as, e.g., epoxy or polyurethane. The
arcuate surfaces of the connector contacts 82a preferably conform
with the outer surface of the electrical insulator 84, such that
the lead connector 18b has a smooth continuous outer surface that
facilitates its insertion into the connector 32 of the
neurostimulation device 30.
[0118] Each of the connector contacts 82a has an arc length that is
greater than 180 degrees, and in the illustrated case, has an arc
length nearly 360 degrees, resulting in disk-shaped connector
contacts 82a. Each connector contact 82a comprises a notch 86 in
which the connector substrate portion 44 is disposed. Preferably,
the dimension of the notch 86 is roughly the same thickness of the
connector substrate portion 44, so that the connector contacts 82a
are firmly in contact with the respective connector pads 52. Thus,
the connector contacts 82a can be slipped onto the connector
substrate portion 44 into firm engagement with the respective
connector pads 52, as illustrated in FIG. 26. An electrically
conductive adhesive can be used to bond the connector contacts 82a
to the respective connector pads 52 to enhance the structural and
electrical contact between the connector contacts 82a and connector
pads 52. The assembly of the connector substrate portion 44 and the
connector contacts 82a can then be over-molded with electrically
insulative material, such as, e.g., epoxy, silicone, polyurethane
or other implantable polymeric material, which fills in the spaces
between the connector contacts 82a, while leaving the arcuate outer
surfaces of the connector contacts 82a exposed, to create the
electrical insulator 84, as illustrated in FIG. 27.
[0119] Referring to FIGS. 28-31, another embodiment of a lead
connector 18c is similar to the lead connector 18b described in
FIGS. 24-27, with the exception that it comprises at least one
rigid arcuate connector contact 82b (two shown) that has an arc
length of 180 degrees or less. In this case, the connector contact
82b has an arc length of 180 degrees, resulting in a half-moon
shaped connector contact 82b. As with the lead connector 18b, the
arcuate surfaces of the connector contacts 82a preferably conform
with the outer surface of the electrical insulator 84, such that
the lead connector 18b has a smooth continuous outer surface that
facilitates its insertion into the connector 32 of the
neurostimulation device 30.
[0120] The connector contacts 82b can be bonded to the respective
connector pads 52 using an electrically conductive adhesive, as
illustrated in FIG. 30, and the assembly of the connector substrate
portion 44 and the connector contacts 82b can be over-molded with
electrically insulative material, such as, e.g., epoxy or
polyurethane, which fills in the spaces between the connector
contacts 82b, while leaving the arcuate outer surfaces of the
connector contacts 82b exposed, to create the electrically
insulator 84, as illustrated in FIG. 31.
[0121] Referring to FIGS. 32-33, still another embodiment of a lead
connector 18d comprises the connector substrate portion 44 and
connector pads 52 of the flexible circuit 34 described above, a
cylindrical connector portion 88 having at least one connector
contact 90 (two shown), at least one wire 92 (two shown) coupled
between the connector pads 52 and the connector contact 90, and a
cylindrical, rigid, electrical insulator 94 fully encapsulating the
connector substrate portion 44. The cylindrical connector portion
88 may be a conventional in-line lead connector, and the connector
contacts 90 are ring contacts that circumferentially extend around
the cylindrical connector portion 88.
[0122] The wires 92, which may be included as part of the
conventional cylindrical portion 88 may extend longitudinally along
the cylindrical connector portion 88 from the respective connector
contacts 90 out of the distal face of the cylindrical connector
portion 88. The wires 92 extending from the cylindrical connector
portion 88 can be wire-bonded to the respective connector pads 52
of the connector substrate portion 44, e.g., via soldering,
welding, or otherwise an electrically conductive adhesive. As with
the electrical insulator 84 described above with respect to the
lead connector 18a, the electrical insulator 94 may be composed of
a suitable material that can be over-molded over the connector
substrate portion 44, such as, e.g., epoxy, silicone, or
polyurethane, after the wires 92 from the cylindrical connector
portion 88 have been wire-bonded to the respective connector pads
52. The outer surface of the electrical insulator 86 preferably
conforms to the outer surface of the cylindrical connector portion
88, such that the lead connector 18d has a smooth continuous outer
surface that facilitates its insertion into the connector 32 of the
neurostimulation device 30.
[0123] Having described the structure and function of various
embodiments of electrode leads 10, one method 100 of manufacturing
electrode leads 10 will now be described with respect to FIG. 34.
In this specific embodiment, multiple electrode leads 10 may be
efficiently fabricated in parallel, although it should be
appreciated that, in alternative embodiments, one electrode lead 10
may be fabricated at a time. First, two dielectric sheets (e.g.,
LCP sheets), i.e., a bottom dielectric sheet and a top dielectric
sheet, are provided (step 102).
[0124] Next, sets of electrically conductive traces 48 for the
multiple electrode leads 10 are disposed on the top surface of the
bottom LCP sheets using a suitable process, such as semiconductor
etching (step 104). For example, the sets of electrically
conductive traces 48 can be disposed on the top surface of the
bottom LCP sheet in a side-by-side relationship. The ends of these
electrically conductive traces 48 will be enlarged to accommodate
the formation of the connector pads 52 and electrode pads 54.
[0125] Next, windows 50 for the multiple electrode leads 10 are
formed through the top LCP sheet (e.g., via cutting) at select
locations (step 106), and LCP sheets are laminated together by,
e.g., fusion bonding with heat and pressure, thereby forming the
planar dielectric substrate 36 with embedded electrically
conductive traces 48 (step 108). The windows 50 formed through the
top LCP sheet expose portions of the embedded electrically
conductive traces 48 to form connector pads 52 and electrode pads
54. The windows 50 may be cut, such that the connector pads 52 and
electrode pads 54 are not embedded in the planar dielectric
substrate 36, as illustrated in FIG. 8a, but preferably are cut in
a manner, such that the electrode pads 54 are partially embedded in
the planar dielectric substrate 36, as illustrated in FIG. 8b or
8c.
[0126] Next, the laminated LCP sheets are cut into the shapes of
multiple planar dielectric substrates 36, each having a lead
substrate portion 38, a connector substrate portion 44, a cuff
substrate portion 46, and if existing, a branch lead substrate
portion 38' (step 110). For example, the laminated LCP sheets may
be in the shape of the flexible circuit 34 illustrated in FIG. 5,
the flexible circuit illustrated in FIG. 14, the flexible circuit
34b illustrated in FIG. 18, or the flexible circuit illustrated in
FIG. 20. In the case where the lead substrate portion 38 of the
planar dielectric substrate 36 is sigmoid-shaped, as illustrated in
FIG. 21h, the center portions of the dielectric sheets may be
accordingly cut into a sigmoid shape.
[0127] Then, each of the planar dielectric substrates 36 is
thermoformed into an appropriate three-dimensional shape (step
112). For example, the cuff substrate portion 46 of each dielectric
plane substrate 36 may be thermoformed into a generally cylindrical
shape with a desired diameter. In the case where the lead substrate
portion 38 of the planar dielectric substrate 36 is
helically-shaped, as illustrated in FIG. 21b, the lead substrate
portion 38 may be appropriately thermoformed into this helical
shape. For example, the lead substrate portion 38 may be wrapped
around or bonded to a core and then thermoformed. In the case where
the connector substrate portion 46 is affixed to the cylindrical
rod 80, as illustrated in FIG. 23, the connector substrate portion
46 may be thermoformed into a generally cylindrical shape with a
diameter equal to the diameter of the cylindrical rod 80. It should
be appreciated that the thermoformed cuff substrate portion 46,
lead substrate portion 38, and connector substrate portion 46 may
be manipulated into other shapes, but will return to the shapes
into which they were thermoformed in the absence of an external
force.
[0128] Next, a pre-molded thin silicone sacrificial layer is
disposed over the windows 50 (step 114). A colored pigment, such as
a black pigment, can be used to highlight the molded silicone
sacrificial layer. Then, elastic layers 64 are entirely disposed
over top and bottom surfaces of the cuff substrate portion 46s of
the planar dielectric substrates 36, e.g., by laminating or
over-molding (step 116). Alternatively, the elastic layer 64 may be
only disposed on the peripheral region of the cuff substrate
portion, leaving the windows 50 inward from the peripheral region
exposed.
[0129] Soft polymer tubings 70 may then be slid over the lead
substrate portions 38 of the planar dielectric substrates 36 (step
118). A silicone tube of the appropriate dimensions can, for
example, be immersed in heptane, which will cause the silicone tube
72 to swell and increase its diameter, making it possible to slide
the expanding silicone tube 72 onto the lead substrate portion
38.
[0130] At this stage, the flexible circuit 34 (34a, 34b, or 34c) is
complete. Lastly, lead connectors 18 are formed onto the connector
substrate portions 44 of this flexible circuits 34 using suitable
means to complete the lead electrode 10 (step 120). For example, in
the case where the lead connector 18a illustrated in FIG. 23 is to
be formed, the connector substrate portion 44 may be affixed around
the cylindrical rod 80, such that the connector pads 52 face
outwardly away from the cylindrical rod 80 to create the connector
contacts 20. In the case where the lead connector 18b illustrated
in FIG. 27 is to be formed, the connector contacts 82a can be
slipped onto the connector substrate portion 44 via the notches 86,
bonded to the connector contacts 82a to the respective connector
pads 52 on the connector substrate portion 44, and over-molding the
assembly with electrically insulative material to create the
electrical insulator 84. In the case where the lead connector 18c
illustrated in FIG. 31 is to be formed, the connector contacts 82b
can be bonded to the connector substrate portion 44 in electrical
contact with the respective connector pads 52 on the connector
substrate portion 44, and the assembly can then be over-molded with
electrically insulative material to create the electrical insulator
84. In the case where the lead connector 18d illustrated in FIG. 33
is to be formed, the wires 92 extending from the conventional
cylindrical connector portion 88 are wire-bonded to the respective
connector pads 52 of the connector substrate portion 44, and the
connector substrate portion 44 is over-molded with electrically
insulative material to create the electrical insulator 94.
[0131] Lastly, optional anti-inflammatory coatings 66 may be
disposed over or within the elastic layers 64 on the cuff substrate
portions 46 of the planar dielectric substrates 36 (step 122). It
is desirable that the elastic layer 64 and optional
anti-inflammatory coating 66 not cover the windows 50 that expose
the connector pads 52 and electrode pads 54. Thus, the silicone
sacrificial layer in the windows 50, along with the thin overmolded
elastic layer 64 and optional inflammatory costing 66 directly over
the windows 50, may then be removed (step 124). For example, under
a microscope, using a scalpel blade and the pigmented color as a
visual aid, the silicone sacrificial layer may be carefully removed
out of the windows 50. Notably, since the silicone sacrificial
layer is not bonded to the LCP, it can be easily peeled off.
[0132] Although particular embodiments of the present inventions
have been shown and described, it will be understood that it is not
intended to limit the present inventions to the preferred
embodiments, and it will be obvious to those skilled in the art
that various changes and modifications may be made without
departing from the spirit and scope of the present inventions.
Thus, the present inventions are intended to cover alternatives,
modifications, and equivalents, which may be included within the
spirit and scope of the present inventions as defined by the
claims.
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