U.S. patent application number 15/043353 was filed with the patent office on 2016-06-09 for acutely stiff implantable electrodes.
The applicant listed for this patent is Boston Scientific Neuromodulation Corporation. Invention is credited to Michael S. Colvin, Michael A. Moffitt, Michael Onuscheck.
Application Number | 20160158539 15/043353 |
Document ID | / |
Family ID | 55919976 |
Filed Date | 2016-06-09 |
United States Patent
Application |
20160158539 |
Kind Code |
A1 |
Moffitt; Michael A. ; et
al. |
June 9, 2016 |
ACUTELY STIFF IMPLANTABLE ELECTRODES
Abstract
An implantable device for stimulating body tissue that includes
an electrode lead body and at least one stimulating electrode
contact disposed on the electrode lead body. The electrode lead
body may be a percutaneous electrode lead or an electrode paddle
that is configured and arranged to be substantially stiff outside
the patient's body and during insertion into the patient's body and
then becomes non-stiff within the patient's body. The stiffness may
be modified using, for example, resorbable materials, temperature
sensitive materials, or a lumen within the lead body for
introducing a pressurized gas or liquid to modify a stiffness of
the lead body. In one embodiment, the lead body may have different
acute and/or chronic shapes.
Inventors: |
Moffitt; Michael A.;
(Valencia, CA) ; Colvin; Michael S.; (Newburry
Park, CA) ; Onuscheck; Michael; (Stevenson Ranch,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Boston Scientific Neuromodulation Corporation |
Valencia |
CA |
US |
|
|
Family ID: |
55919976 |
Appl. No.: |
15/043353 |
Filed: |
February 12, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11694769 |
Mar 30, 2007 |
|
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15043353 |
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Current U.S.
Class: |
607/116 |
Current CPC
Class: |
A61N 1/05 20130101; A61N
1/0553 20130101; A61N 1/375 20130101; A61N 1/0476 20130101 |
International
Class: |
A61N 1/05 20060101
A61N001/05 |
Claims
1. A device for stimulating tissue inside a patient's body,
comprising: an electrode paddle comprising a resorbable material,
wherein the resorbable material of the electrode paddle is
configured to render the electrode paddle acutely stiff outside the
patient's body and during insertion into the patient's body and
then chronically non-stiff within the patient's body; and a
plurality of stimulating electrode contacts disposed on the
electrode paddle in at least two adjacent columns, each column
comprising a plurality of the stimulation electrode contacts;
wherein the electrode paddle further comprises a paddle body layer
having a front surface and a back surface opposing the front
surface with the plurality of stimulating electrode contacts
disposed on the front surface of the paddle body layer and the
resorbable material disposed in a resorbable layer disposed over
substantially the entire back surface of the paddle body layer,
wherein the front surface of the paddle body and the resorbable
layer are configured and arranged for contact with solid tissue of
the patient's body when the device is implanted inside the
patient's body.
2. The device of claim 1, wherein the resorbable material is
configured and arranged to be absorbed into the patient to modify
the electrode paddle from acutely stiff to chronically non-stiff
over a period of time. The device of claim 1, wherein the
resorbable layer is disposed solely on the back surface of the
paddle body layer.
4. The device of claim 1, wherein the resorbable material comprises
a copolymer.
5. The device of claim 1, wherein the paddle body layer comprises
an internal lumen transitioning from a proximal end towards a
distal end of the paddle body layer along a longitudinal axis of
the electrode paddle
6. The device of claim 5, wherein the internal lumen further
includes at least one external port in communication with the
resorbable layer and configured and arranged to introduce a
solvent, passing through the inner lumen and through the at least
one external port, to assist in degrading the resorbable material
of the resorbable layer.
7. The device of claim 1, wherein the resorbable layer further
comprises at least one of a steroid, anti-inflammatory agent, or an
antibiotic to be introduced over time to the patient's body as the
resorbable material of the resorbable layer is resorbed.
8. The device of claim 1, wherein the resorbable material further
comprises a substance that promotes tissue growth.
9. A device for stimulating tissue inside a patient's body,
comprising: an electrode paddle comprising a temperature sensitive
material, wherein the temperature sensitive material of the
electrode paddle is configured to render the electrode paddle
acutely stiff outside the patient's body and during insertion into
the patient's body and then chronically non-stiff within the
patient's body; and a plurality of stimulating electrode contacts
disposed on the electrode paddle in at least two adjacent columns,
each column comprising a plurality of the stimulation electrode
contacts.
10. The device of claim 9, wherein the electrode paddle further
comprises a paddle body layer having a front surface and a back
surface opposing the front surface with the plurality of
stimulating electrode contacts disposed on the front surface of the
paddle body layer and the temperature sensitive material disposed
in a layer disposed over substantially the entire back surface of
the paddle body layer, wherein the front surface of the paddle body
and the layer of temperature sensitive material are configured and
arranged for contact with solid tissue of the patient's body when
the device is implanted inside the patient's body.
11. The device of claim 9, wherein the temperature sensitive
material is acutely stiff at 25.degree. C. and chronically
non-stiff at 37.degree. C.
12. The device of claim 9, wherein the temperature sensitive
material has a glass transition temperature within a range of
25.degree. C. to 37.degree. C.
13. A method of implanting a device into body tissue, the method
comprising: inserting the electrode paddle of the device of claim 1
into the body tissue; and making the electrode paddle chronically
non-stiff after insertion into the body tissue.
14. The method of claim 13, wherein making the electrode paddle
chronically non-stiff further comprises absorbing the resorbable
material into the patient over a period of time.
15. The device of claim 14, wherein the resorbable layer further
comprises at least one of a steroid, anti-inflammatory agent, or an
antibiotic to be introduced over time to the patient's body as the
resorbable material of the resorbable layer is resorbed.
16. The method of claim 13, wherein making the electrode paddle
chronically non-stiff further comprises introducing a solvent
through an internal lumen in the electrode paddle to modify a rate
of transition from acutely stiff to chronically non-stiff.
17. The method of claim 13, wherein the resorbable material further
comprises a substance that promotes tissue growth.
18. A method of implanting a device into body tissue, the method
comprising: inserting the electrode paddle of the device of claim 8
into the body tissue; and making the electrode paddle chronically
non-stiff after insertion into the body tissue.
19. The method of claim 18, wherein the temperature sensitive
material is acutely stiff at 25.degree. C. and chronically
non-stiff at 37.degree. C.
20. The method of claim 18, wherein the temperature sensitive
material has a glass transition temperature within a range of
25.degree. C. to 37.degree. C.
Description
FIELD
[0001] The invention is generally directed towards electrode
paddles and leads for neural stimulation, and more particularly but
not exclusively to electrode paddles and leads that are acutely
stiff outside of a patient's body and during insertion into the
patient's body and subsequently becomes chronically flexible, or
substantially non-stiff, within the patient's body.
BACKGROUND
[0002] Electrical stimulation of body tissues can be used for
treatment of many different conditions and ailments, including
treating pain. For example, pacemakers and implantable cardiac
defibrillators have proven effective in the treatment of cardiac
conditions. Spinal cord stimulation systems have been used as a
therapeutic modality for the treatment of chronic pain syndromes.
Deep brain stimulation has also been useful for treating refractory
chronic pain syndromes and has been applied to treat movement
disorders and epilepsy. Peripheral nerve stimulation has been used
to treat chronic pain syndrome and incontinence, with a number of
other applications under investigation.
[0003] In many instances, an electrode lead or a paddle with one or
more stimulating electrode contacts may be inserted into the body
to position the electrode contacts near the tissue to be
stimulated. In many instances, a stylet, such as a metallic wire,
is inserted into a lumen running through the center of the lead
from the proximal end to the distal end to aid in insertion of the
lead into the body. The stylet is intended to provide lead
stiffness during positioning and anchoring of the lead in the body.
Once the lead is positioned, the stylet can be removed and the lead
then becomes flaccid.
[0004] However, use of a stylet can have several limitations. For
example, the stylet may perforate the lead assembly and may thereby
damage the lead and/or body tissue. Further, a stylet may apply
stiffness to a limited volume of the paddle or lead. Therefore, it
is with respect to these considerations and others that the present
invention has been made.
BRIEF SUMMARY
[0005] One embodiment is a device for stimulating tissue inside of
a patient's body and includes an electrode paddle that is
configured to be acutely stiff outside the patient's body and
during insertion into the patient's body and then becomes
chronically non-stiff within the patient's body. At least one
stimulating electrode contact is disposed on the electrode
paddle.
[0006] Another embodiment is a method for stimulating tissue inside
of a patient's body. The method includes inserting an electrode
lead into the patient's body. The electrode lead includes at least
one stimulation electrode contact useable to stimulate a portion of
the patient's body. The electrode lead further includes an internal
lumen transitioning from a proximal end towards a distal end of the
electrode lead. The method also includes making the electrode lead
selectively pressurized to modify a stiffness of the electrode
lead.
[0007] Yet another embodiment is a method for implanting a device
into body tissue. The method includes inserting an electrode paddle
into the body tissue. The electrode paddle includes at least one
stimulation electrode contact for use in stimulating the body
tissue. The electrode paddle is configured to maintain an acute
substantially stiff configuration prior to and during insertion.
After insertion into the body tissue, the method includes making
the electrode paddle chronically non-stiff.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Non-limiting and non-exhaustive embodiments of the present
invention are described with reference to the following drawings.
In the drawings, like reference numerals refer to like parts
throughout the various figures unless otherwise specified.
[0009] For a better understanding of the present invention,
reference will be made to the following Detailed Description, which
is to be read in association with the accompanying drawings,
wherein:
[0010] FIGS. 1A-1B show one embodiment of a top view of a paddle
(1A) and a cross-sectional frontal view of the paddle (1B) having a
resorbable material;
[0011] FIGS. 2A-2B show one embodiment of another top view of a
paddle (2A) and a cross-sectional frontal view of the paddle (2B)
having an internal lumen useable for providing temporal stiffness
of the paddle using pressurization;
[0012] FIGS. 3A-3B show another embodiment of a view of a paddle
top (3A) and a cross-sectional frontal view of the paddle (3B)
having an internal lumen useable for providing temporal stiffness
of the paddle using pressurization;
[0013] FIGS. 4A-4B show one embodiment illustrating another view of
a paddle top (4A) and a cross-sectional frontal view of the paddle
(4B) having an internal lumen with branches;
[0014] FIG. 4C shows another embodiment illustrating a view of a
paddle top having an internal lumen with branches;
[0015] FIGS. 5A-5B show one embodiment a view of a paddle top (5A)
and a cross-sectional frontal view of the paddle (5B) having an
internal lumen with external ports;
[0016] FIGS. 6A-6B show one embodiment of another paddle in an
acute configuration (6A) and a chronic configuration (6B);
[0017] FIGS. 7A-7B show one embodiment of an electrode lead having
a lumen that can he pressurized to modify a stiffness of the
electrode lead; and
[0018] FIG. 8 shows one embodiment of an electrode paddle with a
stimulation unit, in accordance with the invention.
DETAILED DESCRIPTION
[0019] The invention now will be described more fully hereinafter
with reference to the accompanying drawings, which form a part
hereof, and which show, by way of illustration, specific exemplary
embodiments by which the invention may be practiced. This invention
may, however, be embodied in many different forms and should not be
construed as limited to the embodiments set forth herein; rather,
these embodiments are provided so that this disclosure will be
thorough and complete, and will fully convey the scope of the
invention to those skilled in the art. Among other things, the
invention may be embodied as methods or devices. The following
detailed description is, therefore, not to be taken in a limiting
sense.
[0020] Throughout the specification and claims, the following terms
take the meanings explicitly associated herein, unless the context
clearly dictates otherwise. The phrase "in one embodiment" as used
herein does not necessarily refer to the same embodiment, though it
may. Furthermore, the phrase "in another embodiment" as used herein
does not necessarily refer to a different embodiment, although it
may. Thus, as described below, various embodiments of the invention
may be readily combined, without departing from the scope or spirit
of the invention.
[0021] In addition, as used herein, the term "or" is an inclusive
"or" operator, and is equivalent to the term "and/or," unless the
context clearly dictates otherwise. The term "based on" is not
exclusive and allows for being based on additional factors not
described, unless the context clearly dictates otherwise. In
addition, throughout the specification, the meaning of "a," "an,"
and "the" include plural references. The meaning of "in" includes
"in" and "on."
[0022] Briefly stated the invention is directed towards an
implantable device for stimulating body tissue and includes an
electrode lead body and at least one stimulating electrode contact
disposed on the electrode lead body. The electrode lead body may be
an electrode lead, in one embodiment. In another embodiment, the
electrode lead body may be an electrode paddle. In any event, the
electrode lead body is configured and arranged to be substantially
stiff outside the patient's body and during insertion into the
patient's body and then becomes chronically non-stiff within the
patient's body. The stiffness may be modified using, for example,
resorbable materials, temperature sensitive materials, or a lumen
within the lead body for introducing a pressurized gas or liquid to
modify the temporal stiffness of the electrode lead body. In one
embodiment, the electrode lead body may have different acute and/or
chronic shapes.
[0023] FIG. 8 illustrates one embodiment of a stimulation system
800 that may be configured to provide electrical stimulation to
selected nerves or other body tissue throughout a patient's body.
As shown, stimulation system 800 includes an implantable electrode
paddle 802, and a lead connector 808 for use in connection of the
electrode contacts 120 to a control unit 804.
[0024] Examples of implantable electrode paddles are provided in
U.S. patent application Ser. Nos. 11/376,360; 11/319,291; and
11/396,309, each of which is incorporated herein by reference.
However, the invention is not constrained to electrode paddles. For
example, electrode cuff or electrode lead arrangements may also be
employed. Examples of implantable electrode cuffs are provided in
U.S. patent applications Ser. Nos. 11/393,991, and 11/294,283, each
of which is incorporated herein by reference.
[0025] The electrode contacts 120 may be arranged in any of a
variety of configurations, other than that which is illustrated in
FIG. 8. The electrode contacts 120 may be made of any of a variety
of suitable body-compatible metal, alloy, conductive oxide, or
other conductive material. Examples of suitable materials include
platinum, iridium, platinum iridium alloy, stainless steel,
titanium, or tungsten. Any type of electrode contact 120 can be
used including monopolar electrodes, bipolar electrodes, and other
multipolar electrodes. A variety of shapes can be used for the
electrode contacts 120 including, for example, rings around the
lead or electrodes in the form of circles, ovals, squares,
rectangles, triangles, or the like, disposed on or within an
electrode paddle layer 110, as shown in FIG. 1B.
[0026] In some embodiments, two or more different types of
electrode contacts 120 can be provided including, for example,
recording electrode contacts and stimulation electrode contacts.
Examples of deep brain stimulation leads that include electrode
contacts are provided in U.S. patent applications Ser. Nos.
11/030,546; 11/230,052; 11/120,526; 11/237,159; and 11/241,156,
each of which is incorporated herein by reference. Recording
electrode contacts can be used, for example, to monitor insertion
of the paddle or lead and determine where the tissue to be
stimulated is located, Subsequently, the stimulation electrode
contacts 120 can be used to stimulate the tissue. In some
embodiments, the stimulation electrode contacts can also function
as recording electrode contacts.
[0027] Examples of suitable control units 804 and lead connectors
808 include those described in U.S. Pat. Nos. 6,516,227, 6,609,029,
and 6,741,892, each of which are incorporated herein by reference,
as well as the Precision.TM. Spinal Cord Stimulation System
available from Advanced Bionics Corporation, Sylmar, Calif., and/or
other commercially available stimulator units.
[0028] FIG. 1A illustrates one embodiment of a top view of an
implantable electrode paddle 102, having resorbable material 106.
Electrode contacts 120 (shown in FIG. 1B's cross-sectional view,
are not illustrated in FIG. 1A, for clarity). The resorbable
material 106 provides stiffness during the implantation of
electrode paddle 102 into a patient's body. After implantation, the
resorbable material 106 may be absorbed into the body to provide a
chronically non-stiff or flexible electrode paddle 102.
[0029] FIG. 1B illustrates a cross-sectional frontal view of the
implantable electrode paddle 102, showing electrode contacts 102,
electrode paddle layer 110 with resorbable material 106. In one
embodiment, resorbable material 106 may be configured as a coating
layered upon electrode paddle 102. However, the invention is not so
limited, and resorbable material 106 may be integrated within at
least a portion of electrode paddle layer 110.
[0030] Electrode paddle layer 110 may be constructed from any of a
variety of suitable body compatible non-conductive substrate
flexible or non-stiff material, including but not limited to,
silicone, polyurethane. Silastic.TM., or the like, wherein one or
more electrode contacts 120 may be placed on or within at least one
major surface.
[0031] Also shown in FIG. 1A is one embodiment of a layer of
resorbable material 106 on electrode paddle 102. Such resorbable
material 106 arrangement allows the implantable electrode paddle
102 to maintain a stiff configuration when it is outside of a
patient's body and during insertion into the body. However, the
electrode paddle 102 may then become chronically non-stiff or
flexible upon extended exposure inside of the patient's body. The
transition from the acute substantially stiff state to the chronic
flexible or non-stiff state may be achieved by absorption of the
resorbable material 106 by the body of the patient over time. The
transition time from a stiff state to a non-stiff or flexible state
should be sufficient to allow a physician to implant and position
the electrode paddle 102.
[0032] Moreover, a degree of stiffness may be based on a variety of
factors, For example, the acute substantially stiff state may be
determined based on being sufficiently stiff to enable a physician
to implant the electrode lead body within a patient, while being
adequately flexible to accommodate its shape to the patient's
anatomy, so as to minimize harm to the patient due to being
excessively rigid.
[0033] The resorbtion time for the resorbable material 106 can be
based on one or more factors, such as, for example, the implantable
device, a site of implantation, an expected lifetime of the
implantable device, an expected duration of implantation, an age of
the patient, expected growth rate of tissue around the implanted
device, or a variety of other factors. It will be recognized that
there may be a substantial variation from an average resorbtion
time in actual devices. Thus, actual resorbtion times may depend on
the conditions within the patient's body.
[0034] Examples of suitable resorbable materials include, but are
not limited to, a copolymer, including polylactide (PLA),
polyglycolide (PGA), poly(lactide-co-glycolide) (PLGA),
poly(e-caprolactone), polydioxanone, polyanhydride, trimethylene
carbonate, poly(.beta.-hydroxybutyrate), poly(g-ethyl glutamate),
poly(DTH iminocarbonate), poly(bisphenol A iminocarbonate),
poly(ortho ester)s (POEs), polycyanoacrylate, polyphosphazene,
modified polysaccharides (for example, cellulose, chitin, dextran),
and modified proteins (for example, fibrin, casein). Moreover, the
resorbable material 106 may include a combination of one or more of
possible substances.
[0035] In some embodiments, the resorbable material 106 may also
have a drug, medication, tissue growth enhancer, or other agent
disposed within and/or on the resorbable material for time release.
For example, the resorbable material 106 may be combined with a
drug or other medication to treat the tissue at the implantation
site or to reduce pain or inflammation. As another example, the
resorbable material 106 may be combined with a substance that
promotes tissue growth and encapsulation of at least a portion of
the implantable device. Generally, the drug, medication, or other
agent is released over time as the resorbable material 106 is
resorbed by the patient's body.
[0036] In another embodiment, the resorbable material 106 may be
replaced with a temperature sensitive material that is acutely
stiff at a nominal room temperature and transitions to a
chronically non-stiff or flexible material at a nominal body
temperature so that the material is substantially flaccid at body
temperature. In one embodiment, the temperature sensitive material
transitions to chronically non-stiff or flexible in a temperature
range that begins at or above room temperature, but below body
temperature, and ends below, at, or above body temperature. For
example, in one embodiment, the temperature sensitive material may
be acutely stiff at a temperature of about 25.degree. C., non-stiff
at about 37.degree. C., and may be configured to transition from
acutely stiff to chronically non-stiff over a temperature range
lying between these two temperatures.
[0037] In another embodiment, the temperature sensitive material
may also be integrated into the lead material.
[0038] In one embodiment, the temperature sensitive material may be
made of a plastic material that has a glass transition temperature
(T.sub.g) that is near or less than a nominal body temperature.
Preferably, the glass transition temperature is greater than room
temperature, but in some embodiments the glass transition
temperature can be less than or equal to room temperature. In one
embodiment, the glass transition temperature of the temperature
sensitive material is in a range of between about 25.degree. C. to
about 38.degree. C. In one embodiment, the implantable electrode
paddle 102 may be stored in or temporarily submitted to a
sufficiently cold environment prior to insertion.
[0039] The temperature sensitive material may include a polymer
which can be a homopolymer, a copolymer formed using two or more
different monomeric units, or a mixture of polymers. The
temperature sensitive material can also include additives such as
filler, colorants, anti-oxidants, and the like. In particular,
plasticizer additive(s) can be particularly useful to modify the
glass transition temperature of the base polymer or mixture of
polymers.
[0040] The selection of a suitable glass transition temperature and
temperature sensitive material can be based on one of more factors
including, but not limited to, biocompatibility, cost, ease of
manufacture, stability, glass transition temperature of the
temperature sensitive material, heat capacity of the temperature
sensitive material, thermal mass of the electrode lead body (paddle
or lead), type of tissue to be stimulated, the depth of the tissue
to be stimulated, thickness of the electrode lead body, flexibility
of the electrode lead body material, and the like. The electrode
lead body should remain sufficiently stiff during insertion of the
electrode lead body into the body to allow the electrode lead body
to be positioned without becoming too flexible or non-stiff. The
rapidity with which the electrode lead body increases temperature
will be determined, at least in part, by the heat capacity and
thermal mass of the electrode lead body. Thus, an electrode lead
body with a relatively low glass transition temperature, low heat
capacity, and small thermal mass will typically become non-stiff
prior to a lead with higher glass transition temperature, higher
heat capacity, and larger thermal mass.
[0041] In one embodiment, the temperature sensitive material may be
configured as a layer of material over the electrode paddle layer
110. However, the invention is not so limited. For example, in one
embodiment, electrode paddle layer 110 may be configured from the
temperature sensitive material such that the electrode paddle layer
110 becomes acutely stiff at temperatures below the nominal body
temperature, and upon returning to the nominal body temperature,
becomes chronically non-stiff or flexible.
[0042] Although an implantable electrode paddle configuration is
illustrated in FIGS. 1A-1B, the invention is not so limited. Thus,
for example, resorbable layer 106, and/or temperature sensitive
materials may also be employed with other electrode lead body
configurations. For example, in one embodiment, a percutaneous lead
may also be configured to employ one or more of mechanisms to
modify its stiffness, without departing from the scope of the
invention.
[0043] Modifying the stiffness of an electrode lead body (e.g., an
electrode paddle, or percutaneous lead) may also be achieved
employing an internal lumen that is configured for receiving a
liquid, gas, or similar substance, Thus, FIGS. 2A-2B show one
embodiment of another top view of an electrode paddle (FIG. 2A) and
a cross-sectional frontal view of the electrode paddle (FIG.
2B).
[0044] As shown in FIGS. 2A-2B, electrode paddle 202 includes an
internal lumen 204 useable for providing temporal stiffness of the
paddle using pressurization. Internal lumen 204 may be configured
to receive a liquid and/or a gas. The presence of the liquid and/or
gas modifies an internal pressure within the lumen and thereby
results in modifying a stiffness of electrode paddle 202. In one
embodiment, the addition of the liquid and/or gas into internal
lumen 204 modifies the electrode paddle 202 from a non-stiff or
flexible arrangement to a stiff arrangement. Upon implantation of
electrode paddle 202 into a patient's body, at least a portion of
the liquid and/or gas may be removed, thereby reducing the pressure
and thus producing the chronic non-stiff or flexible
arrangement.
[0045] In one embodiment, internal lumen 204 is configured as a
single lumen within electrode paddle 202 transitioning linearly
from a proximal end to a distal end of the electrode paddle 202
along a longitudinal axis of electrode paddle 202. In one
embodiment, the internal lumen 204 may be cylindrical in shape.
However, the invention is not so limited, and other shapes may be
employed. Thus, for example, shown in FIGS. 3A-3B are views of one
embodiment of an electrode paddle 302 having an internal lumen 304
with an oblong cross-section. Thus, internal lumens may have an
oval shape, oblong shape, or any of a variety of other shapes.
Moreover, in one embodiment internal lumen 304 may have a first
portion having a first shape, and at least one other portion having
at least a second shape.
[0046] In another embodiment, the internal lumen may include
branches. For example, FIGS. 4A-4B show another embodiment of views
of an electrode paddle 402 having an internal lumen with branches.
As shown, the internal lumen includes a first portion 404 that
transitions within electrode paddle 402 longitudinally from a
proximal end to a distal end of the electrode paddle 402. At the
distal end of the internal lumen, the internal lumen divides into
branches 406, where the branches 406, are arranged to circle back
internally within electrode paddle 402. In one embodiment, branches
406 may transition longitudinally back towards the proximal end of
the electrode paddle 402. in one embodiment, branches 406 may
extend longitudinally within the electrode paddle 402, along
opposing sides within the electrode paddle 402. In one embodiment,
the branches 406 may traverse an entire length of the electrode
paddle 402. In another embodiment, the branches 406 may traverse
less than the entire length of the electrode paddle 402.
[0047] However, internal lumens with branches may also be
configured with branches that branch closer to a proximal end of
the electrode paddle 402. Thus, another embodiment of an internal
lumen with branches is illustrated in FIG. 4C. As shown, branches
406C may divide outward from the first portion 404 near the
proximal end of electrode paddle 402, and extend towards the distal
end of the electrode paddle 402, along opposing sides within the
electrode paddle 402. Employing the opposing branches, such as
those illustrated in FIG. 4A-4C, provides stiffness to the central
portion of the electrode paddle 402, as well as along the
peripheral portions of the electrode paddle 402.
[0048] In another embodiment, FIGS. 5A-5B show views of an
electrode paddle 502 having an internal lumen 504 with external
ports 506. In one embodiment, internal lumen 504 may be employed in
conjunction with a resorbable material 106, such as described above
in conjunction FIGS. 1A-1B. In one embodiment, the external ports
506 are holes that enable a solvent or other substance to be
injected from internal lumen 504 into the resorbable material. In
one embodiment, the solvent may be used to assist in degrading the
resorbable material. Such solvents may be employed to modify the
resorbtion rate of the resorbable material. This may be desirable,
for example, where the electrode paddle (or electrode lead) is
implanted in a body area surrounded by fat in an epidural space, or
the like, that may negatively impact the resorbtion rate. In one
embodiment, the solvent may include, for example, a saline
solution, or other biocompatible solution. In one embodiment, the
internal lumen 504 may also contain a resorbable material that may
be resorbed through external ports 506 to the tissue side. In
another embodiment, internal lumen 504 may be used to inject a
material to change the temperature of electrode paddle 502. For
example, in one embodiment, a warm saline solution may be injected
through internal lumen 504 after placement of electrode paddle 502
to initiate transition to an acutely non-stiff state. In another
embodiment, external ports 506 may also be employed to introduce a
medication to the body area.
[0049] It may be desirable to have the implantable electrode paddle
or lead maintain one shape acutely to facilitate implantation, and
a different shape chronically to facilitate stimulation of tissue.
For example, in one embodiment, an acute shape may be selected that
fits a patient's anatomy, a nerve structure, or the like. In one
embodiment, the chronic shape may be selected for placement of the
stimulating electrode contacts within a desired range of a target
tissue. Thus, as shown in FIGS. 6A-6B are one embodiment of another
electrode paddle 602 in an acute configuration 600A (see FIG. 6A)
and a chronic configuration 600B (see FIG. 6B). The acute
configuration of electrode paddle 602 may, in one embodiment, be
obtained by the use of shaped resorbable material 604. As the
shaped resorbable material 604 is resorbed, electrode paddle 602
may take on the chronic configuration. Moreover, in one embodiment,
electrode paddle 602 may employ a temperature sensitive material,
such as described above, in addition to, or in place of the
resorbable material 604.
[0050] As discussed above, embodiments of the invention are not
limited to electrode paddles. Thus, FIGS. 7A-7B show one embodiment
of an electrode lead 702 having an internal lumen 704 that can be
pressurized to modify a stiffness of the electrode lead 702.
Internal lumen 704 may be configured to transition longitudinally
from a distal end to a proximal end within electrode lead 702.
[0051] A liquid and/or gas may be employed within internal lumen
704 to pressurize internal lumen 704, and thereby maintain an acute
substantially stiff configuration outside of and during insertion
into the patient's body. Release of the pressure within internal
lumen 704 is directed towards making the electrode lead 702
chronically non-stiff or flexible within the patient's body.
[0052] Thus, in one example of a method of using the selectively
stiff electrode body, access to the desired position in the body
can be accomplished by opening a hole through the patient's skin.
The point of entry, as well as whether a hole may be made in other
tissues prior to inserting the selectively stiff electrode body,
will depend on the application. The selectively stiff electrode
body, which is acutely stiff, can be inserted into the tissue. The
selectively stiff electrode body can be guided to the target
location within the body while it maintains sufficient stiffness.
The optional recording electrode(s) can be observed using an
external control unit to identify the target tissue, if desired.
Once in place, the selectively stiff electrode body can be
positioned and, if desired, anchored using any of a variety of
mechanisms, The selectively stiff electrode body then becomes
chronically non-stiff or flexible based on the mechanism employed,
as described above.
[0053] The above specification, examples, and data provide a
description of the manufacture and use of the composition of the
invention, Since many embodiments of the invention can be made
without departing from the spirit and scope of the invention, the
invention also resides in the claims hereinafter appended.
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