U.S. patent application number 15/092454 was filed with the patent office on 2016-07-28 for self-expanding neurostimulation leads having broad multi-electrode arrays.
The applicant listed for this patent is Advanced Neuromodulation Systems, Inc.. Invention is credited to Alan De La Rama.
Application Number | 20160213916 15/092454 |
Document ID | / |
Family ID | 50071746 |
Filed Date | 2016-07-28 |
United States Patent
Application |
20160213916 |
Kind Code |
A1 |
De La Rama; Alan |
July 28, 2016 |
SELF-EXPANDING NEUROSTIMULATION LEADS HAVING BROAD MULTI-ELECTRODE
ARRAYS
Abstract
Self-expanding lead including a lead body having a distal body
end, a proximal body end, and a central axis extending
therebetween. The lead body includes first and second outer arms
and an inner arm disposed between the first and second outer arms.
The first and second outer arms and the inner arm extend lengthwise
between the proximal body end and the distal body end. The lead
also includes an array of electrodes that are configured to apply a
neurostimulation therapy within an epidural space of a patient. At
least some of the electrodes are positioned along the first and
second outer arms. Each of the first and second outer arms includes
a resilient member that is biased to flex the corresponding first
and second outer arms from a collapsed condition to an expanded
condition in a lateral direction away from the inner arm.
Inventors: |
De La Rama; Alan; (Cerritos,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Advanced Neuromodulation Systems, Inc. |
Plano |
TX |
US |
|
|
Family ID: |
50071746 |
Appl. No.: |
15/092454 |
Filed: |
April 6, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14048352 |
Oct 8, 2013 |
|
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15092454 |
|
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61753429 |
Jan 16, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2034/2051 20160201;
A61B 5/0422 20130101; A61N 1/0551 20130101; A61B 2018/00577
20130101; A61B 5/6869 20130101; A61N 1/0476 20130101; A61B 5/6859
20130101; A61B 5/0408 20130101; A61B 2018/00351 20130101; A61N
1/0553 20130101; A61B 2018/00839 20130101; A61B 2217/007 20130101;
A61B 5/6852 20130101; A61B 18/1492 20130101; A61B 2090/3966
20160201; A61N 1/36071 20130101; A61B 2218/002 20130101 |
International
Class: |
A61N 1/05 20060101
A61N001/05 |
Claims
1. A self-expanding lead comprising: a lead body having a distal
body end, a proximal body end, and a central axis extending
therebetween, the lead body comprising first and second outer arms
and first and second inner arms, with first and second inner arms
being disposed generally between the first and second outer arms,
the first and second outer arms and first and second inner arms
extending lengthwise between the proximal body end and the distal
body end; a first arcuate joint connecting the distal ends of the
first and second outer arms and a second arcuate joint connecting
the distal ends of the first and second inner arms; an array of
electrodes configured to apply a neurostimulation therapy within an
epidural space of a patient, at least some of the electrodes being
positioned along the first and second outer arms and the first and
second inner arms; a resilient member disposed within each of the
first arcuate joint and second arcuate joint, the resilient members
being biased to flex the corresponding first and second outer arms
and first and second inner arms from a collapsed condition to an
expanded condition in a lateral direction away from the central
axis, the resilient members permitting the corresponding first and
second outer arms and the corresponding first and second inner arms
to flex toward the central axis from the expanded condition to the
collapsed condition when a force is applied; wherein the first and
second outer arms and the first and second inner arms are all
substantially coplanar when in the expanded condition.
2. The self-expanding lead of claim 1, and further including a
center arm along the central axis, the center includes a steering
lumen at the distal body end, the steering lumen sized and shaped
to receive an elongated tool for directing the lead body during an
insertion process.
3. The self-expanding lead of claim 2, wherein the steering lumen
extends through the proximal body end to the distal body end.
4. The self-expanding lead of claim 1, wherein the first and second
outer arms partially define first and second elongated windows,
respectively, the first and second elongated windows extending
between the proximal body end and distal body end and between the
respective outer arm and the inner arm.
5. The self-expanding lead of claim 6, further comprising a
flexible membrane that is coupled to the lead body and covers at
least one of the first and second elongated windows.
6. The self-expanding lead of claim 4, wherein the lead body has
opposite paddle sides when the first and second arms are in the
expanded conditions, the self-expanding lead further comprising a
flexible membrane that is coupled to the lead body and covers at
least one of the paddle sides.
7. The self-expanding lead of claim 1, wherein each of the first
and second arms has an arm cross-section that includes first and
second dimensions, the first and second dimensions being
perpendicular with respect to each other and differing by at most
50%.
8. A self-expanding lead comprising: first and second outer arms
and first and second inner arms, extending between respective base
and distal arm ends; a center arm disposed generally between the
first and second inner arms, the center arm extending between a
respective base end and a respective distal arm end, the base ends
of the first and second inner arms and the center arm and second
outer arms being coupled to each other proximate to a proximal body
end of the self-expanding lead; and a multi-electrode array
including a plurality of electrodes, the first and second arms
including at least one electrode of the multi-electrode array and
the first and second inner arms including at least one electrode; a
first arcuate joint connecting the distal ends of the first and
second outer arms; a second arcuate joint connecting the distal
ends of the first and second inner arms; a first resilient member
disposed within the first arcuate joint and a second resilient
member being disposed in the second arcuate joint, the resilient
members being biased to flex the corresponding first and second
outer arms and first and second inner arms from a collapsed
condition to an expanded condition in a lateral direction away from
the central axis, the resilient members permitting the
corresponding first and second outer arms and the corresponding
first and second inner arms to flex toward the central axis from
the expanded condition to the collapsed condition when a force is
applied; and the center arm being connected to each of the first
arcuate joint and the second arcuate joint; wherein the first and
second outer arms and the first and second inner arms are all
substantially coplanar when in the expanded condition.
9. The self-expanding lead of claim 8, wherein the center arm
includes a steering lumen, the steering lumen sized and shaped to
receive an elongated tool for directing the lead body during an
insertion process.
10. The self-expanding lead of claim 9, wherein the first outer arm
and the first inner arm are adjacent to each other and the second
outer arm and the second inner arm are adjacent to each other, the
first outer arm and first inner arm moving in a common direction
toward the second outer arm and the second inner arm when the lead
is collapsed.
11. The self-expanding lead of claim 8, wherein the self-expandable
lead has opposite paddle sides when the first and second arms are
in the expanded conditions, the self-expandable lead further
comprising a flexible membrane that is coupled to the lead body and
covers at least one of the paddle sides.
12. The self-expandable lead of claim 11, wherein the flexible
membrane extends along only one of the paddle sides.
13. The self-expanding lead of claim 11, wherein the flexible
membrane has electrode openings that expose portions of the
electrodes along the at least one paddle side.
14. The self-expanding lead of claim 8, wherein each of the first
and second arms has an arm cross-section that includes first and
second dimensions, the first and second dimensions being
perpendicular with respect to each other and differing by at most
50%.
Description
RELATED APPLICATION
[0001] The present application is a continuation of U.S. patent
application Ser. No. 14/048,352, filed Oct. 8, 2013, which claims
the benefit of U.S. Provisional Application No. 61/753,429, filed
on Jan. 16, 2013, which is incorporated by reference in its
entirety.
FIELD OF THE INVENTION
[0002] One or more embodiments of the subject matter described
herein generally relate to systems having leads for generating
electric fields proximate to nerve tissue.
BACKGROUND
[0003] Neurostimulation systems (NS) include devices that generate
electrical pulses and deliver the pulses to nerve tissue to treat a
variety of disorders. Spinal cord stimulation (SCS) is a common
type of neurostimulation. In SCS, electrical pulses are delivered
to nerve tissue in the spine typically for the purpose of chronic
pain control. While a precise understanding of the interaction
between the applied electrical energy and the nerve tissue is not
fully appreciated, it is known that application of an electric
field to spinal nerve tissue can effectively mask or alleviate
certain types of pain transmitted from regions of the body
associated with the stimulated nerve tissue. SCS may have
applications other than pain alleviation as well.
[0004] NS and SCS systems generally include a pulse generator and
one or more leads electrically coupled to the pulse generator. A
lead includes an elongated body of insulative material. A
stimulating end portion of the lead includes multiple electrodes
that are electrically coupled to the pulse generator through wire
conductors. The stimulating end portion of a lead is implanted
proximate to nerve tissue (e.g., within epidural space of a spinal
cord) to deliver the electrical pulses. A trailing end portion of
the lead body includes multiple terminal contacts, which are also
electrically coupled to the wire conductors. The terminal contacts,
in turn, are electrically coupled to the pulse generator. The
terminal contacts receive electrical pulses from the pulse
generator that are then delivered to the electrodes through the
wire conductors to generate the electric fields. The pulse
generator is typically implanted within the individual and may be
programmed (and re-programmed) to provide the electrical pulses in
accordance with a designated sequence.
[0005] Typically, one of two types of leads is used. The first type
is a percutaneous lead, which has a rod-like shape and includes
electrodes spaced apart from each other along a single axis. The
second type of lead is a laminectomy or laminotomy lead
(hereinafter referred to as a paddle lead). A paddle lead has an
elongated planar body with a thin rectangular shape (i.e.,
paddle-like shape). Although the paddle lead may include only one
row or column of electrodes, the paddle lead typically includes an
array of electrodes that are spaced apart from each other along a
substantially common plane. The number of electrodes may be, for
example, two, four, eight, or sixteen.
[0006] A single paddle lead enables more coverage of the nerve
tissue relative to a single percutaneous lead. However, due to
their dimensions and physical characteristics, paddle leads require
a surgical procedure (e.g. a partial laminectomy) to implant the
lead. The paddle lead is typically positioned within the epidural
space adjacent to the dura of the spinal cord. Conventional
percutaneous leads are inserted into the body through a narrow
introducer. Compared to paddle leads, the percutaneous leads have
dimensions that may enable an easier insertion into the spinal cord
and/or may cause less trauma to the insertion site of the spinal
cord.
[0007] Therefore, a need remains for implantable leads that may be
inserted into the spinal cord with a simpler insertion procedure
than conventional paddle leads and also have electrode coverage of
the nerve tissue that is broader than conventional percutaneous
leads.
BRIEF SUMMARY
[0008] In accordance with an embodiment, a self-expanding lead is
provided that includes a lead body having a distal body end, a
proximal body end, and a central axis extending therebetween. The
lead body includes first and second outer arms and an inner arm
disposed between the first and second outer arms. The first and
second outer arms and the inner arm extend lengthwise between the
proximal body end and the distal body end. The lead also includes
an array of electrodes that are configured to apply a
neurostimulation therapy within an epidural space of a patient. At
least some of the electrodes are positioned along the first and
second outer arms. Each of the first and second outer arms includes
a resilient member that is biased to flex the respective outer arm
from a collapsed condition to an expanded condition in a direction
that is away from the inner arm. The resilient member permits the
respective outer arm to flex toward the inner arm from the expanded
condition to the collapsed condition when a force is applied.
[0009] In accordance with another embodiment, a self-expanding lead
is provided that includes first and second outer arms extending
between respective proximal and distal arm ends. Each of the first
and second outer arms includes electrodes that are positioned along
a length of the respective outer arm. The lead also includes an
inner arm that is disposed between the first and second outer arms.
The inner arm extends between a respective base end and a
respective distal arm end. The proximal ends of the inner arm and
the first and second outer arms are coupled to each other proximate
to a proximal body end of the self-expanding lead. The lead also
includes a multi-electrode array having the electrodes of the first
and second arms. The multi-electrode array is configured to apply a
neurostimulation therapy within an epidural space of a patient.
Each of the first and second outer arms includes a resilient member
that is biased to flex the respective outer arm from a collapsed
condition to an expanded condition in a direction that is away from
the inner arm. The resilient member permits the respective outer
arm to flex toward the inner arm from the expanded condition to the
collapsed condition when a force is applied.
[0010] While multiple embodiments are described, still other
embodiments of the described subject matter will become apparent to
those skilled in the art from the following detailed description
and drawings, which show and describe illustrative embodiments of
disclosed inventive subject matter. As will be realized, the
inventive subject matter is capable of modifications in various
aspects, all without departing from the spirit and scope of the
described subject matter. Accordingly, the drawings and detailed
description are to be regarded as illustrative in nature and not
restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic view of one embodiment of a
neurostimulating (NS) system in accordance with one embodiment.
[0012] FIG. 2A illustrates a plan view of a self-expanding lead
that is in an expanded or relaxed state in accordance with one
embodiment.
[0013] FIG. 2B is an enlarged view of a distal portion of the
self-expanding lead shown in FIG. 2A.
[0014] FIG. 2C is an enlarged view of a proximal portion of the
self-expanding lead shown in FIG. 2A.
[0015] FIG. 3 is a cross-section of the self-expanding lead taken
along the line 3-3 in FIG. 2A while in the expanded state.
[0016] FIG. 4 is a cross-section of the self-expanding lead taken
along the line 4-4 in FIG. 2A while in the expanded state.
[0017] FIG. 5 is a cross-section of the self-expanding lead taken
along the line 5-5 in FIG. 2A while in the expanded state.
[0018] FIG. 6 is a cross-section of the self-expanding lead in a
collapsed state while within an insertion tool in accordance with
one embodiment.
[0019] FIG. 7 is a cross-section of a self-expanding lead in
accordance with one embodiment while the lead is in a collapsed
state within an insertion tool.
[0020] FIG. 8 illustrates a series of stages during an insertion
process in which a self-expanding lead clears an insertion
tool.
[0021] FIG. 9 illustrates a guide wire device that may be used to
direct a self-expanding lead into an anatomical space of a patient
in accordance with one embodiment.
[0022] FIG. 10 is a perspective view of a self-expanding lead in
accordance with one embodiment that utilizes a flexible
membrane.
[0023] FIG. 11 is a cross-section of a self-expanding lead having a
flexible membrane in accordance with one embodiment.
[0024] FIG. 12 is a cross-section of a self-expanding lead having a
flexible membrane in accordance with one embodiment.
[0025] FIG. 13 illustrates a plan view of a self-expanding lead
that is in an expanded state in accordance with one embodiment.
[0026] FIG. 14 illustrates a plan view of a self-expanding lead
that is in an expanded state in accordance with one embodiment.
[0027] FIG. 15 is a block diagram illustrating a method of
manufacturing a self-expandable lead in accordance with one
embodiment.
DETAILED DESCRIPTION
[0028] Embodiments described herein include self-expanding leads
that are capable of flexing into an operative shape or
configuration as the self-expanding lead is inserted into the
epidural space. For example, the self-expanding lead may include
one or more resilient members that are biased to expand the
self-expanding lead when the self-expanding lead is permitted to
expand (e.g., when a force is removed). The self-expanding lead may
include a plurality of arms, at least one of which may be capable
of flexing into an expanded condition. The individual arms may
reduce the amount of pressure along the spinal nerves within the
epidural space relative to conventional paddle leads.
[0029] The individual arms of the lead may include one or more
electrodes. Collectively, the electrodes of the individual arms may
form a multi-electrode array (e.g., two-dimensional array) that
provides electrode coverage comparable to conventional paddle
leads. For instance, the multi-electrode array may be configured to
have a coverage similar to Penta.TM. paddle leads distributed by
St. Jude. In addition to the broad electrode coverage, the
expandable/collapsible lead may enable delivery of the lead through
introducers that are typically used for inserting percutaneous
leads. As such, incisions for inserting the lead into the patient
may be smaller than those used for inserting paddle leads, which
may reduce recovery and clinical cost.
[0030] FIG. 1 depicts a neurostimulation (NS) system 100 that
generates electrical pulses for application to tissue, such as
spinal cord tissue, of a patient according to one embodiment. For
embodiments that stimulate spinal cord tissue, the nerve tissue may
include dorsal column (DC) fibers and/or dorsal root (DR) fibers.
The NS system 100 includes an NS device (or pulse generator) 150
that is adapted to generate electrical pulses in order to apply
electric fields to the tissue. The NS device 150 is typically
implantable within an individual (e.g., patient) and, as such, may
be referred to as an implantable pulse generator (IPG). The
implantable NS device 150 typically comprises a housing 158 that
encloses a controller 151, which may include or be operably coupled
to a pulse generating circuit module 152, a charging coil 153, a
battery 154, a far-field and/or near field communication circuit
module 155, a battery charging circuit module 156, a switching
circuit module 157, etc. of the device. The controller 151 may
include a processor or other logic-based device for controlling the
various other components of the NS device 150. Software code is
typically stored in memory of the NS device 150 for execution by
the NS device 150 to control the various components of the
device.
[0031] The controller 151 may be programmable controller that
controls the various modes of stimulation therapy for the NS device
150. The controller 151 may include a microprocessor, or equivalent
control circuitry, designed specifically for controlling delivery
of stimulation therapy and may further include RAM or ROM memory,
logic and timing circuitry, state machine circuitry, and I/O
circuitry. The microcontroller 151 may have the ability to process
or monitor input signals (data) as controlled by a program code
stored in memory. The details of the design and operation of the
microcontroller 151 are not critical to the present invention.
Rather, any suitable microcontroller 151 may be used.
[0032] FIG. 1 illustrates various blocks in which some of the
blocks are referred to as a "circuit module." It is to be
understood that the circuit modules that may be implemented as
hardware with associated instructions (e.g., software stored on a
tangible and non-transitory computer readable storage medium, such
as a computer hard drive, ROM, RAM, or the like) that perform the
operations described herein. The hardware may include state machine
circuitry hard wired to perform the functions described herein.
Optionally, the hardware may include electronic circuits that
include and/or are connected to one or more logic-based devices,
such as microprocessors, processors, controllers, or the like.
Optionally, the circuit modules may represent processing circuitry
such as one or more field programmable gate array (FPGA),
application specific integrated circuit (ASIC), or microprocessor.
The circuit modules in various embodiments may be configured to
execute one or more algorithms to perform functions described
herein. The one or more algorithms may include aspects of
embodiments disclosed herein, whether or not expressly identified
in a flowchart or a method.
[0033] The NS device 150 may comprise a separate or an attached
extension component 170. If the extension component 170 is a
separate component, the extension component 170 may connect with
the "header" portion of the NS device 150 as is known in the art.
If the extension component 170 is integrated with the NS device
150, internal electrical connections may be made through respective
conductive components. Within the NS device 150, electrical pulses
are generated by the pulse generating circuit module 152 and are
provided to the switching circuit module 157. The switching circuit
module 157 connects to outputs of the NS device 150. Electrical
connectors (e.g., "Bal-Seal" connectors) within a connector portion
171 of the extension component 170 or within the header portion may
be employed to conduct the electrical pulses. Terminal contacts
(not shown) of one or more neurostimulator leads 110 are inserted
within the connector portion 171 or within the header for
electrical connection with respective connectors. Thereby, the
pulses originating from NS device 150 are provided to the
neurostimulator lead 110. The pulses are then conducted through
wire conductors of the lead 110 and applied to tissue of an
individual via electrodes 111. In the illustrated embodiment, the
neurostimulator lead is a lead configured for insertion after a
laminectomy or a laminotomy. The neurostimulator lead 110 is
hereinafter referred to as a "self-expanding lead."
[0034] For implementation of the components within NS device 150, a
processor and associated charge control circuitry for an
implantable pulse generator is described in U.S. Patent Application
Publication No. 2006/0259098, entitled "SYSTEMS AND METHODS FOR USE
IN PULSE GENERATION," which is incorporated herein by reference in
its entirety. Circuitry for recharging a rechargeable battery of an
implantable pulse generator using inductive coupling and external
charging circuits are described in U.S. Pat. No. 7,212,110,
entitled "IMPLANTABLE DEVICE AND SYSTEM FOR WIRELESS
COMMUNICATION," which is incorporated herein by reference in its
entirety. One or more NS devices and one or more paddle leads that
may be used with embodiments described herein are described in U.S.
Patent Application Publication No. US 2013/0006341 in its
entirety.
[0035] An example and discussion of "constant current" pulse
generating circuitry is provided in U.S. Patent Application
Publication No. 2006/0170486 entitled "PULSE GENERATOR HAVING AN
EFFICIENT FRACTIONAL VOLTAGE CONVERTER AND METHOD OF USE," which is
incorporated herein by reference in its entirety. One or multiple
sets of such circuitry may be provided within the NS device 150.
Different pulses on different electrodes may be generated using a
single set of pulse generating circuitry using consecutively
generated pulses according to a "multi-stimset program." Complex
pulse parameters may be employed such as those described in U.S.
Pat. No. 7,228,179, entitled "METHOD AND APPARATUS FOR PROVIDING
COMPLEX TISSUE STIMULATION PATTERNS," and International Patent
Publication No. WO 2001/093953A1, entitled "NEUROMODULATION THERAPY
SYSTEM," each of which is incorporated herein by reference in its
entirety. Alternatively, multiple sets of such circuitry may be
employed to provide pulse patterns that include simultaneously
generated and delivered stimulation pulses through various
electrodes of one or more stimulation leads as is also known in the
art. Various sets of parameters may define the pulse
characteristics and pulse timing for the pulses applied to various
electrodes as is known in the art. Although constant current pulse
generating circuitry is contemplated for some embodiments, any
other suitable type of pulse generating circuitry may be employed
such as constant voltage pulse generating circuitry.
[0036] In some embodiments, a controller device 160 may be
implemented to recharge battery 154 of the NS device 150. For
example, a wand 165 may be electrically connected to the controller
device 160 through suitable electrical connectors (not shown). The
electrical connectors may be electrically connected to a primary
coil 166 at the distal end of wand 165 through respective wires
(not shown). The primary coil 166 may be placed against the
patient's body immediately above the charging coil (or secondary
coil) 153 of the NS device 150. The controller device 160 may
generate an AC-signal to drive current through the primary coil
166. Current may be induced in the secondary coil 153 to recharge
the battery 154.
[0037] In some embodiments, the controller device 160 preferably
provides one or more user interfaces to allow the user to the NS
device 150 according to one or more stimulation programs to treat
the patient's disorder(s). Each stimulation program may include one
or more sets of stimulation parameters including pulse amplitude,
pulse width, pulse frequency or inter-pulse period, pulse
repetition parameter (e.g., number of times for a given pulse to be
repeated for respective stimset during execution of program), etc.
The NS device 150 modifies its internal parameters in response to
the control signals from controller device 160 to vary the
stimulation characteristics of stimulation pulses transmitted
through stimulation lead 110 to the tissue of the patient.
Neurostimulation systems, stimsets, and multi-stimset programs are
discussed in PCT Publication No. WO 01/93953, entitled
"NEUROMODULATION THERAPY SYSTEM," and U.S. Pat. No. 7,228,179,
entitled "METHOD AND APPARATUS FOR PROVIDING COMPLEX TISSUE
STIMULATION PATTERNS," which are incorporated herein by
reference.
[0038] FIG. 2A is a plan view of a self-expandable lead 200 and
includes two isolated, enlarged views of the lead 200. The lead 200
may be similar or Identical to the lead 110 (FIG. 1) and may be
used with an NS system, such as the NS system 100 (FIG. 1). The
lead 200 includes a lead body 202 having a distal body end 204, a
proximal body end 206, and a central axis 208 extending
therebetween. A portion of the lead body 202 near the distal body
end 204 is shown in greater detail in FIG. 2B, and a portion of the
lead body 202 near the proximal body end 206 is shown in greater
detail in FIG. 2C. With respect to FIG. 2A, the central axis 208
extends generally along a geometric center of a cross-section of
the lead 200. As shown, the lead body 202 includes a plurality of
arms or splines 211-215 that extend lengthwise between the distal
body end 204 and the proximal body end 206 of the lead body
202.
[0039] In the illustrated embodiment, the arms 211-215 include
first and second outer arms 211, 214, first and second inner arms
212, 213, and a center inner arm 215. The inner arms 212, 213, 215
are disposed between the outer arms 211, 214, and the center inner
arm 215 is disposed between the first and second inner arms 212,
213. In some embodiments, the inner arms 212, 213 may be described
or characterized intermediate arms 212, 213. Each of the arms
211-215 extends lengthwise between a respective distal arm end 218
(shown in FIG. 2B) and a respective proximal arm end 220 (shown in
FIG. 2C). The distal arm ends 218 are located proximate to the
distal body end 204, and the proximal arm ends 220 are located
proximate to the proximal body end 206. The proximal body end 206
may include an end 216 (or cable end) of a lead cable 210. The lead
body 202 also includes a first paddle side 222, which is shown in
FIG. 2, and a second paddle side 224 (shown in FIG. 3). The first
and second paddle sides 222, 224 face in opposite directions and
extend lengthwise between the distal body end 204 and the proximal
body end 206.
[0040] In the illustrated embodiment, the lead body 202 has a lead
profile or footprint 225 that constitutes a spatial volume defined
by exterior surfaces of the lead body 202 when the leady body 202
is in a relaxed state. In FIG. 2, the lead profile 225 is
represented by a dashed line that extends alongside a perimeter of
the lead body 202. For illustrative purposes, the dashed line is
spaced apart from the exterior surfaces of the lead body 202 that
define the lead profile 225. By way of example, the lead body 202
may have a first dimension or width 231 that extends between
exterior surfaces of the outer arms 211, 214 and which face in
opposite directions. The lead body 202 also has a second dimension
or length 232 that extends between an exterior surface of the
distal body end 204 and a location where the proximal body end 206
joins the lead cable 210. The lead body 202 may also have a third
dimension or thickness 233 (shown in FIG. 3) that extends between
paddle sides 222, 224. Each of the width 231, the length 232, and
the thickness 233 may have a varying or non-uniform value as the
lead body 202 extends along the dimensions. For instance, the
length 232 is greatest when measured along the central axis
208.
[0041] As shown, the lead profile 225 may include elongated windows
or openings 241-244 that are defined between adjacent arms. More
specifically, with respect to the illustrated embodiment, the lead
body 202 defines the elongated window 241 between the outer arm 211
and the inner arm 212, the elongated window 242 between the inner
arm 212 and the inner arm 215, the elongated window 243 between the
inner arm 215 and the inner arm 213, and the elongated window 244
between the inner arm 213 and the outer arm 214. The elongated
windows 241 extend lengthwise along the central axis 208 and
widthwise between the adjacent arms. The elongated windows 241-244
reduce or shrink when the lead 200 is in a collapsed state.
[0042] When the lead 200 is in a relaxed state prior to insertion
as shown in FIG. 2, the lead profile 225 of the lead body 202 may
be substantially planar widthwise and lengthwise. For example, the
arms 211-215 may be substantially coplanar (e.g., substantially
coincide along a common plane). In other embodiments, the lead
profile 225 may have a curved contour when the lead body 202 is in
a relaxed state. For example, the lead profile 225 may curve as the
lead body 202 extends along the length 232 (e.g., such that the
central axis 208 is not linear and has a curved or bent shape)
and/or as the lead body 202 extends along the width 231 (e.g., the
lead body 202 may be C-shaped as viewed along the central axis
208). The contours may be predetermined by the manufacturing
process of the lead 200. For example, the contours may be
predetermined to complement the anatomical structure that the lead
200 will interface.
[0043] During an implantation procedure, the distal body end 204 is
typically the first end that is inserted through an incision and
into the spinal column. As shown, the lead cable 210 extends away
from the lead body 202 from the proximal body end 206. The lead
cable 210 may include conductive pathways 286 (shown in FIG. 3),
such as wire conductors, which extend from the lead body 202 to an
NS device or pulse generator (not shown), such as the NS device 150
(FIG. 1). The conductive pathways 286 also extend lengthwise along
the arms 211-215 to electrically couple the corresponding
electrodes 250 to the pulse generator.
[0044] As shown in FIG. 2, the lead 200 also includes a plurality
of electrodes 250 that are disposed along the outer arms 211, 214
and the inner arms 212, 213, but not the inner arm 215. In other
embodiments, the inner arm 215 may include one or more of the
electrodes 250. The electrodes 250 may comprise Platinum-Iridium
(Pt--Ir) or other equivalent material. As one specific example
only, the electrodes may be 90-10 Pt--Ir (i.e., 90% Platinum, 10%
Iridium). The electrodes 250 may be positioned relative to each
other to form a multi-electrode array 252. The multi-electrode
array 252 is a two-dimensional array in the illustrated embodiment.
The electrodes 250 and/or the multi-electrode array 252 may be
configured to provide a neurostimulation therapy in an epidural
space of a patient. For example, electrical pulses transmitted from
the NS device 150 may be provided at a predetermined schedule or
frequency to provide therapy to the patient. It is noted that the
FIG. 2 illustrates only one arrangement of the electrodes 250.
However, in other embodiments, the electrodes 250 may have any one
of a variety of arrangements.
[0045] When the lead 200 is disposed in the epidural space, one of
the paddle sides may interface with nerve tissue and the other
paddle side may interface with an anatomical structure (e.g., bone,
ligament, or other portions of the spine). In some embodiments, the
electrodes 250 may be exposed along each of the paddle sides 222,
224. In other embodiments, the electrodes 250 may be exposed only
along one of the paddle sides, such as the paddle side 222 shown in
FIG. 2, and not the other paddle side.
[0046] In the illustrated embodiment, each of the outer arms 211,
214 and each of the inner arms 212, 213 include a series or column
of electrodes 250 that are spaced apart from each other along a
length of the respective arm. When in an operative state (e.g., an
expanded state), the arms are spaced apart from each other thereby
laterally separating the electrodes 250 of adjacent arms. To form
the multi-electrode array 252 with a predetermined configuration,
the electrodes 250 may be disposed along the lengths of the
respective arms at designated locations and the arms 211-215 may be
configured to have a designated separation when in the expanded
state so that the electrodes 250 form the multi-electrode array
252.
[0047] In the illustrated embodiment, multi-electrode array 252
includes a 4.times.5 grid of electrodes 250 in which the electrodes
250 are substantially evenly distributed along (e.g. parallel to)
the central axis 208. In alternative embodiments, the electrodes
250 may form a single row or column that extends along the central
axis 208 and are spaced apart from each other. In other
embodiments, the multi-electrode array 252 may have a 4.times.4
grid of electrodes 250 or a 4.times.8 grid of electrodes 250. In
particular embodiments, the multi-electrode array 252 may be
configured to have a coverage similar to Penta.TM. paddle leads
distributed by St. Jude.
[0048] To this end, the lead body 202 may include a plurality of
resilient members 261-264 (shown in FIG. 2B) proximate to the
distal body end 204 and a plurality of resilient members 271-274
(shown in FIG. 2C) proximate to the proximal body end 206. In the
illustrated embodiment, the resilient members 261-264 are located
within the arms 211-214, respectively, and the resilient members
271-274 are located within the arms 211-214, respectively. In an
exemplary embodiment, the resilient members 261-264 and 271-274
include a resilient material that is capable of being collapsed
when a force is applied and biased to flex back to a designated
shape when the force is removed. In certain embodiments, the
resilient material is a metal or metal alloy. The resilient
material may have shape memory. In particular embodiments, the
resilient material includes nitinol, which is a metal alloy of
nickel and titanium. However, other materials, including
combinations of materials, may be used.
[0049] FIGS. 2A-2C show the lead 200 in a relaxed or expanded
state. The resilient members are biased to flex the respective arm
from a collapsed condition to an expanded condition in a direction
that is away from the central axis 208 (or the center inner arm
215). The resilient members also permit the respective arm to flex
toward the central axis 208 (or the center inner arm 215) from the
expanded condition to the collapsed condition when a force is
applied.
[0050] FIGS. 3-5 illustrate different cross-sections of the lead
200 as shown in FIG. 2A. FIG. 3 is taken along the line 3-3 in FIG.
2A and illustrates cross-section of the arms 211-215 in greater
detail. For illustrative purposes, the lead profile 225 is shown.
The lead body 202 includes the paddle sides 222 and 224. Each of
the arms 211-215 has a cross-section that includes an arm width 281
and an arm height 283. In some embodiments, the arm height 283 may
be substantially equal to the thickness 233 of the lead body 202 or
the lead profile 225 at the cross-section shown in FIG. 3. In
particular embodiments, the arms 211-215 are narrow, elongated
splines or beams in which the arm width 281 and the arm height 283
are approximately equal. For example, the arm width 281 and the arm
height 283 may differ by at most 50% of the greater of the arm
width 281 and the arm height 283. For example, if the arm width 281
were about 1.5 mm, the arm height 283 may be about 0.75 mm. If the
arm height 283 is larger and is, for example, about 1.0 mm, the arm
width 281 may be about 0.75 mm. In other embodiments, the arm width
281 and the arm height 283 may differ by at most 25% of the greater
of the arm width 281 and the arm height 283 or, more particularly,
by at most 10% of the greater of the arm width 281 and the arm
height 283.
[0051] In the illustrated embodiment, the cross-section of the arms
211-215 have a substantially circular shape or substantially square
shape such that the arm width 281 and the arm height 283 are
substantially equal In other embodiments, the arms 211-215 may have
a substantially rectangular shape. For example, the arm width 281
may be about 2.25 mm and the arm height 283 may be about 1.0
mm.
[0052] As shown, the arms 211-215 comprise an insulative material
284 that may include the exterior surfaces of the arms 211-215. In
FIG. 3, the arms 211-214 also include conductive pathways 286
(e.g., wire conductors). The conductive pathways 286 comprise a
conductive material, such as copper, and are configured to transmit
electrical signals (e.g., current) to corresponding electrodes 250
(FIG. 2A). The conductive pathways 286 are electrically coupled to
the pulse generator of the NS system 100. As described above, a
designated frequency may be transmitted to the electrodes 250 in
order to provide therapy to a patient. In an exemplary embodiment,
the conductive pathways 286 may include jackets that insulate the
conductive pathways 286 from each other.
[0053] The inner arm 215 includes a steering lumen 288. The
steering lumen 288 may be defined by an interior surface of the
insulative material 284. The steering lumen 288 may extend
lengthwise through the inner arm 215 from the proximal body end 206
(FIGS. 2A and 2C) to and, optionally, through the distal body end
204 (FIGS. 2A and 2B). The steering lumen 288 is sized and shaped
to receive an elongated tool 290, such as a guide wire. The
elongated tool 290 may be used during the insertion process to
guide the lead 200 (FIG. 2A).
[0054] The insulative material 284 may include one or more
biocompatible materials. Non-limiting examples of such materials
include polyimide, polyetheretherketone (PEEK), polyethylene
terephthalate (PET) film (also known as polyester or Mylar),
polytetrafluoroethylene (PTFE) (e.g., Teflon), or parylene coating,
polyether bloc amides, polyurethane. In some embodiments, the
material of the lead body 202 that surrounds the metal components
(e.g., electrodes 250 and the conductive pathways 286 that couple
to the electrodes 250) includes at least one of polyimide,
polyetheretherketone (PEEK), polyethylene terephthalate (PET) film,
polytetrafluoroethylene (PTFE), parylene, polyether bloc amides, or
polyurethane.
[0055] FIG. 4 shows cross-sections of the arms 211-215 taken along
the line 4-4 of FIG. 2A. In FIG. 4, each of the arms 211-214
includes one of the electrodes 250. The electrode 250 is configured
to be exposed along an outer surface of the respective arm so that
the electrode 250 may interface with an anatomical structure, such
as nerve tissue. In FIG. 4, the electrodes 250 are completely
exposed along the outer surface. In other embodiments, one or more
portions of the electrodes 250 may be covered such that the
corresponding portion(s) is not exposed. For instance, the
insulative material 284 may cover the one or more portions of the
electrodes 250. As shown in FIG. 4, the electrode 250 may be
separated from an adjacent electrode 250 by a gap 292. The gaps 292
may be part of the elongated windows 241-244.
[0056] FIG. 5 shows cross-sections of the joints 265-268 of the
respective arms 211-215 (FIG. 2A) taken along the line 5-5 in FIG.
2A. As shown, each of the joints 265-268 includes the respective
resilient member 261-264 that is at least partially surrounded by
the insulative material 284. The resilient members 261-264 of the
respective joints 265-268 are dimensioned and shaped to function as
described herein. For example, the resilient members 261-264 may be
etched, creased, and/or have varying dimensions in order to provide
sufficient resiliency for returning the arms 211-214 to the
expanded state when the force is removed. In some embodiments, the
resilient members 261-264 may be etched (e.g., laser-cut) to
provide the designated shape.
[0057] FIG. 6 shows a cross-section of the lead body 202 when each
of the arms 211-214 is in a collapsed condition within an insertion
tool 296, which may also be referenced as an introducer. The
resilient members 261-264, 271-274 (FIGS. 2B and 2C, respectively)
may be configured such that the arms 211-214 collapse in a
designated manner. For example, the resilient members 261-264,
271-274 may be shaped such that when a laterally-inward force F,
(indicated by the inwardly pointing arrows) is provided, the arms
211-214 collapse toward (e.g., move toward) the inner arm 215
and/or the central axis 208. The laterally-inward force F, may be
applied when the lead body 202 is drawn into or advanced into a
cavity of an insertion tool. The cavity may be defined by interior
surfaces of the insertion tool. The lead body 202 may slide through
the insertion tool when a linear force is applied. The linear force
may be translated into the laterally-inward force F, as the
unyielding interior surface of the insertion tool collapses the
arms 211-214.
[0058] In the illustrated embodiment, when the lead body 202 is in
an expanded state, each of the arms 211-214 coincides with a body
plane 298 prior to the arms 211-214 collapsing. As the arms 211-214
collapse, the arms 211-214 move along the body plane 298 in an
inward direction toward the inner arm 215 and/or toward the central
axis 208. When the arms 211-214 are in the collapsed conditions as
shown in FIG. 6, the arms 211-214 may be co-planar with one another
such that the arms 211-214 coincide with the body plane 298.
[0059] FIG. 7 shows a cross-section of a lead body 302 when the
lead body 302 is located within an insertion tool 396. The lead
body 302 may be similar or identical to the lead body 202 (FIG.
2A). For example, the lead body 302 includes arms 311-315. As shown
in FIG. 7, each of the arms 311-314 is in a collapsed condition
within a cavity 397 of the insertion tool 396. The cavity 397 is
defined by one or more interior surfaces of the insertion tool 396.
Although not shown, the arms 311-314 may include resilient members,
such as the resilient members 261-264, 271-274 (FIGS. 2B and 2C,
respectively), which may be configured to expand the arms 311-314
in a designated manner and permit the arms 311-314 to collapse in a
designated manner. For instance, the resilient members may be
shaped such that when an inward force F.sub.2 (indicated by arrows)
is provided, the arms 311-314 collapse toward the inner arm 315
and/or a central axis 308 of the lead body 302. However, the
resilient members of the arms 311-314 may be biased such that the
arms 311-314 move toward the inner arm 315 or the central axis 308
in a different manner than the arms 211-214 shown in FIG. 6. For
instance, the inner arms 312, 313 may move above or below the inner
arm 315 and the outer arms 311, 314 may move below or above the
inner arms 312, 313, respectively. As such, the arms 311-315 may
have a substantially stacked or overlapping configuration as shown
in FIG. 7. In other embodiments, the stacked configuration may
include the arms 311-314 forming a square perimeter that surrounds
the inner arm 315 within a center of the stacked configuration.
[0060] FIG. 8 illustrates a series of stages 401-406 during an
insertion process in which a self-expanding lead 410 clears an end
opening 412 of an insertion tool 414 (e.g., an introducer). The
lead 410 may be similar or identical to other self-expanding leads
described herein and have a distal body end 416 and a proximal body
end 418 (shown with respect to the stage 406). The lead 410 may
include arms 421-424 that have resilient members (not shown) that
enable the arms 421-424 to flex between collapsed and expanded
conditions. Unlike other self-expandable leads described herein,
the lead 410 does not include a central inner arm through which a
steering lumen extends. In alternative embodiments, the lead 410
may include such an inner arm.
[0061] At stage 401, the lead 410 is disposed within a cavity, such
as the cavity 397 (FIG. 7), of the insertion tool 414. As described
above, the relaxed state of the lead 410 may be the expanded state.
When the lead 410 is advanced into the cavity 397, interior
surfaces of the insertion tool 414 that define the cavity may
engage one or more of the arms, such as the arms 421 and 424. The
insertion tool 414 may resist lateral deformation such that the
insertion tool 414 pushes the arms 421 and 424 and, consequently,
the arms 422, 423 laterally-inward as the lead 410 is advanced into
the cavity. Thus, the linear insertion force that is applied to the
lead 410 may be translated by the interior surface(s) of the
insertion tool 414 into a laterally-inward force that collapses the
arms 211-214.
[0062] Before or after the lead 410 has been disposed within the
insertion tool 414, the insertion tool 414 may be advanced into a
patient (not shown) through one or more incisions. For example, the
insertion tool 414 may be advanced through one or more incisions
that provide access to the spinal cord (not shown). In some
embodiments, the insertion tool 414 may be identical to the
introducers that are used to insert percutaneous leads into the
spinal cord. In other embodiments, the insertion tool 414 may not
be identical, but may have dimensions that are approximate to or
similar to the dimensions of conventional percutaneous
introducers.
[0063] At stage 402, the distal body end 416 clears the end opening
412 of the insertion tool 414. As the lead 410 transitions to stage
403, the distal body end 416 may expand to have a larger lead
profile. At this time, the distal body end 416 may engage tissue
within the anatomical space (not shown). Geometries of the
anatomical space, including the epidural space, vary from patient
to patient. In some cases, it may be desirable for the lead 410 to
be capable of moving around obstructions, such as bone or tissue,
and/or to be capable for moving tissue without causing significant
trauma to the patient. In accordance with some embodiments, the
resiliency of the arms 421-424 at the distal body end 416 may be
configured such that the distal body end 416 is capable of engaging
and flexing to slide around tissue and/or is capable of engaging
and moving tissue within the anatomical space.
[0064] At stage 404, the distal body end 416 has cleared the end
opening 412 of the insertion tool 414 and a majority of a length of
the lead 410 has advanced into the anatomical space. At stages 405
and 406, the proximal body end 418 has expanded such that the arms
421-424 are fully expanded and the lead 410 has a maximum lead
profile. Before or after the lead 410 is properly position within
the epidural space, the tool 414 may be withdrawn through the one
or more incision cites.
[0065] FIG. 9 illustrates a guiding device 500 that may be used to
direct the self-expanding lead 200 into an anatomical space of a
patient. As shown, the guiding device 500 includes a guide wire 502
that is operably coupled to a handle 504 that is configured to be
gripped by an individual (e.g., doctor). In FIG. 9, the guide wire
502 is inserted entirely through the steering lumen 288 (FIG. 3) of
the inner arm 215 such that the guide wire 502 extends beyond the
distal body end 204 of the lead 200.
[0066] The insertion process with respect to the lead 200 may be
similar to the insertion process described with respect to FIG. 8.
However, before or after the lead 200 is loaded into the insertion
tool (not shown), the guide wire 502 of the guiding device 500 may
be inserted through the steering lumen 288 of the inner arm 215.
After the insertion tool has been advanced through the incision
site and positioned proximate to the designated anatomical space as
described above, the guide wire 502 may be moved into the
anatomical space before the lead 200 clears the end opening (not
shown) of the insertion tool. With the guide wire 502 located
within the anatomical space, the lead 200 may be advanced into the
anatomical space with the guide wire 502 directing or guiding the
lead 200. As the lead 200 is advanced into the anatomical space,
the distal body end 204 of the lead 200 expands. In some
embodiments, the expanding of the lead 200 may displace tissue or
other obstructions thereby permitting the guide wire 502 to
advance. After the lead 200 has partially expanded, the lead 200
may then be further advanced into the anatomical space.
[0067] FIGS. 10-13 illustrate self-expandable leads having flexible
membranes. For some applications, it may be desirable to have a
flexible membrane extend across the width of the lead and join the
arms of the lead body. The flexible membranes may impede growth of
tissue around the arms which may enable a simpler process for
withdrawing the lead with a decreased likelihood of trauma or
injury to the patient. For example, FIG. 10 is a perspective view
of a self-expanding lead 600 that utilizes a flexible membrane 602
in accordance with one embodiment. Other than the flexible membrane
602, the lead 600 may be identical to the lead 200 (FIG. 2A). For
example, the lead 200 may include a lead body 604 having arms
611-615. In the expanded state shown in FIG. 10, the lead body 604
has first and second paddle sides 622, 624. Also shown, the lead
600 includes elongated windows or openings 641-644 that are defined
between adjacent arms. The flexible membrane 602 extends along the
paddles side 624 and covers the elongated windows 641-644.
[0068] FIG. 11 is a cross-section of the lead 600 taken along the
line 11-11 in FIG. 10. The flexible membrane 602 may be attached to
the arms 611-615 along the paddle side 624 in one or more manners.
For example, the flexible membrane 602 may comprise a biocompatible
material, which may be the same as or similar to the insulative
material 284, that is attached by selectively applying heat to the
flexible membrane 602. In other embodiments, an adhesive may be
applied to the flexible membrane 602, which may then be attached to
the arms 611-614.
[0069] In the embodiment of FIG. 11, the lead 600 has a
uni-directional configuration. More specifically, the flexible
membrane 602 may extend along the paddle side 624 such that
electrodes 650 (FIG. 10) of the lead 600 are covered by the
flexible membrane 602 and are only exposed along the paddle side
622. In such embodiments, it may be necessary to orient the lead
600 so that a predetermined paddle side interfaces with the nerve
tissue.
[0070] FIG. 12 is a cross-section of a self-expanding lead 700
having a flexible membrane 702 in accordance with one embodiment.
Other than the flexible membrane 702, the lead 700 may be identical
to the lead 200 (FIG. 2A). In the embodiment of FIG. 12, the
flexible membrane 702 is applied to a paddle side 724 of the lead
700. The flexible membrane 702 may have electrode openings 752 that
expose the electrodes 750 along the paddle side 724. The electrode
openings 752 may be fabricate by etching the flexible membrane 702
material after the flexible membrane 702 has been applied to the
paddle side 724. In some embodiments, the flexible membrane 702 may
be applied through an injection molding process. With injection
molding, the lead 700 may be positioned within a mold that covers
portions of the electrodes 750 so that molten membrane material
cures at designated portions thereby forming the electrode openings
752.
[0071] Accordingly, embodiments described herein may have a
flexible membrane along one or both paddle sides. The flexible
membrane may limit adhesion of the self-expanding lead to the
patient by limiting growth of tissue or other material within the
epidural space around the arms of the lead. In such embodiments
that utilize a flexible membrane, the flexible membrane may be
capable of folding over within the cavity of the insertion tool,
such as the insertion tool 414, thereby permitting the
expanding/collapsing abilities of the leads described herein.
[0072] FIG. 13 illustrates a plan view of a self-expanding lead 850
in an expanded state. The lead 850 may be similar to other leads
described herein, such as the lead 200 (FIG. 2A). For example, the
lead 850 includes a lead body 852 having a distal body end 854, a
proximal body end 856, and a central axis 858 extending
therebetween. The proximal body end 856 may include an end 866 (or
cable end) of a lead cable 860. As shown, the lead body 852
includes a plurality of arms or splines 861-865 that extend
lengthwise between the distal body end 854 and the proximal body
end 856 along the central axis 858. In the illustrated embodiment,
the arms 861-865 include first and second outer arms 861, 864,
first and second inner arms 862, 863, and a center inner arm 865.
The inner arms 862, 863, 865 are disposed between the outer arms
861, 864, and the center inner arm 865 is disposed between the
first and second inner arms 862, 863.
[0073] The lead cable 860 may include conductive pathways (not
shown), such as wire conductors, which extend from the lead body
852 to an NS device or pulse generator (not shown), such as the NS
device 150 (FIG. 1). The conductive pathways also extend lengthwise
along the arms 861-865 to electrically couple corresponding
electrodes 890 to the pulse generator. As shown, the corresponding
electrodes 890 are disposed along each of the arms 861-865,
including the inner arm 865. The electrodes 890 may be positioned
relative to each other to form a multi-electrode array 896.
[0074] Although not shown, the lead body 852 may include a
plurality of resilient members proximate to the distal body end 854
and a plurality of resilient members proximate to the proximal body
end 856. The resilient members may be similar to the resilient
members 261-264 and 271-274 (FIGS. 2B and 2C, respectively)
described with respect to the lead 200 and located within the arms.
The resilient members may include a resilient material that is
capable of being collapsed when a force is applied and biased to
flex back to a designated shape when the force is removed.
[0075] In the illustrated embodiment, the inner arm 865 includes a
steering lumen 888. The steering lumen 888 extends through the lead
cable 860 into the inner arm 865. The steering lumen 888 may be
defined by an interior surface of an insulative material of the
lead cable 860 and the inner arm 865. As shown, the steering lumen
888 extends lengthwise through the inner arm 865 from the proximal
body end 856 and through the distal body end 854. The steering
lumen 888 is sized and shaped to receive an elongated tool, which
is illustrated as a guide wire 892 in FIG. 13. The guide wire 892
may be used during the insertion process to guide the lead 850 to a
designated position in the epidural space (not shown). More
specifically, the distal body end 854 may have an opening that
permits a wire end 894 of the guide wire 892 to clear the distal
body end 854 and be positioned within the epidural. With the wire
end 894 located within the epidural space, the lead 850 may then be
directed along the guide wire 892 and delivered to the epidural
space. The path taken by the lead 850 is determined by the shape of
the guide wire 892.
[0076] In some embodiments, the center inner arm 865 may not
include resilient material for flexing between different positions.
For example, in particular embodiments, the center inner arm 865
may not include such resilient material and, instead, may include a
more rigid material. The rigid material may be more suitable for
receiving a tool, such as the guide wire 892.
[0077] FIG. 14 illustrates a plan view of a self-expanding lead 900
in an expanded state. The lead 900 may have a lead body 902 that is
similar in shape as the lead body 852. However, as shown in FIG.
14, a center inner arm 925 of the lead body 902 may not have a
steering lumen that extends entirely through the lead body 902.
Instead, the center inner arm 925 may end short of a distal body
end 932 and permit inner arms 922 and 923 to be directly coupled by
a joint 927 and outer arms 921 and 924 to be directly coupled by a
joint 928.
[0078] However, the lead body 902 may have a steering lumen 904
that extends to and ends at a cable end 906 of a lead cable 908. As
shown, a guide wire 910 may be inserted into the steering lumen 904
until a wire end 912 of the guide wire 910 engages the cable end
906 of the lead body 902. The guide wire 910 may be operated to
move the lead body 902 into a designated orientation. For example,
when the lead body 902 is inserted into the epidural space (not
shown), the lead body 902 may be moved to into a designated
orientation by the guide wire 910. More specifically, the lead body
902 may pivot (as indicated by the arrows) about a point 930
located within the cable end 906.
[0079] FIG. 15 is a block diagram illustrating a method 800 of
manufacturing a self-expandable lead in accordance with one
embodiment. The lead may be similar to the leads shown and
described in the present application. The method 800 includes
fabricating (at 802) resilient members. The resilient members may
be fabricated (at 802) by etching a sheet of resilient material
(e.g., metal alloy or plastic). In particular embodiments, the
sheet of resilient material includes nitinol. The etching may
include laser-cutting the sheet material. The resilient members may
be elongated structures that extend along curved paths. For
instance, in a relaxed state, the resilient members may extend
along curved paths that have similar shapes as the arms that the
resilient members will be located within. As one example, the
resilient members may be shaped similar to the resilient members
261-264 and 271-274 shown in FIGS. 2B and 2C, respectively.
[0080] The method 800 also includes assembling (at 804) wire
conductors and electrodes of the lead. The assembling (at 804) may
include positioning the resilient members relative to the wire
conductors and the electrodes. At 806, an insulative material may
be applied (e.g., molded) to the assembly of wire conductors,
electrodes, and resilient members. The insulative material may be a
biocompatible material, such as the materials described herein. The
insulative material may completely cover or insulate the wire
conductors and at least partially cover the electrodes. The
resilient members may be at least partially covered by the
insulative material.
[0081] A lead body may be formed upon applying the insulative
material at 806. The lead body may be similar to other leads or
lead bodies described herein, such as the lead body 200. In
particular, the lead body may include a plurality of arms that
extend between a distal body end and a proximal body end of the
lead body. For example, the arms may include first and second outer
arms and an inner arm generally disposed between the first and
second outer arms. The first and second outer arms and the inner
arm may extend lengthwise between the proximal body end and the
distal body end.
[0082] The electrodes may form a multi-electrode array that is
configured to apply a neurostimulation therapy. Some or all of the
electrodes may be positioned along the first and second outer arms.
Each of the first and second outer arms may include at least one of
the resilient members. The resilient members may bias the
respective outer arm to flex from a collapsed condition to an
expanded condition in a laterally-outward direction. The resilient
members may also permit the respective outer arm to flex
laterally-inward from the expanded condition to the collapsed
condition when a force is applied.
[0083] Optionally, at 808, a flexible membrane may be applied to a
paddle side of the lead body. The flexible membrane may be similar
to the flexible membranes 602 or 702 (FIGS. 10 and 12,
respectively). In some embodiments, the flexible membrane may be
applied (at 808) after the lead body is formed. In other
embodiments, the flexible membrane may be applied as the lead body
is formed. For example, the flexible membrane may be molded with
the arms of the lead body. In some embodiments, a flexible membrane
may be applied on each of the paddle sides.
[0084] It is to be understood that the subject matter described
herein is not limited in its application to the details of
construction and the arrangement of components set forth in the
description herein or Illustrated in the drawings hereof. The
subject matter described herein is capable of other embodiments and
of being practiced or of being carried out in various ways. Also,
it is to be understood that the phraseology and terminology used
herein is for the purpose of description and should not be regarded
as limiting. The use of "including," "comprising," or "having" and
variations thereof herein is meant to encompass the items listed
thereafter and equivalents thereof as well as additional items.
[0085] Unless specified or limited otherwise, the terms "mounted,"
"connected," "supported," and "coupled" and variations thereof are
used broadly and encompass both direct and indirect mountings,
connections, supports, and couplings. Further, "connected" and
"coupled" are not restricted to physical or mechanical connections
or couplings. Also, it is to be understood that phraseology and
terminology used herein with reference to device or element
orientation (such as, for example, terms like "central," "upper,"
"lower," "front," "rear," "distal," "proximal," and the like) are
only used to simplify description of one or more embodiments
described herein, and do not alone indicate or imply that the
device or element referred to must have a particular orientation.
In addition, terms such as "outer" and "inner" are used herein for
purposes of description and are not intended to indicate or imply
relative importance or significance.
[0086] It is to be understood that the above description is
intended to be illustrative, and not restrictive. For example, the
above-described embodiments (and/or aspects thereof) may be used in
combination with each other. In addition, many modifications may be
made to adapt a particular situation or material to the teachings
of the presently described subject matter without departing from
its scope. While the dimensions, types of materials and coatings
described herein are intended to define the parameters of the
disclosed subject matter, they are by no means limiting and are
exemplary embodiments. Many other embodiments will be apparent to
those of skill in the art upon reviewing the above description. The
scope of the inventive subject matter should, therefore, be
determined with reference to the appended claims, along with the
full scope of equivalents to which such claims are entitled. In the
appended claims, the terms "including" and "in which" are used as
the plain-English equivalents of the respective terms "comprising"
and "wherein." Moreover, in the following claims, the terms
"first," "second," and "third," etc. are used merely as labels, and
are not intended to impose numerical requirements on their objects.
Further, the limitations of the following claims are not written in
means--plus-function format and are not intended to be interpreted
based on 35 U.S.C. .sctn.112, sixth paragraph, unless and until
such claim limitations expressly use the phrase "means for"
followed by a statement of function void of further structure.
[0087] The following claims recite aspects of certain embodiments
of the inventive subject matter and are considered to be part of
the above disclosure.
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