U.S. patent application number 10/834743 was filed with the patent office on 2004-12-02 for system, method, and combined electrical and chemical stimulation lead for stimulation of a person's nerve tissue.
Invention is credited to Tadlock, Charles H..
Application Number | 20040243206 10/834743 |
Document ID | / |
Family ID | 32713271 |
Filed Date | 2004-12-02 |
United States Patent
Application |
20040243206 |
Kind Code |
A1 |
Tadlock, Charles H. |
December 2, 2004 |
System, method, and combined electrical and chemical stimulation
lead for stimulation of a person's nerve tissue
Abstract
According to one embodiment, a combined electrical and chemical
stimulation lead adapted for implantation proximate target nerve
tissue in a person for combined electrical and chemical stimulation
of the target nerve tissue, includes a lead body. One or more
electrodes located along the lead body and adapted to be positioned
proximate the target nerve tissue and to deliver electrical
stimulation pulses transmitted through the lead to the target nerve
tissue. One or more infusion ports located along the lead body and
adapted to be positioned proximate the target nerve tissue and to
deliver chemical stimulation pulses transmitted through the lead to
the target nerve tissue. The lead is adapted to provide combined
electrical and chemical stimulation of the target nerve tissue
using the one or more electrodes and the one or more infusion
ports.
Inventors: |
Tadlock, Charles H.;
(Henderson, NV) |
Correspondence
Address: |
BAKER BOTTS L.L.P.
2001 ROSS AVENUE
SUITE 600
DALLAS
TX
75201-2980
US
|
Family ID: |
32713271 |
Appl. No.: |
10/834743 |
Filed: |
April 28, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10834743 |
Apr 28, 2004 |
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10750788 |
Jan 2, 2004 |
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60438053 |
Jan 3, 2003 |
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Current U.S.
Class: |
607/116 ;
607/120 |
Current CPC
Class: |
A61N 1/36071 20130101;
A61N 1/36082 20130101; A61N 1/0539 20130101; A61N 1/0529 20130101;
A61N 1/0534 20130101 |
Class at
Publication: |
607/116 ;
607/120 |
International
Class: |
A61N 001/05 |
Claims
What is claimed is:
1. A combined electrical and chemical stimulation lead adapted for
implantation proximate target nerve tissue in a person for combined
electrical and chemical stimulation of the target nerve tissue,
comprising: a lead body; one or more electrodes located along the
lead body and adapted to be positioned proximate the target nerve
tissue and to deliver electrical stimulation pulses transmitted
through the lead to the target nerve tissue; and one or more
infusion ports located along the lead body and adapted to be
positioned proximate the target nerve tissue and to deliver
chemical stimulation pulses transmitted through the lead to the
target nerve tissue; the lead adapted to provide combined
electrical and chemical stimulation of the target nerve tissue
using the one or more electrodes and the one or more infusion
ports.
2. The stimulation lead of claim 1, wherein the lead comprises a
plurality of electrodes and at least one infusion port is located
between two of the electrodes.
3. The stimulation lead of claim 1, wherein the lead comprises a
plurality of infusion ports and at least one electrode is located
between two of the infusion ports.
4. The stimulation lead of claim 1, wherein the one or more
electrodes are adapted to be electrically coupled to an implantable
electrical stimulation source operable to generate the electrical
stimulation pulses.
5. The stimulation lead of claim 1, wherein the one or more
infusion ports are adapted to be fluidly coupled to an implantable
infusion pump operable to supply the chemical stimulation
pulses.
6. The stimulation lead of claim 1, wherein the lead is adapted to
provide simultaneous electrical and chemical stimulation of the
target nerve tissue.
7. The stimulation lead of claim 1, further comprising an inner
channel formed through the lead body, fluidly coupled to the one or
more infusion ports, and adapted to transmit the chemical
stimulation pulses through the lead to the one or more infusion
ports.
8. The stimulation lead of claim 1, wherein each chemical
stimulation pulse comprises a bolus of a medication.
9. The stimulation lead of claim 1, wherein the target nerve tissue
is located in the brain stem.
10. The stimulation lead of claim 1, further comprising a tapered
end adapted to aid in dissection of tissue during implantation of
the lead.
11. A neurological stimulation system for stimulating nerve tissue
in a person, comprising: a combined electrical and chemical
stimulation lead adapted for implantation proximate target nerve
tissue in the person and comprising: a lead body; one or more
electrodes located along the lead body and adapted to be positioned
proximate the target nerve tissue and to deliver electrical
stimulation pulses transmitted through the lead to the target nerve
tissue; and one or more infusion ports located along the lead body
and adapted to be positioned proximate the target nerve tissue and
to deliver chemical stimulation pulses transmitted through the lead
to the target nerve tissue; the lead adapted to provide combined
electrical and chemical stimulation of the target nerve tissue
using the one or more electrodes and the one or more infusion
ports; an electrical stimulation source adapted for implantation
into the person and operable to generate the electrical stimulation
pulses for transmission through the lead to the electrodes to cause
the electrodes to deliver the electrical stimulation pulses to the
target nerve tissue; and a chemical stimulation source adapted for
implantation into the person and operable to supply the chemical
stimulation pulses for transmission through the lead to the
infusion ports to cause the infusion ports to deliver the chemical
stimulation pulses to the target nerve tissue.
12. The system of claim 11, wherein the lead comprises a plurality
of electrodes and at least one infusion port is located between two
of the electrodes.
13. The system of claim 11, wherein the lead comprises a plurality
of infusion ports and at least one electrode is located between two
of the infusion ports.
14. The system of claim 11, wherein the system is operable to
provide simultaneous electrical and chemical stimulation of the
target nerve tissue.
15. The system of claim 11, wherein the lead further comprises an
inner channel formed through the lead body, fluidly coupled to the
one or more infusion ports, and adapted to transmit the chemical
stimulation pulses through the lead to the one or more infusion
ports.
16. The system of claim 11, wherein each chemical stimulation pulse
comprises a bolus of a medication.
17. The system of claim 11, wherein the target nerve tissue is
located in the brain stem.
18. The system of claim 11, wherein the lead further comprises a
tapered end adapted to aid in dissection of tissue during
implantation of the lead.
19. The system of claim 11, wherein the electrical stimulation
source is operable to generate the electrical stimulation pulses
according to one or more stimulation sets each specifying a
plurality of stimulation parameters, the stimulation parameters for
a stimulation set comprising a polarity for each electrode at each
of one or more times within an electrical stimulation pulse.
20. The system of claim 19, wherein the electrical stimulation
source is operable to generate the electrical stimulation pulses
according to a plurality of stimulation programs each comprising
one or more stimulation sets.
21. The system of claim 11, wherein the electrical and chemical
stimulation sources are integrated into a single implantable
device.
22. A method for stimulating nerve tissue in a person, comprising:
implanting a combined electrical and chemical stimulation lead
proximate target nerve tissue in the person, the lead comprising: a
lead body; one or more electrodes located along the lead body and
adapted to be positioned proximate the target nerve tissue and to
deliver electrical stimulation pulses transmitted through the lead
to the target nerve tissue; and one or more infusion ports located
along the lead body and adapted to be positioned proximate the
target nerve tissue and to deliver chemical stimulation pulses
transmitted through the lead to the target nerve tissue; the lead
adapted to provide combined electrical and chemical stimulation of
the target nerve tissue using the one or more electrodes and the
one or more infusion ports; implanting an electrical stimulation
source into the person, the electrical stimulation source operable
to generate electrical stimulation pulses for transmission through
the lead to the electrodes to cause the electrodes to deliver the
stimulation pulses to the target nerve tissue; implanting a
chemical stimulation source into the person, the chemical
stimulation source operable to supply the chemical stimulation
pulses for transmission through the lead to the infusion ports to
cause the infusion ports to deliver the chemical stimulation pulses
to the target nerve tissue; using the electrical stimulation source
to generate the electrical stimulation pulses for transmission
through the lead to the electrodes to cause the electrodes to
deliver the stimulation pulses to the target nerve tissue; and
using the chemical stimulation source to supply the chemical
stimulation pulses for transmission through the lead to the
infusion ports to cause the infusion ports to deliver the chemical
stimulation pulses to the target nerve tissue; the electrical and
chemical stimulation sources providing combined electrical and
chemical stimulation of the target nerve tissue.
23. The method of claim 22, wherein the lead comprises a plurality
of electrodes and at least one infusion port is located between two
of the electrodes.
24. The method of claim 22, wherein the lead comprises a plurality
of infusion ports and at least one electrode is located between two
of the infusion ports.
25. The method of claim 22, wherein the electrical and chemical
stimulation are provided simultaneously to the target nerve
tissue.
26. The method of claim 22, wherein the lead further comprises an
inner channel formed through the lead body, fluidly coupled to the
one or more infusion ports, and adapted to transmit the chemical
stimulation pulses through the lead to the one or more infusion
ports.
27. The method of claim 22, wherein each chemical stimulation pulse
comprises a bolus of a medication.
28. The method of claim 22, wherein the target nerve tissue is
located in the brain stem.
29. The method of claim 22, further comprising using a tapered end
of the lead in dissection of tissue during implantation of the
lead.
30. The method of claim 22, wherein the electrical stimulation
source generates the electrical stimulation pulses according to one
or more stimulation sets each specifying a plurality of stimulation
parameters, the stimulation parameters for a stimulation set
comprising a polarity for each electrode at each of one or more
times within an electrical stimulation pulse.
31. The method of claim 30, wherein the electrical stimulation
source generates the electrical stimulation pulses according to a
plurality of stimulation programs each comprising one or more
stimulation sets.
32. The method of claim 22, wherein the electrical and chemical
stimulation sources are integrated into a single implantable
device.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 10/750,788 filed Jan. 2, 2004, entitled "System and Method for
Stimulation of a Person's Brain Stem," which claims the benefit of
U.S. Provisional Application No. 60/438,053 filed Jan. 3, 2003.
[0002] This application is also related to U.S. application Ser.
No. ______ (Attorney's Docket 02-044 Con1 (065274.0135)), filed
______, entitled "System, Method, and Resilient Neurological
Stimulation Lead for Stimulation of a Person's Nerve Tissue," which
is also a continuation of U.S. application Ser. No. 10/750,788.
TECHNICAL FIELD
[0003] This invention relates generally to electrical stimulation
leads and infusion catheters for medical applications and in
particular to a system, method, and combined electrical and
chemical stimulation lead for stimulation of a person's nerve
tissue.
BACKGROUND
[0004] Stimulation may be applied to target nerve tissue in the
brain or spinal cord to treat a variety of clinical conditions.
According to one technique, a set of efficacious neurological
stimulation parameters are determined, the set of parameters is
entered into the system, and the system is used to stimulate,
either electrically or chemically, the target nerve tissue
according to the set of parameters to treat a condition.
[0005] For electrical stimulation, typically, an implanted pulse
generator (IPG) transmits a pulse of efficacious electrical energy
to an implanted electrical stimulation lead according to the set of
parameters and, in response to the pulse, the electrodes of the
implanted stimulation lead deliver the electrical energy to the
target nerve tissue to treat the condition. For chemical
stimulation, typically, an implantable drug pump transmits a pulse
of efficacious drugs through a catheter according to the set of
parameters and, in response to the pulse, infusion ports of the
implanted catheter deliver the chemical dose to the target nerve
tissue to treat the condition.
[0006] However, there exists a certain population of patients with
conditions that are intractable to standard therapies. For example,
some patients with neurodegenerative diseases or trauma such as
cerebral infarct or spinal cord injury may experience pain or
undesirable movements such as spasticity or dyskinesia that are not
responsive to stimulation of the cortex or spinal cord. As another
example, some patients with chronic pain in multiple locations may
not obtain full relief using previous stimulation techniques.
Alternative stimulation methods are desirable to treat the
population of patients with conditions that are intractable to
standard therapies.
SUMMARY OF THE INVENTION
[0007] The neurological stimulation system and the associated
electrical stimulation leads, infusion catheters, and methods of
the present invention may reduce or eliminate certain problems and
disadvantages associated with prior techniques for stimulating
nerve tissue.
[0008] According to one embodiment, a combined electrical and
chemical stimulation lead adapted for implantation proximate target
nerve tissue in a person for combined electrical and chemical
stimulation of the target nerve tissue, includes a lead body. One
or more electrodes located along the lead body and adapted to be
positioned proximate the target nerve tissue and to deliver
electrical stimulation pulses transmitted through the lead to the
target nerve tissue. One or more infusion ports located along the
lead body and adapted to be positioned proximate the target nerve
tissue and to deliver chemical stimulation pulses transmitted
through the lead to the target nerve tissue. The lead is adapted to
provide combined electrical and chemical stimulation of the target
nerve tissue using the one or more electrodes and the one or more
infusion ports.
[0009] According to another embodiment, a neurological stimulation
system is provided for stimulating nerve tissue in a person. The
system includes a combined electrical and chemical stimulation lead
adapted for implantation proximate target nerve tissue in the
person. The lead includes a lead body, one or more electrodes
located along the lead body and adapted to be positioned proximate
the target nerve tissue and to deliver electrical stimulation
pulses transmitted through the lead to the target nerve tissue, and
one or more infusion ports located along the lead body and adapted
to be positioned proximate the target nerve tissue and to deliver
chemical stimulation pulses transmitted through the lead to the
target nerve tissue. The lead is adapted to provide combined
electrical and chemical stimulation of the target nerve tissue
using the one or more electrodes and the one or more infusion
ports. The system includes an electrical stimulation source adapted
for implantation into the person and operable to generate the
electrical stimulation pulses for transmission through the lead to
the electrodes to cause the electrodes to deliver the electrical
stimulation pulses to the target nerve tissue. The system also
includes a chemical stimulation source adapted for implantation
into the person and operable to supply the chemical stimulation
pulses for transmission through the lead to the infusion ports to
cause the infusion ports to deliver the chemical stimulation pulses
to the target nerve tissue.
[0010] According to another embodiment, a method is provided for
stimulating nerve tissue in a person. The method includes
implanting a combined electrical and chemical stimulation lead
proximate target nerve tissue in the person. The lead includes a
lead body, one or more electrodes located along the lead body and
adapted to be positioned proximate the target nerve tissue and to
deliver electrical stimulation pulses transmitted through the lead
to the target nerve tissue, and one or more infusion ports located
along the lead body and adapted to be positioned proximate the
target nerve tissue and to deliver chemical stimulation pulses
transmitted through the lead to the target nerve tissue. The lead
is adapted to provide combined electrical and chemical stimulation
of the target nerve tissue using the one or more electrodes and the
one or more infusion ports. The method includes implanting an
electrical stimulation source into the person, the electrical
stimulation source operable to generate electrical stimulation
pulses for transmission through the lead to the electrodes to cause
the electrodes to deliver the stimulation pulses to the target
nerve tissue, and implanting a chemical stimulation source into the
person, the chemical stimulation source operable to supply the
chemical stimulation pulses for transmission through the lead to
the infusion ports to cause the infusion ports to deliver the
chemical stimulation pulses to the target nerve tissue. The method
also includes using the electrical stimulation source to generate
the electrical stimulation pulses for transmission through the lead
to the electrodes to cause the electrodes to deliver the
stimulation pulses to the target nerve tissue, and using the
chemical stimulation source to supply the chemical stimulation
pulses for transmission through the lead to the infusion ports to
cause the infusion ports to deliver the chemical stimulation pulses
to the target nerve tissue. The electrical and chemical stimulation
sources provide combined electrical and chemical stimulation of the
target nerve tissue.
[0011] Particular embodiments of the present invention may provide
one or more technical advantages. Certain embodiments allow the
electrical stimulation lead or infusion catheter to be implanted
using any number of techniques, such as percutaneous insertion,
insertion through an open craniotomy, or insertion through a burr
hole formed in the skull. Certain embodiments provide electrical
stimulation leads or infusion catheters configured for optimal
performance and stability when implanted on, in, or near nerve
tissue. For example, certain embodiments may use a resilient spiral
matrix lead having a spiral natural position, adapted to be
straightened for insertion through an introducer to a desired
position on, in, or near the brain stem, and adapted to curl into
its spiral natural position to allow stimulation of a broader area
than would be possible using a conventional "in-line" lead and also
to press against surrounding tissue after insertion to stabilize
and maintain the lead in its desired position. As another example,
certain embodiments may use a resilient sheet matrix lead having a
sheet-like natural position, adapted to be rolled upon itself
similar to a scroll for insertion through an introducer to a
desired position on, in, or near the brain stem, and adapted to
unroll to its sheet-like natural position after insertion for
stimulation of a broader area than would be possible using a
conventional "in-line" lead. Certain embodiments allow a medication
or other chemical to be delivered to target nerve tissue using an
implanted infusion pump and catheter for chemical stimulation of
the target nerve tissue in the brain stem, in conjunction with or
independent from any electrical stimulation of the target nerve
tissue in the brain stem.
[0012] Certain embodiments may provide all, some, or none of these
advantages. Certain embodiments may provide one or more other
advantages, one or more of which may be apparent to those skilled
in the art from the figures, descriptions, and claims included
herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] For a more complete understanding of the present invention
and features and advantages thereof, reference is now made to the
following description taken in conjunction with the accompanying
drawings, in which:
[0014] FIGS. 1A-1B illustrate example electrical stimulation
systems for implantation into a person's body for electrical
stimulation of target nerve tissue in the brain stem;
[0015] FIGS. 2A-2I illustrate example electrical stimulation leads
that may be used for implantation in or near a person's brain stem
for electrical stimulation of target nerve tissue in the brain
stem;
[0016] FIG. 3A illustrates example placement of the electrical
stimulation system shown in FIGS. 1A-1B within a person's body;
[0017] FIG. 3B illustrates example placement of an implantable
medical device for neurological stimulation of target nerve tissue
in the brain stem;
[0018] FIG. 4 is a cross-section of a portion of a person's head
illustrating an example location of an electrical stimulation lead
for electrical stimulation of target nerve tissue in the brain
stem;
[0019] FIG. 5 illustrates steps of an example method for
determining the location for an electrical stimulation lead and
implanting the electrical stimulation system of FIGS. 1A-1B into a
person's body;
[0020] FIG. 6 illustrates an example stimulation set;
[0021] FIG. 7 illustrates a number of example stimulation programs,
each of which includes a number of stimulation sets;
[0022] FIG. 8 illustrates example execution of a sequence of
stimulation sets within an example stimulation program;
[0023] FIGS. 9A-9E illustrate an example method for percutaneous
implantation of an electrical stimulation system in or near a
person's brain stem;
[0024] FIG. 10 illustrates steps of an example method for
implanting an electrical stimulation lead in or near a person's
brain stem using a percutaneous approach;
[0025] FIG. 11 illustrates steps of an example method for
implanting an electrical stimulation lead in or near a person's
brain stem through an open craniotomy;
[0026] FIG. 12 illustrates steps of an example method for
implanting an electrical stimulation lead in or near a person's
brain stem through a burr hole formed in the skull;
[0027] FIGS. 13A-13B illustrate an example spiral matrix electrical
stimulation lead;
[0028] FIG. 14 illustrates an example spiral matrix electrical
stimulation lead situated in the dural layer of the brain stem;
[0029] FIGS. 15A-15H illustrate other example electrical
stimulation leads;
[0030] FIG. 16A-16C illustrates the coiling features of an example
electrical stimulation lead;
[0031] FIGS. 17A-17B illustrate example guide wires for inserting
an electrical stimulation leads;
[0032] FIGS. 18A-18B illustrate an example hollow guide wire with a
retractable blade for inserting an electrical stimulation lead;
[0033] FIGS. 19A illustrates an example hollow guide wires for
inserting a micro electrical stimulation lead;
[0034] FIGS. 19B illustrates an example hollow guide wires through
which a corkscrew probe may be passed;
[0035] FIG. 20 illustrates an example hollow guide wire with a
threaded portion configured to attach to a syringe;
[0036] FIG. 21A illustrates an example spiral matrix electrical
stimulation lead in a straightened position for insertion through
an example introducer;
[0037] FIG. 21B illustrates an example spiral matrix electrical
stimulation lead in its spiral natural position after insertion
inserted through an example introducer;
[0038] FIGS. 22A-22D illustrate example spiral matrix leads;
[0039] FIGS. 23A-23D illustrate example anchoring devices attached
to electrical stimulation leads;
[0040] FIGS. 24A-24B illustrate an example introducers that
includes a needle for fixation of the introducer during insertion
of an electrical stimulation lead; and
[0041] FIGS. 25A-25B illustrate an example tapered electrical
stimulation lead that includes both electrodes and an infusion
port.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0042] The present invention provides a system and method for
stimulating a person's brain stem to treat various neurological
disorders such as pain. The brain stem is the stem-like portion of
the brain that connects the cerebral hemispheres with the spinal
cord and includes the medulla oblongata, the pons, and the
midbrain. Because the brain stem connects the brain with the spinal
cord, it serves as the main router for the central nervous system
(CNS). This anatomic arrangement allows for the stimulation of all
major nerve tracts and nuclei within a defined, compact area.
Stimulating in the brain stem region also provides the ability to
stimulate deep brain centers via both antegrade and retrograde
conduction. Thus, both nerve tissue in the spinal cord and nerve
centers in the brain may be stimulated from the brain stem
region.
[0043] Stimulation of the brain stem provides a site for
stimulation and hence pain relief for various parts of the body,
notably areas such as the head and face, the meninges, and the
intracranial vessels and associated nerve innervation that would
otherwise be difficult to access for stimulation. In certain
embodiments, the present invention provides for stimulation that
treats patients with intractable headache and head and neck pain.
Furthermore, in certain embodiments, brain stem stimulation allows
the entire body or a substantial portion of it to be stimulated
from one location. Hence, pain throughout the body may be treated
from one location. For example, a patient with diabetic peripheral
neuropathy, having pain in the hands and feet in a "glove" or
"stocking" distribution, respectively, may be treated using a
single IPG and one or more electrical stimulation leads implanted
on, in, or near the brain stem. In certain embodiments, the present
invention allows multiple sites to be stimulated using a single
unilateral electrical stimulation lead implanted at one location
on, in, or near the brain stem. For example, such multiple sites
may include both hands and both feet, multiple sites in both the
back and neck, or any other suitable combination of sites. As
another example, for patients with peripheral vascular disease
present in the upper and lower extremities, certain embodiments may
provide pain relief and improve blood flow to multiple sites
throughout the body by stimulating a single site in the brain stem.
The present invention contemplates stimulating target nerve tissue
in the brain stem for treatment of pain in any region of the body
according to particular needs and circumstances.
[0044] In certain embodiments, stimulation of the brain stem may
provide a method for treating depression and seizures. In addition,
certain embodiments may provide a method for treating cardiac
disease, such as heart failure, arrhythmias, or cardiac pain for
example, through vagal nerve stimulation. Furthermore, in certain
embodiments, cardiac accelerator and decelerator nerves identified
within the brain stem may be electrically stimulated.
[0045] In certain embodiments, stimulation of the brain stem allows
for precise targeting of specific sites. For example, specific
nuclei (such as the dorsal motor nucleus of the vagus), specific
neural cell clusters, and the entry zone of the vagus may be
stimulated. As another example, the nucleus solitarius that
controls ventilation and taste may be stimulated. As another
example; the expiratory and inspiratory centers in the medulla
oblongata and the olivary nuclei, cerebellar tracts (the
olivocerebellar tract, and dorsal spinocerebellar tract) that
control spasticity and motor control may be stimulated. As another
example, the inferior cerebellar peduncle and extrapyramidal
system, accessible via cerebellar tracts, and other sites that
affect the symptoms of Parkinson's disease, vestibular disease, and
tremor may be stimulated. As another example, corticospinal tracts
either for direct pyramidal control (to treat movement disorders)
or for stimulation of a portion of the pyramidal tract, thought to
represent descending inhibition of lower spinal centers, may be
stimulated to control spasticity. As another example, other nuclei,
such as the nuclei that control nausea, may be stimulated. The
present invention contemplates precise targeting of any specific
site according to particular needs and circumstances.
[0046] In certain embodiments, the present invention also provides
for stimulation of the brain stem by direct, targeted infusion of
medications or other chemical directly into a specific area of the
brain stem. Direct epidural infusion of local anesthetic at low
doses may provide total body analgesia. Therefore, in certain
embodiments, previously untreatable patients with intractable pain,
from thalamic pain syndrome for example, may now be treated. Also,
in certain embodiments, continuous infusion of local anesthetics
may enable intubated patients (patients on ventilators) to be kept
comfortable while administering only minimal medications.
Additionally, in certain embodiments, by administering only minimal
medications, the medications may be readily and quickly reversed
when the intubated patient is ready for unassisted ventilation.
Furthermore, in certain embodiments, such treatment may be achieved
using relatively inexpensive local anesthetics or combinations of
local anesthetics, narcotics, or other centrally active drugs
(e.g., clonidine or dexmeditomidine) that are delivered, for
example, from an implantable medical device such as a drug pump
through a catheter. Higher concentrations of these medications are
currently used to induce general anesthesia. In certain
embodiments, by providing a method of infusing only small amounts
of these medications to targeted areas in the brain stem, these
medications can be utilized for purposes other than general
anesthesia.
[0047] In certain embodiments, infusion of low doses of narcotics
or local anesthetics directly into the brain stem and contained in
the dural barrier at the foramen magnum enables the implantation of
totally implantable epidural pumps. The use of implanted epidural
pumps has been limited because the medications infused into the
epidural space may spread throughout the body. By using an epidural
pump targeted to a site in the brain stem, smaller doses of
medications may be used thereby alleviating the concern for
toxicity associated with using larger doses of medications. A
variety of biologically active substances may be infused, for
example, neurotrophic substances stimulating nerve growth or
regeneration.
[0048] Certain embodiments provide combination electrical
stimulation leads and infusion catheters that offer improved pain
control to patients with chronic pain and other conditions. The use
of electrical stimulation in combination with epidurally-infused
local anesthetics and narcotic medications, immediately after
surgery for example, may significantly reduce a patient's pain and
decrease the incidence of chronic pain. Combination electrical
stimulation leads and infusion catheters on, in, or near the brain
stem may be used to control pain in cardiac patients, for example,
to relieve angina and improve coronary perfusion.
[0049] FIG. 1A-1B illustrate example electrical stimulation systems
10 for implantation into a person's body for electrical stimulation
of target nerve tissue in the brain stem. Such stimulation may be
used to treat various neurological disorders such as pain.
Stimulation system 10 generates and applies a stimulus to a target
area of the brain stem. In general terms, stimulation system 10
includes an implantable electrical stimulation source 12 and an
implantable electrical stimulation lead 14 for applying the
stimulation signal to the target brain tissue. In operation, both
of these primary components are implanted in the person's body, as
discussed below with reference to FIG. 3A. Stimulation source 12 is
coupled to a connecting portion 16 of electrical stimulation lead
14. Stimulation source 12 controls the electrical signals
transmitted to one or more electrodes 18 located on a stimulating
portion 20 of electrical stimulation lead 14, which is located on,
in, or near the target brain tissue, according to suitable signal
parameters (e.g., duration, intensity, frequency, etc.). A doctor,
the patient, or another user of stimulation source 12 may directly
or indirectly input signal parameters into stimulation source 12
for controlling the nature of the electrical stimulation
provided.
[0050] In one embodiment, as shown in FIG. 1A, stimulation source
12 includes an IPG. An example IPG may be one manufactured by
Advanced Neuromodulation Systems, Inc., such as the Genesis.RTM.
System, part numbers 3604, 3608, 3609, and 3644. In another
embodiment, as shown in FIG. 1B, stimulation source 12 includes an
implantable wireless receiver. An example wireless receiver may be
one manufactured by Advanced Neuromodulation Systems, Inc., such as
the Renew.RTM. System, part numbers 3408 and 3416. The wireless
receiver is capable of receiving wireless signals from a wireless
transmitter 22 located external to the person's body. The wireless
signals are represented in FIG. 1B by wireless link symbol 24. A
doctor, the patient, or another user of stimulation source 12 may
use a controller 26 located external to the person's body to
provide control signals for operation of stimulation source 12.
Controller 26 provides control signals to wireless transmitter 22,
wireless transmitter 22 transmits the control signals and power to
the wireless receiver of stimulation source 12, and stimulation
source 12 uses the control signals to vary the parameters of the
electrical pulse transmitted through electrical stimulation lead 14
to the stimulation site. An example wireless transmitter 122 may be
one manufactured by Advanced Neuromodulation Systems, Inc., such as
the Renew.RTM. System, part numbers 3508 and 3516.
[0051] FIGS. 2A-21 illustrate example electrical stimulation leads
14 that may be used for implantation into a person's body for
electrical stimulation of target nerve tissue in the brain stem.
Such stimulation may be used to treat various neurological
disorders such as pain. As described above, each of the one or more
leads 14 incorporated in stimulation system 10 includes one or more
electrodes 18 adapted to be positioned near the target brain tissue
and used to deliver electrical stimulation energy to the target
brain tissue in response to electrical signals received from
stimulation source 12. A percutaneous lead 14, such as example
leads 14a-d, may include one or more circumferential electrodes 18
spaced apart from one another along the length of lead 14.
Circumferential electrodes 18 emit electrical stimulation energy
generally radially in all directions and may be inserted
percutaneously or through a needle. The electrodes 18 of a
percutaneous lead 14 may be arranged in configurations other than
circumferentially, for example as in a "coated" lead, 14. A
laminotomy or paddle style lead 14, such as example leads 14e-i,
includes one or more directional electrodes 18 spaced apart from
one another along one surface of lead 14. Directional electrodes 18
emit electrical stimulation energy in a direction generally
perpendicular to the surface of lead 14 on which they are located.
Although various types of leads 14 are shown as examples, the
present invention contemplates stimulation system 10 including any
suitable type of lead 14 in any suitable number, including
three-dimensional leads and matrix leads as described below. In
addition, the leads may be used alone or in combination. For
example, unilateral stimulation of the brain is typically
accomplished using a single lead 14 implanted in one side of the
brain, while bilateral stimulation of the brain is typically
accomplished using two leads 14 implanted in opposite sides of the
brain.
[0052] FIG. 3A illustrates example placement of the electrical
stimulation system 10 shown in FIG. 1A-1B within a person's body.
Electrical stimulation lead 14 is implanted on, in, or near target
nerve tissue in brain stem. In certain embodiments, electrical
stimulation lead 14 is located at least partially within or below
the dura mater adjacent the brain stem. Stimulation source 12 may
be implanted within a subcutaneous pocket formed in the person's
torso (such as in the chest or buttocks), and connecting portion 16
tunneled, at least in part, subcutaneously (i.e. underneath the
person's skin) to connect stimulation source 12 with electrical
stimulation lead 14. However, stimulation source 12 may be located
at any suitable location within the person's body according to
particular needs.
[0053] FIG. 3B illustrates example placement of an implantable
medical device 12a for neurological stimulation of target nerve
tissue in the brain stem. For example, as discussed above, a
neurological stimulation system may include an implantable medical
device 12a for the delivery of medications to target nerve tissue
in the brain stem. Catheter tip 14a is implanted on, in, or near
target nerve tissue in the brain stem. In certain embodiments,
catheter tip 14a is located at least partially within or below the
dura mater adjacent the brain stem. Implantable medical device 12a,
for example, a medication infusion pump 12a, may be implanted
within a subcutaneous pocket formed in the person's torso (such as
in the chest or buttocks), and catheter 16a tunneled, at least in
part, subcutaneously (i.e. underneath the person's skin. However,
infusion pump 12a may be located at any suitable location within
the person's body according to particular needs. In certain
embodiments, appropriate infusion pumps 12a may include those
illustrated and described in U.S. Pat. Nos. 4,772,263 and
6,666,845, which are hereby incorporated by reference herein as if
fully illustrated and described herein.
[0054] FIG. 4 is a cross-section of a portion of the person's head
illustrating an example location of electrical stimulation lead 14
for electrical stimulation of target nerve tissue in the brain stem
30. In certain embodiments, as discussed above, electrical
stimulation lead 14 is located in the extradural region 32 outside
the dura mater 34 adjacent the brain stem 30. In FIG. 4,
stimulation lead electrodes are directed towards the specific area
of the brain stem 30 in which electrical stimulation is desired. In
other embodiments, electrical stimulation lead 14 could be replaced
with infusion catheter. 14a, or a combined electrical stimulation
lead and infusion catheter such as are described in FIGS. 21A-21B,
depending on the type of stimulation desired at the targeted
site.
[0055] FIG. 5 illustrates steps of an example method for
determining the location for electrical stimulation lead 14 and
implanting the electrical stimulation system 10 of FIG. 1A-1B into
a person's body. At step 40, an electrical stimulation lead is
implanted on, in, or near the brain stem by accessing the brain
tissue through a percutaneous route, an open craniotomy, or a burr
hole. Where a burr hole is the means of accessing the brain stem,
for example, stereotactic equipment suitable to aid in placement of
an electrical stimulation lead 14 on, in, or near the brain stem
may be positioned around the head. Then, an insertion cannula or
introducer for electrical stimulation lead 14 may be inserted
through the burr hole into the brain at step 40, but a cannula is
not typically used where lead 14 is a laminotomy or paddle style
lead 14. A cannula and electrical stimulation lead 14 may be
inserted together or lead 14 may be inserted through the cannula
after the cannula has been inserted. Guided by the navigation
system with any necessary data obtained from previous imaging or
other tests, electrical stimulation lead 14 is precisely positioned
on, in, or near the brain stem at step 42 such that one or more
electrodes 18 are located on, in, or near target nerve tissue in
the brain stem. In certain embodiments, electrical stimulation lead
14 may be positioned extradurally.
[0056] Once electrical stimulation lead 14 has been properly
positioned on, in, or near the targeted brain tissue, such that the
targeted nucleus or other area of stimulation has been contacted
for example, lead 14 is uncoupled from any stereotactic equipment
that may have been used, and any cannula and stereotactic equipment
are removed. Where stereotactic equipment is used, any cannula may
be removed before, during, or after removal of the stereotactic
equipment.
[0057] Once electrical stimulation lead 14 has been inserted and
secured the patient might undergo a trial stimulation period at
steps 44 through 48, which is familiar to those skilled in the art.
With or without a trial stimulation period, stimulation source 12
may be implanted in the person's body at step 50 if permanent
implantation is desired. The implant site is typically a
subcutaneous pocket formed to receive and house stimulation source
12. The implant site is usually positioned a distance away from the
insertion site, such as in the chest, buttocks, or another suitable
location. However, a suitably small stimulation source 12 may be
used to allow stimulation source 12 to be implanted at or near the
stimulation site, for example, on, in, or near the brain stem.
Connecting portion 16 of lead 14 extends from the lead insertion
site to the implant site at which stimulation source 12 is
implanted. Those skilled in the art will recognize that an
extension might be used to connect electrical stimulation lead 14
to stimulation source 12 if required. A doctor, the patient, or
another user of stimulation source 12 may directly or indirectly
input appropriate signal parameters for the stimulation therapy to
specify the nature of the stimulation provided. The same or
analogous steps may be used for the implantation of a system for
chemical stimulation of the brain stem, as described above with
reference to FIG. 3B, substituting an infusion pump 12a for
stimulation source 12 and an infusion catheter 14a for electrical
stimulation lead 14.
[0058] Although example steps are illustrated and described, the
present invention contemplates two or more steps taking place
substantially simultaneously or in a different order. In addition,
the present invention contemplates using methods with additional
steps, fewer steps, or different steps, so long as the steps remain
appropriate for implanting an example stimulation system 10 into a
person for electrical stimulation of the person's brain stem.
[0059] FIG. 6 illustrates an example stimulation set 60. One or
more stimulation sets 60 may be provided, each stimulation set 60
specifying a number of stimulation parameters for the stimulation
set 60. For example, as described more fully below with reference
to FIGS. 7-8, multiple stimulation sets 60 may be executed in a
suitable sequence according to a pre-programmed or randomized
stimulation program. Example stimulation parameters for a
stimulation set 60 may include an amplitude, a frequency, phase
information, and a pulse width for each of a series of stimulation
pulses that electrodes 18 are to deliver to the target brain tissue
during a time interval during which stimulation set 60 is executed,
along with a polarity 62 for each electrode 18 within each
stimulation pulse. Stimulation parameters may also include a pulse
shape, for example, biphasic cathode first, biphasic anode first,
or any other suitable pulse shape. Stimulation parameters are not
limited to the preceding but may include any suitable parameters
known to those skilled in the art.
[0060] The polarity for an electrode 18 at a time 64 beginning a
corresponding stimulation pulse or sub-interval within a
stimulation pulse may be a relatively positive polarity 62, a
relatively negative polarity 62, or an intermediate polarity 62
between the relatively positive polarity 62 and relatively negative
polarity 62. For example, the relatively positive polarity 62 may
involve a positive voltage, the relatively negative polarity 62 may
involve a negative voltage, and the relatively intermediate
polarity 62 may involve a zero voltage (i.e. "high impedance"). As
another example, the relatively positive polarity 62 may involve a
first negative voltage, the relatively negative polarity 62 may
involve a second negative voltage more negative than the first
negative voltage, and the relatively intermediate polarity 62 may
involve a negative voltage between the first and second negative
voltages. The availability of three distinct polarities 62 for an
electrode 18 may be referred to as "tri-state" electrode operation.
The polarity 62 for each electrode 18 may change for each of the
sequence of times 64 corresponding to stimulation pulses or to
sub-intervals within a stimulation pulse according to the
stimulation parameters specified for the stimulation set 60. For
example, as is illustrated in FIG. 6 for an example stimulation set
60 for a lead 14 with sixteen electrodes 18, the polarities 62 of
the sixteen electrodes 18 may change for each of the sequence of
times 64. In the example of FIG. 6, a relatively positive polarity
62 is represented using a "1," a relatively intermediate polarity
62 is represented using a "0," and a relatively negative polarity
62 is represented using a "-1," although any values or other
representations may be used.
[0061] FIG. 7 illustrates a number of example stimulation programs
66, each including a number of stimulation sets 60. One or more
simulation programs 66 may be set up to provide electrical
stimulation of the brain stem. As described above, each stimulation
set 60 specifies a number of stimulation parameters for the
stimulation set 60. In one embodiment, within each stimulation
program 66, stimulation system 10 consecutively executes the
sequence of one or more stimulation sets 60 associated with
stimulation program 66. The sequence may be executed only once,
repeated a specified number of times, or repeated an unspecified
number of times within a specified time period. For example, as is
illustrated in FIG. 8 for the third example stimulation program 66c
including eight stimulation sets 60, each of the eight stimulation
sets 60 is consecutively executed in sequence. Although the time
intervals 68 (t.sub.1-t.sub.0, t.sub.2-t.sub.1, etc.) during which
the stimulation sets 60 are executed are shown as being equal, the
present invention contemplates a particular stimulation set 60
being executed over a different time interval 68 than one or more
other stimulation sets 60 according to particular needs.
[0062] Although stimulation system 10 is illustrated for example as
accommodating up to twenty-four stimulation programs 66 each
including up to eight stimulation sets 60, the present invention
contemplates any number of stimulation programs 66 each including
any number of stimulation sets 60. For example, in a very simple
case, a single stimulation program 66 may include a single
stimulation set 60, whereas in a more complex case twenty-four
stimulation programs 66 may each include eight stimulation sets
60.
[0063] In one embodiment, stimulation system 10 executes only a
single stimulation program 66 in response to user selection of that
stimulation program for execution. In another embodiment, during a
stimulation period, stimulation system 10 executes a sequence of
pre-programmed stimulation programs 66 for each lead 14 until the
stimulation period ends. Depending on the length of the stimulation
period and the time required to execute a sequence of stimulation
programs 66, the sequence may be executed one or more times. For
example, the stimulation period may be defined in terms of a
predetermined number of cycles each involving a single execution of
the sequence of stimulation programs 66, the sequence of
stimulation programs 66 being executed until the predetermined
number of cycles has been completed. As another example, the
stimulation period may be defined in terms of time, the sequence of
stimulation programs 66 being executed until a predetermined time
interval has elapsed or the patient or another user manually ends
the stimulation period. Although a sequence of stimulation programs
66 is described, a single stimulation program being executed one or
more times during a stimulation period according to particular
needs. Furthermore, the present invention contemplates each
stimulation program 66 being executed substantially immediately
after execution of a previous stimulation program 66 or after a
suitable time interval has elapsed since the completion of the
previous stimulation program 66.
[0064] Where stimulation system 10 includes multiple leads 14,
stimulation programs 66 for one lead 14 may be executed
substantially simultaneously as stimulation programs 66 for one or
more other leads 14, may be alternated with stimulation programs 66
for one or more other leads 14, or may be arranged in any other
suitable manner with respect to stimulation programs 66 for one or
more other leads 14.
[0065] In general, each stimulation program 66 may, but need not
necessarily, be set up for electrical stimulation of different
target nerve tissue. As an example, for electrical stimulation of
the brain stem, one or more stimulation programs 66 may be set up
for therapeutic electrical stimulation of certain target brain
tissue in the brain stem and one or more other stimulation programs
66 may be set up for electrical stimulation certain other target
brain tissue in the brain stem.
[0066] The present invention contemplates any suitable circuitry
within stimulation source 12 for generating and transmitting
signals for electrical stimulation of a person's brain stem.
Example circuitry that may be suitable for use is illustrated and
described in U.S. Pat. No, 6,609,031 B1, which is hereby
incorporated by reference herein as if fully illustrated and
described herein.
[0067] An electrical stimulation lead 14 or infusion catheter 14a
may be implanted on, in, or near the brain stem using any suitable
technique. For example, brain stem stimulation may be achieved by
implanting an electrical stimulation lead 14 or infusion catheter
14a using either a percutaneous route, through an open craniotomy,
or through a burr hole formed in the skull.
[0068] FIGS. 9A-9E illustrate an example method for percutaneous
implantation of an electrical stimulation system 14 in or near a
person's brain stem 70. Those skilled in the art will recognize
that similar methods can be used for percutaneous implantation of
infusion catheter 14a. In certain embodiments, as for example in
the percutaneous approach, needle 72 is used to enter epidural
space 74 at any vertebral level that is suitable to gain access to
epidural space 74, for example, the posterior cervical or thoracic
level or alternatively midline or paramedian at the level of the
foramen magnum. Fluoroscopy may be used at any stage of the
implantation procedure to ascertain the anatomic position of any
particular device or instrumentation. The loss of resistance
technique or hanging drop technique may be used to ascertain
direction and depth in epidural space 74. Sterile saline or,
alternatively, myelographic dye may be used to dilate epidural
space 74 to facilitate passage of introducers, guide wires,
electrical stimulation leads 14, and any other device that is to be
introduced into epidural space 74. As shown in FIG. 9B, guide wire
76 may be inserted through needle 72 into dorsal epidural space 74
under continuous fluoroscopy to verify posterior placement in
epidural space 74, lack of parathesia, the presence of
cerebrospinal leak, and proper positioning of guide wire 76 in
epidural space 74. As shown in FIG. 9C, after positioning guide
wire 76 in epidural space 74, needle 72 may be removed and an
introducer 78 may be inserted over guide wire 76 in order to avoid
subsequent trauma to electrical stimulation lead 14. In alternative
embodiments, electrical stimulation lead 14 may be placed through
needle 72 without the use of introducer 78.
[0069] Guide wire 76 may be guided posteriorly in the midline of
posterior epidural space 74 to the level of the foramen magnum, an
opening at the base of a person's skull. It may be necessary to
pass guide wire 76 more than once to dissect a passage under the
second cervical vertebrae where epidural space 74 is narrow. Guide
wire 76 may be slightly bent or curved to facilitate guidance.
Alternating use of straight or bent guide wires 76 may be desired
for different stages of the passage. Upon reaching the level of the
foramen magnum, guide wire 76 may be used to tease open a small
passage through the adhesions attaching the spinal dura to the
periosteal dura, which is attached approximately at the level of
the foramen magnum, thus entering epidural space 74 overlying the
medulla, the lower portion of the brain stem 70. Guide wire 76 is
removed and, as shown in FIG. 9D, electrical stimulation lead 14 is
passed through introducer 78 and the passage created by guide wire
76. Alternatively, a relatively small "micro" electrical
stimulation lead 14 may be passed directly through a hollow guide
wire 76 that may be used in place of solid guide wire 76.
Alternating use of straight or bent stylets, thin probes that
insert into an inner channel in electrical stimulation lead 14 to
straighten and stiffen it, may be used to guide electrical
stimulation lead 14 along the correct path and into a desired
position on, in, or near brain stem 70. As shown in FIG. 9E,
electrical stimulation lead 14 is positioned at the level of
epidural space 74, overlying the medulla for example, although it
may be positioned on, in, or near any other structures in the brain
stem to be stimulated according to particular needs.
[0070] Example steps for percutaneous implantation of electrical
stimulation lead 14 are shown in FIG. 10. Those skilled in the art
will recognize that similar methods can be used for percutaneous
implantation of infusion catheter 14a. At step 80, needle 72 is
inserted into epidural space 74. At step 82, guide wire 76 is
inserted through needle 72 into epidural space 74 and threaded up
epidural space 74 to the level of the foramen magnum at the base of
the skull. At step 84, needle 72 is removed and introducer 78 is
threaded over guide wire 76. At step 86, guide wire 76 is removed
and electrical stimulation lead 14 is inserted through introducer
78. At step 88, electrical stimulation lead 14 is positioned on,
in, or near target nerve tissue to be stimulated in brain stem 70,
using stereotactic imaging for example. If electrical stimulation
lead 14 includes a stylet to aid in inserting lead 14, the stylet
is removed at step 90. At step 92, any stereotactic equipment that
may have been used to assist in placement is removed. Electrical
stimulation lead is connected to stimulation source 12 at step 94,
a subcutaneous pocket is created for stimulation source 12 in the
chest, buttocks, or elsewhere at step 96, and stimulation source 12
is inserted into the subcutaneous pocket at step 98.
[0071] In other embodiments, electrical stimulation lead 14 may be
placed using an open craniotomy procedure. Those skilled in the art
will recognize that similar methods can be used for the same
implantation technique of infusion catheter 14a. FIG. 11
illustrates steps of an example method for implantation of an
electrical stimulation lead 14 into a person's brain stem through
an open craniotomy. At step 100, an incision may be made
approximately over the junction of the occiput and the first or
second cervical vertebrae, or in any other desired location to
access the brain stem. The dura is opened at step 102. At step 104,
electrical stimulation lead 14 may be placed under direct
visualization after teasing open the dura at its attachment to the
foramen magnum, directing lead 14 over the medulla portion of brain
stem 70. At step 106, electrical stimulation lead 14 may be
positioned more precisely using stereotactic imaging. Electrical
stimulation lead is connected to stimulation source 12 at step 108,
a subcutaneous pocket is created for stimulation source 12 in the
chest, buttocks, or elsewhere at step 110, and stimulation source
12 is inserted into the subcutaneous pocket at step 112.
[0072] In other embodiments, electrical stimulation lead 14 may be
placed through a burr hole formed in the skull. Those skilled in
the art will recognize that similar methods can be used for the
same implantation technique of infusion catheter 14a. FIG. 12
illustrates steps of an example method for implantation of an
electrical stimulation lead 14 into a person's brain stem through a
burr hole. After the burr hole is created at step 120, an apparatus
to maintain the position of electrical stimulation lead 14, a burr
hole cap for example, may be seated in the burr hole. Electrical
stimulation lead 14 may be directed into position using
stereotactic guidance. Stereotactic equipment may be positioned
around the head at step 122 if desired. At step 124, electrical
stimulation lead 14 may be inserted through introducer 78 or
otherwise, through a hollow guide wire 76 for example. At step 126,
electrical stimulation lead 14 is positioned on, in, or near brain
stem 70 using stereotactic guidance. Once electrical stimulation
lead 14 has been inserted, the introducer 78, hollow guide wire 76,
or other insertion cannula is removed at step 128, leaving
electrical stimulation lead 14 substantially in position. At step
130, stereotactic equipment is removed. Electrical stimulation lead
is connected to stimulation source 12 at step 132, a subcutaneous
pocket is created for stimulation source 12 in the chest, buttocks,
or elsewhere at step 134, and stimulation source 12 is inserted
into the subcutaneous pocket at step 136.
[0073] The implant site is typically a subcutaneous pocket formed
to receive and house stimulation source 12. The implant site is
usually positioned a distance away from the insertion site, such as
in the chest, buttocks, or another location. A doctor, the patient,
or another user of stimulation source 12 may directly or indirectly
input signal parameters for controlling the nature of the
electrical stimulation provided. The various surgical approaches to
implantation of an electrical stimulation lead 14, including
percutaneously, through an open craniotomy, and through a burr
hole, may similarly be used for implantation of an infusion
catheter 14a on, in, or near the brain stem for neurological
stimulation.
[0074] After successful implantation, the electrical stimulation
lead 14 or infusion catheter 14a may be anchored using a variety of
techniques. Standard techniques for anchoring such as suturing or
the use of an adhesive may be applied to the dura. Instead or in
addition, an adhesive such as benzoin, opsite, or steri-strips may
be used to fix electrical stimulation lead 14 or its extension to
the skin surface at the exit site of lead 14 from the body. Instead
or in addition, as described more fully above, electrical
stimulation lead 14 may be tunneled subcutaneously and attached to
an implanted stimulation source 12.
[0075] In an alternative embodiment, a temporal approach for
placement of electrical stimulation lead 14 or infusion catheter
14a may be used with or without fiber optic assistance to stimulate
the trigeminal ganglion and divisions. For example, percutaneous
lead placement may occur via the foramen torundum (cranial nerves
II and V, the maxillary division of the trigeminal nerve, cranial
nerve V) or the foramen ovale (cranial nerves III and V, the
mandibular division of the trigeminal nerve, cranial nerve V) and
via the sphenopalatine fossa or the sphenoid sinus respectively. A
standard technique for blockade of the maxillary or mandibular
nerves may be performed by injecting local anesthetic in the skin
and passing an epidural needle and electrical stimulation lead 14
perpendicular to the skin under fluoroscopic guidance with the
patient in the supine position and with the head turned toward the
contralateral side. An epidural needle is inserted posterior to the
coronoid process and under the zygomatic arch and advanced until
contacting the lateral pterygoid plate. The needle is withdrawn to
the subcutaneous tissue and reinserted in an anterior-superior
direction approximately one centimeter deeper than the point at
which the lateral pterygoid plate is contacted. Electrical
stimulation lead 14 can then be threaded along the maxillary
division of the trigeminal nerve. Alternatively, the needle may be
inserted below the midpoint of the zygomatic arch in the mandibular
notch and advanced until parathesia is reported along the
mandibular nerve. Electrical stimulation lead 14 may be passed
under fluoroscopy. If the lateral pterygoid plate is reached, the
needle is reinserted slightly posteriorly and the process repeated.
A suitable guide wire, bent or straight, may be used under
fluoroscopic guidance.
[0076] Although example steps for implanting electrical stimulation
lead 14 or infusion catheter 14a on, in, or near the brain stem are
illustrated and described, the present invention contemplates two
or more steps taking place substantially simultaneously or in a
different order. In addition, the present invention contemplates
using methods with additional steps, fewer steps, or different
steps, so long as the steps remain appropriate for implanting
electrical stimulation lead 14 or infusion catheter 14a for
neurological stimulation of target nerve tissue in the brain
stem.
[0077] In certain embodiments, the present invention provides
electrical stimulation leads 14 having multiple electrodes 18
available in a variety of geometrical shapes that include lines,
squares, circles, two-dimensional spirals, three-dimensional
spirals, or other shapes known to those skilled in the art, which
may be used to place and shape lead 14 as shown in FIGS.
13A-15H.
[0078] FIGS. 13A-13B illustrate an example spiral matrix electrical
stimulation lead 14. Electrical stimulation lead includes a number
of electrodes 18 along its length. Although electrical stimulation
lead 14 is shown for example as including eight electrodes 18, lead
14 may include any appropriate number of electrodes 18 according to
particular needs. In one embodiment, as shown in FIG. 13A,
electrical stimulation lead 14 is formed of a resilient material
and has a spiral natural position in which an array of electrodes
14 may be spaced in a matrix-like fashion over an area to be
stimulated. As shown in FIG. 13B, electrical stimulation lead 14
may be straightened, for example, when a stylet is inserted in an
inner channel of lead 14. When the stylet is removed, electrical
stimulation lead 14 again curls into its spiral natural position as
shown in FIG. 13A. Although electrical simulation lead 14 is of
course three-dimensional, lead 14 may be referred to if appropriate
as a "two-dimensional" lead 14 because it has a substantially
planar rather than linear shape when in its spiral natural
position. This type of electrical stimulation lead 14 may aid in
the direct placement of electrodes 18 over the desired area. For
example, once electrical stimulation lead 14 is in place, the
programmer may choose the particular electrode 18 or combination of
electrodes to stimulate a particular location in the brain
stem.
[0079] In certain embodiments, as discussed above, electrical
stimulation lead 14 may include a stylet that maintains lead 14 in
a straightened position during insertion as shown in FIG. 13B. The
straightened position facilitates passage of electrical stimulation
lead 14 through epidural space 74. Once electrical stimulation lead
14 is properly positioned on, in, or near the brain stem, the
stylet is removed and lead 14 may then curl back into its spiral
natural shape as shown in FIG. 13A. Once electrical stimulation
lead 14 has returned to its natural spiral position, its
"two-dimensional" nature allows for an array of electrodes 18 to be
situated in matrix-like fashion on, in, or near target nerve tissue
in the brain stem and may allow stimulation of a broader area than
would be possible using a conventional "in-line" lead. In addition,
the resilient "two-dimensional" nature of electrical stimulation
lead 14 helps anchor lead 14 to prevent migration or movement of
lead 14 from its desired location once implanted.
[0080] Although a spiral shape is primarily described, electrical
stimulation lead 14 may have any suitable substantially planar
shape according to particular needs. As another example, certain
embodiments may use a sheet matrix electrical stimulation lead 14
having a sheet-like natural position, adapted to be rolled upon
itself similar to a scroll for insertion to a desired position on,
in, or near the brain stem, through an introducer 78 or hollow
guide wire 76 for example, and adapted to unroll to its sheet-like
natural position after insertion. Like the spiral matrix electrical
stimulation lead 14 discussed above, this may allow stimulation of
a broader area than would be possible using a conventional
"in-line" lead.
[0081] FIG. 14 illustrates an example "three-dimensional"
electrical stimulation situated in the dural layer of the brain
stem. Electrical simulation lead 14 may be referred to as
"three-dimensional" rather than "two-dimensional" because it has
one or more portions extending out of the plane of electrodes 18
adapted to press against surrounding tissue to further stabilize
lead 14. For example, the spiral portion of electrical stimulation
lead 14 containing electrodes 18 may assume its natural spiral
shape in, above, or adjacent to the dura 140. Other portions of
electrical stimulation lead 14 may extend into epidural space 74 to
help stabilize lead 14.
[0082] FIGS. 15A-15H illustrate other examples of configurations
for electrical stimulation lead 14. Electrical stimulation lead 14
may be configured to situate in a particular anatomic region of the
brain stem. The number, spacing and location of electrodes 18 on
electrical stimulation lead 14 may vary according to anatomic
location and electrical stimulation considerations. Certain
embodiments of electrical stimulation lead 14 may allow stimulation
of multiple sites on, in, or near the brain stem. Certain
embodiments of electrical stimulation lead 14, such as the "T-type"
lead 14 shown in FIG. 15B, may be configured to effect stimulation
across the width of the brain stem over the nucleus and tractus
cuneatus and the nucleus and tractus gracilis as well as the
trigeminal nuclei and tracts. Certain embodiments of electrical
stimulation lead 14, such as the "Y-type" lead 14 shown in FIG.
15F, may be configured to fit the area around the fourth ventricle.
Certain embodiments of electrical stimulation lead 14, such as the
"mirror image" leads shown in FIGS. 15G-5H, provide a matched pair
of leads 14 that are mirror images of each other and may be used to
provide symmetrical electrical stimulation to bilateral structures
of the brain stem. FIG. 15G illustrates a "hockey stick" electrical
stimulation lead 14, which fits one side of the medulla lateral to
the fourth ventricle. Both left and right hand models are possible.
FIG. 15H illustrates another "hockey stick" electrical stimulation
lead 14, with both lateral and ventral electrodes 18 for
stimulation of the lateral and ventral brain stem structures.
[0083] FIG. 16A-16C illustrates the coiling features of certain
embodiments of electrical stimulation lead 14. In FIG. 16A,
electrical stimulation lead 14 is tightly coiled because of the
configuration of a stylet inserted into an inner channel of lead
14. FIG. 16B illustrates electrical stimulation lead 14 more
loosely coiled, with a larger diameter, because the stylet is not
as tightly coiled as in FIG. 16A. FIG. 16C illustrates electrical
stimulation lead 14 even more loosely coiled, with an even larger
diameter, because the stylet is not as tightly coiled as in FIG.
16B or has been removed entirely.
[0084] As described above, in certain embodiments electrical
stimulation leads 14 may be implanted through an open craniotomy or
burr hole formed in the skull. In these embodiments, because the
brain stem may be readily accessed through the open craniotomy or
burr hole, there is no need to traverse the narrow epidural
channel. Accordingly, these embodiments may be most appropriate for
electrical stimulation leads 14, such as those described above with
reference to FIGS. 15-16, which may be placed and positioned
through these larger openings in the skull.
[0085] In certain embodiments, as describe above, a guide wire 76
may be used to guide electrical stimulation lead 14 into position
on, in, or near target nerve tissue in the brain stem. FIGS. 17-20
illustrate example guide wires 76 that may be used in connection
with insertion of an electrical stimulation lead 14. Guide wire 76
may be blunt as shown in FIG. 17A or tapered as shown in FIG. 17B.
FIGS. 18A and 18B show a hollow guide wire 76 that includes a
retractable blade 150, shown in a retracted position in FIG. 18A
and an extended position in FIG. 18B. Retractable blade 150 in
hollow guide wire 76 may be useful for dissecting through dural
tissue at the level of the foramen magnum during passage of the
guide wire 76.
[0086] FIG. 19A illustrates hollow guide wire 76 through which a
small diameter "micro" electrical stimulation lead 14 may be
passed. In certain embodiments, the present invention provides
finer stimulation control as well as simplified operative placement
compared to previously available electrical stimulation leads 14,
because of the unique design of hollow guide 76 wire in combination
with micro electrical stimulation lead 14. FIG. 19B illustrates a
hollow guide wire 76 through which a corkscrew probe 152 may be
passed. Corkscrew probe 152 may be used to dissect through dural
tissue present at the level of the foramen magnum or any other site
where dural tissue or adhesions of other origin are obstructing
passage of a guide wire 76 or electrical stimulation lead.
[0087] Hollow guide wire 76 illustrated in FIG. 20 includes
threaded portion 154 configured to attach to a syringe, for example
a luer lock syringe. Attachment of a syringe to hollow guide wire
76 allows injection of solutions, such as dye, saline, or
medications for example, that may assist in passage of hollow guide
wire 76.
[0088] In certain embodiments, an electrical stimulation lead 14
may also be used to infuse medications or other solutions into
target nerve tissue in the brain stem. For example, FIGS. 21A-21B
illustrate an example electrical stimulation lead 14 that includes
both electrodes 18 and infusion ports 160 through which medications
and other solutions may be delivered into epidural space 74 or to
the targeted brain stem tissue. Electrical stimulation lead 14 may
include one or more ports 160 on its side, at its tip, or both
through which medications or other solutions are infused.
Electrical stimulation lead 14 includes an inner channel through
which medications or other solutions are delivered to ports 160. In
a particular embodiment, electrical stimulation lead 14 may include
side infusion ports 160 alternately situated with electrodes 18
along the length of the stimulating portion 20 of lead . In certain
embodiments, an infusion catheter 14a that does not include
electrodes 18 may be implanted with or without implantation of an
electrical stimulation lead 14. For perioperative use, an
electrical stimulation lead 14 with both electrodes 18 and ports
160 may allow for infusion initially and electrical stimulation
later. Electrical stimulation leads 14 such as illustrated in FIGS.
21A-21B may also be used in central and peripheral nerve
stimulation and infusion. Temporary and permanent versions of
electrical stimulation leads 14 that provide for infusion and of
infusion catheters 14a are possible. Long-term (e.g., up to one
month) tunneled electrical stimulation leads 14 or catheters 14a
can be used for perioperative pain treatment.
[0089] FIGS. 22A-22D illustrates various examples of
"two-dimensional" matrix electrical stimulation leads 14. For
example, particular electrode arrays allow for stimulation in a
substantially two by four electrode array as shown in FIG. 22A, a
substantially three by four electrode array as shown in FIG. 22B, a
substantially in-line eight electrode array as shown in FIG. 22C,
and a substantially three by five electrode array as shown in FIG.
22D.
[0090] In certain embodiments, a flexible electrical stimulation
lead 14 may include two or more electrodes that can be wrapped
around a nerve root, ganglion, or nerve structure in the brain
stem. A variable "collar" can thus be readily tailored to fit a
particular clinical and anatomical situation. Such an electrical
stimulation lead 14, which may be similar in appearance to a
standard percutaneous lead 14, provides increased flexibility and
thus can be wrapped around or corkscrewed around various nervous
structures.
[0091] In certain embodiments, the present invention provides an
improved method of anchoring an electrical stimulation lead 14 on,
in, or near the brain stem using, for example, the embodiments
illustrated in FIGS. 23A-23D. FIGS. 23A-23D illustrate example
anchoring devices attached to electrical stimulation leads 14. In
one embodiment, as shown in FIGS. 23A-23B, one or more round,
tapered, or other balloons 170 may be attached to electrical
stimulation lead 14 to hold lead 14 in a desired position. In
another embodiment, instead or in addition, one or more pins or
barbs may extend from electrical stimulation lead 14 to help
prevent horizontal or vertical movement. In another embodiment,
instead or in addition, a glue-like or tacky substance may be
inserted through an inner channel 172 that runs the length of
electrical stimulation lead 14 as shown in FIGS. 23C-23D. Channel
172 may intersect with a cross-channel 174 through which adhesive
may be delivered to tissue or surrounding structures to help anchor
electrical stimulation lead 14 and prevent its migration out of the
desired position. Suitable adhesives may include cyanoacrylates,
biocompatible glues, or other adhesives known to those skilled in
the art.
[0092] FIGS. 24A-24B illustrate an example introducer 78 that
includes a needle 180 attached to its side. Needle 180 is deployed
when stylet 182 compresses spring 184. Needle 180 may aid in
fixation of introducer 78 during insertion of an electrical
stimulation lead 14 or catheter 14a or may aid in fixation of lead
14 or catheter 14a after positioning. Although needle 180 is
attached to introducer 78 in this example, it may be attached to
any device introduced into epidural space 74 including a guide wire
76, and electrical stimulation lead 14, or a catheter 14a.
[0093] FIGS. 25A-25B illustrate an example tapered electrical
stimulation lead 14 that includes both electrodes 18 and an
infusion port 160. FIGS. 25A and 25B show tope and side views,
respectively, of electrical stimulation lead 14. The tapered end of
electrical stimulation lead 14 aids in dissection under the dura at
the level of the foramen magnum.
[0094] In certain embodiments, an electrical stimulation lead 14
includes a dural cover. Such an electrical stimulation lead 14 may
be used in the subarachnoid space or directly over a nerve
(peripheral or central). The dural cover may be electrically
identical in its properties (e.g., resistance, conductivity,
impedance, etc.) to the single layer of dura and cerebrospinal
fluid surrounding the spinal cord. Thus, the dural cover enables
stimulation to be utilized successfully in the subarachnoid space
and peripherally.
[0095] In certain embodiments, the present invention may provides
smaller electrical stimulation leads 14 and electrodes 18, for
example "micro" leads 14, than currently available in order to
stimulate numerous sites within the brain stem. The compact nature
of the brain stem, and the presence of upper limb, lower limb,
trunk, and facial nerve fibers in near proximity has prevented
larger electrical stimulation leads 14 from providing the fine
stimulation made possible by the present invention. In certain
embodiments, electrical stimulation leads 14 may be introduced
using a 14-gauge modified epidural needle. In other embodiments, a
16-gauge hollow guide wire 76 may be used, through which
specialized boring guides, small electrode electrical stimulation
leads 14, or dye or other liquids may be injected. Any suitable
sized needle, guide wire 76, introducer 78, or other device be
used.
[0096] In certain embodiments, the electrical stimulation leads 14,
infusion catheters 14a, guide wires 76, introducers 78, and other
devices described herein facilitate stimulation of brain stem
structures and fibers including but not limited to the trigeminal
nucleus, nucleus and tractus gracilis and cuneatus, arcuate fibers,
vagal nuclei, the vagal entry zone, nucleus and tractus solitarius,
medial lemniscus, corticospinal tracts, nucleus ambiguus,
cerebellar tracts, trigeminal nerves, the spinothalamic tracts, the
overlying cerebellum, and any other structures in the brain stem or
surrounding brain structures.
[0097] In certain embodiments, the present invention may be used to
treat headache, depression, cardiac respiratory disorders, migraine
headache, cluster headache, atypical facial pain, trigeminal
neuralgia, occipital neuralgia, occipital headache, pseudotumor
cerebri, nausea, head and neck pain, facial pain, sinus headache,
upper extremity pain, lower extremity pain, trunk pain, groin pain,
neck and back pain, reflex sympathetic dystrophy and causalgia of
the head, neck, trunk and extremities, peripheral nerve injury,
chronic regional pain syndromes, peripheral vascular disease,
ischemic pain, ataxia, Parkinson's disease, movement disorders,
tremor, akinesia, rigidity, dyskinesia, bladder dysfunction;
detrusor dyssynergia, plexopathies, urge incontinence, interstitial
cystitis, depression, seizures, thalamic pain, postsurgical pain,
neuropathic pain and neuropathies, peripheral neuropathies, failed
back surgery syndrome, radiculopathy, diabetic neuropathy,
Raynaud's disease and syndrome, Wegener's; cancer and cancer pain,
sexual dysfunction, paraplegia; spinal cord injuries, pelvic floor
dysfunction, angina, obesity, anorexia, neurological disease, and
spasticity.
[0098] In certain embodiments, the present invention provides a
method for stimulating brain stem nuclei to treat various
neurological disorders including pain. Electrodes are placed in the
epidural space adjacent the targeted brain tissue to be stimulated
in the brain stem. Electrical stimulation is then delivered to the
nuclei resulting in stimulation of the painful region of the body
or other site of desired clinical effect. Some example nuclei that
may be stimulated include the gracile, cuneate and trigeminal
nuclei. Stimulation of these nuclei have the potential of providing
paresthesia to any area of the body. In particular, trigeminal pain
has historically been difficult to treat with spinal cord
stimulation. Many physicians have attempted to access the
trigeminal nuclei by directly stimulating the trigeminal nerve in
the periphery of the body. In certain embodiments, the present
invention provides paresthesia coverage to any part of the body,
including the face, through direct stimulation of brain stem
nuclei.
[0099] In certain embodiments, the present invention facilitates
the infusion of medications, chemotherapeutic substances, local
anesthetics, general anesthetics, gene therapies, narcotics,
steroids, neurolytic solutions, analgesics, radiopharmaceuticals,
and other substances into the brain stem either in the subarachnoid
or epidural space. Furthermore, certain embodiments may facilitate
administration of general and regional anesthesia and analgesia,
for example, for use in an intensive care unit, preoperatively,
intraoperatively, and postoperatively. In certain embodiments, the
present invention allows for the treatment of preoperative,
intraoperative and postoperative pain by electrical stimulation,
infusion, or a combination of the two. For example, this might
include somatic perioperative pain relief by infusion, coupled with
longer term neuropathic pain relief by electrical stimulation using
the same combination lead/catheter, in cases of limb
amputation.
[0100] Although the present invention has been described above in
connection with several embodiments, a number of changes,
substitutions, variations, alterations, transformations, and
modifications may be suggested to one skilled in the art, and it is
intended that the present invention encompass such changes,
substitutions, variations, alterations, transformations, and
modifications as fall within the spirit and scope of the appended
claims.
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