U.S. patent application number 12/258317 was filed with the patent office on 2010-01-28 for systems and methods for treating essential tremor or restless leg syndrome using spinal cord stimulation.
This patent application is currently assigned to Boston Scientific Neuromodulation Corporation. Invention is credited to Ahmed A. Elborno.
Application Number | 20100023103 12/258317 |
Document ID | / |
Family ID | 41569344 |
Filed Date | 2010-01-28 |
United States Patent
Application |
20100023103 |
Kind Code |
A1 |
Elborno; Ahmed A. |
January 28, 2010 |
Systems and Methods for Treating Essential Tremor or Restless Leg
Syndrome Using Spinal Cord Stimulation
Abstract
A method for treating essential tremor or restless leg syndrome
using spinal cord stimulation includes implanting a lead near a
spinal cord of a patient. The lead includes a plurality of
electrodes disposed on a distal end of the lead and electrically
coupled to at least one contact terminal disposed on a proximal end
of the lead. Electrical signals are provided from a control module
coupled to the lead to stimulate a portion of the spinal cord of
the patient using at least one of the electrodes. The electrical
signals reduce, alleviate, or eliminate at least one adverse effect
of essential tremor or restless leg syndrome.
Inventors: |
Elborno; Ahmed A.;
(Oakbrook, IL) |
Correspondence
Address: |
Boston Scientific Neuromodulation Corp.;c/o DARBY & DARBY P.C.
P.O. BOX 770, Church Street Station
NEW YORK
NY
10008-0770
US
|
Assignee: |
Boston Scientific Neuromodulation
Corporation
Valencia
CA
|
Family ID: |
41569344 |
Appl. No.: |
12/258317 |
Filed: |
October 24, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12180924 |
Jul 28, 2008 |
|
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12258317 |
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Current U.S.
Class: |
607/117 |
Current CPC
Class: |
A61N 1/0556 20130101;
A61N 1/3752 20130101; A61N 1/0553 20130101; A61N 1/36067 20130101;
A61N 1/36082 20130101; A61N 1/36071 20130101 |
Class at
Publication: |
607/117 |
International
Class: |
A61N 1/00 20060101
A61N001/00 |
Claims
1. A method for treating essential tremor using spinal cord
stimulation, the method comprising: implanting a lead near a spinal
cord of a patient, the lead comprising a plurality of electrodes
disposed on a distal end of the lead and electrically coupled to at
least one contact terminal disposed on a proximal end of the lead;
and providing electrical signals from a control module coupled to
the lead to stimulate a portion of the spinal cord of the patient
using at least one of the electrodes, wherein the electrical
signals reduce, alleviate, or eliminate at least one adverse effect
of essential tremor.
2. The method of claim 1, wherein implanting the lead near the
spinal cord of the patient comprises implanting the lead such that
at least one of the electrodes is in proximity to a segment of the
spinal cord to which at least one nerve attaches, the at least one
nerve also attaching to at least one skeletal muscle at a portion
of the patient's body that is adversely affected by essential
tremor.
3. The method of claim 1, wherein implanting the lead near the
spinal cord of the patient comprises implanting the lead in an
epidural space of the patient.
4. The method of claim 1, wherein implanting the lead comprises
implanting the lead near a portion of the spinal cord with nerve
roots extending to an upper extremity.
5. The method of claim 1, wherein implanting the lead comprises
implanting the lead near a portion of the spinal cord with nerve
roots extending to a lower extremity.
6. The method of claim 1, wherein the electrical signals reduce,
alleviate, or eliminate tremors associated with essential
tremor.
7. The method of claim 1, wherein the electrical signals reduce,
alleviate, or eliminate pain associated with essential tremor.
8. The method of claim 1, wherein implanting the lead adjacent to
the spinal cord of the patient comprises implanting at least one of
a percutaneous lead, a paddle lead, or a cuff lead.
9. The method of claim 1, further comprising adjusting stimulation
parameters of the electrical signals to reduce, alleviate, or
eliminate the at least one adverse effect of essential tremor.
10. An implantable system for treating essential tremor comprising:
a lead having a distal end and a proximal end and configured and
arranged for implantation near a spinal cord of a patient, the lead
comprising a plurality of electrodes disposed on the distal end, a
plurality of terminals disposed on the proximal end, and a
plurality of conductors, each conductor electrically coupling at
least one of the electrodes to at least one of the terminal; and a
control module configured and arranged to electrically couple to
the lead, the control module comprising a housing, and an
electronic subassembly disposed in the housing.
11. The implantable system of claim 10, wherein the control module
is configured and arranged for implantation in the patient.
12. A method for treating restless leg syndrome using spinal cord
stimulation, the method comprising: implanting a lead near a spinal
cord of a patient, the lead comprising a plurality of electrodes
disposed on a distal end of the lead and electrically coupled to at
least one contact terminal disposed on a proximal end of the lead;
and providing electrical signals from a control module coupled to
the lead to stimulate a portion of the spinal cord of the patient
using at least one of the electrodes, wherein the electrical
signals reduce, alleviate, or eliminate at least one adverse effect
of restless leg syndrome.
13. The method of claim 12, wherein implanting the lead near the
spinal cord of the patient comprises implanting the lead such that
at least one of the electrodes is in proximity to a segment of the
spinal cord to which at least one nerve attaches, the at least one
nerve also attaching to at least one skeletal muscle at a portion
of the patient's body that is adversely affected by restless leg
syndrome.
14. The method of claim 12, wherein implanting the lead near the
spinal cord of the patient comprises implanting the lead in an
epidural space of the patient.
15. The method of claim 12, wherein implanting the lead comprises
implanting the lead near a portion of the spinal cord with nerve
roots extending to an upper extremity.
16. The method of claim 12, wherein implanting the lead comprises
implanting the lead near a portion of the spinal cord with nerve
roots extending to a lower extremity.
17. The method of claim 12, wherein the electrical signals reduce,
alleviate, or eliminate unpleasant sensations associated with
restless leg syndrome.
18. The method of claim 12, wherein the electrical signals reduce,
alleviate, or eliminate pain associated with restless leg
syndrome.
19. The method of claim 12, wherein implanting the lead adjacent to
the spinal cord of the patient comprises implanting at least one of
a percutaneous lead, a paddle lead, or a cuff lead.
20. The method of claim 12, further comprising adjusting
stimulation parameters of the electrical signals to reduce,
alleviate, or eliminate the at least one adverse effect of restless
leg syndrome.
21. An implantable system for treating restless leg syndrome
comprising: a lead having a distal end and a proximal end and
configured and arranged for implantation near a spinal cord of a
patient, the lead comprising a plurality of electrodes disposed on
the distal end, a plurality of terminals disposed on the proximal
end, and a plurality of conductors, each conductor electrically
coupling at least one of the electrodes to at least one of the
terminal; and a control module configured and arranged to
electrically couple to the lead, the control module comprising a
housing, and an electronic subassembly disposed in the housing.
22. The implantable system of claim 21, wherein the control module
is configured and arranged for implantation in the patient.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. Ser. No.
12/180,924, filed Jul. 28, 2008, the benefit of the earlier filing
date of which is hereby claimed under 35 U.S.C. .sctn.120, and the
entire contents of which are hereby incorporated by reference.
FIELD
[0002] The present invention is directed to the area of implantable
spinal cord stimulation systems and methods of making and using the
systems. The present invention is also directed to the use of
implantable spinal cord stimulation systems for treating
Parkinsonism, essential tremor, or restless leg syndrome, as well
as methods of making the spinal cord stimulation systems.
BACKGROUND
[0003] Parkinsonism is a neurodegenerative syndrome of the central
nervous system that belongs to a group of conditions called motor
system disorders. The symptoms of Parkinsonism may vary from
patient to patient. In general, Parkinsonism impairs motor skills
and speech, as well as other functions. Most patients experience
tremors (resting or functional) in one or more body locations
(e.g., at least one hand or arm, foot or leg, jaw, face, and the
like), rigidity (e.g., stiffness in one or more of the limbs or
trunk), slowness of movement (bradykinesia), or postural
instability (e.g., impaired balance or coordination, stooping
posture, etc.). Many additional signs and symptoms may also occur
including, for example, difficulty with speech and swallowing,
difficulty with limb movement (e.g., shuffling gate), fatigue,
reduced facial expressions (i.e., facial masking), mood
disturbances, reduced sensation, reduced cognitive ability,
incontinence, light sensitivity, and dermatitis.
[0004] There are many known underlying causes of Parkinsonism
including, for example, Parkinson's disease, Autoimmune Deficiency
Syndrome (AIDS), corticobasal degeneration, Creutzfeldt-Jakob
disease, diffuse Lewy body disease, drug-induced Parkinsonism,
encephalitis lethargica, multiple system atrophy, pantothenate
kinase-associated neurodegeneration, progressive supranuclear
palsy, exposure to toxins (e.g., carbon monoxide, carbon disulfide,
manganese, paraquat, hexane, rotenone, toluene, and the like), side
effects of medications (e.g., phenothiazines, thioxanthenes,
butyrophenones, piperazines, antidepressants, and the like),
vascular Parkinsonism, Wilson's disease, paraneoplastic syndrome,
head trauma, mental disorders, and the like.
[0005] Currently there is no known cure for Parkinsonism. Many
patients suffering from Parkinsonism take one or more medications
for reducing, alleviating, or eliminating one or more of the
symptoms of Parkinsonism. However, some patients are either
unresponsive to medications or detrimentally affected by
medications and, instead, undergo brain surgery to reduce,
alleviate, or eliminate one or more Parkinsonism-related
symptoms.
[0006] Essential tremor is a progressive neurological disease. The
symptoms of essential tremor may vary from patient to patient. Many
patients experience tremors. Some patients may experience impaired
speech in addition to, or instead of, tremors. Most patients
experience tremors during voluntary movement which dissipate during
sleep or periods of inactivity. Tremors may occur in the upper
body, for example, in one or more of the arms and hands, as well as
in the head, neck, jaw, eyelids, and voice. However, tremors may
also occur in one or more of the lower extremities. Essential
tremor patients may also experience one or more additional signs
and symptoms including, for example, decreased balance, anxiety,
depression, decreased cognitive ability, and dementia. Some
patients may experience an increase in the severity of essential
tremors in response to caffeine, tobacco, fatigue, fear, anger, low
blood sugar, lithium salts, anti-depressants, and the like.
[0007] Currently there is no known cure for essential tremor. Many
patients suffering from one or more of the adverse affects of
essential tremor take one or more medications for reducing,
alleviating, or eliminating one or more of the symptoms of
essential tremor. However, some patients are either unresponsive to
medications or detrimentally affected by medications and, instead,
undergo brain surgery to reduce, alleviate, or eliminate one or
more of the symptoms of essential tremor.
[0008] Restless leg syndrome is a progressive disease of the
nervous system often characterized by an irresistible urge to move
one's body in response to an unpleasant sensation that is sometimes
characterized as being uncomfortable, creepy, like
pins-and-needles, itchy, tickly, or burning. Many patients may
experience the unpleasant sensation in at least one lower leg.
However, some patients with restless leg syndrome experience the
unpleasant sensation in other body locations in addition to, or
instead of, the legs including, for example, one or both feet, one
or both thighs, the torso, or one or both arms. Some patients may
experience an increase in the severity of the unpleasant sensation
as the day progresses from morning to evening. Additionally, some
patients may experience an increase in the severity of the
unpleasant sensations when sitting or lying down. Some patients
only experience the unpleasant sensations when sitting or lying
down.
[0009] Patients with restless leg syndrome may also experience one
or more additional signs and symptoms including, for example,
walking discomfort, insomnia, sleepiness, anxiety, depression,
confusion, and decreased cognitive ability. Some restless leg
syndrome patients may experience an increase in the severity of
restless leg syndrome in response to iron deficiency, stress,
hypoglycemia, pregnancy, alcohol, caffeine, undergoing surgery,
aberrant dopamine levels, varicose veins, folate deficiency, sleep
apnea, uremia, diabetes, thyroid disease, peripheral neuropathy,
anticonvulsive medication, lithium salts, tobacco, antidepressants,
beta blockers, H2 blockers, antipsychotics, Lyme disease, magnesium
deficiency, vitamin B-12 deficiency, amyloidosis, kidney disease,
Parkinson's disease, and some autoimmune diseases such as Sjogren's
syndrome, celiac disease, and rheumatoid arthritis.
[0010] Currently there is no known cure for restless leg syndrome.
Some patients with restless leg syndrome take one or more
medications or vitamin or mineral supplements for reducing,
alleviating, or eliminating one or more of the symptoms of restless
leg syndrome. However, some patients are either unresponsive to, or
detrimentally affected by, medications or vitamin or mineral
supplements.
BRIEF SUMMARY
[0011] In one embodiment, a method for treating essential tremor
using spinal cord stimulation includes implanting a lead near a
spinal cord of a patient. The lead includes a plurality of
electrodes disposed on a distal end of the lead and electrically
coupled to at least one contact terminal disposed on a proximal end
of the lead. Electrical signals are provided from a control module
coupled to the lead to stimulate a portion of the spinal cord of
the patient using at least one of the electrodes. The electrical
signals reduce, alleviate, or eliminate at least one adverse effect
of essential tremor.
[0012] In another embodiment, an implantable system for treating
essential tremor includes a lead and a control module. The lead has
a distal end and a proximal end and is configured and arranged for
implantation near a spinal cord of a patient. The lead includes a
plurality of electrodes disposed on the distal end, a plurality of
terminals disposed on the proximal end, and a plurality of
conductors that each electrically couple at least one of the
electrodes to at least one of the terminal. The control module is
configured and arranged to electrically couple to the lead. The
control module includes a housing and an electronic subassembly
disposed in the housing.
[0013] In yet another embodiment, a method for treating restless
leg syndrome using spinal cord stimulation includes implanting a
lead near a spinal cord of a patient. The lead includes a plurality
of electrodes disposed on a distal end of the lead and electrically
coupled to at least one contact terminal disposed on a proximal end
of the lead. Electrical signals are provided from a control module
coupled to the lead to stimulate a portion of the spinal cord of
the patient using at least one of the electrodes. The electrical
signals reduce, alleviate, or eliminate at least one adverse effect
of restless leg syndrome.
[0014] In still yet another embodiment, an implantable system for
treating restless leg syndrome includes a lead and a control
module. The lead has a distal end and a proximal end and is
configured and arranged for implantation near a spinal cord of a
patient. The lead includes a plurality of electrodes disposed on
the distal end, a plurality of terminals disposed on the proximal
end, and a plurality of conductors that each electrically couple at
least one of the electrodes to at least one of the terminal. The
control module is configured and arranged to electrically couple to
the lead. The control module includes a housing and an electronic
subassembly disposed in the housing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Non-limiting and non-exhaustive embodiments of the present
invention are described with reference to the following drawings.
In the drawings, like reference numerals refer to like parts
throughout the various figures unless otherwise specified.
[0016] For a better understanding of the present invention,
reference will be made to the following Detailed Description, which
is to be read in association with the accompanying drawings,
wherein:
[0017] FIG. 1 is a schematic view of one embodiment of dopaminergic
pathways in a brain, the left side of the brain showing a normal
dopaminergic pathway and the right side of the brain showing an
abnormal dopaminergic pathway for a patient with Parkinson's
disease, according to the invention;
[0018] FIG. 2 is a schematic view of one embodiment of a brain
coupled to a skeletal muscle via a spinal cord, motor nerves, and
sensory nerves, according to the invention;
[0019] FIG. 3 is a schematic side view of one embodiment of a
spinal cord, according to the invention;
[0020] FIG. 4 is a schematic view of one embodiment of a spinal
cord stimulation system, according to the invention;
[0021] FIG. 5 is a schematic view of another embodiment of a spinal
cord stimulation system, according to the invention;
[0022] FIG. 6A is a schematic view of one embodiment of a proximal
portion of a lead and a control module of a spinal cord stimulation
system, according to the invention;
[0023] FIG. 6B is a schematic view of one embodiment of a proximal
portion of a lead and a lead extension of a spinal cord stimulation
system, according to the invention; and
[0024] FIG. 7 is a schematic overview of one embodiment of
components of a spinal cord stimulation system, including an
electronic subassembly disposed within a control module, according
to the invention.
DETAILED DESCRIPTION
[0025] The present invention is directed to the area of implantable
spinal cord stimulation systems and methods of making and using the
systems. The present invention is also directed to the use of
implantable spinal cord stimulation systems for treating
Parkinsonism, essential tremors, or restless leg syndrome, as well
as methods of making the spinal cord stimulation systems.
[0026] Spinal cord stimulation involves delivering an electrical
current to a site on or near a target nerve. This stimulation
generally creates a tingling sensation, known as parasthesia,
throughout a particular region of the body associated with the
stimulated nerve. The size, intensity, and character of the
parasthesia may be controlled by adjusting the parameters (e.g.,
stimulus pulsewidth, amplitude, and frequency) of the stimulating
current.
[0027] It has been discovered that stimulating the spinal cord with
an electrical stimulation current in proximity to selected nerves
can alleviate or eliminate one or more of the adverse effects of
Parkinsonism occurring at the site of skeletal muscle to which the
one or more stimulated nerves couple. Thus, abnormalities that
originate from the brain due to Parkinsonism can be modulated at
the level of the spinal cord to normalize movement adversely
affected by the Parkinsonism.
[0028] Dopamine is a neurotransmitter involved in the control of
body movement. Although the present invention is not limited by any
particular theory, it is thought that the symptoms of Parkinsonism
arise when dopamine-secreting cells degenerate, causing a
subsequent depletion of dopamine in other portions of the brain.
Eventually, deficient dopamine levels results in undesired signals
being sent to skeletal muscles, thereby causing disordered body
movements. It is thought that, stimulating the spinal cord in
proximity to one or more nerves transmitting the undesired signals
to skeletal muscles can be used to counteract the ill effects of
deficient dopamine levels and normalize muscle movement.
[0029] FIG. 1 is a schematic view of one embodiment of dopaminergic
pathways in a brain 102 under normal conditions (left side) and
with Parkinson's disease (right side). The brain 102 includes a
midbrain (mesencephalon) 104, a left hemisphere 106, and a right
hemisphere 108. Each of the hemispheres 106 and 108 include a
thalamus 110, a basal ganglia 112, and a cerebral cortex 114. Each
of the basal ganglia 112 includes a substantia nigra 116, a
subthalamic nucleus 118, a caudate nucleus 120, a putamen 122, a
globus pallidus externus 124, and a globus pallidus internus
126.
[0030] Dopamine is secreted from dopaminergic cells in the
substantia nigra 116 and transported to other portions of the basal
ganglia 122 before transport to the thalamus 110 and the cerebral
cortex 114. Each of the other portions of the brain 102 through
which dopamine interacts is involved in the control of movement. By
interacting with these other regions, the substantia nigra 116
facilitates smooth, fluid, and controlled movement. The left
hemisphere 106 includes arrows of uniform thickness showing an
exemplary normal amount of dopamine along a dopaminergic pathway.
The right hemisphere 108 includes arrows of various thicknesses
showing an exemplary abnormal dopaminergic pathway consistent with
a patient with Parkinsonism. As dopamine-secreting cells
degenerate, reduced amounts of dopamine are released, resulting in
reduced stimulation of dopamine-receiving cells, which, in turn,
results in many different possible adverse affects, such as
disordered movement.
[0031] One of the hallmarks of Parkinsonism is tremors, either
resting or functional. The mechanisms of Parkinsonian tremor are
currently not fully understood. Although the present invention is
not limited by any particular theory, at least some theories
suggest that Parkinsonian tremor is due to oscillating neuronal
activity within the central nervous system. At least some studies
have shown that multiple oscillators are involved which are
believed to be produced in basal ganglia loops.
[0032] The neuronal mechanisms forming the oscillations are also
currently not fully understood. Several possible hypotheses for
neuronal mechanisms forming the oscillations have been proposed
based on animal models and collected patient data, One hypothesis
suggests that oscillations form from hyperpolarization of cells
within a cortico-subthalamo-pallido-thalamic loop. Another
hypothesis suggests that hyperpolarization of cells form a
pacemaker in the globus pallidus externus 124 and the subthalamic
nucleus 118. Yet another hypothesis suggests that abnormal
synchronization is due to unknown mechanisms within a
striato-pallido-thalamic pathway which leads to a loss of
segregation between two or more of the basal ganglia loops.
[0033] Currently, Parkinsonism is managed in many patients by
medication or brain surgery. Two common types of medications are
levodopa and dopamine agonists. Levodopa transforms into dopamine
in the brain and can be used to supplement reduced dopamine levels.
Unfortunately, because levodopa is also metabolized in other
regions of a patient's body, many possible side effects may result
from continued use of levodopa including, for example, nausea,
vomiting, orthostatic hypotension, excessive sleepiness,
hallucinations, dyskinesias, and the like or combinations thereof.
Additionally, due to feedback inhibition, increased circulation of
levodopa may result in reduced endogenous levodopa formation.
[0034] Dopamine agonists (e.g., pergolide, pramipexole,
bromocriptine, ropinirole, and apo-morphine) are medications that
mimic the effect of dopamine on the cells which normally receive
dopamine from the substantia nigra 116. Unfortunately, long-term
use of dopamine agonists may result in similar side effects as with
levodopa. Other medications may be used in conjunction with
levodopa or dopamine agonists, or in lieu of levodopa or dopamine
agonists including, for example, carbidopa, catechol-0-methyl
transferase (COMT) inhibitors, anti-cholinergics, selegiline,
amantadine, and the like or combinations thereof.
[0035] Brain surgery is a treatment option for patients with
late-stage Parkinsonism or patients that are unresponsive to
medications or that exhibit unacceptable levels of dyskinesias, or
other adverse effects, at therapeutic levels of medication. It is
possible that brain surgery disrupts oscillations by
desynchronizing the activity of one or more of the pathways
discussed above. Two common types of brain surgery include ablation
and deep brain stimulation. Ablative surgery removes or destroys a
malfunctioning portion of the brain in order to restore balance of
neural activity with the movement control centers of the brain.
Ablation may be performed at one or more of the movement control
centers of the brain including, for example, the globus pallidus
internus (a "pallidotomy"), or the thalamus, However, ablation can
be difficult, dangerous, invasive, and expensive.
[0036] Deep brain stimulation provides high-frequency electrical
stimulation to a region surrounding an abnormally functioning
structure, such as the globus pallidus internus 126 or the
subthalamic nucleus 118. The stimulation causes global
hyperpolarization of cell membranes which, in turn, causes a
reduction of excitability and subsequent tremor. In other words,
the stimulation jams signal flow out of the abnormally functioning
structure, thereby disrupting abnormal oscillations. Additionally,
antidromic or orthodromic depolarization currents may form which
may modulate neural activity at remote locations.
[0037] As discussed above, abnormal levels of dopamine may
eventually lead to disordered movements. Dopamine-initiated signals
originating in the brain are transmitted to skeletal muscles via
the peripheral nervous system. FIG. 2 is a schematic view of one
embodiment of a brain 202 coupled to a skeletal muscle 204 via a
spinal cord 206, motor nerves 208, and sensory nerves 210.
Typically, signals transmit in both directions along a longitudinal
length of the spinal cord 206, as shown by two-headed directional
arrow 212, and in only one direction along a longitudinal length of
the motor nerves 208 and a longitudinal length of the sensory
nerves 210, as shown by directional arrows 214 and 216,
respectively.
[0038] The motor nerves 208 and the sensory nerves 210 that couple
with the muscle 204 at one end, couple to the spinal cord 206 at a
segment 218 which contains the roots of the motor nerves 208 and
the sensory nerves 210. Other skeletal muscles in different
locations in a patient attach at different segments along the
longitudinal length of the spinal cord 206.
[0039] FIG. 3 is a schematic side view of one embodiment of a
spinal cord 302. The spinal cord 302 is typically divided into
thirty-one different segments which connect to the spinal cord 302
between vertebrae of a vertebral column. Each segment includes
motor and sensory nerve roots. There are typically eight cervical
segments (C1-C8) 304, twelve thoracic segments (T1-T12) 306, five
lumbar segments (L1-L5) 308, five sacral segments (S1-S5) 310, and
a coccygeal segment 312.
[0040] Each segment of the spinal cord 302 sends and receives
signals corresponding to muscle movement, such as skeletal muscle
movement at different locations of a patient's body. For example,
muscles used to control movement of the head and neck typically
connect to the spinal cord 302 at C1-C3; muscles used to control
movement of the hands typically connect to the spinal cord 302 at
T1; muscles used to control movement of the wrists and elbows
typically connect to the spinal cord 302 at C6-C7; muscles used to
control movement of the hips typically connect to the spinal cord
302 at L2; muscles used to control movement of the quadriceps
typically connect to the spinal cord 302 at L3; muscles used to
control movement of the hamstrings and knees typically connect to
the spinal cord 302 at L4-L5; and muscles used to control movement
of the feet and knees typically connect to the spinal cord 302 at
L4-S1, In at least some embodiments, Parkinsonism may be treated
using spinal cord stimulation. Although the present invention is
not limited by any particular theory, at least one patient has
shown that the symptoms of Parkinsonism can be reduced, alleviated,
and even eliminated, by stimulating the spinal cord at the segment
of the spinal cord connecting motor and sensory nerves to skeletal
muscles affected by Parkinsonism. For example, for a patient with a
hand tremor, the hand tremor may be alleviated, or even entirely
eliminated, by implanting a spinal cord stimulation lead ("lead")
adjacent to the patient's spinal cord at T1. As discussed below, in
at least some embodiments, tremors that are unrelated to
Parkinsonism may also be treated using spinal cord stimulation.
[0041] In at least some embodiments, a lead is positioned in
proximity to one or more motor nerves When a motor nerve is
stimulated, the motor nerve transmits electrical pulses along the
motor nerve to one or more attached muscle fibers and elicits
contractions in the attached muscle fiber(s). In at least some
embodiments, a lead is positioned in proximity to one or more
sensory nerves. When a sensory nerve is stimulated, the sensory
nerve produces an electrical impulse that is transmitted along the
nerve into the spinal cord, where it can produce perceptible
sensations, modulation of spinal cord circuits, and reflex effects
on motor pathways. In at least some embodiments, a lead is
positioned in proximity to one or more motor nerves and one or more
sensory nerves. In at least some embodiments, a plurality of leads
may be used to stimulate one or more motor or sensory nerves
coupled to one or more muscles or muscle groups.
[0042] In at least some embodiments, Parkinsonism-related tremors
of at least a portion of one of the upper extremities are reduced,
alleviated, or eliminated by spinal cord stimulation. In at least
some embodiments, Parkinsonism-related tremors of at least a
portion of one of the lower extremities are reduced, alleviated, or
eliminated by spinal cord stimulation. In at least some
embodiments, Parkinsonism-related tremors of at least a portion of
one of the upper extremities and at least a portion of one of the
lower extremities are reduced, alleviated, or eliminated by spinal
cord stimulation.
[0043] In at least some embodiments, Parkinsonism-related tremors
are reduced, alleviated, or eliminated in severity by spinal cord
stimulation. In at least some embodiments, Parkinsonism-related
tremors are reduced, alleviated, or eliminated in frequency by
spinal cord stimulation. In at least some embodiments,
Parkinsonism-related tremors are reduced, alleviated, or eliminated
in severity and in frequency by spinal cord stimulation.
[0044] In at least some embodiments, Parkinsonism-related
functional tremors are reduced, alleviated, or eliminated by spinal
cord stimulation. In at least some embodiments,
Parkinsonism-related resting tremors are reduced, alleviated, or
eliminated by spinal cord stimulation. In at least some
embodiments, both Parkinsonism-related functional tremors and
resting tremors are reduced, alleviated, or eliminated by spinal
cord stimulation.
[0045] In at least some embodiments, tremors (either resting or
functional) are reduced, alleviated, or eliminated in severity by
spinal cord stimulation. In at least some embodiments, tremors
(either resting or functional) are reduced, alleviated, or
eliminated in frequency by spinal cord stimulation. In at least
some embodiments, tremors (either resting or functional) are
reduced, alleviated, or eliminated in severity and in frequency by
spinal cord stimulation.
[0046] In at least some embodiments, Parkinsonism-related
bradykinesia is reduced, alleviated, or eliminated in a patient by
spinal cord stimulation. In at least some embodiments,
Parkinsonism-related shuffling gate is reduced, alleviated, or
eliminated in a patient by spinal cord stimulation. In at least
some embodiments, Parkinsonism-related stooping posture is reduced,
alleviated, or eliminated in a patient by spinal cord stimulation.
In at least some embodiments, Parkinsonism-related pain associated
with one or more body regions is reduced, alleviated, or eliminated
in a patient by spinal cord stimulation.
[0047] In one patient, the spinal cord of a patient with
Parkinsonism was stimulated and the results were monitored over a
five month period. At the beginning of the study, the patient
presented with resting and functional tremors of the upper and
lower extremities, pain in the upper and lower extremities,
bradykinesia in the upper extremities, as well as a shuffling gait.
Due to instability, the patient had been confined to a motorized
wheelchair for twelve years which the patient had difficulty
operating due to the severity of the right upper-extremity tremors.
After a five day trial period for the lower extremities, the
patient was able to stand up and walk approximately 70 feet without
assistance. The patient was subsequently fitted with a permanent
stimulator. After three weeks, the associated pain was reduced
80-90%, the shuffling gait was eliminated, the instability was
eliminated, the patient was able to walk, and the tremors were
eliminated in the lower extremities. A trial stimulation was
subsequently performed on the upper extremities two-months later.
After the 5 day trial period for the upper extremities, the tremors
were eliminated, the associated pain was eliminated, and the
bradykinesia was eliminated. Additionally, the patient showed
reduced light sensitivity and showed improved mental focus.
Moreover, the patient showed increased ability to form facial
expressions.
[0048] In at least some embodiments, stimulating the spinal cord
with an electrical stimulation current in proximity to selected
nerves can reduce, alleviate, or eliminate one or more of the
adverse effects of essential tremor occurring at the site of
skeletal muscle to which the one or more stimulated nerves couple.
Thus, abnormalities that originate from the brain due to essential
tremor can be modulated at the level of the spinal cord to
normalize movement adversely affected by the essential tremor.
[0049] The mechanisms of essential tremor are currently not fully
understood. Although the present invention is not limited by any
particular theory, at least some theories suggest that essential
tremor is due to disorders of the cerebellum or the
cerebello-thalamo-cortical circuits or an abnormally functioning
central oscillator.
[0050] Currently, essential tremor is managed in many patients by
medication or brain surgery. Common types of medications are
tranquilizers (e.g., alprazolam, clonazepam, or diazepam),
beta-blockers (e.g, propranolol, atenolol, metoprolol, or nadolol),
antiseizure medications (e.g., primidone, gabapentin, or
topiramate), antipsychotics (e.g., clozapine), antidepressants
(e.g., mirtazapine), and calcium-channel blockers (e.g.,
flunarizine or nimodipine), as well as alcohol and botulinum toxin.
Many different adverse side effects may result from continued use
of beta-blockers or antiseizure medication including, for example,
fatigue, shortness of breath, decreased heart rate, nasal
congestion, drowsiness, difficulty concentrating, nausea, decreased
coordination, and the like or combinations thereof.
[0051] Brain surgery is a treatment option for patients with severe
essential tremor or patients that are unresponsive to medications
or that exhibit unacceptable levels of dyskinesias, or other
adverse effects, at therapeutic levels of medication. It is
possible that brain surgery disrupts oscillations by
desynchronizing the activity of one or more of the pathways
discussed above. Two common types of brain surgery include ablation
and deep brain stimulation. Ablative surgery removes or destroys a
malfunctioning portion of the brain in order to restore balance of
neural activity with the movement control centers of the brain.
Ablation may be performed at one or more of the movement control
centers of the brain including, for example, the thalamus. However,
ablation can be difficult, dangerous, invasive, and expensive.
[0052] Deep brain stimulation provides high-frequency electrical
stimulation to a region surrounding an abnormally functioning
structure, such as the thalamus. The stimulation causes global
hyperpolarization of cell membranes which, in turn, causes a
reduction of excitability and subsequent tremor. In other words,
the stimulation obstructs signal flow out of the abnormally
functioning structure, thereby disrupting abnormal oscillations.
Additionally, antidromic or orthodromic depolarization currents may
form which may modulate neural activity at remote locations.
[0053] In at least some embodiments, essential tremor may be
treated using spinal cord stimulation. Although the present
invention is not limited by any particular theory, it has shown
that the symptoms of essential tremor can be reduced, alleviated,
and even eliminated, by stimulating the spinal cord at the segment
of the spinal cord connecting motor or sensory nerves to skeletal
muscles affected by essential tremor. For example, for a patient
with a hand tremor, the hand tremor may be alleviated, or even
entirely eliminated, by implanting a spinal cord stimulation lead
("lead") adjacent to the patient's spinal cord at Ti.
[0054] In at least some embodiments, a lead is positioned in
proximity to one or more motor nerves coupling the spinal cord to
one or more skeletal muscles in the portion of the body affected by
essential tremor. When a motor nerve is stimulated, the motor nerve
transmits electrical pulses along the motor nerve to one or more
attached muscle fibers and elicits contractions in the attached
muscle fiber(s). In at least some embodiments, a lead is positioned
in proximity to one or more sensory nerves coupling the spinal cord
to one or more skeletal muscles in the portion of the body affected
by essential tremor. When a sensory nerve is stimulated, the
sensory nerve produces an electrical impulse that is transmitted
along the nerve into the spinal cord, where it can produce
perceptible sensations, modulation of spinal cord circuits, and
reflex effects on motor pathways. In at least some embodiments, a
lead is positioned in proximity to one or more motor nerves and one
or more sensory nerves coupling the spinal cord to one or more
skeletal muscles in the portion of the body affected by essential
tremor. In at least some embodiments, a plurality of leads may be
used to stimulate one or more motor or sensory nerves coupling one
or more skeletal muscles in the spinal cord to the portion of the
body affected by essential tremor.
[0055] In at least some embodiments, essential-tremor-related
tremors of at least a portion of one of the upper extremities are
reduced, alleviated, or eliminated by spinal cord stimulation. In
at least some embodiments, essential-tremor-related tremors of at
least a portion of one of the lower extremities are reduced,
alleviated, or eliminated by spinal cord stimulation. In at least
some embodiments, essential-tremor-related tremors of at least a
portion of one of the upper extremities and at least a portion of
one of the lower extremities are reduced, alleviated, or eliminated
by spinal cord stimulation.
[0056] In at least some embodiments, essential-tremor-related
tremors are reduced, alleviated, or eliminated in severity by
spinal cord stimulation. In at least some embodiments,
essential-tremor-related tremors are reduced, alleviated, or
eliminated in frequency by spinal cord stimulation. In at least
some embodiments, essential-tremor-related tremors are reduced,
alleviated, or eliminated in severity and in frequency by spinal
cord stimulation.
[0057] In at least some embodiments, stimulating the spinal cord
with an electrical stimulation current in proximity to selected
nerves can reduce, alleviate, or eliminate one or more of the
adverse effects of restless leg syndrome occurring at the site of
skeletal muscle to which the one or more stimulated nerves couple.
Thus, abnormalities that originate from the brain due to restless
leg syndrome can be modulated at the level of the spinal cord to
normalize adversely affects caused by the restless leg
syndrome.
[0058] Symptoms associated with restless leg syndrome may include
an unpleasant sensation which may cause bodily movements to be made
to temporarily reduce, alleviate, or eliminate the unpleasant
sensation. As discussed above, the unpleasant sensation may occur
at other body locations besides the leg including, for example, in
the feet, hands, torso, or arms. The mechanisms of restless leg
syndrome are currently not fully understood. Although the present
invention is not limited by any particular theory, at least some
theories suggest that restless leg syndrome is due to a dopamine
imbalance.
[0059] Currently, restless leg syndrome is managed in many patients
by medication. Common types of medications are pain relievers
(e.g., ibuprofen, aspirin, or acetaminophen), medications taken for
Parkinsonism (see above), opioids (e.g., codeine, oxycodone,
methadone, or propoxyphene), muscle relaxants/sedatives (e.g.,
benzodiazepine, clonazepam, eszopiclone, ramelteon, temazepam,
zaleplon, alprazolam, or zolpidem), antiseizure medications (e.g.,
gabapentin), tranquilizers (e.g., clonazepam), .alpha.2 adrenergic
agonists (e.g., clonidine), and the like or combinations
thereof.
[0060] In at least some embodiments, restless leg syndrome may be
treated using spinal cord stimulation. Although the present
invention is not limited by any particular theory, it has been
shown that the symptoms of restless leg syndrome can be reduced,
alleviated, and even eliminated, by stimulating the spinal cord at
the segment of the spinal cord connecting motor and sensory nerves
to skeletal muscles affected by restless leg syndrome. For example,
for a patient with an unpleasant sensation in the foot, the
unpleasant sensation may be alleviated, or even entirely
eliminated, by implanting a spinal cord stimulation lead ("lead")
adjacent to the patient's spinal cord at L4-S1.
[0061] In at least some embodiments, a lead is positioned in
proximity to one or more motor nerves coupling the spinal cord to
one or more skeletal muscles in the portion of the body affected by
restless leg syndrome. When a motor nerve is stimulated, the motor
nerve transmits electrical pulses along the motor nerve to one or
more attached muscle fibers and elicits contractions in the
attached muscle fiber(s). In at least some embodiments, a lead is
positioned in proximity to one or more sensory nerves coupling the
spinal cord to one or more skeletal muscles in the portion of the
body affected by restless leg syndrome. When a sensory nerve is
stimulated, the sensory nerve produces an electrical impulse that
is transmitted along the nerve into the spinal cord, where it can
produce perceptible sensations, modulation of spinal cord circuits,
and reflex effects on motor pathways. In at least some embodiments,
a lead is positioned in proximity to one or more motor nerves and
one or more sensory nerves coupling the spinal cord to one or more
skeletal muscles in the portion of the body affected by restless
leg syndrome. In at least some embodiments, a plurality of leads
may be used to stimulate one or more motor or sensory nerves
coupling the spinal cord to one or more skeletal muscles in the
portion of the body affected by restless leg syndrome.
[0062] In at least some embodiments, restless-leg-syndrome-related
unpleasant sensations of at least a portion of one of the upper
extremities are reduced, alleviated, or eliminated by spinal cord
stimulation. In at least some embodiments,
restless-leg-syndrome-related unpleasant sensations of at least a
portion of one of the lower extremities are reduced, alleviated, or
eliminated by spinal cord stimulation. In at least some
embodiments, restless-leg-syndrome-related unpleasant sensations of
at least a portion of one of the upper extremities and at least a
portion of one of the lower extremities are reduced, alleviated, or
eliminated by spinal cord stimulation.
[0063] In at least some embodiments, restless-leg-syndrome-related
unpleasant sensations are reduced, alleviated, or eliminated in
severity by spinal cord stimulation. In at least some embodiments,
restless-leg-syndrome-related unpleasant sensations are reduced,
alleviated, or eliminated in frequency by spinal cord stimulation.
In at least some embodiments, restless-leg-syndrome-related
unpleasant sensations are reduced, alleviated, or eliminated in
severity and in frequency by spinal cord stimulation.
[0064] Suitable implantable spinal cord stimulation systems
include, but are not limited to, a spinal cord stimulation lead
("lead") with one or more electrodes disposed on a distal end of
the lead and one or more terminals disposed on one or more proximal
ends of the lead. Leads include, for example, percutaneous leads,
paddle leads, and cuff leads. Examples of spinal cord stimulation
systems with leads are found in, for example, U.S. Pat. Nos.
6,181,969; 6,516,227; 6,609,029; 6,609,032; and 6,741,892; and U.S.
patent applications Ser. Nos. 10/353,101, 10/503,281, 11/238,240;
11/319,291; 11/327,880; 11/375,638; 11/393,991; and 11/396,309, all
of which are incorporated by reference.
[0065] FIG. 4 illustrates schematically one embodiment of a spinal
cord stimulation system 400. The spinal cord stimulation system
includes a control module (e.g., a stimulator or pulse generator)
402, a paddle body 404, and at least one lead body 406 coupling the
control module 402 to the paddle body 404. The paddle body 404 and
the one or more lead bodies 406 form a lead. The paddle body 404
typically includes an array of electrodes 434. The control module
402 typically includes an electronic subassembly 410 and an
optional power source 420 disposed in a sealed housing 414. The
control module 402 typically includes a connector 444 (FIG. 5 and
6A, see also 622 and 650 of FIG. 6B) into which the proximal end of
the one or more lead bodies 406 can be plugged to make an
electrical connection via conductive contacts on the control module
402 and terminals (e.g., 610 in FIG. 6A and 636 of FIG. 6B) on each
of the one or more lead bodies 406. It will be understood that the
spinal cord stimulation system can include more, fewer, or
different components and can have a variety of different
configurations including those configurations disclosed in the
spinal cord stimulation system references cited herein. For
example, instead of a paddle body 404, the electrodes 434 can be
disposed in an array at or near the distal end of the lead body 406
forming a percutaneous lead, as illustrated in FIG. 5. A
percutaneous lead may be isodiametric along the length of the lead.
In addition, one or more lead extensions 612 (see FIG. 6B) can be
disposed between the one or more lead bodies 406 and the control
module 402 to extend the distance between the one or more lead
bodies 406 and the control module 402 of the embodiments shown in
FIGS. 4 and 5.
[0066] The spinal cord stimulation system or components of the
spinal cord stimulation system, including one or more of the lead
bodies 506, the paddle body 504, and the control module 402, are
typically implanted into the body of a patient. In at least some
embodiments, the lead is implanted into an epidural space, between
the spinal cord and the vertebral column, of a patient in proximity
to the segment of the spinal cord where at least one motor nerve or
at least one sensory nerve of the body portion affected by
Parkinsonism attaches to the spinal cord. In at least some
embodiments, the lead is in proximity to the one or more nerves of
interest when the one or more nerves of interest are near enough to
be contacted with stimulation pulses equal to or above a minimum
therapeutic stimulation level. The minimum distance needed to
ensure that the one or more nerves of interest are contacted with
stimulation pulses equal to or above the minimum therapeutic
stimulation level may be affected by a variety of factors
including, for example, the amplitude of the stimulation pulses,
the types of tissue surrounding the one or more nerves of interest,
the types of tissue surrounding the lead, the types of tissue
between the one or more nerves and the lead, the distance between
the lead and the one or more nerves of interest, and the like.
[0067] In at least some embodiments, implantation of the lead may
involve surgery. For example, in at least some embodiments,
implantation of the lead involves inserting an introducer needle,
such as an epidural needle, into a patient. Once the introducer
needle is inserted into the patient and positioned in a desired
location (e.g., the epidural space in proximity to the attachment
of one or more nerves to the spinal cord, the one or more nerves
connected to an affected body portion), the lead is inserted into
the introducer needle. Once the lead is fully inserted in the
introducer sheath, the introducer needle is pulled out of the
patient by sliding the introducer needle off a proximal end of the
lead. The proximal end of the lead may then be electrically coupled
to a control module and implanted in the patient, or the proximal
end of the lead may be electrically connected to an external trial
stimulator for trial stimulation to test the efficacy of the spinal
cord stimulation system 400. In at least some embodiments,
implantation of the lead may involve more invasive surgery. For
example, implantation of a paddle lead may require a laminectomy.
Additionally, other techniques may be needed to properly position
the paddle lead in the desired location.
[0068] The electrodes 434 can be formed using any conductive,
biocompatible material. Examples of suitable materials include
metals, alloys, conductive polymers, conductive carbon, and the
like, as well as combinations thereof. The number of electrodes 434
in the array of electrodes 434 may vary. For example, there can be
two, four, six, eight, ten, twelve, fourteen, sixteen, or more
electrodes 434. As will be recognized, other numbers of electrodes
434 may also be used.
[0069] The electrodes of the paddle body 404 or one or more lead
bodies 406 are typically disposed in, or separated by, a
non-conductive, biocompatible material including, for example,
silicone, polyurethane, polyetheretherketone ("PEEK"), epoxy, and
the like or combinations thereof The paddle body 404 and one or
more lead bodies 406 may be formed in the desired shape by any
process including, for example, molding (including injection
molding), casting, and the like. Electrodes and connecting wires
can be disposed onto or within a paddle body either prior to or
subsequent to a molding or casting process. The non-conductive
material typically extends from the distal end of the lead to the
proximal end of each of the one or more lead bodies 406. The
non-conductive, biocompatible material of the paddle body 404 and
the one or more lead bodies 406 may be the same or different. The
paddle body 404 and the one or more lead bodies 406 may be a
unitary structure or can be formed as two separate structures that
are permanently or detachably coupled together.
[0070] Terminals (e.g., 610 in FIG. 6A and 636 of FIG. 6B) are
typically disposed at the proximal end of the one or more lead
bodies 406 for connection to corresponding conductive contacts
(e.g., 614 in FIG. 6A and 640 of FIG. 6B) in connectors (e.g., 444
in FIGS. 4-6A and 622 and 650 of FIG. 6B) disposed on, for example,
the control module 402 (or to other devices, such as conductive
contacts on a lead extension, an operating room cable, or an
adaptor). Conductive wires ("conductors") (not shown) extend from
the terminals (e.g., 610 in FIG. 6A and 636 of FIG. 6B) to the
electrodes 434. Typically, one or more electrodes 434 are
electrically coupled to a terminal (e.g., 610 in FIG. 6A and 636 of
FIG. 6B). In some embodiments, each terminal (e.g., 610 in FIG. 6A
and 636 of FIG. 6B) is only connected to one electrode 434. The
conductors may be embedded in the non-conductive material of the
lead or can be disposed in one or more lumens (not shown) extending
along the lead. In some embodiments, there is an individual lumen
for each conductor. In other embodiments, two or more conductors
may extend through a lumen. There may also be one or more lumens
(not shown) that open at, or near, the proximal end of the lead,
for example, for inserting a stylet rod to facilitate placement of
the lead within a body of a patient. Additionally, there may also
be one or more lumens (not shown) that open at, or near, the distal
end of the lead, for example, for infusion of drugs or medication
into the site of implantation of the paddle body 404. In at least
one embodiment, the one or more lumens may be flushed continually,
or on a regular basis, with saline, epidural fluid, or the like. In
at least some embodiments, the one or more lumens can be
permanently or removably sealable at the distal end.
[0071] In at least some embodiments, leads are coupled to
connectors disposed on control modules. In FIG. 6A, a lead 608 is
shown configured and arranged for insertion to the control module
402. The connector 444 includes a connector housing 602. The
connector housing 602 defines at least one port 604 into which a
proximal end 606 of a lead 608 with terminals 610 can be inserted,
as shown by directional arrow 612. The connector housing 602 also
includes a plurality of conductive contacts 614 for each port 604.
When the lead 608 is inserted into the port 604, the conductive
contacts 614 can be aligned with the terminals 610 on the lead 608
to electrically couple the control module 402 to the electrodes
(434 of FIG. 4) disposed at a distal end of the lead 608. Examples
of connectors in control modules are found in, for example, U.S.
Pat. No. 7,244,150 and U.S. patent application Ser. No. 11/532,844,
which are incorporated by reference,
[0072] In FIG. 6B, a connector 622 is disposed on a lead extension
624. The connector 622 is shown disposed at a distal end 626 of the
lead extension 624. The connector 622 includes a connector housing
628. The connector housing 628 defines at least one port 630 into
which a proximal end 632 of a lead 634 with terminals 636 can be
inserted, as shown by directional arrow 638. The connector housing
628 also includes a plurality of conductive contacts 640. When the
lead 634 is inserted into the port 630, the conductive contacts 640
disposed in the connector housing 628 can be aligned with the
terminals 636 on the lead 634 to electrically couple the lead
extension 624 to the electrodes (434 of FIG. 4) disposed at a
distal end (not shown) of the lead 634.
[0073] In at least some embodiments, the proximal end of a lead
extension is similarly configured and arranged as a proximal end of
a lead. The lead extension 624 may include a plurality of
conductors (not shown) that electrically couple the conductive
contacts 640 to a proximal end 648 of the lead extension 624 that
is opposite to the distal end 626. In at least some embodiments,
the conductive wires disposed in the lead extension 624 can be
electrically coupled to a plurality of terminals (not shown)
disposed on the proximal end 648 of the lead extension 624. In at
least some embodiments, the proximal end 648 of the lead extension
624 is configured and arranged for insertion into a connector
disposed in another lead extension. In other embodiments, the
proximal end 648 of the lead extension 624 is configured and
arranged for insertion into a connector disposed in a control
module. As an example, in FIG. 6B the proximal end 648 of the lead
extension 424 is inserted into a connector 650 disposed in a
control module 652.
[0074] FIG. 7 is a schematic overview of one embodiment of
components of a spinal cord stimulation system 700 including an
electronic subassembly 710 disposed within a control module. It
will be understood that the spinal cord stimulation system can
include more, fewer, or different components and can have a variety
of different configurations including those configurations
disclosed in the stimulator references cited herein.
[0075] Some of the components (for example, power source 712,
antenna 718, receiver 702, and processor 704) of the spinal cord
stimulation system can be positioned on one or more circuit boards
or similar carriers within a sealed housing of an implantable pulse
generator, if desired. Any power source 712 can be used including,
for example, a battery such as a primary battery or a rechargeable
battery. Examples of other power sources include super capacitors,
nuclear or atomic batteries; mechanical resonators, infrared
collectors, thermally-powered energy sources, flexural powered
energy sources, bioenergy power sources, fuel cells, bioelectric
cells, osmotic pressure pumps, and the like including the power
sources described in U.S. Patent Application Publication No.
2004/0059392, incorporated herein by reference.
[0076] As another alternative, power can be supplied by an external
power source through inductive coupling via the optional antenna
718 or a secondary antenna. The external power source can be in a
device that is mounted on the skin of the user or in a unit that is
provided near the user on a permanent or periodic basis, If the
power source 712 is a rechargeable battery, the battery may be
recharged using the optional antenna 718, if desired. Power can be
provided to the battery for recharging by inductively coupling the
battery through the antenna to a recharging unit 716 external to
the user. Examples of such arrangements can be found in the
references identified above.
[0077] In one embodiment, electrical current is emitted by the
electrodes 434 on the paddle or lead body to stimulate nerve
fibers, muscle fibers, or other body tissues near the spinal cord
stimulation system. A processor 704 is generally included to
control the timing and electrical characteristics of the spinal
cord stimulation system. For example, the processor 704 can, if
desired, control one or more of the timing, frequency, strength,
duration, and waveform of the pulses. In addition, the processor
704 can select which electrodes can be used to provide stimulation,
if desired. In some embodiments, the processor 704 may select which
electrode(s) are cathodes and which electrode(s) are anodes. In
some embodiments, the processor 704 may be used to identify which
electrodes provide the most useful stimulation of the desired
tissue.
[0078] Any processor can be used and can be as simple as an
electronic device that, for example, produces pulses at a regular
interval or the processor can be capable of receiving and
interpreting instructions from an external programming unit 608
that, for example, allows modification of pulse characteristics. In
the illustrated embodiment, the processor 704 is coupled to a
receiver 702 which, in turn, is coupled to the optional antenna
718. This allows the processor 704 to receive instructions from an
external source to, for example, direct the pulse characteristics
and the selection of electrodes, if desired.
[0079] In one embodiment, the antenna 718 is capable of receiving
signals (e.g., RF signals) from an external telemetry unit 706
which is programmed by a programming unit 708. The programming unit
708 can be external to, or part of, the telemetry unit 706. The
telemetry unit 706 can be a device that is worn on the skin of the
user or can be carried by the user and can have a form similar to a
pager, cellular phone, or remote control, if desired. As another
alternative, the telemetry unit 706 may not be worn or carried by
the user but may only be available at a home station or at a
clinician's office. The programming unit 708 can be any unit that
can provide information to the telemetry unit 706 for transmission
to the spinal cord stimulation system 700. The programming unit 708
can be part of the telemetry unit 706 or can provide signals or
information to the telemetry unit 706 via a wireless or wired
connection. One example of a suitable programming unit is a
computer operated by the user or clinician to send signals to the
telemetry unit 706.
[0080] The signals sent to the processor 704 via the antenna 718
and receiver 702 can be used to modify or otherwise direct the
operation of the spinal cord stimulation system. For example, the
signals may be used to modify the pulses of the spinal cord
stimulation system such as modifying one or more of pulse duration,
pulse frequency, pulse waveform, and pulse strength. The signals
may also direct the spinal cord stimulation system 700 to cease
operation, to start operation, to start charging the battery, or to
stop charging the battery. In other embodiments, the spinal cord
stimulation system 700 does not include an antenna 718 or receiver
702 and the processor 704 operates as programmed.
[0081] Optionally, the spinal cord stimulation system 700 may
include a transmitter (not shown) coupled to the processor 704 and
the antenna 718 for transmitting signals back to the telemetry unit
706 or another unit capable of receiving the signals. For example,
the spinal cord stimulation system 700 may transmit signals
indicating whether the spinal cord stimulation system 700 is
operating properly or not or indicating when the battery needs to
be charged or the level of charge remaining in the battery. The
processor 704 may also be capable of transmitting information about
the pulse characteristics so that a user or clinician can determine
or verify the characteristics.
[0082] The stimulating current that is output by an implanted
spinal cord stimulation system is not constant, but is delivered in
a regular cycle. Consequently, there are a number of parameters
that characterize the current that is output by the implanted
spinal cord stimulation system 700. As noted above, the effect of
the stimulation can be controlled by adjusting these parameters of
the stimulation current. For example, the size, intensity and
character of the parasthesia created (or the location or amount of
relief) can be controlled by adjusting the amplitude, frequency,
pulse width, duty cycle, ramp up time, ramp down time, and other
parameters of the stimulation current. One or more of the
abovementioned parameters can be adjusted to tailor the stimulation
to the needs of a particular patient.
[0083] In at least some embodiments, a range of stimulation
frequencies may be used that includes one or more frequencies of no
less than 2 Hertz. In at least some embodiments, a range of
stimulation frequencies may be used that includes one or more
frequencies of no more than 200 Hertz. In at least some
embodiments, a range of stimulation frequencies may be used that
includes one or more frequencies of no more than 150 Hertz. In at
least some embodiments, a range of pulse widths for stimulation
currents may be used that includes pulse widths of at least 50
microseconds. In at least some embodiments, a range of pulse widths
for stimulation currents may be used that includes pulse widths of
no more than 1500 microseconds.
[0084] The abovementioned parameters can be adjusted over various
ranges to determine the best result for a particular patient.
Stimulation adjustment may also be achieved by manually moving one
or more electrodes relative to the stimulation site. Different sets
or programs of stimulation current parameters may be applied at
different times or to different nerves to adjust the relief from
Parkinsonism afforded to a patient.
[0085] In at least some embodiments, spinal cord stimulation
systems include multiple pre-programmed settings. In at least some
embodiments, the spinal cord stimulation system may cycle through
two more different settings either automatically or manually. In at
least some embodiments, at least one of the settings corresponds to
providing patient relief tailored to a specific patient activity
(e.g., lying horizontally, standing, sitting, and the like). In at
least some embodiments, a patient may be able to select a desired
pre-programmed setting at will. In at least some embodiments, the
patient may be able to adjust other functions as well, such as the
intensity of the current setting The above specification, examples
and data provide a description of the manufacture and use of the
composition of the invention. Since many embodiments of the
invention can be made without departing from the spirit and scope
of the invention, the invention also resides in the claims
hereinafter appended.
* * * * *