U.S. patent application number 15/423791 was filed with the patent office on 2017-05-25 for implantable neurostimulator with integral hermetic electronic enclosure, circuit substrate, monolythic feed-through, lead assembly and anchoring mechanism.
The applicant listed for this patent is AUTONOMIC TECHNOLOGIES, INC.. Invention is credited to Carl Lance Boling, Anthony V. Caparso, Benjamin David Pless, Ryan Powell.
Application Number | 20170143959 15/423791 |
Document ID | / |
Family ID | 42992798 |
Filed Date | 2017-05-25 |
United States Patent
Application |
20170143959 |
Kind Code |
A1 |
Boling; Carl Lance ; et
al. |
May 25, 2017 |
Implantable neurostimulator with integral hermetic electronic
enclosure, circuit substrate, monolythic feed-through, lead
assembly and anchoring mechanism
Abstract
An implantable medical device is provided for the suppression or
prevention of pain, movement disorders, epilepsy, cerebrovascular
diseases, autoimmune diseases, sleep disorders, autonomic
disorders, abnormal metabolic states, disorders of the muscular
system, and neuropsychiatric disorders in a patient. The
implantable medical device can be a neurostimulator configured to
be implanted on or near a cranial nerve to treat headache or other
neurological disorders. One aspect of the implantable medical
device is that it includes an electronics enclosure, a substrate
integral to the electronics enclosure, and a monolithic
feed-through integral to the electronics enclosure and the
substrate. In some embodiments, the implantable medical device can
include a fixation apparatus for attaching the device to a
patient.
Inventors: |
Boling; Carl Lance; (San
Jose, CA) ; Pless; Benjamin David; (Atherton, CA)
; Powell; Ryan; (Menlo Park, CA) ; Caparso;
Anthony V.; (San Jose, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AUTONOMIC TECHNOLOGIES, INC. |
Redwood City |
CA |
US |
|
|
Family ID: |
42992798 |
Appl. No.: |
15/423791 |
Filed: |
February 3, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14858904 |
Sep 18, 2015 |
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15423791 |
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14223765 |
Mar 24, 2014 |
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14858904 |
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13939068 |
Jul 10, 2013 |
8886325 |
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14223765 |
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12765712 |
Apr 22, 2010 |
8494641 |
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13939068 |
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61171749 |
Apr 22, 2009 |
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61177895 |
May 13, 2009 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61N 1/0551 20130101;
A61N 1/36071 20130101; A61N 1/36075 20130101; A61N 1/0558 20130101;
A61N 1/0526 20130101; A61N 1/36082 20130101; A61N 1/37217 20130101;
A61N 1/36078 20130101; A61N 1/0546 20130101; A61N 1/3787 20130101;
A61N 1/3754 20130101; A61N 1/36064 20130101; A61N 1/36067 20130101;
A61N 1/37518 20170801 |
International
Class: |
A61N 1/36 20060101
A61N001/36; A61N 1/378 20060101 A61N001/378; A61N 1/375 20060101
A61N001/375; A61N 1/05 20060101 A61N001/05; A61N 1/372 20060101
A61N001/372 |
Claims
1-20. (canceled)
21. A system for treating a medical condition in a patient, the
system comprising: an isodiametric neurostimulator sized and
dimensioned for insertion into a pterygopalatine fossa (PPF) of the
patient comprising: a stimulator body comprising a hermetic
electronics enclosure housing an electrical circuit; and a
stimulation lead extending from the hermetic electronics enclosure
and comprising electrodes integral with the electrical circuit,
wherein the size of the isodiametric neurostimulator is maintained
or decreases from a proximal-most portion of the stimulator body to
a distal-most portion of the stimulation lead; and an external
controller in electrical communication with the neurostimulator and
programmed to deliver electrical current to the patient.
22. The system of claim 21, wherein the stimulator body and a
portion of the stimulation lead comprises a biocompatible outer
layer.
23. The system of claim 22, wherein the biocompatible outer layer
is molded to the stimulatory body and the portion of the
stimulation lead.
24. The system of claim 21, wherein the isodiametric
neurostimulator has a diameter between about 1 millimeter (mm) to
about 10 mm.
25. The system of claim 21, wherein the isodiametric
neurostimulator has a length of between about 1 mm to about 25
mm.
26. A method of treating a medical disorder in a patient
comprising: receiving an isodiametric neurostimulator within a
pterygopalatine fossa (PPF) of the patient, the isodiametric
neurostimulator comprising: a stimulator body comprising a hermetic
electronics enclosure housing an electrical circuit; and a
stimulation lead extending from the hermetic electronics enclosure
and comprising electrodes integral with the electrical circuit,
wherein the size of the isodiametric neurostimulator is maintained
or decreases from a proximal-most portion of the stimulator body to
a distal-most portion of the stimulation lead; and delivering an
electrical signal to a neural structure of the patient to treat the
medical disorder.
27. The method of claim 26, wherein the medical disorder is pain, a
movement disorder, epilepsy, a cerebrovascular disease, an
autoimmune disease, a sleep disorder, an autonomic disorder, an
abnormal metabolic state, a disorder of the muscular system, or a
neuropsychiatric disorder.
28. The method of claim 26, wherein the medical disorder is a
neurological or behavior disorder.
29. The method of claim 28, wherein the neurological disorder is a
primary headache, atypical facial pain, or trigeminal
neuralgia.
30. The method of claim 29, wherein the primary headache is a
migraine or a cluster headache.
31. The method of claim 26, wherein the neural structure is a
peripheral neural structure.
32. The method of claim 26, wherein the neural structure is an
autonomic neural structure.
33. The method of claim 32, wherein the autonomic structure is a
sphenopalatine ganglion.
33. The method of claim 26, wherein the neural structure is a
central neural structure.
34. The method of claim 26, wherein delivering an electrical signal
comprises delivering an electrical signal from an external
controller.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 14/223,765, filed Mar. 24, 2014; which is a division of U.S.
application Ser. No. 13/939,068, filed. Jul. 10, 2013, now U.S.
Pat. No. 8,886,325; which is a continuation of U.S. application
Ser. No. 12/765,712, filed Apr. 22, 2010, now U.S. Pat. No.
8,494,641; which application claims the benefit under 35 U.S.C. 119
of U.S. Provisional Application No. 61/171,749, filed Apr. 22,
2009, and U.S. Provisional Application No. 61/177,895, filed May
13, 2009. These applications are herein incorporated by reference
in their entirety.
FIELD OF THE INVENTION
[0002] The invention relates generally to a stimulating apparatus
used to deliver electrical stimulation to a peripheral, central or
autonomic neural structure. More specifically, the current
invention relates to a neurostimulator apparatus designed to
deliver electrical stimulation to the sphenopalatine ganglion (SPG)
to treat primary headaches, such as migraines, cluster headaches
and/or many other neurological disorders, such as atypical facial
pain and/or trigeminal neuralgias.
BACKGROUND OF THE INVENTION
[0003] Electrical stimulation of peripheral, central and autonomic
neural structures have shown increased interest due to the
potential benefits it may provide to individuals suffering from
many neurological and behavioral diseases. Many of these therapies
today are not well accepted or are considered last in the
therapeutic options due to the invasive nature of the therapy even
though the efficacy may be quite good. This has created a need for
less invasive therapies that are directed toward patient and
physician clinical needs.
[0004] Primary headaches are one of the most debilitating ailments
that afflict millions of individuals worldwide. The specific
pathophysiology of headaches is unknown. Known sources of headache
pain consist of trauma, vascular, autoimmune, degenerative,
infectious, drug and medication-induced, inflammatory, neoplastic,
metabolic-endocrine, iatrogenic, musculoskeletal and myofacial
causes. Also, even though the possible underlying cause of the
headache pain is identified and treated, the headache pain may
persist.
[0005] Currently, the sphenopalatine (pterygopalatine) ganglion
(SPG) is a target of manipulation in clinical medicine to treat
headaches. The SPG is a large extra cranial parasympathetic
ganglion. It consists of parasympathetic neurons that innervate (in
part) the middle cerebral and anterior cerebral blood vessels, the
facial blood vessels, and the lacrimal glands. A ganglion is a mass
of nervous tissue found in some peripheral and autonomic nerves.
Ganglia are located on the roots of the spinal nerves and on the
roots of the trigeminal nerve. Ganglia are also located on the
facial, glossopharyngeal, vagus and vestibulochoclear nerves. The
SPG is a complex neural ganglion with multiple connections,
including autonomic, sensory and motor. The maxillary branch of the
trigeminal nerve and the nerve of the pterygoid canal, also known
as the vidian nerve, which is formed by the greater and deep
petrosal nerves send neural projections to the SPG. The fine
branches from the maxillary nerve (pterygopalatine nerves) form the
sensory component of the SPG, and these fibers pass through the SPG
and do not synapse. The greater petrosal nerve carries the
preganglionic parasympathetic axons from the superior salivary
nucleus, which is located in the Pons, to the SPG. These fibers
synapse onto the postganglionic neurons within the SPG. The deep
petrosal nerve connects the superior cervical sympathetic ganglion
to the SPG and carries postganglionic sympathetic axons that again
pass through the SPG without any synapses.
[0006] The sphenopalatine ganglion (SPG), also called the
pterygopalatine ganglion, is located within the pterygopalatine
fossa. The pterygopalatine fossa (PPF) is bounded anteriorly by the
maxilla, posteriorly by the medial plate of the pterygoid process
and greater wing of the sphenoid process, medially by the palatine
bone, and superiorly by the body of the sphenoid process. Its
lateral border is the pterygomaxillary fissure (PMF), which opens
to the infratemporal fossa.
[0007] Treatment of the SPG is mostly performed in attempted
treatments of severe headaches, such as cluster headaches or
chronic migraines. Various clinical approaches have been used for
over 100 years to modulate the function of the SPG to treat
headaches. These procedures vary from least invasive (e.g.,
transnasal anesthetic blocks) to much more invasive (e.g., surgical
ganglionectomy) as well as procedures such as surgical anesthetic
injections, ablations, gamma knife and cryogenic surgery. Most of
these procedures have very good short term efficacy outcomes (days
to months), however these results are usually temporary and the
headache pain returns. A chronically implanted neurostimulator
apparatus designed to deliver electrical stimulation to the SPG may
provide much better long term efficacy in these patients. This
application details the design of a neurostimulator for this
purpose.
SUMMARY OF THE INVENTION
[0008] In some embodiments, an implantable medical device
configured for delivery of electrical stimulation to the
Sphenopalatine Ganglion (SPG) is provided, comprising an
electronics enclosure, a substrate integral to the electronics
enclosure, and a monolithic feed-through integral to the
electronics enclosure and the substrate.
[0009] In some embodiments, the device further comprises a fixation
apparatus integral to the electronics enclosure. The fixation
apparatus can comprise at least one preformed hole configured to
accept a bone screw. In some embodiments, the fixation apparatus is
malleable and configured to be formed around the
zygomaticomaxillary buttress.
[0010] In some embodiments, the electronics enclosure comprises an
ASIC, an inductive coil, and a diode array.
[0011] In some embodiments, the implantable medical device is sized
and configured for implantation into the pterygopalatine fossa. In
other embodiments, the implantable medical device is sized and
configured for implantation on the posterior maxilla.
[0012] In one embodiment, the device further comprises a
stimulation lead coupled to the electronics enclosure. The
stimulation lead can be constructed to an angle off an axis of the
electronics enclosure. In some embodiments, the angle is
approximately 0 to 60 degrees. In other embodiments, the angle is
approximately 30 degrees.
[0013] In one embodiment, the implantable medical device is
configured to lay fiat against the posterior maxilla, and the
stimulation lead is angled so as to maintain contact with the
posterior maxilla as it extends to the pterygopalatine fossa.
[0014] In another embodiment, the stimulation lead is sized and
configured to pass through a lateral opening of the pterygopalatine
fossa. In some embodiments, a diameter of the stimulation lead is
approximately 2-12 mm.
[0015] In one embodiment, the device can further comprise at least
one electrode disposed on the stimulation lead. The device can
further comprise at least one electrode wire coupling the at least
one electrode to the electronics enclosure.
[0016] In some embodiments, the device further comprises a
platinum/iridium tubing configured to connect the at least one
electrode wire to the monolithic feed-through. In some embodiments,
the platinum/iridium tubing comprises at least one witness
hole.
[0017] In another embodiment, the device comprises a thin-film flex
circuit configured to connect the at least one electrode wire to
the monolithic feed-through. In another embodiment, a protrusion
feature is disposed on the monolithic feed-through.
[0018] Some embodiments of the device further comprise an inductive
coil configured to receive power and communication from an external
controller at a depth of approximately 1-3 cm.
[0019] In some embodiments, the electronics enclosure comprises an
ASIC printed on the electronics enclosure. Another embodiment
further comprises at least one annular ring coupled to the
electronics enclosure and configured to receive exposed ends of the
monolithic feed-through.
[0020] Another embodiment of the device further comprises a
stiffening mechanism configured to increase the linear stiffness of
the stimulation lead. In some embodiments, the stiffening mechanism
comprises a malleable wire. In other embodiments, the stiffening
mechanism comprises a coiled wire. In yet another embodiment, the
stiffening mechanism comprises a tapered supporting wire.
[0021] An implantable stimulator configured for delivery of
electrical stimulation to a nerve is provided, comprising a
housing, an electronics enclosure disposed on or in the housing,
and a stimulation lead coupled to the electronics enclosure, the
stimulation lead including a malleable wire configured give the
stimulation lead rigidity to penetrate tissue and malleability to
conform to a target anatomy.
[0022] In some embodiments, the stimulator comprises an attachment
plate coupled to the housing, the attachment plate configured to
accept a bone screw for attachment to bone.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a lateral view the neurostimulator in
communication with the anatomy;
[0024] FIG. 2 is an isometric view of the neurostimulator;
[0025] FIGS. 3a-3b are top and side section views of the
neurostimulator;
[0026] FIG. 4 is a transparent view illustrating the electrode wire
interconnects;
[0027] FIG. 5 is a transparent view illustrating an electrode flex
circuit interconnect;
[0028] FIG. 6 is an isometric view of a feed-through interconnect
embodiment;
[0029] FIG. 7 is an exploded view of the neurostimulator's
electronics enclosure;
[0030] FIG. 8 is an exploded view of an electronics enclosure
embodiment;
[0031] FIG. 9 is an isometric view of the electronics enclosure
embodiment;
[0032] FIG. 10 is a top down view of the neurostimulator's
electronics and enclosure;
[0033] FIG. 11 is an isometric view of a feed-through interconnect
embodiment;
[0034] FIG. 12 illustrates embodiments of the lead
cross-sections;
[0035] FIG. 13 illustrates axial cross-sectional insets of lead
embodiments;
[0036] FIG. 14 is an isometric view of an embodiment of a bendable
lead;
[0037] FIG. 15 is an isometric view of an embodiment of a bendable
lead;
[0038] FIG. 16 is an isometric view of an embodiment of a bendable
lead.
DETAILED DESCRIPTION OF THE INVENTION
[0039] Referring to FIG. 1, a neurostirnulator 100 is shown within
the intended anatomy for the treatment of primary headaches and
other neurological disorders. The neurostimulator of this
embodiment comprises of a stimulator body 200a, an integral
stimulation lead 200b, and an integral fixation apparatus 200c. The
neurostimulator 100 can be implanted such that the stimulator body
200b is positioned medial to the zygoma 205 on the posterior
maxilla 206 within the buccal fat pad of the cheek, and the
integral fixation apparatus 200c is anchored to the
zygomaticomaxillary buttress 203, such as by using standard
craniomaxillofacial bone screws, for example. The integral
stimulation lead 200c can be placed within the pterygopalatine
fossa 202, or more specifically, in very close proximity to the
sphenopalatine ganglion 204.
[0040] FIG. 2 illustrates one embodiment of an implantable
neurostirnulator 200. In this embodiment, the neurostimulator 200
comprises of a stimulator body 200a, an integral stimulation lead
200b, which includes one or more stimulating electrodes 201, and an
integral fixation apparatus 200c, The neurostimulator 200 of this
embodiment can be an inductively powered device having the
necessary micro-electronics to store programmable stimulation
parameters, deliver electrical stimulation per the programmed
parameters and to allow bi-directional telemetry to enable
communication with an external controller. An external transmitter
(not shown) provides powers to and communications with the
implanted neurostimulator.
[0041] The neurostimulator's micro-electronics can be housed in the
stimulator body 200a, a hermetic enclosure that protects the
micro-electronics from fluid ingress when implanted within the
body. The stimulator body can further include an electronics
enclosure, a micro-electronics assembly, a monolithic feed-through
assembly, and a lead interconnect assembly, and the stimulator body
can be molded with a protective outer layer. In some embodiments
the dimensions of the stimulator body are 8 mm wide, 4 mm thick,
and 14 mm long.
[0042] The neurostimulator is sized and configured to be implanted
on the posterior maxilla, so the neurostimulator thickness is
limited by the available free space between the posterior maxilla
and the coronoid process of the mandible. The average distance
between the posterior maxilla and the coronoid process, measured
from 79 patients using computed tomography, was 13.+-.3 mm with a
range of 6-24 mm (unpublished work). Thus, in some embodiments the
thickness of the neurostimulator can range from 1 to 10 mm. The
width and length of the neurostimulator are also limited by the
surrounding anatomy, but in some embodiments the width and length
are such that the neurostimulator maintains physical contact with
the posterior maxilla. Thus, the neurostimulation width can range
from 1-20 mm, and the length can range from 1-25 mm.
[0043] Electrical stimulation can be carried from the
micro-electronics to one or more of the stimulating electrodes 201
through the stimulation lead 200b. The stimulation lead can be
connected to the stimulator body through a series of feed-through
assemblies. In the embodiment of FIG. 2, the stimulator body 200a
and a portion of the stimulating lead 200b are shown with a
biocompatible outer layer 202, created using a reaction injection
molding (RIM) process, to protect the feed-through assemblies,
provide strain relief to the stimulation lead and create an
isodiametric neurostimulator. The neurostimulator is isodiametric
because the size is maintained or decreases from the most proximal
portion of the stimulator body to the most distal portion of the
stimulating lead. In addition, the configuration of the outer layer
does not contain any sharp corners or edges. This allows the
neurostimulator to be implanted and explanted without grabbing or
tearing of surrounding tissue. In some embodiments, the outer
protective layer is created from biocompatible urethane and
silicone co-polymer. The protective layer can be up to 1 mm thick,
however in some embodiments the protective layer can be 0.1 to 2 mm
thick. In other embodiments, different encapsulations methods and
materials may be used, including but not limited to, potting,
injection molding, casting, conformal coating, or adhering a
compliant, semi-compliant, or rigid silicone rubber, epoxy,
thereto-set or thermoplastic polymers or combination of any of the
described methods and materials around the electronic assembly,
lead interconnect, and lead assembly.
[0044] Also referring to FIG. 2, the integral fixation apparatus
200c can include a. biocompatible mini-plate with one or more
preformed holes extending off the body of the neurostimulator. The
preformed holes can be designed to accept a standard bone screw.
For example, the preformed holes can be approximately 1.9 mm in
diameter and be sized to accept a standard bone screw with a
diameter between 1.5-1.8 mm. The preformed holes can also be
designed with a ninety-degree chamfer that allows the head of the
standard bone screw to recess into the mini-plate and reside flush
with the outboard face of mini-plate. In one embodiment the
mini-plate is made from titanium (grade 2), which provides both
good mechanical fatigue resistance and good flexibility. However,
in other embodiments, the mini-plate can be made from other
materials such as: commercially pure titanium such as grades 1,3,
or 4 and alloys such as grade 5 or 23; stainless steels such as 304
or 316; other biocompatible metals; and biocompatible plastics such
as PEEK, nylon, or polypropylene.
[0045] Additionally, as shown in FIG. 2 the one or more preformed
holes are set in a linear configuration off the proximal end of the
stimulator body to increase the flexibility of the mini-plate. In
the intended target anatomy, the mini-plate can be anchored to the
thick dense bone of the zygomatic process of the maxilla, generally
referred to the zygomaticomaxillary buttress. When the stimulator
body is positioned on the posterior maxilla, the mini-plate must be
formed around the buttress without adversely moving or dislodging
the stimulator body and the stimulation lead. Thus, the mini-plate
must be malleable so that it can be formed around the buttress as
well as resistant to flex fatigue from repeat bending. In one
embodiment, in which the mini-plate is made from titanium (grade
2), the center-to-center distance between each of the preformed
holes can be 6 mm, and the width of the beam between each preformed
hole can be 1.3 mm. In this embodiment, the mini-plate provides the
proper amount of malleability and flex resistance needed to form
the mini-plate around the buttress and to allow for long term
reliability for the chronic implantable neurostimulator. Also, the
second moment of area across the mini-plate is designed to be
constant, which facilitates uniform bending and typically creates a
larger more uniform arch. The larger arch that is formed from
bending of the mini-plate helps to resist stress concentrations and
promotes matching of the surface of the mini-plate to the
underlying anatomical bone features. In other embodiments, the
center-to-center distance between each of the preformed holes can
be between 3-10 mm and the width of the beam between each preformed
hole can be 0.5 to 3 mm.
[0046] Additionally, in another embodiment, the arrangement of the
preformed holes on the mini-plate can be configured into a Y
configuration (a single mini-plate extending off the stimulator
body with two tails extending out like a Y), a T configuration (a
single mini-plate formed into a T), an L configuration (a single
mini-plate formed into an L) or an X configuration (a single
mini-plate formed into a X, with one leg of the X attached to the
stimulator body). In any of these configurations, each of the
mini-plates can contain one or more preformed holes and include the
same features described above. In additional embodiments, the
neurostimulator can include one or more mini-plates projecting off
the stimulator body, including but not limited to a mini-plate
extending off the opposing end of the stimulator body from the
stimulating lead, and one or more mini-plates extending off the two
other adjacent sides of the neurostimulator.
[0047] FIG. 2 also illustrates the stimulating lead 200b of
neurostimulator 200. In this embodiment, the stimulating lead
comprises of one or more stimulation electrodes 201 and a
corresponding number of connecting lead wires for each of the
stimulating electrodes. Each connecting lead wire connects to a
feed-through on the stimulating body. The connecting wires provide
a conduit to deliver electrical stimulation pulses between the
micro-electronics and the stimulating electrodes. In one
embodiment, the stimulation lead projects from the distal face of
the stimulator body constructed to an angle of 30 degrees off the
stimulator axis. In this embodiment, the inboard planer side of the
neurostimulator body is configured to lay flat against and in
interment communication with the posterior maxilla, which also
coincides with the stimulator surface from which the integral
fixation apparatus 200c extends. The angle of the stimulating lead
projecting off the stimulator body allows the lead to maintain
contact with the posterior maxilla as it courses from the
stimulator body to the pterygopalatine fossa and reduces any stress
on the stimulating lead by reducing the lead curvature. In some
embodiments, the degree of the angle between the stimulator body
and stimulating lead can range from between approximately 0 to 60
degrees. In yet other embodiments the stimulating lead may contain
multiple compound angles with the neurostimulator, the angles may
be on or off axis with the stimulator body.
[0048] In the embodiment of FIG. 2, the stimulating lead includes
seven cylindrical stimulating electrodes 201 that can be configured
to provide either cathodic or anodic stimulation. In this
embodiment the stimulating lead comprises at least 5 stimulating
cathodic electrodes, or working electrodes. The working electrodes
are configured to be implanted in very close proximity to the SPG
within the pterygopalatine fossa and to be used for delivering the
stimulation pulses from the micro-electronics. In some embodiments,
the two most proximal electrodes to the stimulator body 200a can be
electronically coupled to create a larger reference or return
electrode. This reference electrode can be configured as an anode
and positioned on the stimulating lead such that it is the farthest
electrode from the SPG.
[0049] The length and spacing of the electrodes are configured to
optimize stimulation of the SPG. The average height and width of
the SPG has been found to be 3.28 mm, range 2-6 mm and 1.76 mm,
range 1-3 mm respectively. In some embodiments, the spacing
distance between any two adjacent stimulation electrodes is no
greater than 1.0 mm and each electrode is 1.5 mm in length. The
electrode length and the spacing assures that at least one
electrode maintains communication with the SPG. In other
embodiments the electrode spacing can range from 0.3-4 mm, and the
length of each electrode can range from 0.4 to 4 mm. In one
embodiment, the stimulating lead and hence each electrode, is 1 mm
in diameter. The diameter of the stimulating lead can be designed
such that the lead passes through the lateral opening the
pterygopalatine fossa, called the pterygopalatine fissure, which
has been reported to be between 2-12 mm wide. In other embodiment,
the diameter of the lead can range from 0.5 to 3 mm. Each
stimulation electrode has a thickness of 0.1 mm; a minimum
thickness of 0.05 mm is needed prevent damage during manufacturing
and implantation. The stimulation electrodes can be made from 90/10
platinum/iridium alloy. However, in other embodiments the
stimulation electrodes can be made from other biocompatible
metallic alloys, including but not limited to platinum, platinum
alloys, palladium, palladium alloys, titanium, titanium alloys,
various stainless steels, or any other conductive biocompatible
metals and biocompatible non-metals such as but not limited to
carbon.
[0050] FIG. 3a is an elevated view and FIG. 3b is a sectioned side
view of neurostimulator 300, and illustrates the integral design of
the neurostimilator. In FIG. 3a, the neurostimulator 300 includes
stimulator body 300a, integral stimulating lead 300b, which
includes one or more stimulation electrodes 301, and integral
fixation apparatus 300c. FIG. 3b shows a sectioned side view of the
neurostimulator through the line A-A in FIG. 3a. In this
embodiment, the sectioned side view shows the hermetic electronics
enclosure within the stimulator body 300a, integral stimulation
lead 300b, electrode wire interconnect assembly 305 and the
electrode connection wires 303. Also shown in FIG. 3b is the
protective (insulation) outer layer 304, which encapsulates the
stimulator body and the proximal portion of the stimulation lead.
The protective layer also covers the proximal portion of the
stimulation lead to provide additional strain relief at the
junction between the lead and the stimulator body. This layer is
formed by reaction injection molding (RIM) with a biocompatible
urethane and silicone co-polymer. Other encapsulations methods and
materials may include potting, injection molding, casting,
conformal coating, or adhering a compliant, semi-compliant, or
rigid silicone rubber, epoxy, thermo set or thermoplastic polymers
or combination of any of the described methods and materials around
the electronic assembly, lead interconnect, and lead assembly.
[0051] FIG. 4 shows an enlarged detail view of the encapsulated
hermetic electronics enclosure 411, feed through assembly and
interconnect assembly. The feed-through wires 410 projecting from
the upper surface of the hermetic electronic enclosure 411 can be
bonded to the enclosure. In some embodiments, the feed-through
wires are brazed onto the enclosure using gold braze 412. In other
embodiments the feed-through wires can be adhered using a glass
frit to the enclosure or otherwise molded or bonded to the
enclosure. The feed-through wires can be served upward and then
down along the enclosure toward the stimulation lead and connected
to the electrode wires 414. In some embodiments, a platinum/iridium
tube 413 is used to connect the electrode wires to the feed-through
wires. The proximal segment of the platinum/iridium tubing can be
crimped onto the feed-through wires and the distal end of the
tubing can be crimped to the electrode wires 414. The
platinum/iridium tubing includes at least two witness holes 416.
These witness holes allow the operator to verify that the wires are
appropriately placed prior to applying the crimp. In other
embodiments the platinum/iridium tubing can be resistance welded;
laser welded, brazed, or otherwise secured using epoxy or other
conductive adhesives to the feed-through and electrode wires.
[0052] FIG. 4 also shows the outer protective encapsulation layer
(in transparency). In one embodiment, the outer protective layer is
a copolymer; a blend of biocompatible urethane and silicone
co-polymer uniquely compounded to provide superior adhesion to the
substrate while providing a tissue friendly interface. The
protective layer can be molded over the stimulator body and a
portion of the stimulating lead using a reaction injection molding
(RIM) process. The material can be stable, biocompatible, resistant
to oxidation and have increased mechanical properties compared to
other polyurethanes and silicones. The protective layer is designed
to provide electrical isolation between exposed conductors as well
as a primary biocompatible interface between the tissue and the
implanted device. The use of this material to surround the
electrode wire interconnect assembly to the feed-through assembly
provides stability and electrical insulation to each
interconnection. The material can also be molded onto a proximal
portion of the stimulation lead to act as a strain relief.
[0053] FIG. 5 illustrates an alternative embodiment of an electrode
wire to feed-through interconnect system similar to the embodiment
described above, except that each electrode is connected to the
feed-through assembly using an organic thin-film flex circuit 520.
The flex circuit can comprise of a polyamide film with printed
trace lines made of a conductive material such as gold. In one
embodiment, the flex circuit contains at least six trace lines
printed on the polyamide film with each trace line corresponding to
one electrode. In another embodiment, the polyamide film is
expanded near the interconnect assembly, such that the printed
trace lines are equally spaced with the feed-through assembly
wires. Then each trace tine on the polyamide film is extended off
the film like a comb with individual fingers, each finger
representing on printed trace line. Each trace can then be crimped
onto the feed-through assembly wires as described above. The
polyamide film can be narrowed once it enters into the stimulating
lead assembly. In one embodiment, the narrowed film is no wider
than 0.5 mm, such that the film is smaller than the diameter of the
lead assembly (e.g., 1.0 mm). In one embodiment, the polyamide film
that comprises the flex circuit is 0.1 mm thick, however in other
embodiments the flex circuit can be approximately 0.05 to 0.5 mm
thick. In other embodiments, the flex circuit can take on the shape
needed to facilitate the interconnection between the stimulation
electrodes and the feed-through assembly.
[0054] In one embodiment, as shown in 6, the electronics enclosure
610 and integral feed-through wires 611 are shown and include an
additional protrusion feature 612 in the feed-through assemblies.
The protrusion feature is used to increase the surface distance
between each of the monolithic feed-through wires and provide a
larger surface area for increased adhesion of the copolymer. Once
the outer protective layer is molded onto the electronics enclosure
it provides stability and protects the electrical connections
between the feed-through wires and the electrode wires. If fluid
ingress occurs, coupled with the copolymer delaminating, the
increased surface distance (i.e., the electrical path) between
electrodes will help prevent electrical shorting. In one
embodiment, the protrusion features extend above the surface of the
electronics enclosure by approximately 0.25 mm. In other
embodiments, the protrusions can extend between 0.1 to 0.5 mm above
the enclosure. Also shown in FIG. 6, is a staggered configuration
of the feed-through assemblies. Due to size constraints on the
electronic enclosure, the feed-through assemblies may not be able
to be arranged in a linear fashion without unintended electrical
shorting between two adjacent feed-through assemblies. By
staggering the feed-through assemblies, an increased number of
feed-through wires can be used and the distance between adjacent
feed-through assemblies could be increased, reducing the risk of
electrical shorting.
[0055] FIG. 7 is an isometric exploded view of a hermetic
electronics enclosure of a neurostimulator. In this embodiment, the
hermetic enclosure comprises a substrate and monolithic
feed-through 721, a bezel 723 and a lid 724. The hermetic enclosure
houses the micro-electronic assembly, an inductive coil 726 and a
ferrite core 727. In one embodiment, the substrate is manufactured
from stabilized zirconium oxide and the feed-through wires are gold
brazed into place and are manufactured from platinum-iridium
(80/20). In other embodiments, the substrate and integral
monolithic feed-through assembly 721 can be manufactured from one
of many ceramic materials, including, but not limited to aluminum
oxide, transparent polycrystalline aluminum oxide, stabilized
zirconium oxide, aluminum nitride, and silicon nitride. The
substrate and monolithic feed-through assembly can be produced
using a variety of manufacturing methods including but not limited
to post sintering machining, green form pressing and sintering, and
injection molding and sintering.
[0056] In one embodiment, the bezel 723 and the lid 724 can be
manufactured using a high resistance, biocompatible metal such as
commercially pure or alloyed titanium. In other embodiments, the
bezel can be made out of but not limited to other materials
including corrosion resistant stainless steels, refractory's such
as aluminum oxide, transparent polycrystalline aluminum oxide,
stabilized zirconium oxide, aluminum nitride, and silicon nitride
or glass frit.
[0057] In one embodiment, the bezel 723 is brazed at the location
to the mating edge of the ceramic substrate and monolithic
feed-through assembly using pure gold braze. This braze provides a
gas tight seal between the bezel and the ceramic substrate of the
electronics enclosure. The bezel also exhibits recessed
self-alignment nesting features suitable to receive and accommodate
the lid 724, which is welded to the bezel providing another gas
tight seal at location between the bezel and the lid. The bezel is
brazed on the ceramic substrate prior to populating the electrodes
within the substrate. By doing so, the titanium lid can be welded
onto the titanium bezel after the electronics assembly has been
populated within the substrate. The welding between the bezel and
the lid can be a low temperature process, which does not affect the
electronics within the enclosure. However, if the bezel is not
used, the lid would need to be brazed onto the substrate, which is
a high temperature process. The high temperature process would
adversely affect the electronics. The gold braze between the
substrate and the bezel can be done prior to populating the
electronics within the substrate allowing a lower temperature weld
to be done between the lid and the bezel after populating the
electronics.
[0058] Referring to FIG. 7, the electronics enclosure can house a
micro-electronics assembly, an inductive coil 726 and a ferrite
core 727. In this embodiment the inductive coil is connected and
bonded into the electronics enclosure and used to inductively
receive power and provide bi-directional communication with an
external controller (not shown). The inductive coil can be
configured such that when implanted within the neurostimulator at a
depth of 1-3 cm, the inductive coil can still receive power and
communicate with the external controller. The inductive coil can be
part of an RC (resistor- capacitor) circuit designed to resonate
between 120 and 130 kHz. In one embodiment, the inductive coil
resonates via 2.7 to 3.3 nF capacitor. The coil can be 200 turns of
41 gauge bondable solid core magnetic wire and wound into a
rectangular orientation, 11.47 mm long by 5.47 mm wide, for
example. In one embodiment, the thickness of the coil is 1.5 mm. In
other embodiments, the coil is configured such that it includes a
step on the inner surface. This step allows for the coil to sit
flat on a specific surface of the ceramic substrate and clear the
protrusions of the feed-through wires on another portion of the
inside surface of the ceramic substrate. The step in the coil can
increase the number of turns that can be allowed to fit into the
electronics enclosure. The increased number of turns allows for
greater distance in which the coil can be externally powered, thus
allowing for a greater distance over which bi-directional
communication can occur. Additionally, in other embodiments, the
length, width and thickness of the coil can be adjusted to fit into
the electronics enclosure and configured such to optimize the power
transfer and communication distances. The ferrite core can be
bonded into the top side of the inductive coil and used to align
the magnetic flux to optimize energy transfer. The
micro-electronics, inductive coil and ferrite core are all
contained within the electronics enclosure and hermetically sealed
using a titanium lid.
[0059] The hermetic electronics enclosure also supports an integral
fixation apparatus 728. The fixation apparatus as described above
can be fixed to the enclosure, and in one embodiment the fixation
apparatus is laser welded to the enclosure. In other embodiment the
fixation apparatus can be bonded using standard biocompatible
adhesives, or otherwise mechanical attached, e.g., swage or press
fit to the hermetic enclosure. Additionally, the fixation apparatus
includes an additional routing feature 729 located on the distal
side of the stimulator body. In one embodiment, the routing feature
is made from the same titanium as the fixation mini-plate and is
configured to curve around the electrode wires as they pass from
the stimulating lead to the stimulator body. The electrode wires
are guided through the routing feature on the fixation apparatus,
where they can be organized and crimped to the feed-through wires
on the electronics enclosure.
[0060] In an alternative embodiment, as illustrated in FIG. 8, an
isometric exploded view of the hermetic electronics enclosure 810
including the integral fixation apparatus which includes the bezel
811 and a lid 812 is shown without the stimulation lead assembly
and protective outer layer. In this embodiment, the fixation
apparatus is integral to the bezel. The integral bezel and fixation
apparatus are then brazed onto the ceramic electronics
enclosure.
[0061] In this embodiment, the braze bezel 811 also exhibits a
recessed self-alignment nesting features suitable to receive and
accommodate the lid 812 which can be welded to the braze bezel
providing a gas tight seal between the braze bezel and the lid, as
shown in FIG. 8.
[0062] FIG. 9 illustrates one embodiment of a three-dimensional
micro-electronics assembly. In this embodiment the
micro-electronics assembly comprises of an Application Specific
Integrated. Circuit (ASIC) 730, a diode array 731, a diode array
interposer 732, an ASIC interposer, and discrete components
including but not limited to a resonating capacitor 734 and a
smoothing capacitor. In one embodiment, the diode array is soldered
or conductive adhesive bonded onto an organic or ceramic
interposer. The diode interposer provides a conductive patterned
electrical circuit between the arranged diodes. In one embodiment,
the diode interposer is then adhesive bonded to the upper surface
of the ASIC. The diode array rectifies the alternating current
coming from the RC circuit which is then used to power the
ASIC.
[0063] As shown in FIG. 9, the AISC with the bonded diode array
interposer can be adhesive bonded onto a second organic or ceramic
interposer. In one embodiment the ASIC is wire-boned using gold
ball bonding or wedge bonding between exposed circuit pads on the
interposer and exposed pads on the ASIC. The ASIC interposer
provides a patterned electrical circuit between discrete components
and the ASIC including but not limited to a resonating capacitor
and smoothing capacitors. The discrete components are soldered or
conductive adhesive bonded to the ASIC interposer. In one
embodiment, the micro-electronic assembly, including the ASIC 730,
diode array 731, diode array interposer 732, ASIC interposer,
resonating capacitor 734 and smoothing capacitor, is bonded or
adhered to the lower surface of the brazed hermetic ceramic
electronics enclosure, or alternatively, is printed directly into
the brazed hermetic ceramic electronics enclosure.
[0064] In one embodiment, as shown in FIG. 9, the ASIC interposer
contains one or more apertures 736, which are metalized annular
rings, to receive the exposed ends of the conductive feed-through
pins. The electrical connection between the ASIC interposer and the
feed-through wire is done using conductive epoxy. In other
embodiments the electrical connections between the ASIC interposer
and the feed-through wires can be done using traditional
wire-bonding techniques, or soldering the metalized annular rings
around the aperture to the feed-through pins.
[0065] In other embodiments, as illustrated in FIG. 10, the ASIC
interposer described above is metalized directly onto the inner
bottom surface of the ceramic substrate. The metalized patterned
electrical circuit is metalized using thick film, or a sputtered
metal deposition to impose the circuit pattern on the substrate, in
which to affix electronic components. Metalizing the substrate
facilitates communication between the assembled components and the
outside environment at the location where the metalized substrate
interfaces with the monolithic feed-through using wires brazed into
the enclosure. In one embodiment, the metalized thick film or
sputter is a few angstroms thick, and more specifically a 2000
angstrom thick layer of platinum and gold is laid directly on the
ceramic substrate to create the patterned electrical circuit.
[0066] In other embodiments, as illustrated in FIG. 11, the
position of the monolithic feed-through assemblies 911 on the
ceramic substrate 910 can protrude through the distal wall of the
ceramic substrate. In this embodiment, the substrate can be
manufactured from stabilized zirconium oxide and the feed-through
pins can be, gold brazed into place and can be manufactured from
platinum-iridium (80/20). In various other embodiments the integral
substrate and monolithic feed-through assembly may be manufactured
from one of many ceramic materials, including, but not limited to
aluminum oxide, transparent polycrystalline aluminum oxide,
aluminum nitride, and silicon nitride. Also the electronics
enclosure, integral substrate and monolithic feed-through assembly
can be produced using a variety of manufacturing methods including
but not limited to post sintering machining, green form pressing
and sintering, and injection molding and sintering. The pins may
also be manufactured from platinum or other platinum alloys,
palladium, titanium, or stainless steel.
[0067] FIG. 12 illustrates a side view of one embodiment of the
neurostimulator 1200, which can comprise of a stimulator body
1200a, a stimulation lead 1200b, which contains one or more
stimulation electrodes 1201, and an integral fixation apparatus
1200c. FIG. 12 also shows two embodiments of the cross-section
through the diameter of the stimulation lead 1200b. In one
embodiment, the cross-section view AA in FIG. 12, the electrode
wires or conductors 1202 that are electrically connected to the
feed-through assemblies on the electronic enclosure for each
electrode are discrete, independently insulated conductor wires
serviced within individual lumens 1203 in the integral stimulation
lead 1200b. In one embodiment the stimulation lead is manufactured
using a multi-lumen extruded copolymer. The copolymer used in the
extruded multi-lumen lead is very similar to the copolymer used in
the outer protective (insulating) layer that covers the stimulator
body and a portion of the stimulation lead. In this embodiment, the
copolymer used has an increased hardness compared to the outer
protective layer copolymer. In one embodiment, the conductive
electrode wires can be made of stranded platinum-iridium (90/10)
wire with a diameter of 0.1 mm. In other embodiments the conductive
wire can be made from but not limited to stranded or finely bundled
cable assemblies or in alternate embodiments a solid wire. The
conductive electrode wires can be manufactured from but not limited
to platinum, platinum-iridium alloy, MP35N or a variation of MP35N
including a DFT, drawn and filled tubing, stainless steel, gold, or
other biocompatible conductor materials. The center lumen in the
cross-section can includes a malleable wire segment made from
platinum-iridium (90/10) with a diameter up to 0.4 mm. The
malleable wire segment in the center lumen, in one embodiment, can
be made from but not limited to platinum, platinum-iridium alloy,
MP35N or a variation of MP35N including a DFT. The additional of
the malleable wire or other stiffening mechanism to the center
lumen, in one embodiment, provides the stimulation lead assembly
with added mechanical properties, such as, increasing the linear
stiffness of the lead and providing increased flex fatigue
properties to the entire lead assembly. The increase in the linear
stiffness of the stimulation lead is needed to ease the
implantation of the neurostimulator. For example, the stimulation
lead having a malleable wire can be configured to have the rigidity
to penetrate and dissect through blunt tissue, but remain malleable
enough to be bent into a shape to conform to the target
anatomy.
[0068] In one embodiment, the neurostimulator is configured to be
implanted within the pterygopalatine fossa, a deep structure
located behind the base of the nose, and just anterior the skull
base. As described in U.S. patent application Ser. No. 61/145,122
to Papay, which is incorporated herein by reference, the intended
implantation of the neurostimulation into the pterygopalatine fossa
is through a trans-oral approach using a custom implantation tool
to aid in the placement of the neurostimulator. An increased linear
stiffness of the stimulation lead will greatly add to the ease of
the implantation. Additionally, as referenced the Papay
application, the intended implant location of the stimulator body
is on the posterior maxilla with the stimulation lead extending to
the pterygopalatine fossa along the posterior maxilla. In this
location, the stimulator body and the stimulator lead will be
subject to compressive forces due to the motion of the surrounding
anatomy from movements of the lower jaw. Thus increasing the flex
fatigue resistance of the stimulation lead will increase the life
time of the chronically implanted neurostimulator.
[0069] Referring still to FIG. 12, in other embodiments, the center
lumen of the stimulation lead may not be used to support a wire
segment. In one embodiment, a supporting wire 1202 may be floating
within the lumen or directly contacting the stimulation lead
over-molding encapsulation, as shown in the cross-sectional view AA
"ALT" on the right in FIG. 12. This view is in reference to the
thin film flex circuit embodiment described above. In this
embodiment, the flex circuit 1205 is suspended within the
encapsulation of the stimulation lead. Also as discussed above the
flex circuit contains one or more printed conductive traces 1206
that electrically connect each electrode to the feed-through
assembly on the electronics enclosure.
[0070] FIG. 13 shows additional alternate embodiment of a
neurostimulator in side view. FIGS. 13a, b, and c also show three
sectional details of the neurostimulator illustrating alternative
embodiments that include methods to facilitate mechanical
manipulation and resistance to fatigue in-vivo. FIG. 13a shows one
embodiment in which a coiled wire 1301 may be added to the proximal
portion of the stimulation lead as it mates with the stimulator
body. In this embodiment the coiled wire can be manufactured from a
straight or partially coiled wire made of a highly malleable
biocompatible alloy such as palladium, platinum, or annealed
platinum. In this embodiment the coiled wire is configured such
that the stimulation lead has optimal resistance to fatigue in
vivo. To optimize the flex resistance of the inserted coil within
the stimulation lead the following parameters can be adjusted; the
diameter of the wire, the outer diameter of the coil, pitch of the
coil, and the number of turns in the coil. In one embodiment, the
coil was manufactured using a palladium wire with a diameter of
0.25 mm, and manufactured into a coil with 5 turns, a coil pitch of
1.0 mm, and an outer diameter 1.0 mm. The coil is then suspended
within the over-mold material 1302 of the lead as described above.
In this embodiment the electrode wires 1303 that electrically
connect the electrodes to the feed-through interconnects transverse
through the center of the coiled wire segment.
[0071] In alternate embodiments, as shown in FIG. 13c, the
supporting wire 1304 can be straight and be manufactured from more
rigid materials such as titanium, stainless steel, or nitinol. In
other embodiment, a combination between the more rigid straight
section of the wire and a coiled wire can be employed. In this
embodiment the coiled/straight material can be manufactured using
the one wire or using discrete wires for each segment of the
supporting wire. In this embodiment, the supporting wire can be
manufactured from highly malleable biocompatible alloy such as
palladium, platinum, or annealed platinum allow or from more rigid
materials such as annealed titanium, stainless steel, nitinol, or
any combination thereof.
[0072] In yet another alternative embodiment, as shown in FIG. 13b,
a tapered supporting wire 1305 can be used. In this embodiment, a
tapered wire with a heaver diametric cross-section proximally and
tapering to a finer cross-section distally is used to provide
support to the stimulation lead. In one embodiment, the tapered
wire may be manufactured from either highly malleable biocompatible
alloy such as palladium, platinum, or annealed platinum allow. In
alternate embodiments the wire can be manufactured from more rigid
materials such as annealed titanium, stainless steel, or nitinol.
In one embodiment, the tapered supporting wire can start at a
diameter of 0.5 mm and taper to a diameter 0.1 mm at the distal
portion of the wire. In other embodiments, the tapered wire can
start with a diameter between 0.5 to 0.8 mm and taper to a diameter
of 0.4 to 0.05 mm. The tapered support wire can provide increased
mechanical stability and improved flex resistance at the junction
between the stimulation lead and the stimulator body, as well as
provide increased bending at the distal tip of the stimulation lead
over a straight non-tapered supporting wire.
[0073] FIGS. 14, 15 and 16 illustrate the ability of the integral
stimulation lead, in one or more embodiments to be bent and/or
shaped into any direction and the ability to retain the directional
manipulation made to the stimulation lead during implant. FIGS. 14
and 15 depict the ability of the distal stimulation lead to be bent
in any direction to accommodate the needed implantation of the
neurostimulator. FIG. 16 depicts the ability of the entire
stimulation lead to be manipulated into any angle compared to the
stimulator body and retain that position during implantation.
[0074] It will be appreciated by persons skilled in the art that
the present invention is not limited to what has been particularly
shown and described. Rather, the scope of the present invention
includes both combinations and sub-combinations of the various
features described, as well as variations and modifications thereof
that are not in the prior art, which would occur to persons skilled
in the art upon reading the foregoing description.
* * * * *