U.S. patent application number 11/107553 was filed with the patent office on 2006-07-13 for combination electrical stimulating and infusion medical device and method.
Invention is credited to Bradley D. Vilims.
Application Number | 20060155343 11/107553 |
Document ID | / |
Family ID | 38140440 |
Filed Date | 2006-07-13 |
United States Patent
Application |
20060155343 |
Kind Code |
A1 |
Vilims; Bradley D. |
July 13, 2006 |
Combination electrical stimulating and infusion medical device and
method
Abstract
A combined electrical and chemical stimulation lead is
especially adapted for providing treatment to intervertebral discs.
The combination lead may be placed proximate to intervertebral disc
cellular matrix and nucleus pulposus tissue to promote tissue
regeneration and repair, as well as nociceptor and neural tissue
modulation. The stimulation lead includes electrodes that may be
selectively positioned along various portions of the stimulation
lead in order to precisely direct electrical energy to stimulate
the target tissue. The lead also includes a central infusion
passageway or lumen that communicates with various infusion ports
spaced at selected locations along the lead to thereby direct the
infusion of nutrients/chemicals to the target tissue. One
embodiment utilizes a dissolvable matrix for infusion as opposed to
remote delivery through an infusion pump.
Inventors: |
Vilims; Bradley D.;
(Evergreen, CO) |
Correspondence
Address: |
SHERIDAN ROSS PC
1560 BROADWAY
SUITE 1200
DENVER
CO
80202
US
|
Family ID: |
38140440 |
Appl. No.: |
11/107553 |
Filed: |
April 14, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11033591 |
Jan 11, 2005 |
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11107553 |
Apr 14, 2005 |
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Current U.S.
Class: |
607/43 ; 607/117;
607/3 |
Current CPC
Class: |
A61M 2205/054 20130101;
A61M 2210/1003 20130101; A61N 1/36017 20130101; A61N 1/36103
20130101; A61N 1/36021 20130101; A61M 2205/3523 20130101; A61M
5/172 20130101; A61M 25/007 20130101; A61N 1/0553 20130101; A61N
1/0558 20130101; A61M 5/14276 20130101; A61N 1/36071 20130101; A61N
1/0551 20130101 |
Class at
Publication: |
607/043 ;
607/117; 607/003 |
International
Class: |
A61N 1/34 20060101
A61N001/34 |
Claims
1. A combined electrical and chemical stimulation device especially
adapted for inserting within an intervertebral disc for treatment
of target tissue therein, said device comprising: a stimulation
lead having an elongate, tubular configuration, and a first lumen
extending therethrough; a plurality of first infusion ports
communicating with said first lumen, said first infusion ports
enabling infusion of chemicals/nutrients from the first lumen to
tissue located exterior of said stimulation lead; a second lumen
extending through said stimulation lead and spaced from said first
lumen, said second lumen terminating at a location on said
stimulation lead between a proximal and a distal end of said
stimulation lead, said first lumen extending beyond said first
lumen toward said distal end of said stimulation lead; a plurality
of second infusion ports communicating with said second lumen, said
second infusion port enabling infusion of chemicals/nutrients from
the second lumen to tissue located exterior of said stimulation
lead; and a plurality of electrodes positioned on said stimulation
lead and between said first and second infusion ports, said
electrodes communicating with a source of electrical energy for
providing electrical stimulation of tissue adjacent said
electrodes.
2. A device, as claimed in claim 1, wherein: said first and second
infusion ports are spaced between said electrodes longitudinally
along a length of said stimulation lead.
3. A device, as claimed in claim 1, wherein: said stimulation lead
is semi-rigid so that said bent distal end remains in a bent
position as said stimulation lead traverses through the disc.
4. A device, as claimed in claim 1, wherein: said stimulation lead
has a diameter that progressively narrows from a proximal end of
said lead towards said distal end thereof.
5. A device, as claimed in claim 1, wherein: said electrodes extend
circumferentially around said stimulation lead, and are spaced from
one another longitudinally along a length of said stimulation
lead.
6. A device, as claimed in claim 1, wherein: said electrodes are
arranged substantially linearly along one side of said stimulation
lead, and said plurality of infusion ports are interspersed between
said electrodes.
7. A device, as claimed in claim 1, wherein: said electrodes are
arranged circumferentially around a portion of said distal end
thereof.
8. A device, as claimed in claim 1, wherein: said first and second
infusion ports are selectively spaced along said stimulation lead
in order to treat designated first and second treatment areas
within the disc.
9. A combined electrical and chemical stimulation device especially
adapted for inserting within an intervertebral disc for treatment
of target tissue therein, said device comprising: a stimulation
lead having an elongate, tubular configuration, and a central lumen
extending therethrough; a plurality of infusion ports communicating
with said central lumen, said infusion ports enabling infusion of
chemicals/nutrients from the central lumen to tissue located
exterior of said stimulation lead; a plurality of electrodes
positioned on said stimulation lead and spaced between said
infusion ports, said electrodes communicating with a source of
electrical energy for providing electrical stimulation of tissue
adjacent said electrodes; and an inflatable member attached to said
stimulation lead, said inflatable member communicating with a
source of fluid for selectively inflating said inflatable
member.
10. A device, as claimed in claim 9, wherein: said inflatable
member is attached to said lead near a distal end thereof.
11. A device, as claimed in claim 9, wherein: said inflatable
member is attached to said lead near a proximal end thereof.
12. A stimulation device especially adapted for inserting within an
intervertebral disc for treatment of target tissue therein, said
device comprising: a stimulation lead having an elongate,
substantially tubular configuration, wherein said stimulation lead
is made of a matrix material including nutrients and medications
intermixed therewith, said matrix being dissolvable within the
intervertebral disc to deliver the medication and nutrients to the
patient.
13. A stimulation device, as claimed in claim 12, wherein: said
stimulation lead further includes a central lumen extending
therethrough, and a stylet inserted within said lumen for assisting
in steering of the stimulation lead when emplaced.
14. A stimulation device, as claimed in claim 12, wherein: said
stimulation lead further includes a plurality of electrodes
positioned on said stimulation lead, said electrodes communicating
with a source of energy for providing electrical stimulation of
tissue adjacent said electrodes.
15. A stimulation device, as claimed in claim 12, wherein: said
stimulation lead further includes an outer membrane formed
thereover.
16. A stimulation device, as claimed in claim 12, wherein: said
membrane includes an osmotic membrane for controlling the rate at
which said medication and nutrients are infused into the disc.
17. A device, as claimed in claim 12, wherein: said matrix is
formed in a desired shape to assist in steering of said stimulation
lead when emplaced within the disc.
18. A device, as claimed in claim 12, wherein: said medications and
said nutrients are selected from the group consisting of glucose,
glucosemine, chondroitin, sulphate, oxygen, oxygenating agents,
anti-oxidants, anti-glycosilating agents, pH buffers,
anti-inflammatory agents, growth and differentiating factor-5,
transforming growth factor-beta, insulin-like growth factor-1, and
basic fibroblasts growth factor.
19. A method of managing intervertebral disc pain, said method
comprising the steps of: providing a stimulation lead having a
plurality of electrodes and a plurality of infusion ports, said
electrodes and said infusion ports being selectively spaced and
arranged with one another, said plurality of infusion ports
communicating with a plurality of lumens extending through said
stimulation lead, each lumen of said plurality of lumens capable of
delivering a selected chemical therethrough; implanting the
stimulation lead in the disc so that the plurality of electrodes
and the plurality of infusion ports lie adjacent to a targeted area
within the disc; delivering electrical energy from the electrodes
to the disc; delivering at least one chemical through the infusion
ports into the disc; and wherein the electrical energy and chemical
are especially selected to remediate the type of pain being
experienced.
20. A method, as claimed in claim 19, wherein: said plurality of
electrodes include at least two electrodes that can be separately
energized by a source of electrical energy selectively applied to
the two electrodes.
21. A method, as claimed in claim 19, wherein: said stimulation
lead includes a body made of a dissolvable matrix, said dissolvable
matrix becoming dissolved over time within the disc.
22. A method, as claimed in claim 19, wherein: each lumen of said
plurality of lumens has a different diameter size.
23. A method, as claimed in claim 19, wherein: at least one lumen
of said plurality of lumens has a progressively narrowing size as
said lumen extends in a distal direction.
24. A method, as claimed in claim 19, wherein: said implanting step
further includes the step of imparting a bend angle on a distal end
of the stimulation lead in order to assist in implanting the
stimulation lead within the targeted area within the disc.
25. A method of stimulating a healing response from a damaged
intervertebral disc, said method comprising the steps of: providing
a stimulation lead having a plurality of electrodes and a plurality
of infusion ports, said electrodes and said infusion ports being
selectively spaced and arranged with one another, said plurality of
infusion ports communicating with a plurality of lumens extending
through said stimulation lead, each lumen of said plurality of
lumens capable of delivering a selected chemical therethrough;
implanting the stimulation lead in the disc so that the plurality
of electrodes and the plurality of infusion ports lie adjacent to a
targeted area within the disc; delivering electrical energy from
the electrodes to the disc; delivering at least one chemical
through the infusion ports into the disc; and wherein the
electrical energy and chemical are especially selected to remediate
the type of pain being experienced.
26. A method, as claimed in claim 25, wherein: said plurality of
electrodes include at least two electrodes that can be separately
energized by a source of electrical energy selectively applied to
the two electrodes.
27. A method, as claimed in claim 25, wherein: said stimulation
lead includes a body made of a dissolvable matrix, said dissolvable
matrix becoming dissolved over time within the disc.
28. A method, as claimed in claim 25, wherein: each lumen of said
plurality of lumens has a different diameter size.
29. A method, as claimed in claim 25, wherein: at least one lumen
of said plurality of lumens has a progressively narrowing size as
said lumen extends in a distal direction.
30. A method, as claimed in claim 25, wherein: said implanting step
further includes the step of imparting a bend angle on a distal end
of the stimulation lead in order to assist in implanting the
stimulation lead within the targeted area within the disc.
31. A stimulation device especially adapted for placement within an
intervertebral disc for treatment of target tissue therein, said
device comprising: a stimulation lead having an elongate
configuration, said stimulation lead being made of a dissolvable
matrix material that dissolves over a period of time when the
stimulation lead is implanted within an intervertebral disc, and
wherein the dissolvable matrix is composed of materials selected
from the group consisting of nutrients and medications.
32. A stimulation device, as claimed in claim 31, wherein: said
stimulation lead further includes a plurality of electrodes
positioned on said stimulation lead, said electrodes communicating
with a source of energy for providing electrical stimulation of
tissue adjacent said electrodes.
33. A stimulation device, as claimed in claim 31, wherein: said
stimulation lead further includes an outer membrane formed
thereover.
34. A stimulation device, as claimed in claim 33, wherein: said
membrane includes an osmotic membrane for controlling a rate at
which said materials are infused in the disc.
35. A method of providing selected nutrients and medications to
targeted tissue in the body, said method comprising the steps of:
providing a stimulation lead composed of a dissolvable matrix, said
matrix including materials selected from the group consisting of
nutrients and medications; implanting the stimulation lead in the
body so that the stimulation lead lies adjacent to the targeted
tissue; and leaving the stimulation lead implanted within the body
to enable the dissolvable matrix to dissolve and thereby deliver
the selected nutrients and medications to the tissue.
36. A method, as claimed in claim 35, wherein: said stimulation
lead further includes a central lumen extending therethrough, and a
stilet inserted within said lumen for assisting in steering of the
stimulation lead when implanted.
37. A method, as claimed in claim 35, wherein: said stimulation
lead further includes a plurality of electrodes positioned on said
stimulation lead, said electrodes communicating with a source of
electrical energy for providing electrical stimulation of tissue
adjacent said electrodes.
38. A method, as claimed in claim 35, wherein: said stimulation
lead further includes an outer membrane formed thereover.
39. A method, as claimed in claim 38, wherein: said membrane
includes an osmotic membrane for controlling a rate at which the
nutrients and medication are delivered to the target tissue.
40. A method, as claimed in claim 35, wherein: said stimulation
lead is formed in a desired shape to assist in steering of said
stimulation lead when implaced within the body.
41. A stimulation lead, as claimed in claim 35, wherein: said
stimulation lead has an elongate, substantially tubular
configuration.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part of co-pending
application Ser. No. 11/033,591, filed on Jan. 11, 2005, entitled
"Combination Electrical Stimulating and Infusion Medical Device",
the disclosure of which is hereby incorporated by reference
herein.
TECHNICAL FIELD OF THE INVENTION
[0002] The present invention relates generally to electrical
stimulation leads and chemical infusion catheters for treatment of
medical conditions, and more particularly, to a system, method and
device for providing combined electrical stimulation and
chemical/drug infusion for treatment of intervertebral disc
ailments.
BACKGROUND OF THE INVENTION
[0003] It is known that immersing certain cell types within an
electrical field will cause these cells to proliferate thus
facilitating tissue repair. One known use of an electrical field
for such repair is "in bone" stimulators that are implanted in
fractures and/or spinal fusions. Another type of treatment has
recently been developed for spinal conditions wherein target tissue
is stimulated by an electrical lead using radio-frequency energy to
induce a thermal lesion in the target tissue. In this type of
procedure, the therapeutic benefit is intended to derive from
heating the target tissue and not from immersing the tissue in an
electric field. Thus, the electrical lead in this treatment is
strictly for use in heating the tissue, and there is no therapeutic
electrical field generated. Chemical treatment of target tissues
has also been developed by use of various types of infusion
catheters.
[0004] For both electrical and thermal stimulation, an electrical
current generator, commonly referred to as a pulse generator, may
be used to transmit a pulse of electrical current to an implanted
stimulation lead that has been precisely placed to transmit the
electrical or thermal energy from the electrodes to the target
tissue in order to treat the particular condition. For chemical
stimulation, one or more drugs or nutrients are delivered by a pump
that transfers a desired quantity and frequency of the
drug/nutrient through an infusion port of the catheter to the
target tissue. For chemical stimulation as well as
electrical/thermal stimulation, implanted pumps and generators can
be used to deliver the electrical and chemical stimulation as
opposed to transdermal delivery devices. More particularly,
implanted pulse generators (IPG) as well as implanted drug
dispensers (IDP) are commonly used so that patients do not have to
return to a medical facility each time treatment is to be
conducted.
[0005] The intervertebral disc (IVD) provides separation, shock
absorption, and controlled motion between vertebral bodies. The
disc is comprised of a central nucleus of a semi-fluid mass of
mucoid material, (nucleus pulposus), an outer more dense collagen
ring (annulus fibrosis), and a thin, metabolically active cellular
layer separating the nucleus and the outer collagen ring, referred
to as the annular nuclear interface/transitional zone. Disc
nutrition is tenuous at best and is provided by diffusion through
the vertebral end plate in contact with the outer surface of the
disc. As a result, a disc has limited ability to heal or
regenerate.
[0006] Due to age, injury or other conditions, cracks or fissures
may develop in the wall of invertebral discs causing a chronic
source of pain in many patients. Additionally, the inner disc
tissue (nucleus) will frequently cause the disc to bulge or
herniate into the fissures in the outer region of the disc, thus
causing nerve tissue therein to generate pain signals.
[0007] Current treatment for such disc disorders include
analgesics, physical therapy and epidural steroid injections.
Success with these treatments is frequently disappointing and the
patient will all too often have to undergo spinal fusion. Spinal
fusion is a very invasive, bio-mechanically altering, and
marginally effective treatment.
[0008] One relatively new procedure has been developed to treat
such disc ailments and general discogenic back pain. As an
alternative to other surgical procedures for patients who suffer
from back pain caused by certain types of disc disorders, this new
procedure is made possible by use of thermal stimulation leads that
provide precise temperature control in the delivery of thermal
energy to target tissue. This procedure, commonly referred to as
intradiscal electrothermal annuloplasty (IDET) was initially
believed to function by cauterizing nerve endings within the disc
wall to assist in reduction of pain, and the heat produced by the
stimulation leads would also thicken the collagen of the disc wall
thereby promoting healing of the damaged disc. IDET has proven in
some cases to be a minimally invasive procedure to treat these
types of disc ailments. However, recent research, and clinical
experience has cast doubt as to the exact method of action. More
specifically, for percutaneous treatments like IDET, the general
operating premise in these procedures, is to heat, either through
conduction or induction, causing collagen restructuring and
nociceptor coagulation within the disc that would stabilize the
structure, and dennervate the painful discs while retaining the
motion segment and thus reduce the need for fusion. While these
procedures have proven more effective than placebo, the results are
far from acceptable. Research has demonstrated that collagen
modulation and nociceptor coagulation is unlikely to be the
mechanism of action, and that these devices may simply create
injury patterns, that in a small subset of patients, stimulates a
regenerative response, thereby accounting for the better than
placebo results.
[0009] Combination electrical stimulators and chemical infusion
catheters are known for purposes of treating various spine and
brain ailments. One reference that discloses such a combination
device is the invention in U.S. Publication No. US2004/0243206.
This reference specifically discloses a combination electrical and
stimulation lead for stimulation of a person's nerve tissue in the
brain. One or more electrodes are located along the lead body and
are adapted to be positioned proximate the target nerve tissue and
to deliver electrical stimulation pulses transmitted through the
lead to the target nerve tissue. One or more infusion ports located
along the lead body are adapted for placement proximate the target
nerve tissue and to deliver chemical stimulation pulses transmitted
through the lead to the target nerve tissue.
[0010] While combination electrical and stimulation leads may be
known, special considerations must be made for use of such devices
for intervertebral disc treatment.
[0011] Placement of a stimulation lead within a disc can be quite
difficult. Because a disc does not have a uniform density, known
stimulation leads can be quite difficult to place and may require
the attending physician to make multiple attempts for proper
placement or abandon the procedure. Of course, multiple placement
attempts greatly increase the invasive nature of the procedure and
therefore create unnecessary tissue damage and increased risk.
Inability to perform the procedure denies the patient a therapeutic
option. Improper placement of the stimulation lead can also result
in the undesirable damage of nerve tissue that is not contributing
to the chronic pain or other ailments. Because of the overall
metabolically inactive nature of the disc, it is also important
that chemical infusion be precisely targeted to contact the damaged
area of the disc with the delivered chemicals/nutrients, otherwise
inaccurate delivery to non-damaged portions of the disc can reduce
the effectiveness of the procedure. Thus, there is a need for a
combination electrical and chemical stimulation lead that can be
precisely placed with a high rate of success on a first
attempt.
[0012] The IVD is also a motion segment of the body that is
subjected to many flexion/extension/rotation cycles every day. In
some procedures, it may be necessary to keep the stimulation lead
emplaced for long periods of time, such as weeks or perhaps months.
Thus, it is desirable to have a stimulation lead that maintains a
small profile, yet is resilient enough to withstand the risk of
permanent deformation or shearing during treatment and removal of
the stimulation lead after treatment.
SUMMARY OF THE INVENTION
[0013] In accordance with the present invention, a combined
electrical and chemical stimulation device is provided that is
especially adapted for treatment of intervertebral disc ailments.
The stimulation device is in the form of a stimulation lead
designed to be placed in the disc percutaneously through an
introducer needle using an extra-pedicular approach; however,
micro-surgical or open-surgical techniques may also be utilized.
More specifically, the device of the present invention is
specifically designed to facilitate placement proximate to the
metabolically active cellular, nuclear, annular interface layer by
use of one or more selected embodiments including a straight,
curved or bent tip, as well as a variable stiffness tip. Selection
of one of these embodiments allows the physician to precisely
navigate the lead through the nucleus of the disc. In yet another
embodiment of the present invention, the stimulation lead may be
placed directly into the nuclear annular interface by use of a
introducer needle having a bent tip, and use of a stimulation lead
having a straight tip that can take a substantially linear path to
reach the target tissue.
[0014] The structure of the stimulation lead of the present
invention is characterized by an elongate and tubular shaped body
including one or more electrodes located along selected portions of
the lead body and adapted for positioning proximate the target
tissue to deliver electrical stimulation pulses transmitted through
the lead. Preferably, the electrodes extend circumferentially
around a selected length or portion of the lead since it is
difficult to orient a specific lateral side of the lead against
target tissue. One or more infusion ports are also located along
the lead body and are adapted to be positioned proximate the target
tissue to deliver selected chemicals/nutrients.
[0015] Once the stimulation lead is correctly positioned, the lead
is then connected to a pulse generator for delivery of electrical
energy to the electrodes located on the distal portion of the
stimulation lead, and is connected to an infusion pump that
provides a controlled delivery of chemicals/nutrients through the
lead to the target tissue. Preferably, the electrical pulse
generator and infusion pump are implanted medical devices. These
devices are also preferably refillable and rechargeable. Another
generally desirable characteristic of pulse generators includes
those having a capability to produce either constant or variable
current. It is also desirable to provide electrical
contacts/electrodes that are linked in series, parallel, or
combinations thereof which allow selective activation of all or a
selected group of the electrodes. Other desirable general
characteristics for an infusion pump are those pumps which (i)
control infusion material at either a constant or variable rate,
and at a constant or variable pressure, (ii) provide automatic
compensation for varying infusion pressures, and (iii) have
anti-back flow capability to prevent backflow of infusion material
through the stimulation lead, as well as pressure safety valves to
compensate for overpressure situations. Furthermore, the pump,
pulse generator and stimulation lead may be coated with an
antibacterial coating to decrease the risk of infection. The pulse
generator and pump may also incorporate appropriate alarms to
notify of infusion and stimulation failure/abnormality.
[0016] Particular embodiments of the present invention provide one
or more advantages in terms of navigation of the stimulation lead,
as well as placement of the infusion ports and electrodes for
effectively delivering electrical and chemical treatment. More
specifically, the particular shape of the stimulation lead, as well
as the particular placement of the electrodes and infusion ports
are especially adapted for delivering the electrical stimulation
and chemical infusion to target tissue within a disc. A stiffening
or support element may be incorporated in the wall of the
stimulation lead to ensure the lead does not prematurely shear or
otherwise structurally fail during use and removal. The stiffening
element is preferably in the form of an elongate support that
extends longitudinally within the wall of the stimulation lead and
terminating near the distal tip of the lead.
[0017] Further advantages and features of the present invention
will become apparent from a review of the following detailed
description, taken in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Reference is now made to the following detailed description
taken in conjunction with the accompanying drawings in order for a
more thorough understanding of the present invention.
[0019] FIG. 1 illustrates the system of the present invention
including a stimulation lead inserted in an intervertebral disc,
and a stimulation source that provides a controlled delivery of
electrical field energy and chemicals/nutrients through the
stimulation lead;
[0020] FIG. 2 is a greatly enlarged cross-section of the working
distal portion of one preferred embodiment of the stimulation lead
of the present invention;
[0021] FIGS. 3-7 are greatly enlarged side or elevation views
illustrating other preferred embodiments of the stimulation
lead;
[0022] FIG. 8 is a greatly enlarged cross-section of the working
distal portion of another preferred embodiment that incorporates a
stiffening element;
[0023] FIG. 9 is a section taken along line 9-9 of FIG. 8;
[0024] FIG. 10 illustrates another preferred embodiment of the
present invention in the form of an introducer needle having a bent
distal end for placement of the stimulation lead directly into the
nuclear annular interface;
[0025] FIGS. 11-13 illustrate further embodiments of the present
invention wherein the electrodes and infusion ports are dispersed
substantially along the entire length of the stimulation lead;
[0026] FIG. 14 illustrates a cross section of a further embodiment
of the present invention wherein a dual lumen is provided enabling
greater selective control of infusion through designated portions
of the stimulation lead;
[0027] FIG. 15 illustrates yet a further embodiment of the present
invention wherein an inflatable member is provided near the distal
end of the stimulation lead to help anchor the lead after
emplacement;
[0028] FIG. 16 illustrates the embodiment of FIG. 15 but the
inflatable member being provided near the proximal end of the
stimulation lead.
[0029] FIG. 17 illustrates the stimulation lead of FIG. 14 inserted
in an invertebral disc wherein the lead can selectively treat two
targeted treatment zones or areas within the disc;
[0030] FIG. 18 illustrates a cross section of yet a further
embodiment of the present invention wherein the body of the
stimulation lead is made from a dissolvable matrix with the
stimulating electrical contacts embedded therein;
[0031] FIG. 19 illustrates a cross section of a further variation
of the embodiment of FIG. 18 wherein the stimulation lead has a
preconfigured bend at the distal end thereof and no central lumen;
and
[0032] FIG. 20 is a cross-section taken along line 20-20 of FIG.
18, and further illustrating the use of an outer membrane which may
help maintain the integrity of the stimulation lead when emplaced,
as well as to control the rate at which the constituents
incorporated within the dissolvable matrix are allowed to diffuse
into the invertebral disc.
DETAILED DESCRIPTION
[0033] Referring to FIGS. 1 and 2, the system 10 of the present
invention is shown that includes a combination electrical and
chemical stimulation device 12, a stimulation source 14 that
communicates with the stimulation device 12 for delivering
electrical energy and chemicals to the stimulation device, and an
interventional device such as an introducer needle 32 that allows
introduction of the stimulation lead into the disc. The stimulation
device 12 is shown as inserted within an intervertebral disc D. The
combination device 12 more particularly includes a percutaneous
electrical and chemical stimulation lead 16 in the form of an
elongate tubular member having a desired length and diameter
allowing the lead 16 to be placed within the intervertebral disc of
the patient to be treated. The working distal portion 20 of the
stimulation lead 16 provides the desired stimulation through a
plurality of electrodes 22 which are selectively positioned on the
distal portion 20, along with a plurality of infusion ports 30
which allow delivery of chemicals/nutrients to target tissue. The
proximal portion of the stimulation device 12 can be referred to as
a lead extension 18 that connects to the stimulation source 14. The
lead extension 18 can be made of the same type and diameter
material as the stimulation lead 16, or may be made of a different
type of material and diameter.
[0034] Referring specifically to FIG. 2, in a first embodiment of
the stimulation lead, a plurality of circumferentially extending
electrodes 22 are positioned at the distal portion 20. The
electrodes 22 are also spaced longitudinally along the distal
portion 20. The electrodes produce an array of electrical field
energy, and the target tissue is immersed in the electrical field.
One or more electrical conductors 23 extend through the interior of
the stimulation lead 16 in order to transmit the electrical
impulses to the electrodes 22. It is preferable to utilize a single
conductor 23 along the major length of the lead, and then provide
branch conductors (not shown) at the distal portion 20 that then
extend to contact the various electrodes. The branch conductors
could be a linearly arranged set of wire extensions extending
between each electrode, or any other advantageous combination of
wire conductors to interconnect the electrodes. Use of a single
conductor is a more robust design as opposed to multiple smaller
conductors that are more prone to breakage as a result of the
motion cycles of the ISD. It is also contemplated that the
electrode could be a single electrode wound in a helical pattern
about the distal portion 20. Thus in this helical pattern, only one
conductor 23 would be required with no additional branch
conductors. In order to generate the desired intensity and size
electrical field, the electrodes 22 can be disposed on the distal
portion in a pattern or arrangement that best suits the electrical
field to be generated. For example, in the helical pattern, the
electrode could be wound with a tighter pattern to generate a more
intense field, while a looser more spaced pattern would generate a
less intense field. Of course, the particular signal or impulse
current provided to the electrodes also determines the intensity of
the field generated.
[0035] In order to provide chemical infusion, a central lumen or
passageway 24 is formed through the stimulation lead. The central
lumen 24 may extend completely through the lead thereby forming a
distal opening 28 in the stimulation lead and providing one
infusion port that is directed distally of the stimulation
lead.
[0036] The stimulation lead 16 may be made of a homogeneous
material, or may be made of differing materials that cause the
stimulation lead to have either a more progressively stiff or more
progressively flexible characteristic as the lead extends in the
distal direction. Depending upon the manner in which the
stimulation lead is to be emplaced, it may be desirable to use
either the more progressively stiff or more progressively flexible
arrangement.
[0037] In accordance with the method of the present invention, a
stylet (not shown) is first inserted through the introducer needle
32. The introducer needle 32 is emplaced by penetrating the skin
and muscle tissue, and ultimately into the disc D. When the
introducer needle has penetrated the disc, the stylet is removed
and the stimulation lead 16 is then inserted through the lumen of
the introducer needle.
[0038] Referring again to FIG. 1, the stimulation lead 16 is
illustrated as being emplaced within the disc D. This disc D is
shown in cross section along with an adjacent vertebra V. The
stimulation lead 16 is shown as taking an arcuate or curved path
through the disc nucleus N in order to be precisely positioned at
the area of the disc to be treated, illustrated as a fissure F
which has developed adjacent the spinal fluid sac (not shown). The
other primary features of the disk D are also illustrated including
the annulus fibrosis A and the thin layer L defining the annular
nuclear interface/transitional zone.
[0039] The stimulation source 14 is preferably an implantable
medical device 34 including both an IPG (implantable pulse
generator) 36 and an IDP (implantable drug dispenser) 38. The
implantable device 34 could be contained within a single structural
housing, or two separate housings, one for the IPG 36, and one for
the IDP 38. The IPG and IDP can both be self-contained devices with
internal control for preset delivery of electrical and chemical
pulses. Alternatively, an external controller 44 could be used to
modify the desired treatment protocol by use of RF transmission
wherein an implantable RF receiver 40 is integrated with the IPG 36
and IDP 38. The RF receiver 40 could also be housed within the same
implantable medical device 34, or could be a separate implanted
device. An external RF transmitter 42 transmits RF signals to
control the delivery of electrical stimulation and chemicals to the
stimulation lead 16. A controller 44 provides the specific
instruction set for transmission by the RF transmitter 42.
[0040] In accordance with the apparatus and method of the present
invention, there are a number of nutrients and medications that can
be delivered by the stimulation lead. For nutrients, this list
includes, but is not limited to, glucose, glucosemine, chondroitin
sulphate, oxygen and oxygenating agents, anti-oxidants,
anti-glycosilating agents, and pH buffers. For medications, these
may include, without limitation, anti-inflammatory agents and
growth factors, such as growth and differentiating factor-5,
transforming growth factor-beta, insulin-like growth factor-1, and
basic fibroblasts growth factor. In terms of the types of
electrical impulses provided to the electrodes 22, these electrical
impulses may be continuous or variable over time, and may vary
based upon voltage, amperage, and alternate current frequency.
[0041] Referring to FIG. 3, a different arrangement is illustrated
with respect to the location of the electrodes 22, and the single
infusion port at distal opening 28 is supplemented with a plurality
of additional infusion ports 30. In this embodiment, fewer
electrodes are incorporated, yet additional infusion ports 30 are
provided that are spaced longitudinally along the length of the
lead 16 and placed between the electrodes 22.
[0042] FIG. 4 shows another embodiment with a different arrangement
of electrodes 22 and infusion ports 30 as well as a modification of
the stimulation lead shape to include a bent distal tip having a
chosen bend angle O. The bend angle O helps define the path of
travel of the lead within the disc nucleus during emplacement. In
other words, imparting a particular bend angle on the distal tip of
the stimulation lead causes the stimulation lead to travel in an
arcuate path such as shown in FIG. 1. Imparting a greater bend
angle on the lead results in the stimulation lead traveling in a
tighter arcuate path, while imparting a lesser bend angle generally
results in the stimulation lead traveling in a broader arc or
arcuate path.
[0043] Referring to FIG. 5, another embodiment of the stimulation
lead is illustrated wherein the lead has a progressively narrowing
diameter towards the distal end thereof. With this type of
stimulation lead, travel of the lead through the more dense annulus
tissue is facilitated because the distal tip has a smaller frontal
profile and is more easily controlled.
[0044] Referring to FIG. 6, yet another embodiment of the
stimulation lead is illustrated wherein the electrodes 22 are not
formed circumferentially around the distal portion 20, but are
formed more linearly along one side of the stimulation lead.
Additionally, the infusion ports 30 may have more of an oval shape
and be larger in size which facilitates greater volumetric
infusion. This embodiment may be preferred when it is desired to
more precisely direct the array of electrical energy to the target
tissue. The electrical energy array that is created by
circumferentially arranged electrodes result in transmission
patterns having a radial or circular pattern extending away from
the stimulation lead. Thus, a plurality of circumferentially
arranged electrodes transmit energy in all directions to tissue
that surrounds the stimulation lead. On the contrary, locating the
electrodes only along one side or edge of the stimulation lead
results in transmission of energy in a more linear and less radial
pattern, and directed primarily orthogonal or perpendicular to the
axis of the stimulation lead. The embodiment of FIG. 6 also
illustrates the distal end as being bent at a desired angle.
[0045] FIG. 7 illustrates yet another embodiment of the stimulation
lead wherein the electrodes 22 are concentrated at a particular
location, and the infusion ports 30 are spaced in a pattern
extending a greater longitudinal length of the lead. A stimulation
lead in this particular arrangement may be particularly suitable
for repair of a fissure located at a very defined position within
the disc, yet if the disc shows great overall degeneration, it is
preferable to provide nutrients to a greater length of the annulus
whereby the infusion ports 30 can distribute nutrients to a greater
length of the annulus.
[0046] FIG. 8 illustrates yet another preferred embodiment of the
present invention wherein a stiffening or strengthening member 47
is incorporated within the structural wall of the stimulation lead
to provide increased strength to the lead without enlarging the
frontal profile of the lead. As shown, the stiffening member 47 is
an elongate member that extends longitudinally through the wall of
the lead and terminates near the distal end thereof. The stiffening
member is malleable to a degree that allows the lead to maintain
some desired flexibility during emplacement, but increases the
overall shear and torsional strength of the lead to prevent
premature failure after emplacement or during removal. The member
47 could be made of a selected metal or thermoplastic approved for
medical use.
[0047] Referring to FIG. 10, yet another embodiment of the
invention is shown wherein an introducer needle 46 is not placed
within the disc nucleus, but rather is placed only into the disc
annulus, and then the stimulation lead 16 extends through the disc
annulus to the target tissue, also shown as a fissure F. In this
embodiment, it is preferable that the stimulation lead 16 exits the
introducer needle through a bent distal portion 48 so that the lead
travels in a more parallel fashion within the annulus and along a
more linear path to the target tissue. Accordingly, a stimulation
lead having a straight tip like shown in FIGS. 2, 3 and 5, would be
more suitable according to this embodiment. In the event the distal
opening 28 of the lead 16 is of a size which could allow nuclear
tissue to clog or block the distal opening 28, a guide wire 26 (see
FIG. 12) may be inserted through the lumen 24 of the lead 16, and
the distal tip 27 of the guide wire could be placed flush with the
distal opening 28 in order to prevent clogging of the distal
opening 28, as well as to provide additional rigidity for placement
of the stimulation lead 16. If the guide wire 26 is used, then the
guide wire 26 is removed prior to connecting the stimulation lead
16 to an IDP and/or IPG. Also, the central lumen may terminate
before passing through the distal tip of the lead. Thus, all of the
infusion ports 30 would be arranged on the lead to direct
chemicals/nutrients in a perpendicular direction away from the axis
of the lead.
[0048] FIGS. 11-13 illustrate yet further embodiments of the
present invention wherein the electrodes 22 and infusion ports 30
are dispersed along substantially the entire length of the
stimulation lead. In many cases, the disc to be treated has
undergone such great degeneration that the entire disc is in need
of treatment, as opposed to a more minor degenerative condition
such as a single localized fissure. In such cases, it is
advantageous to provide both electrical and chemical stimulation to
as much of the disc as possible. The embodiments at FIGS. 11-13
show various combinations of the electrodes 22 and ports 30 that
provide greater dispersion of the electrical and chemical
stimulation. Specifically, the electrodes are larger and are spread
out along a greater length of the lead. The infusion ports are also
spread out along a greater length of the lead.
[0049] FIG. 14 illustrates yet another embodiment of the invention
wherein a second lumen 41 is incorporated within the stimulation
lead to provide greater infusion selectivity. More specifically,
FIG. 14 shows that the second lumen 41 terminates at end 39 which
is intermediate between the distal tip of the stimulation lead and
the proximal end thereof. This lumen 41 communicates with the set
of infusion ports 37 which are spaced from the end 39 of the lumen
41 towards the proximal end of the lead. The first or central lumen
24 then communicates with the infusion ports 35 that are located
distally of the end 39 of the second lumen 41.
[0050] During treatment, it may be desirable to administer
nutrients and/or medications to different parts of the disc being
treated. Furthermore, it may be desirable to provide the
nutrients/medications to these different locations within the disc
at differing flow rates and at differing times and frequencies.
With the provision of a dual set of lumens, a physician has the
ability to selectively control infusion to two distinct areas
within the disc, and can vary the treatment protocol between the
two areas of the disc by selecting the particular dosing,
frequency, and makeup of the infusion material to the distinct
locations within the disc. This selective treatment capability may
be advantageous where, for example, the distal end of the
stimulation lead may be placed near the interface/transitional
zone, and the tissue extending therealong together with the annulus
fibrosis may have particular needs in terms of the required type of
nutrients and/or medication, while the tissue within the nucleus
may have slightly different needs. Thus, the embodiment at FIG. 14
provides the treating physician with additional options in
providing effective treatment.
[0051] The particular sizes of the lumens, as well as the sizes and
spacing of the openings 35 and 37 may be configured for optimal
delivery of various types of infusion material. For example,
assuming that the desired nutrient/medication to be delivered to
the distal end of the stimulation lead was fairly viscous, it may
be advantageous to provide the lumen 24 with a larger
cross-sectional size, as well as to provide the infusion openings
35 of an increased size to accommodate the higher viscosity. As a
further example, if the lumen 41 was to deliver a less viscous
nutrient/medication, then the lumen 41 would preferably have a
smaller cross-sectional area, and the openings 37 would preferably
be smaller than the openings 35. Thus, one convenient way in which
to control infusion is to advantageously arrange the particular
size, number, and spacing of the infusion openings as well as the
size of the lumens which deliver the infusion material through the
openings.
[0052] It is further contemplated within the present invention to
also provide non-uniform lumens, as well as infusion openings that
vary in size within the same supplying lumen. As discussed above,
the IDP 38 may be programmed for preset delivery of chemical
"pulses". The IDP 38 is typically programmed to be in an "on" or
"off" state to generate delivery of a set amount of fluid over a
specific period of time. However, once the infusion material is
released from the IDP, the IDP itself does not have control over
the way in which the infusion material is dispersed through the
stimulation lead. Assuming that a lumen of a stimulation lead has a
uniform diameter with infusion openings also being of a uniform
diameter, then the infusion ports located at the more proximal end
of the device will most likely deliver a greater amount of material
to the disc as opposed to the infusion ports located at the distal
end of the device because there will be an inherent loss in the
amount of fluid delivered downstream based on frictional losses
within the lumen and the upstream openings communicating with the
lumen. Therefore, in order to ensure equal distribution of infused
material, it may be desirable to provide a lumen having a diameter
that progressively enlarges as it extends towards the distal end of
the device. Alternatively or in combination with the progressively
changing lumen size, it may be desirable to provide infusion ports
toward the proximal end of the device that are slightly smaller
than the infusion ports located towards the distal end of the
device to further help compensate for any frictional line
losses.
[0053] Referring to FIG. 15, yet another embodiment of the present
invention is provided which further includes an inflatable portion
50 in the form of a bladder or balloon that is selectively inflated
or deflated by an inflation line 52 extending conterminously with
the central lumen. The inflatable portion is mounted to the
exterior surface of the stimulation lead, and the inflation line 52
extends through an opening (not shown) in the sidewall of the lead
that is covered by the inflatable portion 50. The inflation line 52
communicates with a source of compressed fluid (not shown), and the
physician may inflate the inflatable portion 50 to a desired size.
As also shown, the inflatable portion 50 is preferably placed along
a location of the stimulation lead that does not cover or block any
infusion ports 30, as well as any electrodes 22.
[0054] In some instances, the stimulation lead may reside within a
patient for an extended period of time. As time passes, the
stimulation lead may have a tendency to migrate or drift within the
disc. Drifting of the stimulation lead can be problematic for a
number of reasons, to include causing damage to the disc by
penetration of the distal tip of the stimulation lead completely
through the disc, as well as drifting of the stimulation lead so
that it is no longer centered around/along the desired area of the
disc to be treated. To maintain the stimulation lead in its desired
position after the stimulation has been emplaced, the inflatable
portion 50 may be inflated to the desired size, thereby serving as
an anchor to help prevent drifting of the stimulation lead within
the disc. In most instances, it is desirable to place the
inflatable portion 50 near the distal tip of the stimulation lead
to best prevent undesired drift of the stimulation lead; however,
it is also contemplated within the present invention that the
inflatable portion 50 may be selectively placed along other areas
of the stimulation lead to best serve as an anchor. For example, as
shown in FIG. 16, the inflatable portion is located at the proximal
end of the stimulation lead. Furthermore, it may be desirable to
incorporate both a distally located inflation portion 50, and
another inflation portion located at the proximal end of the device
that would further help to prevent the stimulation lead from
drifting or from being inadvertently removed.
[0055] Some disc tissue may have a tendency to adhere to a
stimulation lead that has been emplaced within the disc for a long
period of time, and/or the disc tissue may have a tendency to
harden around the emplaced stimulation lead thereby making it more
difficult to remove the stimulation lead. Thus, it is also
contemplated within the present invention that the inflatable
portion 50 could be provided to extend along a much greater
distance of the stimulation lead, and the inflatable portion 50
could be inflated to a desired level prior to the stimulation lead
being emplaced within a disc. When it is then desired to remove the
stimulation lead, the inflatable portion could be deflated which
would create a small gap or space between the surrounding disc
tissue and the stimulation lead thereby easing removal of the
stimulation lead.
[0056] Thus, the inflatable portion 50 can be used either as an
anchor to maintain positioning of the stimulation lead within the
disc, or the inflatable portion 50 can be used in a reverse role by
enlarging the overall size of the stimulation lead once emplaced,
but then reducing the overall size of the stimulation lead by
deflating the inflatable portion when it is desired to remove the
stimulation lead.
[0057] Referring to FIG. 17, a stimulation lead is shown emplaced
within a disc D, the stimulation lead generally corresponding to
the embodiment shown in FIG. 14. Two oval shaped areas 40 and 42
are shown surrounding the distal and proximal sections of the
stimulation lead, respectively. These areas 40 and 42 may generally
represent targeted treatment areas within the disc. In accordance
with the embodiment of FIG. 14, the physician has the option of
applying different infusion materials through the separate sets of
infusion ports 35 and 37 to specifically target the tissue located
within the areas 40 and 42. Such treatment could be simultaneous,
sequential, or any combination thereof. Furthermore, as mentioned
above, selected sets of electrodes could be energized to provide
treatment. For example, the electrodes may be wired so that the
physician has the ability to energize two primary sets of
electrodes, one set providing an electromagnetic field generated to
cover area 40, and the other set providing an electromagnetic field
to cover area 42. The electrodes may be wired and configured to
provide generation of electromagnetic fields in any desired pattern
along the length of the lead.
[0058] Referring now to FIGS. 18-20, yet another embodiment of the
present invention is illustrated in the form of stimulation lead
60. For some treatments, it may be necessary to leave the
stimulation lead emplaced within the invertebral disc for an
extended period of time; however, for various reasons, it may not
be possible to keep the stimulation lead emplaced for the amount of
time to provide optimal treatment. In order to solve this
particular problem, the embodiment of FIG. 18 contemplates the use
of various chemical agents/medications and nutrients incorporated
within a dissolvable matrix that forms the body 62 of the
stimulation lead 60. The electrodes 64 as well as the conductor(s)
66 could be formed with the dissolvable matrix in a molding process
whereby a particular shape and size stimulation lead could be
produced. The electrodes 64 could function the same as the
electrodes 22 discussed above and could be produced in any desired
pattern and wiring arrangement. The dissolvable matrix can be made
of a material that is biomedically acceptable for enabling a time
release of the chemical agents/medications and nutrients mixed
within the matrix. The matrix is preferably a solid yet flexible
material, allowing the stimulation lead to be steered with the use
of an insertable stylet 56 which could be provided through the
central lumen 68. However, it shall be understood that this central
lumen 68 is optional, and the matrix may be manufactured of a
material which is durable yet flexible enough allowing the
practitioner to steer the stimulation lead without the use of a
stylet. Accordingly, FIG. 19 illustrates another embodiment wherein
there is no lumen present, and a predetermined bend angle is formed
in the stimulation lead enabling the lead to take the desired path
through the disc when emplaced. Once inserted into the disc, the
matrix would dissolve and the regenerating chemicals/medications
and nutrients would slowly diffuse into the surrounding disc tissue
leaving only the electrodes 64 and conducting wire(s) 66 to be
removed at some later time.
[0059] With the embodiment shown in FIGS. 18 and 19, an infusion
pump would not be required, and would thereby also allow for the
subcutaneously placed pulse generator (IPG) to be significantly
smaller. Similar to the combined pump/pulse generator device
described above, this much smaller pulse generator could be
rechargeable, or be powered by a battery source as desired.
[0060] In a modification to the embodiment of FIG. 18, it is also
contemplated within the scope of the present invention that a
stimulation lead can simply comprise a dissolvable matrix having a
desired combination of chemical agents/medications and nutrients,
and no electrodes incorporated within the lead. In some cases,
stimulation by an electromagnetic field may be unnecessary to
achieve the desired regenerative and/or pain relieving disc
response.
[0061] FIG. 20 illustrates the designated cross-section of the
device in FIG. 18. Additionally, FIG. 20 illustrates the use of an
optional outer membrane 72 which could serve multiple purposes. One
purpose for the membrane 72 would be to support the structural
integrity of the matrix material of the body 62, thereby providing
additional support for when the stimulation lead was emplaced.
Additionally, this membrane 72 could serve as an osmotic membrane
to help meter the rate at which the chemical agents/medications and
nutrients were allowed to diffuse into the surrounding tissue.
Thus, in addition to the matrix having a predetermined rate of
diffusion, the membrane 72 could be used as an additional means to
control the rate at which the chemical agents/medications and
nutrients were delivered to the surrounding tissue. It is further
contemplated that if the membrane 72 is provided only for
structural support to the lead when emplaced, the membrane could be
made of a material that quickly dissolves after being emplaced
within the disc and the diffusion rate would be entirely controlled
by the particular diffusion characteristics of the matrix.
[0062] Based upon the foregoing, the present invention provides a
combination electrical and stimulation lead especially adapted for
treatment of disc ailments. The various embodiments provide a
treating physician with stimulation leads of various
configurations, which optimizes a physician's ability to precisely
position the stimulation lead, as well as to precisely direct both
electrical and chemical stimulation.
[0063] While the above description and drawings disclose and
illustrate embodiments of the present invention, it should be
understood that the invention is not limited to these embodiments.
Those skilled in the art may make other modifications and changes
employing the principles of the present invention, particularly
considering the foregoing teachings. Therefore, by the appended
claims, the applicant intends to cover such modifications and other
embodiments.
* * * * *