U.S. patent application number 11/204749 was filed with the patent office on 2006-08-17 for medical electrical lead with interchangeable fixation member.
This patent application is currently assigned to Medtronic, Inc.. Invention is credited to Antoine Camps, Victor Duysens, Martin T. Gerber, Leo J.G. Kretzers.
Application Number | 20060184222 11/204749 |
Document ID | / |
Family ID | 23937111 |
Filed Date | 2006-08-17 |
United States Patent
Application |
20060184222 |
Kind Code |
A1 |
Camps; Antoine ; et
al. |
August 17, 2006 |
Medical electrical lead with interchangeable fixation member
Abstract
A medical electrical lead, a system for providing electrical
stimulation or sensing using such a lead, and methods of
implanting, making and using same are described. The lead includes
a rapidly connectable and/or interchangeable distal line that may
be attached to a connector located distally from a distal end of a
stimulating electrode. The rapidly connectable or interchangeable
line may be sutured to a patient's muscle or other tissue. A
physician may select a distal suture line of the present invention
on the basis of the desired characteristics of the line, and then
connect, secure or attach same to the lead body just prior to the
surgical operation in which the stimulating or sensing medical
electrical lead of the present invention is to be employed. The
desired characteristics of the suture line may relate to thickness
or diameter, length, the material from which the line is made,
biodegradability, and the like.
Inventors: |
Camps; Antoine; (Eys,
NL) ; Duysens; Victor; (Grevenbicht, NL) ;
Kretzers; Leo J.G.; (Sittard, NL) ; Gerber; Martin
T.; (Maple Grove, MN) |
Correspondence
Address: |
MEDTRONIC, INC.
710 MEDTRONIC PARK
MINNEAPOLIS
MN
55432-9924
US
|
Assignee: |
Medtronic, Inc.
Minneapolis
MN
|
Family ID: |
23937111 |
Appl. No.: |
11/204749 |
Filed: |
August 16, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10132513 |
Apr 26, 2002 |
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11204749 |
Aug 16, 2005 |
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09487787 |
Jan 20, 2000 |
6434431 |
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10132513 |
Apr 26, 2002 |
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Current U.S.
Class: |
607/129 |
Current CPC
Class: |
A61N 1/05 20130101; A61N
1/059 20130101 |
Class at
Publication: |
607/129 |
International
Class: |
A61N 1/05 20060101
A61N001/05 |
Claims
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. (canceled)
11. (canceled)
12. (canceled)
13. (canceled)
14. (canceled)
15. (canceled)
16. (canceled)
17. (canceled)
18. (canceled)
19. (canceled)
20. (canceled)
21. (canceled)
22. A method of selecting a location for and implanting a muscular
lead, wherein the muscular lead comprises: a needle having a needle
point; a test wire that is configured to supply current to needle;
a lead that is connected to the needle comprising the steps of: (a)
placing the needle point in contact with at least one test location
on the surface of a muscle; (b) providing current to the needle
point with the test wire; (c) observing the response of the
contacted muscle to the current from the needle point; (d)
selecting a location for implantation of the muscular lead; (e)
severing the test wire adjacent to its attachment point with the
needle: and (f) penetrating the selected muscle location with the
needle to draw the lead into the muscle.
23. The method of claim 22, wherein steps (a)-(c) are carried out
more than once.
24. The method of claim 22, wherein the current that is provided in
step (b) is varied and the variable response of the contacted
muscle is observed.
25. The method of claim 22, wherein step (d) is based at least in
part on the amount of current provided in order to observe a
response, the magnitude of the muscle response, or some combination
thereof.
26. The method of claim 22, wherein the step (a) is accomplished by
gripping a portion of the needle that is insulated.
Description
RELATED DISCLOSURES
[0001] This application is a continuation application of U.S.
application Ser. No. 10/132,513, filed Apr. 26, 2002, now pending,
which is a continuation-in-part of U.S. application Ser. No.
09/487,787, filed Jan. 20, 2001, now issued, U.S. Pat. No.
6,434,431 issued Aug. 13, 2002. The entire content of each of these
U.S. Applications is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to medical electrical medical
leads, including intramuscular medical electrical leads.
BACKGROUND OF THE INVENTION
[0003] Surgically implanted medical electrical leads for temporary
stimulation of various organs in the human body are known in the
art, some examples of which may be found in the issued U.S. Patents
listed in Table 1 below. TABLE-US-00001 TABLE 1 U.S. Pat. No. Title
3,474,791 Multiple Conductor Electrode 3,682,162 Combined Electrode
and Hypodermic Syringe Needle 3,757,790 Threshold Analyzer and
Stimulator Testing Device with Internal Generator 4,245,643 Method
and Apparatus for Measuring the Ohmic Contact Resistance of an
Electrode Attached to Body Tissue 4,408,617 Apparatus for Detecting
the Acupuncture Points on a Patient and for Applying Electrical
Stimulating Signals to the Detected Points 4,444,207 Method of
Anchoring a Temporary Cardiac Pacing Lead 4,735,205 Method and
Apparatus Including a Sliding Insulation Lead for Cardiac
Assistance 5,300,107 Universal Tined Myocardial Pacing Lead
5,314,463 Bipolar Nerve Electrode 5,423,876 Intramuscular Lead
Having Improved Insertion 5,425,751 Method and Apparatus for
Optimum Positioning of a Muscle Stimulating Implant 5,755,758
Intramuscular Stimulation Lead with Enhanced Infection Resistance
5,792,217 Temporary Bipolar Heart Wire 5,834,051 Intramuscular
Stimulation Lead with Enhanced Infection Resistance 5,871,528
Temporary Bipolar Heart Wire 5,928,278 Defibrillation Electrode
5,938,596 Medical Electrical Lead
[0004] Medical electrical leads and other medical devices having
various types of loops disposed therein or thereon are also known
in the art, some examples of which may be found in the issued U.S.
Patents listed in Table 2 below. TABLE-US-00002 TABLE 2 U.S. Pat.
No. Title 4,317,459 Fixation Loop for Transvenous Leads 5,207,226
Device and Method for Measurement of Blood Flow 5,555,883 Loop
Electrode Array Mapping and Ablation Catheter for Cardiac
Chambers
Incorporated by reference herein, each in its respective entirety.
As those of ordinary skill in the art will appreciate readily upon
reading the Summary of the Invention, Detailed Description of the
Preferred Embodiments and Claims set forth below, at least some of
the devices and methods disclosed in the patents of Tables 1 and 2
may be modified advantageously in accordance with the teachings of
the present invention.
[0005] In respect of known intramuscular medical stimulation leads,
sliding members disposed on the lead bodies thereof may act as a
source of bacterial infection. See, for example, the '758 patent
referenced in Table 1 hereinabove. Additionally, non-conductive
polypropolene monofilaments employed in known intramuscular leads
have been criticized as being too stiff and difficult to tie into a
knot. Moreover, fixation of the aforementioned sliding members to
muscle tissue is not always possible. Indeed, such sliding members
have a tendency to move after a suture has been applied around the
barrel anchor thereof. There also exists the problems of temporary
electrical stimulating leads having suture wires affixed thereto
which are determined to be difficult to suture by the physicians
who implant them, or which should or must be removed
post-operatively from the patient.
[0006] Thus, there exists a need to implant temporary stimulation
leads for intramuscular and other applications which employ suture
wires that are not prone to infection, need not be removed
post-operatively from patients, or which are easier to implant.
SUMMARY OF THE INVENTION
[0007] The present invention has certain objects. That is, the
present invention provides solutions to problems existing in the
prior art. It is an object of the present invention to provide an
intramuscular or other medical electrical lead, which may be
reliably and quickly affixed to muscle or other issue. It is
further object of the present invention to provide an intramuscular
or other medical electrical lead, which is quickly and easily
attached to human muscle or other tissue. It is a still further
object of the present invention to provide an intramuscular or
other medical electrical lead which easier to implant than prior
art leads.
[0008] Various embodiments of the present invention have one or
more advantages, including one or more of the following: (a)
reducing the amount of time required to implant an intramuscular
lead in muscle tissue; (b) permitting one or more electrodes to be
reliably and fixedly implanted within is human muscle tissue; (c)
reducing patient trauma; (d) reducing the number of puncture sites
in the muscle tissue; (e) is easy to use; (f) attaching to external
pacemakers, defibrillators, monitoring equipment and other external
electrical apparatus quickly, easily, securely and reliably; (g)
increasing patient safety owing to shortened implantation times,
quicker connection to external stimulation or monitoring equipment,
and more reliable fixation to muscle tissue; (h) eliminating the
requirement for post-operative removal of suture wires from the
patent; (i) permitting the implanting physician to select from an
array of different suture wires that may be quickly connected to
the lead.
[0009] Various embodiments of the intramuscular medical electrical
lead of the present invention have certain features, including one
or more of the following: (a) an intramuscular lead having at least
one proximal fixation member; (b) an intramuscular medical
electrical lead having at least one distal fixation member; (c) an
intramuscular medical electrical lead having proximal and distal
fixation members, (d) an intramuscular medical electrical lead
having a proximal or distal fixation member, where the fixation
member is selected from a group consisting of a trumpet-shaped
member, a tined member, and a helical screw; (e) an intramuscular
medical electrical lead having an electrode section which may be
elongated or compressed during the implantation procedure; (f) an
intramuscular or other medical electrical lead having an absorbable
or resorbable suture wire section; and (g) an intramuscular or
other medical electrical lead having a suture wire section which
may be readily installed, swapped or replaced, according to the is
particular requirements of the physician who implants the lead.
[0010] Other objects, features, advantages and embodiments of the
present invention will become apparent upon reading the Detailed
Description of the Preferred Embodiments and the Claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 shows a prior art intramuscular lead;
[0012] FIG. 2 shows one embodiment of an intramuscular lead of the
present invention;
[0013] FIG. 3 shows a cross-sectional view of one embodiment of an
intramuscular lead of the present invention implanted in muscle
tissue:
[0014] FIG. 4 shows two embodiments of an intramuscular medical
lead of the present invention implanted within muscle tissue and
connected to an implantable electrical stimulator;
[0015] FIG. 5 shows a perspective view of a one embodiment of an
intramuscular medical electrical lead and corresponding electrical
stimulator implanted within the human body in accordance with a
dynamic graciloplasty surgical procedure;
[0016] FIG. 6(a) shows disk trumpet-and/or disk-shaped embodiments
of the distal and proximal fixation members of the present
invention;
[0017] FIG. 6(b) shows helical screw-and/or cone-shaped embodiments
of the distal and proximal fixation members of the present
invention;
[0018] FIG. 6(c) shows a cross-sectional view of the helical
screw-shaped is embodiment of the proximal fixation member
illustrated in FIG. 6(b);
[0019] FIG. 6(d) shows tin-shaped embodiments of the distal and
proximal fixation members of the present invention;
[0020] FIG. 6(e) shows further embodiments of tine-shaped
embodiments of the distal and proximal fixation members of the
present invention;
[0021] FIG. 7(a) shows a cross-sectional view of one embodiment of
a variable length and flexibility electrode implanted within human
muscle tissue;
[0022] FIG. 7(b) illustrates the mechanical principles involved in
varying the flexibility of the electrode illustrated in FIG.
7(a);
[0023] FIG. 7(c) shows one embodiment of the electrode of FIG. 7(a)
in cross-section in the region of the distal portion thereof,
[0024] FIG. 7(d) shows yet another embodiment of the electrode of
FIG. 7(a) in cross-section in the region of the distal portion
thereof;
[0025] FIG. 8(a) shows one embodiment of a medical electrical lead
of the present invention having a replaceable or resorbable suture
wire forming portions of the distal end thereof,
[0026] FIG. 8(b) shows another embodiment of a medical electrical
lead of the present invention having a replaceable or resorbable
suture wire forming portions of the distal end thereof; and
[0027] FIG. 9 shows one embodiment of a medical electrical lead of
the present invention having a breakable or snappable needle
attached to the distal end thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] FIG. 1 shows a prior art intramuscular medical electrical
lead disclosed in U.S. Pat. No. 4,735,205 to Chachques et al.
entitled "Method and Apparatus for a Sliding Insulation Lead for
Cardiac Assistance". In FIG. 1, pulse generator 5 (not shown in
FIG. 1) is coupled to intramuscular lead 30 comprising suture
needle 32, distal member or line 33, pigtail coil 34, lead body 36,
IPG connector 38, slidable insulating tube or sheet 42 and
electrode 44. Suture needle is adapted to be drawn through the
muscle which is to be electrically stimulated. Electrode 44 is
implanted within the desired muscle by being drawn therethrough
using line 33 attached to suture needle 32. Needle 32 is first
inserted through the muscle and electrode 44 drawn therethrough by
means of line 33. Connector 38 is adapted for coupling to one or
more output terminals of implantable pulse generator (IPG) 5 after
electrode 44 has been appropriately implanted in muscle tissue.
[0029] FIG. 2 illustrates one embodiment of an intramuscular
medical electrical lead of the present invention. Medical
electrical lead 30 in FIG. 2 comprises proximal IPG connector 30,
lead body 36, proximal fixation member 10, electrode 44, distal
fixation member 15, line 33, needle 32, temporary testing wire 19,
and test connector 20. Needle 32 may further comprise pointed
electrically conductive tip 32a and portion 32b having electrically
insulative material disposed thereover. Note that in various
embodiments of the present invention only one fixation disk member
10 or 15 is may be present. Fixation member 10 is preferably
fixedly attached to lead body 36 and/or electrode 44, while distal
fixation member 15 is preferably attached to the distal end of
electrode 44 after electrode 44 has been suitably positioned and
placed within muscle tissue and needle 32 has been removed by the
physician from the distal end of lead 30. In one such embodiment of
the present invention, distal fixation member 15 forms a circular
disk having a hole disposed through the center thereof through
which line 33 is threaded, with fixation member 15 then being slid
proximally up line 33 until it engages the distal end of electrode
44 and is snapped or clicked into place thereover for relatively
rigid fixation thereto.
[0030] Prior to implanting electrode 44, an optimum electrode
implantation location may be determined as follows. To determine
the best location for muscle implant 44, threshold measurements at
various test locations may be carried out on the muscle. One
consideration in evaluating such a location is whether a location
requires only a low threshold stimulation signal (and hence low
energy consumption) to cause muscle contraction. Obviously,
locations having the lowest stimulation thresholds are preferred.
Another consideration in evaluating a stimulation location is
whether stimulation at such a location causes muscle contractions
to be large. It is generally preferred that muscle contractions be
large. The foregoing two considerations are generally weighed
together in determining an optimum electrode location.
[0031] In the present invention, an optimal electrode position may
be determined by using needle 32, and more particularly needle
point 32a, as a is test electrode probe. Needle point 32a is placed
in, contact with various test locations on the surface of a muscle.
Temporary conductor or test wire 10 is provided for supplying
electrical current to needle 32 from an external pulse generator
(not shown). Because needle 32 must be gripped by the surgeon
during the testing of prospective implant electrode locations, the
outside surface of the proximal gripping portion of needle 32
spaced from sharp muscle-contacting probe end 32a thereof may be
provided with a suitable insulating coating 32b such as a
polyurethane adhesive. Distal end 32a of needle 32 must make
electrical contact with the muscle tissue being tested and
therefore is not insulated. It will be understood by those skilled
in the art that needle 32 need not be coated to be functional.
[0032] Use of needle 32 for testing relation of a muscle tissue
area is accomplished by gripping the insulated surface 32b thereof
and holding the uninsulated contact point area 32a and electrical
contact for selected test areas of the muscle tissue. There is a
risk of local tissue damage if sharp point 32a of needle 32
penetrates the surface of the muscle. Non-penetrating contact has
therefore been found to be preferable to inserting the sharp end of
the needle into the tissue.
[0033] After testing the various prospective implant locations,
determining the optimum location, temporary conductor or test wire
10 is severed adjacent to its attachment point with needle 32.
Needle 32 is then employed by the surgeon to penetrate the targeted
muscle and permit electrode 44 of lead 30 to be drawn into an
optimum position for periodic stimulation.
[0034] In a preferred embodiment to the present invention, line 33
is electrically nonconductive and is made of an absorbable or
bioabsorbable suture material so that it is eventually absorbed by
the muscle tissue after implant. Such materials include DEXON.RTM.,
VICRYL.RTM., MAXON.RTM. and PDS.RTM..
[0035] In another embodiment of the present invention,
nonconductive line 33 is replaced with a thin conductor wire having
an outer insulative coating such as is preferably the case with
temporary conductor or test wire 10. Connector 38 is connected to
implantable pulse generator 5 (not shown in FIG. 2). Once the
optimum electrode stimulation location has been determined,
electrode 44 is inserted in the targeted muscle, followed by
cutting temporary conductor wire 10 at the end located near needle
32.
[0036] Continuing to refer to FIG. 2, line or member 33 is most
preferably a monofilament wire formed of polypropylene. Lead body
36 may comprise any suitable flexible electrical conductor, such as
strands of multifilament or twisted stainless steel. Lead body 36
most preferably comprises an electrical conductor that provides a
high degree of flexibility and superior mechanical and electrical
properties. In preferred embodiments of the present invention the
electrical conductor of lead body 36 is covered with an appropriate
electrical insulator such as silicone rubber, polyurethane,
polyethylene, polypropylene, polyamide, combinations and mixtures
of the foregoing, and other suitable materials. The electrical
conductor disposed within lead body 36 is most preferably formed
from twisted or helically wound strands of medical grade stainless
steel wire. Less preferably, the conductor may be formed of single
strands of stainless steel, or of one or more strands of
electrically conductive polymeric material.
[0037] The insulation disposed over the electrical conductor is
most preferably formed of flourinated ethylenepropylene ((FEP),
polytetrafluoroethylene (PTFE), or any other suitable medical
grade, biocompatible dielectric insulating coating such as
co-polymer polytetrafluoroethylene, polyethylene, silastic,
neoprene, polypropylene, or polyurethane. Likewise, proximal and
distal fixation members 10 and 15 may be formed of the same or
similar materials.
[0038] Electrode 44 is most preferably formed of a platinum/iridium
alloy, wherein platinum comprises 90 percent of the alloy and
iridium comprises 10%. Electrode 44 is mechanically and
electrically connected by an electrical conductor disposed within
lead body 36 (not shown in the Figures). The electrical conductor,
in turn, is attached to the distal end of IPG connector 38. Lead 30
includes current needle 32 for piercing muscle tissue preparatory
to drawing electrode 44 within the muscle tissue. The proximal end
of curved needle 32 is connected to line or strand 33.
[0039] Referring now to FIG. 31 there is shown a cross-sectional
view of patients muscle tissue 27 having one embodiment of lead 30
of the present invention disposed therein. Scissors 39 are employed
by a physician to grip portions of needle 32 and draw electrode 44
through and into a desired portion of muscle tissue 27. Proximal
fixation member 15 prevents or impedes pulling lead body 36 into
muscle tissue 27. In similar fashion, distal fixation member 10
(once in place) prevents portions of electrode 44 from moving
outside muscle tissue 27 in the proximal direction. Optional
anchoring sleeve 25 may be employed to appropriately locate or
position lead body 36 in a desired location.
[0040] In preferred embodiments of the present invention, lead 30
is configured to provide satisfactory stimulation thresholds for
appropriate muscle contraction of muscle tissue 27. Needle 32 is
appropriately shaped and of appropriate length to provide optimum
results. The length of lead 30 should be sufficient to provide
adequate slack in lead body 36 to permit bi-lateral implants.
Moreover, in a preferred embodiment of the present invention
proximal and distal affixation members 15 and 10, respectively,
optionally include structures for suturing or anchoring same to
muscle tissue 27 once electrode 44 has been appropriately
positioned within same. It is also desired that at least portions
of lead 30 be visible using x-ray imaging techniques.
[0041] Referring now to FIG. 4, there is shown intramuscular
stimulating system 3 comprising IPG 5 and two leads 30
appropriately implanted in intramuscular tissue 27 such that
electrodes 44 thereof provide appropriate electrical stimulation to
tissue 27. Curved needles 32 of lead 30 are removed by the
physician once distal affixation member 10 has been placed or
located at or near the distal end of electrodes 44. In a preferred
embodiment of the present invention, electrode 44 is about 25 mm in
length, although other electrode lengths are contemplated in the
present invention including, but not limited to, about 5 mm, about
10 mm, about 16 mm, about 20 mm, about 25 mm, about 30 mm, about 35
mm and about 40 mm.
[0042] FIG. 5 shows intramuscular stimulating system 3 comprising
IPG 5 and leads 30. IPG 5 may be, for example, a Medtronic Model No
3023 Interstim IPG. Such an IPG may be programmed using a Medtronic
Model No. 3031 Patient Programmer. In the embodiment of system 3 of
the present invention illustrated in FIG. 5, a gracilis muscle
29127 is wrapped around portions of anus 31. Gracilis muscle 29127
is then electrically stimulated through means of electrodes 44
implanted therewithin, such electrodes being electrically connected
to IPG 5. The configuration of gracilis muscle 29/27 illustrated in
FIG. 5 is known as a dynamic graciloplasty procedure.
[0043] FIGS. 6(a) through 6(c) illustrate various embodiments of
the proximal and distal fixation members of the present invention.
In FIG. 6(a), electrode 44 is positioned within muscle 27, and is
secured reliably and relatively fixedly therein through means of
proximal and distal affixation members 10 and 15, respectively. As
shown in FIG. 6(a), proximal fixation member may from a
toroid-shaped member fabricated most preferably from silicon
rubber. Distal fixation member 15 is shown as comprising snap-on
disk 15a having a central hole disposed therethrough through which
line 33 is threaded, snap-on disk then being pushed over distal
cone or member 15b for frictional engagement thereof. It is
contemplated in the present invention that any of the proximal and
distal fixation members 10 and 15 illustrated in any of the Figures
hereof may be positionally switched.
[0044] In FIG. 6(b), proximal fixation member 10 is of the helical
screw-in type. Distal fixation member 15 again comprises cone 15b
and snap-on disk 15a. FIG. 6(c) shows a cross-sectional view of
portions of lead 30 in the vicinity of screw-in fixation member 10
in FIG. 6(b). Crimp sleeve 65 slides over helical screw 10 and
crimps same to electrical conductor 41 and electrode 44. Electrical
insulation 37 may be disposed between helical screw-in member 10
and electrode 44.
[0045] FIG. 6(d) illustrates yet another embodiment of the present
invention, where proximal and distal fixation members 10 and 15
comprise tined members that prevent or inhibit movement of
electrode 44 following implantation within muscle tissue 27. Tines
attached to fixation member 10 in FIG. 6(d) project proximally and
inhibit movement of electrode 44 in the proximal direction.
Contrariwise, in the embodiment of the present invention
illustrated in FIG. 6(d) tines attached to proximal fixation member
10 prevent or inhibit movement of electrode 44 in the distal
direction.
[0046] FIG. 7(a) illustrates muscle tissue 27 in cross-section
having yet another embodiment of the lead of the present invention
implanted therein. Disk-shaped proximal fixation member 10 prevents
electrode 44 from moving in the distal direction, while
similarly-shaped distal fixation member 15 prevents movement of
electrode 44 in the proximal direction once electrode 44 has been
appropriately positioned within muscle tissue 27. In the embodiment
of the present invention shown in FIG. 7(a), distal fixation member
15 most preferably comprises circular disk 15b having a central
hole is disposed therethrough through which line 33 is threaded,
the hole being dimensioned and configured to snappingly engage a
rim or groove disposed in cone 15b.
[0047] As shown in FIGS. 7(a) and 7(b), an alternative embodiment
of electrode 44 comprises relatively tightly wound electrode wire
which is capable of being pulled apart to thereby elongate
electrode 44 and to increase the flexibility thereof. Additionally,
electrode 44 may also be shaped such that spaces are initially
disposed between adjoining windings thereof. In such an embodiment
of the present invention, those windings may be pushed together to
increase the stiffness of electrode 44 or pulled apart to increase
the flexibility thereof.
[0048] Referring now to FIGS. 7(c) and 7(d) there are shown two
different embodiments for securing wound electrode 44 illustrated
in FIGS. 7(a) and 7(b) to distal portions of lead 30. Cone-shaped
member 15b may be configured to crimpingly engage distal portions
of wound electrode 44 in the region of sleeve 35. Alternatively,
crimp sleeve 35 may be configured such that portions of lead 30
disposed distally therefrom may be separated from lead 30 using
surgical scissors or mechanical breaking or snapping of a weakened
zone.
[0049] The present invention includes within its scope methods of
implanting, using and making the leads described hereinabove. For
example, the invention includes a method for implanting an
intramuscular lead having distal and proximal ends, the lead being
suitable for electrical stimulation or sensing of muscle tissue and
comprising at least one stimulating and/or sensing electrode, the
lead further comprising at least one of a proximal fixation member
located proximally from the electrode and a distal fixation member
located distally from the electrode, the method comprising: (a)
positioning the at least one electrode in electrical contact with
at least a portion of muscle tissue, the electrode being
electrically connected to at least one electrical conductor, the
conductor having a proximal end connected electrically to a
proximal connector, the connector being configured for attachment
to an external electrical apparatus; (b) securing the electrode to
the at least portion of the muscle tissue; and (c) positioning at
least one of the proximal fixation member and the distal fixation
member in or on the muscle issue to prevent or inhibit movement or
relocation of the at least one electrode in the distal or proximal
directions.
[0050] The Figures show disk-shaped fined, trumpet-shaped,
sleeve-shaped, cone-shaped, and helical screw proximal and distal
fixation members 10 and 15, respectively, but any suitably shaped
or configured fixation member, whether proximal or distal, may be
employed. The fixation member may be formed of polyurethane,
silicon rubber, medical grade plastic, suitable to biocompatible
polymers, stainless steel or any other suitable biocompatible,
biostable material. Additionally, either or both of the proximal
and distal fixation members may be fixedly attached to regions near
the proximal and distal ends of the electrode, respectively, or may
be attachable to such regions after the electrode has been
implanted in the muscle tissue at the desired site. For example, a
fixation member may assume a split disk configuration or shape
having two portions which snap together when closed upon one
another, where the two portions are opened for placement around the
lead body, electrode crimping sleeve, cone-shaped member or the
electrode, and are then closed therearound by snapping the two
portions together. As discussed above, one of the fixation members
may slide onto the line or member 33, and then be moved in the
distal or proximal directions into a position where the fixation
member snappingly or otherwise engages at least portions of a
locking member or cone to thereby be secured into position.
[0051] It is also not a requirement of the present invention that
the fixation members be located precisely "at" the proximal or
distal end of the electrode. Instead, either fixation member may be
attached, by way of example only, to a location disposed proximally
or distally from the electrode, to a location on the lead body
disposed distally from the electrode, to a location disposed
proximally from the electrode, to member 33, or even to other
members or portions of lead 10. What is important is that the
electrode be reliably and relatively fixedly positioned within the
muscle tissue at a desired site through means of the one or more
fixation members, and that such positioning of the electrode be so
maintained over a desired period of time.
[0052] Line or member 33 need not be electrically nonconductive,
and may be formed integrally with, by way of example only,
electrode 44 or lead body 36. Line or member 33 may also include a
coil affixation member, such as a pigtail, therein.
[0053] FIG. 8(a) shows one embodiment of a medical electrical lead
of the present invention having replaceable or resorbable suture
wire 33 forming portions of the distal end thereof. In the
embodiment of suture 33 illustrated in FIG. 8(a), suture 33 forms a
loop which is drawn through eyelet 62 formed in distal connector
51. Suture 33 is looped through eyelet 52, and its two ends
terminate where they are attached to the proximal end of needle 32.
The attachment of those two ends to the proximal end of needle 32
may be through welding, swaging, thermosetting, crimping, typing,
knotting, gluing, and other means known in the art. Attachment may
be accomplished when the lead is manufactured, or alternatively be
accomplished just before the lead is implanted when the implanting
physician selects a suture material, which he prefers to employ,
and attaches same to the lead.
[0054] For example, the physician himself may crimp, glue, tie or
otherwise attach the two ends of suture 33 to the proximal end of
needle 32 and/or to distal connector 51. The interchangeable nature
of suture 33 of the present invention permits a physician to select
suture 33 on the basis of desired length, diameter, material,
biocompatbility characteristics, biodegradability characteristics,
and so on.
[0055] Examples of materials from which suture 33 may be formed or
made include, but are not limited to, polydioxanone (PDS II),
coated VICRYL RAPIDE (polyglactin 910), surgical gut suture,
monocryl (poliglecaprone 25), polypropylene, NURULON braided nylon,
PERMA-HAND silk, MERSILENE polyester fiber, ETHIBOND EXCEL
polyester, surgical stainless steel, ETHILON nylon, and PROLENE
polypropylene sutures.
[0056] It is preferred that suture 33 range between about 10 cm and
about 20 cm in length, and have a diameter no larger than that of
the electrode tip (e.g., less than or equal to about 0.6 mm).
Additionally, it may be another feature of suture 33 of the present
that suture 33 be formed or made of a material which is absorbable,
resorbable, and/or biodegradable within the human body after lead
30 has been implanted. Such characteristics of suture 33 can
eliminate the need for a physician to post-operatively perform
surgery on a patient within whom lead 30 has been implanted for the
purpose of retrieving suture 33 or portions thereof. The rate at
which suture 33 degrades or decomposes within the patient can be
controlled by appropriately selecting the material and/or physical
dimensions from which suture 33 is made Examples of appropriate
biodegradable, decomposable, absorbable and/or resorbable materials
suitable for use in suture 33 of the present invention include, but
are not limited to, polydioxanone (PDS II), VICRYL RAPIDE
(polyglacbn 910), coated VICRYL RAPIDE (polyglactin 910), plain
surgical gut suture, chromic surgical gut suture, and MONOCRYL
(poliglecaprone 25) sutures.
[0057] FIG. 8(b) shows another embodiment of a medical electrical
lead of the present invention having a replaceable or resorbable
suture wire forming portions of the distal end thereof. In the
embodiment illustrated in FIG. 8(b), distal connector 51 is a crimp
connector, where the proximal end of suture wire 33 is crimped
thereto. Other types of connectors 51 are contemplated in the
present invention, such as welded connectors, swaged connectors,
thermoset connectors, glued connectors, tied connectors, and
connectors 51 shown in FIGS. 8(c) through 8(f), where set screw
connector 51, one-way mechanically-biased "squeeze" connector 51,
matingly engaging clamshell snap-on connector 51, and hinged
matingly engaging clamshell connector 51, respectively, are
illustrated. It will now become apparent that many different
embodiments of connector 51 not shown explicitly in the drawings
are possible, all falling within the scope of the claims directed
to the present invention.
[0058] FIG. 9 shows one embodiment of a medical electrical lead of
the present invention having a breakable or snappable needle
attached to the distal end thereof. This particular embodiment of
the present invention eliminates the requirement for separate
temporary testing wire 19 shown in FIG. 2 hereof. Instead, needle
32 itself is employed in place of the temporary testing wire as a
testing or temporary stimulating electrode. Once the physician has
completed temporary testing activities, needle 32 is snapped or
broken off at thinned or weakened section 53 thereof. See, for to
example, U.S. Pat. No. 5,792,217 entitled "Temporary Bipolar Hear
wire" to Camps et al. and U.S. Pat. No. 5,871,528 entitled
"temporary Bipolar Hear Wire" to Camps et al., the disclosures of
which are hereby incorporated by reference herein, each in its
respective entirety, where various types of weakened zones suitable
for use in section 53 hereof are disclosed. Suture is wire 33 may
be attached to distal connector 51 using eyelet 53 or other
suitable means.
[0059] Yet another desirable feature of the present invention when
employed in intramuscular applications is that needle 32 possess a
point which is blunt and not sharp. Such a blunt point does not
pierce muscle tissue and instead splices such tissue, thereby
resulting in less traumatic injury to the muscle issue. For
example, ETHICON's ETHIGUARD Blunt Point Needle is desirably
employed in conjunction with other components of the present
invention, as are any one of ETHICON's 1/4 circle, 3/18 circle, 1/2
curve, 1/2 circle, 5/8 circle and straight needles. Moreover,
needle insertion force may be diminished by applying a slippery
coating to needle 32 such as silicone rubber, PTFE, and other
materials which become or remain slippery when wetted.
[0060] Because the connectors of the present invention are required
to be in electrical contact with the electrical conductors of lead
30, the conductors are preferably attached to the distal ends of
the connectors by a combination of compressing, inserting and
crimping steps. Other methods of electrically conductive attachment
such as brazing, soldering or welding may of course be utilized.
The connectors of the present invention are not limited to pin
connectors, but include any plurality of connectors having suitable
configurations for attachment to the blunt end. The proximal ends
of the connectors need not be removed from the needle by manual
means only. Specially configured tools may be used to break or pull
the connectors free of the needle.
[0061] Furthermore, the present invention is not limited to
embodiments where all electrodes are attached to the same lead
body, where one electrode must necessarily be disposed proximally
or distally of the other electrode or electrodes, or where the
electrodes are crimpingly attached to the conductors. For example,
an electrode of the present invention may be formed by merely
stripping away insulation overlying bare wire at a suitable
location, by attaching a clip to bare wire, or by heat shrinking
electrically conductive heat shrink over selected portions of bare
wire.
[0062] The scope of the present invention is not limited to
intramuscular electrical stimulation or sensing applications, but
extends to neural, defibrillation, cardiac mapping, abdominal
stimulation, and other medical and medical device applications and
methods. Moreover, lead 30 of the present invention may be employed
at numerous different muscle implant locations, and is not limited
to use in cardiomyoplasty or graciloplasty applications. For
example, lead 30 of the present invention may be employed in
gluteus muscle implantation procedures to correct fecal or urinary
incontinence, and may further be employed in rectal muscle implants
in bladder myoplasty procedures. The scope of the present invention
is not limited to applications where a human organ or plurality of
organs is sensed monitored, paced, or defibrillated, but includes
similar applications in animals.
[0063] The present invention also includes within its scope methods
of making the leads, electrodes, and fixation members disclosed
hereinabove. Although only a few exemplary embodiments of the
present invention have been described in detail above, those
skilled in the art will appreciate readily that many modifications
are possible in the exemplary embodiments without materially
departing from the novel teachings and advantages of the invention.
Accordingly, all such modifications are intended to be included
within the scope of the present invention as defined in the
following claims.
[0064] In the claims, means-plus-function clauses are intended to
cover the structures described herein as performing the recited
function and not only structural equivalents but also equivalent
structures. Thus, although a nail and a screw may not be structural
equivalents in that a nail employs a cylindrical surface to secure
wooden parts together, whereas a screw employs a helical surface,
in the environment of fastening wooden parts a nail and a screw are
equivalent structures.
[0065] All patents, patent applications and/or printed publications
disclosed hereinabove are hereby incorporated into the
specification hereof, each in its respective entirety.
* * * * *