U.S. patent number 3,737,579 [Application Number 05/135,277] was granted by the patent office on 1973-06-05 for body tissue electrode and device for screwing the electrode into body tissue.
This patent grant is currently assigned to Medtronic, Inc.. Invention is credited to Lee R. Bolduc.
United States Patent |
3,737,579 |
Bolduc |
June 5, 1973 |
BODY TISSUE ELECTRODE AND DEVICE FOR SCREWING THE ELECTRODE INTO
BODY TISSUE
Abstract
A body implantable electrode comprising a flexible insulated
conductor having a proximal end adapted for connection to a power
supply and a distal end portion comprising an uninsulated,
conductive, rigid helix adapted for attachment to body tissue.
Means located and engageable at substantially the distal end
portion are provided for facilitating the screwing of the helix
into body tissue. A device is provided with means for firmly
holding the means for facilitating the screwing of the helix into
body tissue. The device also has means for holding the conductor
and for preventing the transmission of torque to the proximal end
of the conductor when the helix is being screwed into body
tissue.
Inventors: |
Bolduc; Lee R. (Minneapolis,
MN) |
Assignee: |
Medtronic, Inc. (Minneapolis,
MN)
|
Family
ID: |
22467364 |
Appl.
No.: |
05/135,277 |
Filed: |
April 19, 1971 |
Current U.S.
Class: |
607/131 |
Current CPC
Class: |
A61N
1/0587 (20130101) |
Current International
Class: |
A61N
1/375 (20060101); A61N 1/05 (20060101); A61N
1/372 (20060101); A61n 001/04 () |
Field of
Search: |
;128/404,418,419P |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Kamm; William E.
Claims
What is claimed is:
1. In a body implantable electrode assembly that includes a
flexible electrical conductor means having a proximal end thereof
adaptable for connection to a power supply and wherein the distal
end portion of the conductor comprises an uninsulated, conductive,
rigid helix adapted for attachment to body tissue, the improvement
which comprises:
means located and engageable at substantially said distal end
portion for facilitating the screwing of said helix into body
tissue and for preventing the transmission of torque to said
proximal end of said conductor means when said helix is being
screwed into body tissue, said means including further friction
increasing means adapted to be firmly held by means used for
screwing said helix into body tissue, said means and said further
means being substantially inert to body fluids and tissue; and
means substantially inert to body fluids and tissue enclosing
substantially the entire length of said conductor means except for
said distal end portion for permitting said electrode assembly to
be implanted within the body.
2. The invention as set forth in claim 1 wherein:
said means located and engageable at the distal end portion
comprises a raised section of insulation surrounding the conductor,
and wherein;
said further means comprises at least one rib on the outer surface
of said raised section adapted to frictionally fit with a member
having a slot defined therein for receiving said raised section and
said at least one rib.
3. The invention as set forth in claim 1 wherein:
said conductor comprises a plurality of electrically non-conducting
cores, a plurality of conductive metal ribbons, each of said
ribbons being helically wound around a separate one of said
electrically non-conducting cores, and a central electrically
non-conducting core, said plurality of ribbons wound on said cores
being helically wound around said central core.
4. The invention as set forth in claim 3 wherein:
said ribbons are made of platinum.
5. A device for use in screwing the conductive uninsulated distal
end portion of a body implantable electrode assembly into body
tissue, said assembly being of the type including a flexible
insulated electrical conductor having a proximal end thereof
adaptable for connection to a power supply, said device
comprising:
first means for firmly holding a portion of said electrode assembly
near said uninsulated distal end portion thereof, said first means
contacting only an insulated portion of said electrical conductor;
and
second means adapted to contact an insulated portion of said
insulated conductor for holding said conductor to facilitate the
screwing of said distal end portion into body tissue and for
preventing the transmission of torque to said proximal end of said
conductor means when said distal end portion is being screwed into
body tissue.
6. A device for use in screwing the conductive, uninsulated distal
end portion of a body implantable electrode assembly into body
tissue, said assembly being of the type including a flexible
insulated electrical conductor having a proximal end thereof
adaptable for connection to a power supply, said device
comprising:
a substantially cylindrically-shaped member having a pair of end
surfaces;
one end surface of said member having a slot defined therein for
engagement with a portion of said electrode assembly located
proximally with respect to said distal end portion thereof; and
the outer surface of said member having a groove formed therein,
said groove lying substantially parallel to the longitudinal axis
of said member, said groove being engageable with a portion of said
insulated conductor, whereby rotation of said member about said
longitudinal axis permits said distal end portion to be screwed
into body tissue without said member contacting said distal end
portion and without imparting any torque to said conductor along
its length.
7. The device as set forth in claim 6 wherein:
said member has an axially-extending opening extending from said
one end surface to said other end surface.
8. The device as set forth in claim 6 wherein:
said groove extends from said other end surface toward said one end
surface.
9. The combination of a body implantable electrode assembly
including a flexible insulated electrical conductor means having a
proximal end thereof adaptable for connection to a power supply and
a conductive uninsulated distal end portion and a device for use in
screwing the conductive, uninsulated distal end portion of said
assembly into body tissue, said combination comprising:
an electrical conductor having its uninsulated distal end portion
formed as a rigid helix;
slot engageable means surrounding said conductor proximally with
respect to said distal end portion;
first means defining a slot for rigidly engaging said slot
engageable means; and
second means formed integrally with said first means for rigidly
engaging a portion of said insulated conductor, whereby rotation of
said first and second means permits said distal end portion to be
screwed into body tissue without said first and second means coming
into contact with said distal end portion and without imparting any
torque to said conductor along its length.
10. The combination as set forth in claim 9 wherein:
said device for screwing comprises a substantially
cylindrically-shaped member having an axially-extending bore, said
bore extending from said one end surface to said other end surface
of said member, said bore being adapted to receive the proximal end
of said conductor;
said first means comprises one end surface of said member having
said slot formed therein; and
said second means comprises the outer surface of said member having
a groove formed therein, said groove lying substantially parallel
to the longitudinal axis of said member and extending from the
other end surface of said member toward said one end surface.
Description
BACKGROUND OF THE INVENTION
Electrical stimulation of body tissue and organs as a method of
treating various pathological conditions is becoming quite
common-place. Such stimulation generally entails making some type
of electrical contact with the body tissue or organ. In particular,
with respect to the heart, electrical leads have been developed in
which an electrode formed on the end of the lead are physically
implanted into the myocardial tissues. Various electrode structures
and various techniques for implanting those structures into the
myocardium have been developed. One such technique required a
plurality of stab wounds to be made in the myocardium both for the
location of the electrode as well as the suturing of the lead to
myocardial tissue. Obviously, such wounds are undesirable for a
variety of reasons. Other techniques have included the percutaneous
insertion through the chest wall or an open wound by means of a
hollow needle with the subsequent placement of the electrode into
the myocardial tissue. Still another technique involved the
deformation or flattening of one convolution of a rigid helix
serving as the electrode so that a keyed stylet could engage the
deformed convolution to permit the electrode to be screwed into the
myocardial tissue. However, this technique requires that the stylet
be in physical contact with the helix during insertion into the
myocardium and in addition has the undesirable effect of imparting
torque to the proximal end of the coiled conductor.
SUMMARY OF INVENTION
In the present invention a body implantable electrode assembly is
provided in which a flexible insulated electrical conductor has a
proximal end thereof adaptable for connection to a power supply and
a rigid helix serving as the distal end portion thereof. The rigid
helix serves as the electrode to be screwed into the body tissue.
This procedure is facilitated by a tool or member which is
substantially cylindrically-shaped and having a slot located in one
end surface thereof, the slot being substantially orthogonal to the
longitudinal axis of the member. A groove is located in the outer
surface of the member and extends from the end surface opposite the
slotted end surface to just short of the slotted end surface and
lies in a plane substantially parallel to the longitudinal axis.
Also, starting in the same end surface as the groove is a bore
extending for the entire length of the member for receiving the
proximal end of the conductor.
The assembly is used during the implantation of the electrode into
body tissue. A raised portion on the conductor near the distal end
thereof is fitted into the slotted end of the cylindrically-shaped
member. The insulated portion of the conductor is fitted into the
groove and the remaining proximal portion of the conductor is
inserted into the bore, connector end first. In this position the
electrode comprising the rigid helix is securely held by the tool
and by applying a twisting or rotation of the tool, the helical
electrode may be screwed into the tissue, which in the case of the
heart is the myocardium. When the electrode is securely screwed
into the tissue, the portion of the conductor lying in the groove
is removed and then the slotted end of the member is removed from
the raised portion of the conductor.
The present invention has a number of
advantages and features which include: (1) the tool used in
facilitating the screwing-in of the electrode into the tissue or
organ never contacts the electrode; (2) the configuration of the
cylindrically-shaped member and the positioning of the conductor
with respect thereto prevents any torque from being imparted to the
conductor along its entire length during the rotation of the
member; (3) the electrode assembly permits the use of wrapped on
tinsel wire, rather than a coiled wire, which has great strength
and a very good flex tolerance; (4) the electrode is extremely easy
to install, reduces patient trauma, effects a very sound electrical
connection with body tissue and at the same time minimizes the
amount of surgery with respect to the handling of the particular
body tissue or organ involved; and (5) the tool may be used in
periodically producing a tunnel in subcutaneous tissue and in
guiding the connector end of the conductor through the tunnel for
connection to a power supply.
With these and other objects, advantages and features in view, as
will hereinafter more fully appear, and which will be more
particularly pointed out in the appended claims, reference is now
made to the following description taken in connection with the
accompanying drawings.
DESCRIPTION OF DRAWINGS
FIG. 1 shows a diagram of an implantable lead in accordance with
the present invention;
FIG. 2 illustrates an embodiment of the device used in conjunction
with the lead of FIG. 1 for screwing the electrode into body
tissue;
FIG. 3 is a cross-sectional view of the device shown in FIG. 2;
and
FIG. 4 illustrates the lead of FIG. 1 and the device of FIGS. 2 and
3 in operative relationship for the insertion of the electrode into
body tissue .
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows an implantable lead 10 which includes a flexible
electrical conductor 12. Conductor 12 may, for example, be made of
wrapped platinum wire or other suitable conducting material
adaptable to the internal environment of a human or animal body.
Wrapped platinum wire is generally comprised of a plurality of
platinum ribbons each helically wound around a separate
electrically non-conductive core and then all the platinum ribbons
are helically wound around a central electrically non-conductive
core. A specific description of this type of conductor may be found
in my U.S. Pat. No. 3,572,344, issued Mar. 23, 1971, and entitled
"Electrode Apparatus With Novel Lead Construction." Affixed to the
proximal end of conductor 12 is an electrical connector 14 having a
tip or extension 16 which may be connected to a suitable
implantable or external power supply. Affixed to and serving as the
distal end portion of conductor 12 is a rigid helical electrode 18
having several convolutions. Helical electrode 18 is a rigid coil
which may, for example, be made of platinum irridium, and
terminates in a sharply pointed end 19. Electrode 18 serves as the
distal end portion of conductor 12 which may be screwed into body
tissue as will be explained later. Electrode 18 and conductor 12
are electrically joined together by conductive epoxy (not shown)
substantially orthogonally with respect to one another and this
electrical junction is contained in a rubber boot 20.
Conductor 12, connector 14 and boot 20 are covered with a
relatively transparent, flexible insulating covering being
relatively inert with respect to the body, which, for example, may
be a silicone rubber casing 22. The portion of casing 22
surrounding boot 20 forms a raised portion or projection 24. Formed
on both sides of projection 24 are three spaced, substantially
vertical ribs 25 which are adapted to permit projection 24 to be
more securely engaged as will be explained. The distal portion of
casing 22 is terminated and shaped as a circular disc 26 through
which helical electrode 18 projects. Helical electrode 18 projects
through disc 26 at substantially a right angle to conductor 12.
Affixed to the under surface of disc 26 is a circular sheet of
netting 28, which may, for example, be made of Dacron which is a
trademark of E. I. Du Pont De Nemours and Company for a type of
polyester fiber. Netting 28 enhances fibrotic growth, further
insuring a secure connection of the electrode to the tissue.
FIGS. 2 and 3 illustrate the device used in conjunction with lead
10 to facilitate the screwing of electrode 18 into body tissue.
Device 40 comprises a substantially cylindrically-shaped member or
tool having a longitudinal axis 42 and end surfaces 44 and 46.
Member 40 may be made, for example, of a hard plastic material such
as Delrin which is a trademark of the E. I. Du Pont De Nemours and
Company for acetal resins. Preferably member 40 should be made of a
autoclavable material. Formed in end surface 44 is a slot 48. Slot
48 is shaped so as to be adapted to substantially conform to and
securely engage ribs 25 of raised portion 24 of lead 10. The edge
defined by end surface 46 is rounded in order to permit member 40
to be used for surgically producing a tunnel in subcutaneous tissue
without causing severe tissue damage. Formed in the outer surface
of member 40, lying in a plane substantially parallel to axis 42,
and extending from end surface 46 for substantially the entire
length of member 40 is a groove 50. Groove 40 is substantially
aligned with slot 48. Groove 50 is adaptable to receive and
securely engage at least a portion of the length of the insulated
portion of lead 10 housed in casing 22. Also formed in end surface
46 is an axial opening or bore 52 extending the entire length of
member 40 from end surface 46 to slot 48. Bore 52 is adapted to
receive at least a portion of the proximal end of lead 10 including
connector 14 and tip 16.
FIG. 4 illustrates the operative relationship between lead 10 and
member 40 as will now be described. Raised portion 24 is first
inserted into slot 48 so that the surfaces defining slot 48 firmly
grip ribs 25 to provide a friction fit and securely hold projection
24 in the slot. A small loop is left in the portion of casing 22
immediately proximal to raised portion 24 and then casing 22 is
worked into groove 50 so as to be securely held in the groove
against movement. Then connector 14 and tip 16 are inserted into
bore 52 as far as they will go. In this position the electrode 18
is positioned substantially along longitudinal axis 42 of member 40
and the assembly is now ready for the electrode to be screwed into
body tissue.
Pointed end 19 is placed against the tissue or organ and member 40
is rotated as indicated by the curved arrow. The diameter of the
wound is confined to the diameter of the wire of which helical
electrode 18 is formed. As member 40 is rotated, helical electrode
18 is firmly screwed into the tissue or organ until netting 28
firmly contacts the outer surface of the organ. Netting 28 helps to
provide a more secure and permanent placement of electrode 18 in
the tissues in that the netting promotes more rapid fibrosis in and
around the netting, as well as around disc 26 and raised portion 24
of casing 22.
When electrode 18 is firmly screwed into the tissue and netting 28
firmly seated against the outer surface of the tissue or organ, the
connector-end of lead 10 is removed from bore 52, the portion of
casing 22 lying in groove 50 is removed from the groove, and then
slot 48 is disengaged from projection 24 thereby freeing lead 10
from member 40. With the use of the procedure described, since
projection 24 and a substantial portion of casing 22 are firmly
secured during the rotation of member 40, no torque is transmitted
to lead 10 and consequently to conductor 12. In addition, before,
during, and after the insertion procedure, member 40 in no way
contacts the helical convolutions of electrode 18, permitting a
very positive action in screwing electrode 18 into the tissue at
substantially a 90.degree. angle. Then, if desired, end surface 46
of member 40 may be used to provide a tunnel in the subcutaneous
layers. The connector-end of lead 10 may then be inserted into bore
52 and member 40 guided back through the tunnel in order to
facilitate connecting tip 16 of conductor 14 to a power supply to
be implanted under the skin.
Obviously, many modifications and variations of the present
invention are possible in the light of the above teachings even
though only one embodiment of the invention has been shown. For
example, the presence and use of bore 52 are entirely optional and
do not affect the screwing of the electrode into body tissue. Also,
the exact shape and size of the projection 24 and the matching slot
48, as well as the shape, size and extent of groove 50, are all
subject to modification within the scope of the present invention.
It is therefore to be understood, that within the scope of the
appended claims, the invention may be practiced otherwise than as
specifically described.
* * * * *