U.S. patent number 3,722,005 [Application Number 05/198,596] was granted by the patent office on 1973-03-27 for percutaneous myo-electrode system.
This patent grant is currently assigned to Plessey Handel und Investments A.G.. Invention is credited to Frederick Claud Cowland.
United States Patent |
3,722,005 |
Cowland |
March 27, 1973 |
PERCUTANEOUS MYO-ELECTRODE SYSTEM
Abstract
A percutaneous myo-electrode system for facilitating either the
stimulation of, or the extraction of electrical energy due to,
muscular activity within the body of a vertebrate. A percutaneous
member of a biocompatible carbon material is insertable into an
aperture in the body tissue such that a surface thereof is
substantially flush with the outer skin of the body tissue. At
least one connecting member of electrically conductive
biocompatible material is secured within and electrically insulated
from the percutaneous member. One end of the, or each, connecting
member is connectable, at the surface of the body tissue, to an
electrical energy source or user external of the body, whilst the
other end thereof is connected to an electrode of an electrically
conductive biocompatible material by means of a connecting lead of
an electrically conductive biocompatible material. The electrode is
connectable to a muscle within the body. The electrical energy user
can be an artificial limb, and the external electrical energy
source can be used to stimulate the heart of the vertebrate.
Inventors: |
Cowland; Frederick Claud
(Towcester, EN) |
Assignee: |
Plessey Handel und Investments
A.G. (Zug, CH)
|
Family
ID: |
10472606 |
Appl.
No.: |
05/198,596 |
Filed: |
November 15, 1971 |
Foreign Application Priority Data
|
|
|
|
|
Nov 19, 1970 [GB] |
|
|
54,972/70 |
|
Current U.S.
Class: |
623/25 |
Current CPC
Class: |
A61N
1/05 (20130101) |
Current International
Class: |
A61N
1/05 (20060101); A61f 001/00 (); A61b 005/04 ();
A61n 001/36 () |
Field of
Search: |
;3/1,1.1
;128/DIG.4,2.1E,2.6E,404,418,419P |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"A Percutaneous Electrode For Long-Term Monitoring of
Bio-Electrical Signals in Humans" by R. Kadefors et al, Med. &
Biological Engineering, Vol. 8, pp. 129-135, 1970..
|
Primary Examiner: Gaudet; Richard A.
Assistant Examiner: Frinks; Ronald L.
Claims
1. A percutaneous myo-electrode system for facilitating the
simulation of, or the extraction of electrical energy due to,
muscular activity within the body of a vertebrate, including a
percutaneous member of carbon material which is electrically
conductive, microcrystalline in structure and substantially
impermeable, the percutaneous member being insertable into an
aperture in the body tissue such that a surface thereof is
substantially flush with the outer skin of the body tissue; a
connecting member of the said carbon material which is secured
within and electrically insulated from the percutaneous member, one
end of the connecting member being connectable, at the said surface
of the percutaneous member, to an electrical energy source or user
external of the said body; an electrode of an electrically
conductive biocompatible material which is connectable to a muscle
within the said body; and a connecting lead of an electrically
conductive biocompatible material which is secured at one end in
electrical contact with the other end of the connecting member, and
at the other end in electrical contact with the electrode.
2. A percutaneous myo-electrode system as claimed in claim 1 which
includes at least two of the connecting members each one of which
is connected to an electrode by a connecting lead.
3. A percutaneous myo-electrode system as claimed in claim 2 which
includes a layer of a biocompatible electrically insulating
material formed on a surface of the percutaneous member such that
it effects electrical isolation between the said other ends of each
of the connecting members.
4. A percutaneous myo-electrode system as claimed in claim 1
wherein a surface of the percutaneous member for engagement with
the aperture in the body is roughened.
5. A percutaneous myo-electrode system as claimed in claim 1
wherein said connecting member is electrically insulated from the
percutaneous member by a layer of a biocompatible electrically
insulating material interposed between the connecting member and
the percutaneous member.
6. A percutaneous myo-electrode system as claimed in claim 3
wherein the said layer is of a material taken from the group
consisting of silicon carbide, and electrically insulating phenolic
resin.
7. A percutaneous myo-electrode system as claimed in claim 1
wherein the carbon material is taken from the group consisting of
vitreous carbon, glassy carbon, and pyrolytic carbon.
8. A percutaneous myo-electrode system as claimed in claim 1
wherein said electrode is of a material taken from the group
consisting of vitreous carbon, glassy carbon, and pyrolytic
carbon.
9. A percutaneous myo-electrode system as claimed in claim 1
wherein the electrically conductive biocompatible material of said
connecting lead is a carbon fiber filament.
Description
The invention relates to a percutaneous myo-electrode system for
facilitating the stimulation of, or the extraction of electrical
energy due to, muscular activity within the body of a
vertebrate.
It is known that carbon materials which are micro-crystalline in
structure, and substantially impermeable, for example those known
as vitreous, glassy or pyrolytic carbons, are chemically,
biologically and physically compatible with animal tissue and
electrically conductive. These materials are, therefore, ideally
suited for use as a percutaneous myo-electrode system material.
The invention provides a percutaneous myo-electrode system for
facilitating the stimulation of, or the extraction of electrical
energy due to, muscular activity within the body of a vertebrate,
including a percutaneous member of carbon material which is
electrically conductive, microcrystalline in structure and
substantially impermeable, the percutaneous member being insertable
into an aperture in the body tissue such that a surface thereof is
substantially flush with the outer skin of the body tissue; a
connecting member of the said carbon material which is secured
within and electrically insulated from the percutaneous member, one
end of the connecting member being connectable, at the said surface
of the percutaneous member, to an electrical energy source or user
external of the said body; an electrode of an electrically
conductive biocompatible material which is connectable to a muscle
within the said body; and a connecting lead of an electrically
conductive biocompatible material which is secured at one end in
electrical contact with the other end of the connecting member, and
at the other end in electrical contact with the electrode.
The electrical energy user external of the said body can be an
electrical indicating or recording apparatus or an electrically
actuatable mechanism which can form part of an artificial limb. The
external electrical energy source is used to stimulate a body
muscle, for example the heart of the vertebrate.
In order to improve the retention of the percutaneous myo-electrode
system within the body tissue, the surface of the percutaneous
member in contact with the body tissue can be roughened to assist
the keying in of the member by a fibrous interfacial layer.
The foregoing and other features according to the invention will be
better understood from the following description with reference to
the accompanying drawings, in which:
FIG. 1 diagrammatically illustrates a plan view of a percutaneous
myo-electrode system according to the invention, and
FIG. 2 diagrammatically illustrates a cross-sectional side
elevation of the percutaneous myo-electrode system according to
FIG. 1 on the line `X--X.`
Referring to the drawings, a percutaneous myo-electrode system
according to the invention is diagrammatically illustrated therein
implanted in the body tissue of a vertebrate. The myo-electrode
system includes a percutaneous member 1 implanted in the body
tissue 2 of the vertebrate, such that the surface 1a is
substantially flush with the outer skin of the body tissue 2. The
percutaneous member 1 is formed from a carbon material, for example
vitreous carbon, which is electrically conductive, microcrystalline
in structure, and substantially impermeable, and which, as stated
in a preceding paragraph, is compatible with animal tissue and,
therefore, ideally suited for this purpose. Furthermore, the
utilization of a percutaneous implant of this type of material
results in the formation of a germ-free entry to the body of the
vertebrate which, it is thought, is due in the main to the
formation of a protective epithelial downgrowth of fibrous material
at the interface between the body tissue 2 and the carbon
percutaneous member 1.
Two connecting members 3 of a carbon material os the kind outlined
in the preceding paragraph, for example vitreous carbon, are each
secured within an aperture 4 in the member 1 and electrically
insulated from the member 1 and thereby from each other by an
annular layer 5 of a biocompatible electrically insulating
material.
Each of the connecting members 3 is provided at one end with an
aperture 6. The apertures 6 which form a two-pin plug socket, are
arranged to receive a two-pin plug from a co-operating connector
(not illustrated). An aperture 7 is provided in the other end of
each of the connecting members 3 into which is secured in
electrical contact therewith one end of an electrically conductive
lead 8. The leads 8 are of a biocompatible electrically conductive
material.
The other end of each of the leads 8 is secured to an electrode 9
of a biocompatible material which is insertable into, or
connectable to, a muscle of the body of the vertebrate.
The surface 1b of the percutaneous member 1 can be provided with a
layer 10 of a biocompatible electrically insulating material when
the electrical conductivity of the body tissue 2 and/or the body
fluids is such that electrical conduction therein between the
connecting members 3 or between the members 3 and the percutaneous
member 1 affects the operation of the equipment associated with the
percutaneous myo-electrode system.
The members 1 and 3 when of a solid vitreous or glassy carbon, are
formed by the thermal degradation of organic materials. One process
for producing impermeable carbon bodies is described in U.S. Pat.
specification No. 3,109,712 and British Pat. specification No.
956,452. In bulk form, vitreous carbons have a density of
approximately 1.5 and exhibit a conchoidal fracture and are
nonporous.
When the members 1 and 3 are of a solid pyrolytic carbon, they are
formed by carbonizing simple organic compounds, for example as
described in one of the abovementioned Patent specifications.
A suitable biocompatible electrically conductive material for each
of the electrically conductive leads 8 is a carbon fiber filament.
The carbon fiber filament would be sealed at one end into the
aperture 7 and at the other end into the electrode 9. The electrode
9 can be of a carbon material of the kind outlined in a preceding
paragraph, for example vitreous carbon. The sealing of the carbon
fiber filament into the aperture 7 and the electrode 9 can, when
the members 3 and the electrode 9 are of vitreous carbon, be
effected with a phenolic resin such as phenol-formaldehyde which is
a precursor of vitreous carbon and electrically insulating when in
moulding powder or casting resin form. In order to convert the
electrically insulating phenolic resin into an electrically
conductive material it is necessary to cure it at a temperature of
the order of 1,800.degree.C in a nitrogen atmosphere.
The biocompatible electrically insulating layers 5 and 10 can also
be of a phenolic resin such as phenolformaldehyde which should be
cured at a temperature of the order of 400.degree.C in order that
its electrically insulating properties are retained. Other
biocompatible electrically insulating materials can be utilized,
for example a layer of a carbide forming element such as silicon
can be deposited on the cylindrical surface of the connecting
members 3 which will form a seal with the connecting members 3.
When the members 3 are inserted into the apertures 4 and heated to
a temperature of the order of 1,200.degree.C to 1,300.degree.C, the
deposited silicon melts and reacts with the carbon content of the
members 1 and 3 to form annular layers 5 of silicon carbide. The
layer 10, when provided, can also be of silicon carbide and
produced in this manner.
In some instances it may be advantageous for the surface or
surfaces of the percutaneous member 1 in contact with the body
tissue 2 to be roughened in order to assist the keying in of the
member 1 by the previously mentioned epithelial downgrowth of
fibrous material which forms between the body tissue and the carbon
percutaneous member 1. This roughness may be achieved by machining
the surface, preferably before firing, or by first coating the
surface with granules of phenolic resin, or fibers of carbon, or a
suitable polymer before carbonizing.
In operation, the electrodes 9 would be implanted into, or attached
to a muscle which is to be stimulated or whose electrical impulse
are to be transferred to utilization means external of the body
tissue 2, and the percutaneous member 1 and associated parts would
be implanted in the body tissue. Thus, by fitting a two-pin plug
from a co-operating connector of an external apparatus into the
apertures 6 of the connecting members 3, electrical currents
generated by the muscular activity of the muscle or muscles to
which the electrodes 9 are connected can be either measured, or
recorded, or utilized to actuate a mechanism or mechanisms
associated with the operation of an artificial limb.
Alternatively, the electrodes could be connected via the two-pin
plug to an external source of electrical power and utilized to pass
electrical currents into a body muscle in order to stimulate
it.
It should of course be noted that whilst a percutaneous
myo-electrode system has been described and illustrated with a
two-pin plug socket, the invention should not be considered as
being limited to this arrangement since a one-pin or a multi-pin
plug socket are within the scope of the invention. These
arrangements are realized merely by providing the requisite number
of connecting members 3 and associated electrodes 9 and connecting
leads 8, and a percutaneous member 1 of sufficient proportions to
house the connecting members 3.
It is to be understood that the foregoing description of specific
examples of this invention is made by way of example only and is
not to be considered as a limitation in its scope. What is claimed
is:
* * * * *