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Claims  |
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What is claimed is:
1. In an electrical brain-contact device of the type having a
tissue-engagement member with a plurality of electrodes, separate lead
wires from the tissue-engagement member for each electrode, and means away
from the tissue-engagement member to connect the lead wires with
individual conductors, the improvement comprising:
the lead wires extending from the tissue-engagement member to a terminal
mount and to a linear array of lead-wire terminals on and forming a part
of the terminal mount; and
the connector means including:
a base member with a matching array of take-up terminals;
a yoke member movable with respect to the base member, said base member and
yoke member forming therebetween a space for the terminal mount, said
take-up terminals extending from the base member into said space; and
means to removably draw and hold the yoke and base members together with
the arrays in terminal-to-terminal contact, said holding and drawing means
acting through the lead-wire terminals to move the take-up terminals in a
direction away from said space and establish good electrical contact
between said lead-wire terminals and said take-up terminals,
whereby electrical connection of brain-contact devices is facilitated.
2. The electrical brain-contact device of claim 1 wherein the terminal
mount comprises a sheathing with the lead wires therein and the lead-wire
terminals spaced therealong.
3. The electrical brain-contact device of claim 2 wherein the sheathing is
tubular and the lead-wire terminals are rings therearound.
4. The electrical brain-contact device of claim 3 wherein the tubular
sheathing extends from the tissue-engagement member for substantially the
entire length of the lead wires.
5. The electrical brain-contact device of claim 4 wherein the terminal
mount has a tapered lead end thereby facilitating various insertion steps
such as insertion through a needle and insertion into the terminal-mount
space in the connector means over the take-up terminals.
6. The electrical brain-contact device of claim 4 wherein the
tissue-engagement member is a tubular depth probe which is a continuation
of the sheathing such that the tubular sheathing extends along
substantially the entire combined lengths of the depth probe, the lead
wires, and the terminal mount, whereby insertion into the brain is
facilitated when using a stylette within such tubular sheathing and/or
when inserting through a cannula already in place.
7. The electrical brain-contact device of claim 4 wherein:
the tissue-engagement member is a substantially flat flexible
non-conductive member having a proximal edge;
the electrodes are flat members on and coplanar with the flexible member;
and
the lead wires extend within the flexible member to the tubular sheathing
at the proximal edge, whereby the lead wires may be threaded at one time
through a needle to exit the scalp at a site removed from the
tissue-engagement member.
8. The electrical brain-contact device of claim 7 wherein the flexible
member thickness is less than about 0.30 mm.
9. The electrical brain-contact device of claim 2 wherein:
the base and yoke members have major portions which are semi-cylindroids
which together form a cylindroid; and
the holding means is a clamp ring extending around the cylindroid.
10. The electrical brain-contact device of claim 9 wherein the clamp ring
has a gap of dimension enough such that the lead wires may pass
therethrough to facilitate mounting of the clamp ring.
11. The electrical brain-contact device of claim 9 wherein the
terminal-mount space is along the axis of the cylindroid.
12. The electrical brain-contact device of claim 11 wherein:
the base member forms terminal niches along the terminal-mount space;
the take-up terminals, when the terminal mount is removed, extend from the
niches into the terminal-mount space; and
the take-up terminals are depressed by the terminal mount, when the
terminal mount is in place, such that the lead-wire terminals are in firm
electrical contact with the take-up terminals.
13. The electrical brain-contact device of claim 12 wherein:
the sheathing is tubular and the lead-wire terminals are rings therearound;
one of the base and yoke members has brackets at either end, the other of
such members being receivable between the brackets; and
one of the brackets forms a substantially axial opening receiving the
tubular sheathing.
14. The electrical brain-contact device of claim 13 wherein the sheathing
has a marking thereon to facilitate alignment of the arrays.
15. The electrical brain-contact device of claim 13 wherein the other
bracket forms a stop for the tubular sheathing, whereby alignment of the
arrays is facilitated.
16. The electrical brain-contact device of claim 13 wherein the other
bracket forms an axial opening to receive and hold the terminal mount
along the axis of the cylindroid, thereby facilitating proper assembly of
the terminal mount with the connector means.
17. The electrical brain-contact device of claim 2 wherein:
the base member is a first block having a substantially planar first
surface;
the yoke member is a second block having a substantially planar second
surface against the first surface;
at least one of the first and second surfaces has a major groove extending
thereacross to form the space for the terminal mount; and
the take-up terminals are secured to the first block and extend in spaced
fashion across the major groove.
18. The electrical brain-contact device of claim 20 wherein the first
surface includes the major groove.
19. The electrical brain-contact device of claim 18 wherein the second
surface is substantially flat, the terminal mount, the major groove, and
the take-up terminals dimensioned and arranged such that drawing the first
and second surfaces together clamps the arrays firmly together.
20. The electrical brain-contact device of claim 19 wherein the first block
has one open end and one closed end for the major groove, thereby to
facilitate proper alignment of the arrays.
21. The electrical brain-contact device of claim 1 wherein:
the base member forms terminal niches along the terminal-mount space;
the take-up terminals, when the terminal mount is removed, extend from the
niches into the terminal-mount space; and
the take-up terminals are depressed by the terminal mount, when the
terminal mount is in place, such that the lead-wire terminals are in firm
electrical contact with the take-up terminals.
22. In an electrical brain-contact device of the type having a
tissue-engagement member with a plurality of electrodes, separate lead
wires from the tissue-engagement member for each electrode, and means away
from the tissue-engagement member to connect the lead wires with
individual conductors, the improvement comprising:
the lead wires extending from the tissue-engagement member to a terminal
mount and to an array of lead-wire terminals on and forming a part of the
terminal mount, said terminal mount being a tubular sheathing extending
from the tissue-engagement member for substantially the entire length of
the lead wires and having the lead wires therein, and said lead-wire
terminals being rings around and spaced along said sheathing;
the conductor means including a base member with a matching array of
take-up terminals, a yoke member movable with respect to the base member
and forming therebetween a space for the terminal mount, and means to hold
the yoke and base members together with the arrays in terminal-to-terminal
contact; and
a pull line attached to the terminal mount inside the sheathing thereof and
extending from the terminal mount in a direction away from the lead wires,
whereby electrical connection of brain-contact devices is facilitated.
23. The electrical brain-contact device of claim 22 wherein:
the tissue-engagement member is a substantially flat flexible
non-conductive member having a proximal edge;
the electrodes are flat members on and coplanar with the flexible member;
and
the lead wires extend within the flexible member to the tubular sheathing
at the proximal edge,
whereby the lead wires may be threaded at one time through a needle to exit
the scalp at a site removed from the tissue-engagement member.
24. In an electrical brain-contact device of the type having a
tissue-engagement member with a plurality of electrodes, separate lead
wires from the tissue-engagement member for each electrode, and means away
from the tissue-engagement member to connect the lead wires with
individual conductors, the improvement comprising:
the lead wires extending from the tissue-engagement member to a terminal
mount and to an array of lead-wire terminals on and forming a part of the
terminal mount, said terminal mount being a sheathing with the lead wires
therein and said lead-wire terminals spaced therealong; and
the connector means including: a first block having first surface and an
array of take-up terminals matching the array of lead-wire terminals,
a second block having a second surface against the first surface, said
second block movable with respect to the first block, at least one of the
first and second surfaces having a major groove which forms between the
first and second surfaces a space for the terminal mount, said take-up
terminals secured to the first block and extending in spaced fashion
across the major groove, and
a screw member extending between the first and second blocks to
progressively draw the first and second surfaces together with the arrays
in terminal-to-terminal contact,
whereby electrical connection is facilitated.
25. The electrical brain-contact device of claim 24 wherein the first
surface includes the major groove, the second surface is substantially
flat, and the terminal mount, the major groove and the take-up terminals
are dimensioned and arranged such that drawing the first and second
surfaces together clamps the arrays firmly together.
26. The electrical brain-contact device of claim 25 wherein there is only
one screw member as the sole interconnection of the first and second
blocks such that the second block is pivotable with respect to the first
block to substantially uncover the major groove to facilitate insertion of
the terminal mount when the screw member is loosened.
27. In an electrical device of the type having a tissue-engagement member
with a plurality of electrodes, separate lead wires from the
tissue-engagement member for each electrode, and means away from the
tissue-engagement member to connect the lead wires with individual
conductors, the improvement comprising:
the lead wires extending from the tissue-engagement member to a terminal
mount and to an array of lead-wire terminals on and forming a part of the
terminal mount, said terminal mount being a sheathing with the lead wires
therein and said lead-wire terminals spaced therealong; and
the connector means including:
a first block having first surface and an array of take-up terminals
matching the array of lead-wire terminals,
a second block movable with respect to the first block and including a
substantially flat second surface, the first surface having a major groove
which forms between the first and second surfaces a space for the terminal
mount,
the first block having a side surface parallel to the major groove,
said take-up terminals being substantially straight wires embedded in the
first block, extending in spaced fashion across the major groove, and
terminating in connector ends exposed along the side surface, and means to
hold the first and second blocks together with the arrays in
terminal-to-terminal contact, the terminal mount, major groove and take-up
terminals dimensioned and arranged such that drawing the first and second
surfaces together clamps the arrays firmly together,
whereby electrical connection is facilitated.
28. The electrical brain-contact device of claim 27 wherein the holding
means comprises a screw member extending between the first and second
blocks to progressively draw the first and second surfaces together.
29. The electrical brain-contact device of claim 28 wherein there is only
one screw member as the sole interconnection of the first and second
blocks such that the second block is pivotable with respect to the first
block to substantially uncover the major groove to facilitate insertion of
the terminal mount when the screw member is loosened. |
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Claims |
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Description |
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FIELD OF THE INVENTION
This invention is related generally to electrical brain-contact devices
such as those used for monitoring intracranial electrical activity to
define epileptogenic foci and, more particularly, to means on such devices
for facilitating surgical procedures for their placement and set-up,
including their electrical connection away from the brain.
BACKGROUND OF THE INVENTION
Surgical removal of epileptogenic brain is indicated for treatment of many
medically refractory focal seizure disorders. One important factor in
providing good results from such surgery is the degree of accuracy in
identifying epileptogenic foci. Various methods and devices have been used
in attempting to determine epileptogenic foci. All, of course, involve
sensing of intracranial electrical activity using electrical contacts
applied in various ways.
Standard scalp contacts have been used for many years, but accurate
localization is usually very difficult with recordings obtained from such
contacts. In recent years, therefore, many epilepsy centers have adopted
techniques using intracranial contacts to better define regions of
cortical epileptogenicity.
Intracranial sensing techniques have used, broadly speaking, two different
kinds of members for engagement with brain tissue. Such tissue-engagement
members include depth probes and flexible flat surface members.
Depth probes, which are often referred to as "depth electrodes," penetrate
deep into the brain tissue in direct contact with such tissue. On the
other hand, flat flexible surface members, including what are sometimes
referred to as "strip" electrodes and "grid" electrodes, are placed
subdurally in direct contact with brain tissue at the surface of the
brain.
Each of these different kinds of intracranial tissue-engagement members has
a plurality of electrodes which are separated from one another by a
non-conductive material on which the electrodes are mounted. Separate lead
wires extend from the tissue-engagement member for each electrode. Such
lead wires extend away from the tissue-engagement member to means for
connecting the lead wires with individual conductors, which lead to
monitoring or recording equipment.
Depth probes typically have electrode rings sleeved over and spaced along a
non-conductive tubular member, with thin insulated wires extending inside
the tube to a position away from its tissue-engaging portion. An example
of such depth probes is shown in U.S. Pat. No. 4,425,645 (Arseneault et
al.).
Strips and grids have a one-dimensional line and a two-dimensional field,
respectively, of electrode disks which are arranged and held on a
non-conductive flat flexible sheet-like member, usually between two thin
sheet-like layers of non-conductive material. Thin insulated wires
typically extend between the layers to a proximal edge of the sheet-like
member and from there as lead wires away from such tissue-engaging member.
An example of such a strip electrode is disclosed in U.S. patent
application No. 71,075, now U.S. Pat. No. 4,805,625 (Wyler et al.).
For each type of tissue-engagement member used in the prior art for
monitoring electrical activity in the brain, the procedures for placement
and hookup are of great importance.
In the case of depth probes, it is essential that the depth probes be
inserted with a high degree of accuracy in order to avoid damage to veins
and arteries or unnecessary damage to brain tissue which might be caused
by insertion and reinsertion. Precision in insertion is also necessary in
order that placement be in the most advantageous positions for locating
abnormal cells.
In the case of strip and grid electrodes, it is important that the flat
flexible member be in proper contact with brain tissue to obtain reliable
readings. It is also important that the often rather large opening in the
skull, which is necessary for proper placement or insertion of a grid or
strip, be well protected from the possibility of infection o that
intracranial infection does not occur.
For both depth electrodes and strip or grid electrodes, it is essential
that the lead wires extending from the brain-engagement member be properly
connected and that the fragile lead wires themselves remain functional,
without any breakage or disconnection.
While there has been much progress in the field of electrical brain-contact
devices in recent years, existing devices and procedures have a number of
problems and drawbacks. For one thing, the surgical placement and set-up
procedures which precede the test period are far too time-consuming and
complex. Such procedures in some cases also lead to specific problems.
Such problems can be described best by generally describing at least
certain parts of the placement and set-up procedures.
One of the early steps in existing placement and set-up procedures for grid
and strip electrodes is making an incision in the scalp over the site of
proposed electrode placement. Then a burr hole is drilled in the skull or
a skull area otherwise removed. One or more incisions are then made in the
dura to accommodate placement of a grid or insertion of a strip. Dural
tack-up sutures are placed in both dural margins.
The grid or strip electrode is then placed or inserted, with the electrodes
in contact with the brain tissue. When strip electrodes are used, a
plurality of strips are inserted in each burr hole. After the grid or
strips have been positioned, the dural edges are approximated with a
suture.
The lead wires, which extend from the proximal end of each strip or grid,
are passed through the sutured dura incision. All the wires, one for each
electrode on the grid or on every strip, are then brought out through the
skin by passing them through a needle and then drawing them through the
scalp at a distance (usually 4-5 cm) from the skull opening. When there
are numerous wires it is often necessary to tunnel in a number of
directions through the scalp to sites spaced from the skull opening. This
can be both very time-consuming and very hard on the patient's head.
Furthermore, when such wires have exited the scalp at the chosen sites, it
then remains necessary to make electrical hookups of each of such wires in
the appropriate manner. This is itself a time-consuming operation, and one
in which there is a risk of incorrect hookups.
The fragile lead wires are quite susceptible to breakage during these
manipulative operations. When this occurs, it may be necessary to reopen
the dura to remove and replace the grid or strip from which the lead wire
broke, and repeat many of the procedures described above.
In order to minimize the likelihood of lead wire breakage, lead wires of
greater size may be used. However, increasing the diameter of the lead
wires tends to increase the overall thickness of the strip or grid.
Thickness can be undesirable in such flat flexible members and can in some
cases pose problems for the electrical sensing operations. Furthermore,
increasing wire thickness can substantially increase the cost of the
device, particularly if silver or platinum wire is used.
Because of all the problems and difficulties of such wire exit and
connection operations, lead wires are sometimes simply brought out of the
head right at the point of the skull opening. This procedure results in a
greater risk of fluid leakage problems and of dangerous infection
occurring at the site of the major wound, near, of course, to the brain by
virtue of such opening.
Referring now to the insertion and connection of depth probes, such
electrodes have been installed in different ways depending upon the
circumstances. In some cases, depth probes are stiffened by means of a
stylette which is inserted into the tubular depth probe. The probe is then
pushed into the brain tissue, guided by the stylette, and the stylette is
then withdrawn. In other cases, such as when a cannula is already in place
in the brain tissue, the cannula must be removed in order to accommodate
insertion of the depth probe at that site, either with or without the aid
of a stylette.
In either case, various securing steps are then carried out. After that,
electrical connections are made, either with or without the aid of
specialized connector means. Such connection procedures are typically
difficult and time-consuming.
There remains a substantial need for an improved electrical brain-contact
device overcoming the above problems and difficulties arising during
placement and setup procedures.
OBJECTS OF THE INVENTION
It is an object of this invention to provide an improved electrical
brain-contact device which overcomes certain problems of prior art
devices, including those mentioned above.
Another object of this invention is to provide an improved electrical
brain-contact device which facilitates surgical procedures used in
locating epileptogenic foci.
Another object of this invention is to provide an improved electrical
brain-contact device which may be electrically connected easily and
quickly during surgical placement and set-up procedures.
Another object of this invention is to provide an improved electrical
brain-contact device which reduces or eliminates lead wire breakage and
the related problems.
Another object of this invention is to provide an improved electrical
brain-contact device which facilitates placement and set-up of
tissue-engagement members having large numbers of electrodes and lead
wires.
Another object of this invention is to provide an improved electrical
brain-contact device which facilitates accurate insertion of depth probes.
Another object of this invention is to provide an improved electrical
brain-contact device allowing accurate insertion of a depth probe using an
in-place cannula without prior removal of such cannula.
Another object of this invention is to provide an improved electrical
brain-contact device facilitating surgical procedures which minimize the
infection risks.
Another object of this invention is to provide an improved electrical
brain-contact device which eliminates the need for multiple separate
threadings of lead wires in different directions along the scalp, thus
eliminating the related scalp damage.
Another object of this invention is to provide an improved electrical
brain-contact device having lead wires of substantially reduced diameter.
Another object of this invention is to provide an improved electrical
brain-contact device of the strip or grid type having substantially
reduced thicknesses.
These and other important objects will be apparent from the descriptions of
this invention which follow.
SUMMARY OF THE INVENTION
This invention is an improvement in electrical brain-contact devices of the
type having tissue-engagement members with a plurality of electrodes,
separate lead wires from the tissue-engagement members for each of their
electrodes, and means away from the tissue-engagement members to connect
the lead wires with individual conductors. These brain-contact devices may
be used to sense and record intracranial electrical discharges and/or to
stimulate tissue.
In the brain-contact device of this invention, the lead wires extend from
the tissue-engagement member to a terminal mount and to an array of
lead-wire terminals which are on and form a part of the terminal mount. A
connector especially adapted for the terminal mount includes a base member
with an array of take-up terminals matching the array of lead-wire
terminals on the terminal mount, a yoke member which is movable with
respect to the base member, and means to hold the yoke and base members
together with the terminal mount between. This secures the arrays in
terminal-to-terminal contact. The base and yoke members together form a
space for the terminal mount.
The brain-contact device of this invention greatly facilitates placement
and set-up procedures, particularly its electrical connection. Such
electrical connection is made quick and simple by the connectors of this
invention.
The terminal mount has a non-conductive mount base which is preferably a
sheathing with the lead wires (each of which is insulated) in it and the
lead-wire terminals spaced along it. The sheathing is most preferably
tubular, with the lead-wire terminal rings which are sleeved around the
tube and held firmly on the tube. The tubular sheathing preferably extends
from the tissue-engagement member for substantially the entire length of
the lead wires.
In certain preferred embodiments, the base member of the connector
preferably forms terminal niches along the terminal-mount space, with the
take-up terminals being within such niches, most preferably extending,
when the terminal mount is removed, from the niches into the
terminal-mount space. In certain embodiments, the take-up terminals are
preferably spring members, such as small coil springs, which are depressed
by the terminal mount when the terminal mount is in place. This preferred
arrangement holds the lead-wire terminals and the take-up terminals in
firm electrical contact.
In certain preferred embodiments, the base and yoke members have major
portions which are semi-cylindroids which together form a cylindroid, and
the holding means is a clamp ring extending around the cylindroid. In such
configuration, the space for the terminal mount is most preferably along
the axis of the cylindroid.
The clamp ring may be in various forms. In one preferred form, the clamp
ring has a gap in it large enough such that the lead wires may pass
through the gap to facilitate the mounting of the clamp ring on the
cylindroid. The clamp ring may readily be brought into axial alignment
with the cylindroid by virtue of such gap, and then slid over the
cylindroid. The dimensioning and resilient characteristics of the ring
allow it to hold the semi-cylindroids firmly together.
In particularly preferred embodiments of the type just described, either
the base member or the yoke member has brackets at either end, while the
other of such members is dimensioned to be received between such brackets.
One of the brackets forms an axial opening receiving the terminal mount,
which in such embodiments has tubular sheathing with electrode rings on
it.
The tubular sheathing preferably has a marking on it which is alignable
with an end bracket, preferably the bracket having the axial opening
mentioned above, to facilitate alignment of the lead-wire array with the
take-up array. The other bracket may form a stop for the tubular sheathing
as an alternate or additional way to facilitate alignment of the terminal
arrays. Such other bracket may have its own axial opening to receive and
hold the terminal mount in proper position along the axis of the
cylindroid. This serves to facilitate proper assembly of the terminal
mount with the connector means.
In certain other very highly preferred embodiments of this invention, the
base and the yoke are in a very different form having additional
significant advantages. In such embodiments, the base is a first block
having a first surface and the yoke is a second block having a second
surface against the first surface, with at least one of the first and
second surfaces having a major groove which forms the space for the
terminal mount. The take-up terminals are secured to the first block and
extend in spaced fashion across the major groove.
In such embodiments, the blocks are preferably held together by one or more
screw members, preferably one as later explained, extending between the
first and second blocks. Such screw members, which may be completely
removably to allow complete removal of the second block from the first if
desired, are used to progressively draw the first and second surfaces of
such blocks together. The screws are preferably finger-operable.
In preferred embodiments of the types having blocks, the major groove is
preferably in the first surface, that is, in the first block. The second
surface is preferably substantially flat, with the terminal mount, the
major groove, and the take-up terminals dimensioned and arranged such that
drawing the first and second surfaces together clamps the arrays firmly
together. More specifically, the depth of the major groove is small enough
that, when the blocks are drawn tightly together, the terminal mount is
tightly sandwiched between the blocks.
In such embodiments of the invention, there is preferably only one screw
member which serves as the sole interconnection of the first and second
blocks. Such screw member may extend through the second block freely and
be in threaded engagement with the first block. In such embodiments, the
screw member may be loosened short of disengagement with the first block
such that the second block may be pivoted with respect to the first block
to substantially uncover the major groove. This facilitates insertion of
the terminal mount when the screw member is loosened. Indeed, loosening
and retightening to insert the terminal mount, preferably by
finger-turning of the screw member, can be quickly carried out, and with
one hand if necessary.
In embodiments of the type having a pair of blocks, as described, the first
block has a side surface parallel to the major groove and the take-up
terminals are preferably straight wires which are embedded within the
first block, extend across the major groove, and terminate in connector
ends exposed along the side surface. This facilitates organized electrical
connection with the device of this invention, whether by individual
connectors or by a multi-contact plug.
One of the blocks, preferably the first, may be marked with colors,
numbers, letters or other indicia to identify which contact relates to
which electrode in use during a test period.
The first block preferably has one open end and one closed end for the
major groove. This facilitates proper alignment of the contact arrays.
Referring again to characteristics of the terminal mount, earlier
described, the preferred tubular sheathing which forms the terminal mount
preferably has a tapered lead end. Such tapered lead end facilitates
various insertion steps, including in some cases insertion through a
needle, for purposes hereafter explained, as well as insertion through the
axial opening in the preferred bracket, or into the groove in the
block-type connector, and insertion over the take-up terminals as the
sheathing moves into the connector.
In certain preferred embodiments, a pull line is attached to the terminal
mount, such as by connection to the inside of the sheathing forming such
terminal mount, and extends from the terminal mount in a direction away
from the lead wires. This further facilitates threading of the terminal
mount and lead wires through a needle and/or through the aforementioned
bracket or groove openings, making surgical procedures that much easier.
In certain embodiments of this invention, the tissue-engagement member is a
tubular depth probe. In such cases, the tissue-engaging member is a
continuation of the same tubular sheathing which extends over the lead
wires and forms a part of the terminal mount, such that the tubular
sheathing extends along substantially the entire combined lengths of the
depth probe, the lead wires, and the terminal mount. With this essentially
completely tubular structure, insertion into the brain is facilitated.
When a stylette is used, it may enter the tubular structure at the end of
the preferred tubular terminal mount and extend through the terminal
mount, along the lead lines, and through the depth probe until it engages
the preferably closed end of the depth probe. When a cannula is already in
place in the brain and it is desired to insert a depth probe, the depth
probe of this invention can be inserted through the cannula while the
cannula is in place. Then, the cannula can be withdrawn over the tubular
depth probe, lead line portion, and terminal mount without difficulty.
There is no need to withdraw the cannula prior to insertion of the depth
probe into the brain tissue.
In each case, connection of the several electrical wires is facilitated by
the connector devices of this invention.
In certain other preferred embodiments, the tissue-engagement member is a
substantially flat flexible non-conductive member, either a strip or a
grid electrode as described above in which the electrodes are flat members
on and coplanar with the flexible member. In such embodiments, the lead
wires extend within the flexible member to the tubular sheathing at a
proximal edge.
The lead wires may be threaded through a needle all at one time, by
threading the tubular sheathing which is over them from the site of the
dura incision to exit the scalp at a point away from the tissue-engagement
member and such incision. Such single threading operation significantly
simplifies the surgical procedures. It also reduces any risk of lead wire
breakage, because the wires are protected by the full-length sheathing.
Indeed, by virtue of the above configuration, the individual lead wires can
be reduced in size. Wires as small as about 0.125 mm in diameter may be
used, about one-third the diameter of wire previously used. This allows
strip and grid tissue-engagement members to have flexible members less
than about 0.30 mm thick, which is much thinner than previous strips and
grids. Thin flexible members are believed to be helpful in obtaining
accurate readings. The size of the lead wires is removed as a major
consideration in determining desirable dimensions of strips and grids.
The aforementioned pull line is particularly useful for strip and grid
devices since it is helpful in the threading of the terminal mount through
a needle, as described above.
As noted above, the electrical brain-contact device of this invention may
be used for stimulation purposes as well as sensing and recording
purposes. While the sensing of epileptic discharges is a primary concern,
it is to be understood that other sensing applications and uses for
stimulation are contemplated.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is perspective view of a electrical depth probe device in accordance
with this invention.
FIG. 2 is an enlarged fragmentary side elevation of the device of FIG. 1
with the connector removed and a stylette inserted.
FIG. 3 is an enlarged fragmentary sectional view of the device shown in
FIGS. 1 and 2, a portion thereof which is insertable into the connector.
FIG. 4 is perspective view of a grid electrode in device in accordance with
this invention.
FIG. 5 is an exploded perspective of the connector included in the
embodiments of FIGS. 1 and 4, for which the connectors are identical.
FIG. 6 is a side elevation of such connector.
FIG. 7 is a side elevation of the base member of such connector, with
portions cut away.
FIG. 8 is a perspective view, similar to FIG. 1, of another embodiment,
having another connector in accordance with this invention.
FIG. 9 is a fragmentary view of the device of FIG. 8, but showing the
terminal mount inserted into the connector.
FIG. 10 is an exploded view of the connector of FIG. 8.
FIG. 11 is a partially cutaway plan view of the connector of FIG. 8.
FIG. 12 is a partially cutaway end view of the connector of FIG. 8.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The drawings illustrate preferred embodiments of the electrical
brain-contact device of this invention, including embodiments with
different tissue engagement members and embodiments with different
connectors in accordance with this invention. Throughout the drawings,
like parts are identified by like numbers. In some cases, comparable parts
are identified by like numerals followed by the letter "a."
Three embodiments are illustrated, including a depth probe device 10 shown
in FIGS. 1-3 and 5-7, a surface contact device 12 shown in FIGS. 4, 3 and
5-7, and another depth probe device 13 shown in FIGS. 8-12, 2 and 3.
Devices 10 and 12 have identical connectors 46 in accordance with this
invention, while device 13 has a connector 46a in accordance with another
embodiment of this invention.
Devices 10, 12 and 13 all include identical terminal mounts 36, shown in
FIGS. 1-3, 5 (in fragment) and 8. The details of terminal mounts 36 are
shown best in FIGS. 2 and 3.
Devices 10 and 13 have identical tissue-engagement members, that is, depth
probes 14, while surface-contact device 12 has a different
tissue-engagement member, namely, flat flexible member 16, sometimes
referred to as a "grid electrode." Flat flexible member 16 may be part of
a device having a connector like connector 46a, although that is not
specifically shown. Depth probes 14 and flat flexible member 16 each place
a plurality of electrodes directly in contact with brain cells, to sense
electrical discharges.
Depth probe 14 includes a non-conductive hollow plastic tube 18 having
electrode rings (or "collars") 20 spaced along it and attached to it.
Hollow tube 18 has a closed distal end 22. Individual lead wires extend
inside hollow tube 18 from each electrode ring 20 in a direction away from
distal end 22. Depth probe 14 itself is of a type known in the prior art.
Flat flexible member 16 includes a flexible sheet member 24, which is
formed by a pair of flexible sheets, and a number of flat electrode disks
26 on and coplanar with sheet member 24. Electrode disks 26 are held on
sheet member 24 by being placed between its t | | |
