U.S. patent application number 11/262377 was filed with the patent office on 2006-03-16 for depth probe for intracranial treatment.
Invention is credited to David A. Putz.
Application Number | 20060058743 11/262377 |
Document ID | / |
Family ID | 33299158 |
Filed Date | 2006-03-16 |
United States Patent
Application |
20060058743 |
Kind Code |
A1 |
Putz; David A. |
March 16, 2006 |
Depth probe for intracranial treatment
Abstract
A depth probe for intracranial treatment is provided having a
body that includes a distal portion with at least one aperture and
at least one element, a lumen defined by the body that communicates
between an opening and the aperture, and a proximal portion with at
least one proximal-contact. The proximal-contact is conductively
connected with the element. The lumen is preferably sized to
receive an inner catheter adapted to transfer a fluid such as a
drug with a tissue region within the patient's brain. The depth
probe can include a connector adapted to receive a plurality of
proximal-contacts. A depth probe is disclosed that has a distal
portion with an aperture and element, a lumen communicating between
an opening and the aperture, and an inflatable balloon secured upon
its distal portion. The balloon is adapted to seal upon inflation
the tract created by the probe when inserted into the brain.
Inventors: |
Putz; David A.; (Pewaukee,
WI) |
Correspondence
Address: |
Richard W. White;Jansson, Shupe, Munger & Antaramian, Ltd.
245 Main Street
Racine
WI
53403
US
|
Family ID: |
33299158 |
Appl. No.: |
11/262377 |
Filed: |
October 28, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10423587 |
Apr 25, 2003 |
|
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11262377 |
Oct 28, 2005 |
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Current U.S.
Class: |
604/264 ;
604/103.01; 604/173; 604/174 |
Current CPC
Class: |
A61M 25/007 20130101;
A61B 5/1473 20130101; A61B 5/6852 20130101; A61M 25/0662 20130101;
A61M 2025/105 20130101; A61M 2210/0693 20130101; A61M 2025/1052
20130101; A61B 5/031 20130101; A61B 5/4094 20130101; A61M 25/10
20130101; A61B 5/24 20210101 |
Class at
Publication: |
604/264 ;
604/173; 604/103.01; 604/174 |
International
Class: |
A61M 25/00 20060101
A61M025/00 |
Claims
1. A depth probe for intracranial treatment of a patient
comprising: a body extending from a proximal end to a distal end
and having an opening; a distal portion at the distal end having at
least one aperture and at least one element; a lumen defined by the
body in communication with respect to the opening and the aperture;
and a proximal portion at the proximal end having at least one
proximal-contact, the proximal-contact being conductively connected
with the at least one element.
2. The depth probe of claim 1 wherein the body is made from
substantially rigid material and the lumen is sized to receive an
inner catheter for transferring a fluid with a tissue region within
the patient's brain.
3. The depth probe of claim 1 wherein the proximal end includes a
tapered fitting adapted to connect to a pumping instrument for
transferring a fluid with a tissue region within the patient's
brain.
4. The depth probe of claim 3 wherein the body has an axis and the
opening is at the proximal end and coaxial with the lumen.
5. The depth probe of claim 4 wherein at least one aperture is in
axial alignment with the lumen.
6. The depth probe of claim 4 wherein the distal end is closed, the
aperture being spaced from the distal end along the distal
portion.
7. The depth probe of claim 6 wherein the body has at least first
and second apertures in communication with respect to the lumen,
the first and second apertures being spaced axially along the
distal portion.
8. The depth probe of claim 6 wherein the body has at least first
and second apertures in communication with respect to the lumen,
the first and second apertures being spaced radially about the axis
along the distal portion.
9. The depth probe of claim 4 wherein the element is a contact that
provides electrical stimulation to a tissue region within the
patient's brain.
10. The depth probe of claim 4 wherein the element is at least one
contact that monitors activity within the patient's brain.
11. The depth probe of claim 10 wherein the contact monitors
electrical activity within the patient's brain.
12. The depth probe of claim 10 wherein the at least one contact is
a plurality of contacts circumscribing the body and spaced axially
along the distal portion.
13. The depth probe of claim 10 wherein the contact is a
micro-contact.
14. The depth probe of claim 13 wherein the at least one contact is
a plurality of micro-contacts spaced axially and radially along the
distal portion.
15. The depth probe of claim 4 wherein the element is at least one
sensor.
16. The depth probe of claim 15 wherein the sensor senses chemical
activity within the patient's brain.
17. The depth probe of claim 4 wherein the element is a location
marker to identify the position of the distal portion when the
probe is inserted into the brain.
18. The depth probe of claim 17 wherein the location marker is
adapted to be identified by magnetic resonance imaging.
19. The depth probe of claim 1 wherein the proximal portion
includes a plurality of proximal-contacts and a connector adapted
to receive the proximal-contacts is secured with respect to the
body.
20. The depth probe of claim 19 wherein each of the
proximal-contacts is in electrical communication with a
micro-contact.
21. The depth probe of claim 19 wherein the connector extends
outward from the body, the connector having a housing formed to
position the proximal-contacts in a linear array and a lead-conduit
extending from the housing to the body.
22. The depth probe of claim 19 wherein the connector is firmly
attached to the body.
23. The depth probe of claim 1 wherein the proximal portion has a
first diameter and the distal portion has a second diameter such
that the second diameter is less than the first diameter to reduce
the degree of contact with the tissue region by the body when the
probe is inserted into the brain.
24. The depth probe of claim 1 wherein the lumen is sized to
receive an inner catheter for transferring a fluid with a tissue
region within the patient's brain.
25. A depth probe for intracranial treatment of a patient
comprising: a body extending from a proximal end to a distal end
and having an opening; a distal portion at the distal end having at
least one aperture and at least one element; a lumen defined by the
body in communication with respect to the opening and the aperture;
and a conduit extending from a proximal portion at the proximal end
to an inflatable balloon secured to the distal portion.
26. The depth probe of claim 25 wherein the balloon is inflatable
with at least one drug and the balloon is formed from a material
permeable to the drug such that the drug can be introduced into the
tissue region through the balloon.
27. The depth probe of claim 25 wherein the balloon is adapted to
seal upon inflation a tract created upon insertion of the probe
into the brain.
28. The depth probe of claim 25 wherein the balloon is positioned
along the distal portion proximal to the aperture.
29. The depth probe of claim 25 wherein the balloon is positioned
along the distal portion proximal to the element.
30. The depth probe of claim 25 wherein the lumen is sized to
receive an inner catheter for transferring a fluid with a tissue
region within the patient's brain.
31. The depth probe of claim 25 further comprising a proximal
portion at the proximal end having at least one proximal-contact
conductively connected with the element.
Description
RELATED APPLICATION
[0001] This application claims the benefit of U.S. patent
application Ser. No. 10/423,587, filed on Apr. 25, 2003.
FIELD OF INVENTION
[0002] The present invention relates to instrumentation utilized
for intracranial treatment and, in particular, to depth probes
utilized for intracranial treatment.
BACKGROUND OF THE INVENTION
[0003] Movement disorders such as epilepsy and Parkinson's disease
have been estimated to affect some 1-2% of the developed world's
population and up to 10% of people in underdeveloped countries.
Currently, approximately 75% of those who suffer from movement
disorders are responsive in some degree to drugs.
[0004] Electrical stimulation has also been utilized to treat some
movement disorders. In the treatment of epilepsy, studies have been
performed in which awake patients undergoing temporal lobe surgery
underwent cortical stimulation. Such stimulation of the visual and
hearing areas of the brain reproducibly caused the patients to
experience visual and auditory phenomena. This discovery was made
possible by the identification that certain brain subregions served
specific functions, such as sight, hearing, touch and movement of
the extremities and proved that direct electrical stimulation of
the brain regions could cause partial reproduction or suppression
of the functions.
[0005] As suggested by these results, it is known that certain
types of treatment of specific portions of the brain are able to
suppress certain unwanted behavior which results from movement
disorders. This behavior may include seizures such as those
suffered by epileptics. However, the studies faced a major problem
in that there was an inability to precisely electrically stimulate
very small volumes of the brain.
[0006] The advent of needle-shaped penetrating depth electrodes
helped to overcome this obstacle faced by electrical stimulation.
Depth electrodes can be placed within the brain tissue itself,
enabling optimal surface contact with elements of the brain that
are targeted for stimulation. This allowed for safe, chronic
electrical stimulation of very small discrete volumes of brain.
[0007] In treatment, electrical stimulation has been used with the
recording and analysis of changes in brain activity to predict the
occurrence of epileptic seizures. The time of onset of such
seizures is often predictable by neural discharge monitoring, even
when the exact causal nature of precipitating dysfunction is not
understood. Electrodes have been used to obtain signals
representative of current brain activity along with a signal
processor for continuous monitoring and analysis of these
electrical signals in order to identify important changes or the
appearance of precursors predictive of an impending change.
[0008] While the electrical stimulation of brain tissue has been
somewhat effective in the treatment of migraines, epilepsy and
other neurological problems, patients often experience diminishing
returns with such treatment. Furthermore, because each patient
reacts differently to electrical stimulation, substantial time must
be spent to determine the specific amplitude, frequency, pulse
width, stimulation duration, etc. which may result in effective
treatment. In addition, such parameters often require continual
adjustment in order to remain effective.
[0009] Improved intracranial monitoring devices have been shown to
facilitate treatments of movement disorders. Monitoring is
typically performed by instruments which are inserted into the
brain at different locations or along different tracks. Other
systems employ a single device which must be removed and reinserted
to provide for delivery of multiple drugs or use of different
electrical devices.
[0010] Since the introduction of probes or other similar devices
into the brain is common in many surgical procedures today, there
are a variety of probes available. Such probes typically include
ports for drug delivery or electrical, chemical, electrochemical,
temperature and/or pressure contacts which enable the observation
and analysis of the brain state or contacts providing stimulation.
These ports and contacts must typically be positioned at specific
points or regions in the brain.
[0011] Probes used in intracranial penetration are typically
fabricated so that their introduction to the brain is as minimally
traumatic as possible. In addition to being minimally traumatic
during insertion, certain inserted probes must also be able to
remain implanted without causing injury through unintended
movement. In some uses, a probe may be implanted and remain in the
patient's brain for weeks or longer. Changes in the positioning of
the probe often occur during placement or during such extended
periods. Therefore, the probe must be capable of precise placement
and as bio-compatible as possible. In response to these
requirements, state of the art intracranial probes are typically
thin, flexible pieces with smooth surfaces to minimize the amount
of brain tissue contacted and to minimize damage to contacted brain
tissue.
[0012] While such thin, flexible probes are sufficiently
bio-compatible, they are delicate and often difficult to insert
along specific trajectories or lines of insertion. During typical
implantation, a surgeon feeds the probe into the brain through an
aperture in the skull. In this process, the surgeon has very little
control over the distal end of the probe. In order to provide more
rigidity to the probe to overcome this problem, a removable stylet
may be inserted into the probe before implantation. Still, veering
from the intended line of insertion is not altogether prevented by
introduction of a stylet to the probe.
[0013] There is a continuing significant need in the field of
intracranial treatment, particularly with insertion of probes into
the interior of the brain, for improvements in accuracy of
insertion and avoidance of injury, while retaining efficiency and
ease of use.
[0014] In addition, there is a need in the field of intracranial
treatment to minimize the invasiveness of intracranial treatment
and to reduce the number of instruments which penetrate brain
tissue or the number of times a single instrument must penetrate
brain tissue.
[0015] Furthermore, there is a need in the field of intracranial
treatment to provide the ability to precisely locate the position
of a probe during insertion to ensure proper positioning.
OBJECTS OF THE INVENTION
[0016] It is a primary object of the invention to provide an
improved depth probe for intracranial treatment of a patient that
overcomes some of the problems and shortcomings of the prior
art.
[0017] Another object of the invention is to provide a novel depth
probe that is simple in structure and operation in order to
facilitate intracranial procedures.
[0018] Another object of the invention is to provide an exceptional
depth probe having a body adapted to avoid extensive trauma to and
scarring of brain tissue.
[0019] Another object of the invention is to provide an excellent
depth probe having a body that includes contacts for stimulation
and/or for monitoring of the brain.
[0020] Another object of the invention is to provide a desirable
depth probe having a lumen for receiving and guiding an inner
catheter for the delivery of a drug to targeted brain tissue and
that can remain in position when the inner catheter is removed,
thereby permitting repeated insertions of different inner catheters
without extended contact with brain tissue during insertion.
[0021] Another object of the invention is to provide an exceptional
depth probe that provides an attached connector conductively
connected to a plurality of monitoring and sensing elements for
efficient and effective transmission of readings from the elements
to external analysis and control devices.
[0022] Yet another object of the invention is to provide a novel
depth probe having a distal portion provided with an inflatable
balloon capable of sealing off the insertion tract formed by the
probe to prevent a drug being introduced into the brain by the
probe from migrating back through the tract and further allows for
the monitoring of cellular function within the brain prior to and
after introduction of the drug.
SUMMARY OF THE INVENTION
[0023] The invention is for a depth probe utilized to provide
intracranial treatment of a patient. The depth probe comprises a
body having a distal portion with at least one aperture and at
least one element, a lumen defined by the body that communicates
between an opening and the aperture, and a proximal portion with at
least one proximal-contact. The proximal-contact is conductively
connected with the element. The term "conductively connected" is
meant to include a connection via a lead in the form of a wire or
fiber-optic bundle for the transmission of electrical and/or
optical signals.
[0024] A number of highly preferred embodiments have the lumen
sized to receive an inner catheter adapted to transfer a fluid with
a tissue region within the patient's brain. In other embodiments,
the body is made from substantially inflexible material.
[0025] One preferred embodiment finds the opening on the body
having a tapered fitting so that a pumping instrument can be
connected to the probe at the fitting for the transfer of a fluid
with a tissue region of the patient's brain. Much preferred is
where the opening is at the proximal end of the body and coaxial
with the lumen. Also preferred is where the aperture is in axial
alignment with the lumen.
[0026] In another desirable embodiment, the distal end of the probe
is closed and the aperture is spaced away from the distal end along
the distal portion. More desirable is where the body has at least
first and second apertures in communication with the lumen, each
aperture being spaced axially along the distal portion. Highly
desirable is where the probe has first and second apertures
communicating with the lumen that are spaced radially about the
body's axis along the distal portion.
[0027] In certain preferred cases, the element is a contact that
can provide electrical stimulation to tissue regions within the
patient's brain. Also desirable is where the element is a contact
that monitors activity, preferably electrical activity, within the
patient's brain. More desirable is where the probe has a plurality
of contacts spaced axially along its distal portion, each of these
contacts being a macro-contact that collars, i.e., circumscribes,
the body. Highly desirable is where the contact is a micro-contact
and preferably where the probe has a plurality of micro-contacts
spaced axially and radially along its distal portion.
[0028] Another appreciated embodiment finds the element to be a
sensor. Much preferred is where the sensor senses chemical activity
within the brain. Another element found desirable is where it is a
location marker that allows the position of the distal portion of
the probe to be identified when it is inserted into the brain. This
embodiment is especially desirable when the marker is adapted to be
identified, i.e. seen, under magnetic resonance imaging.
[0029] One very preferred example of this invention is where there
are a plurality of proximal-contacts and a connector adapted to
receive these proximal-contacts is secured to the body. It is
desirable that each of these proximal-contacts be in electrical
communication with a micro-contact. More desirable is where the
connector extends outward from the body and has a housing formed to
position the proximal-contacts in a linear array. The connector in
this embodiment has a lead-conduit extending from this housing that
connects it to the body of the probe. A highly preferred embodiment
finds the connector as being firmly attached to the body.
[0030] Another highly desirable embodiment is where the proximal
portion of the body has a first diameter and its distal portion has
a second diameter such that the second diameter is less than the
first diameter. Having this structure, the degree of contact with
the tissue region by the body is reduced when the probe is inserted
into the brain.
[0031] Another interesting aspect of this invention finds a depth
probe comprising a body having a distal portion with at least one
aperture and one element, a lumen defined by the body that
communicates between an opening and the aperture, and a conduit
extending from its proximal portion to an inflatable balloon
secured upon its distal portion. Much desired is where the balloon
is inflatable with at least one drug and the balloon is formed from
a material permeable to this drug so that the drug can be
introduced into the tissue region through the balloon. Also
preferred is where the balloon is adapted to seal upon inflation
the tract created by the probe upon its insertion into the
brain.
[0032] A most desirable embodiment has the balloon positioned along
the distal portion of the body at a point proximal to the aperture.
Highly preferred is where the balloon is positioned along the
distal portion and is also proximal to the element on the
probe.
[0033] In a very appreciated example, this probe also includes at
least one proximal-contact along a proximal portion at its proximal
end. The proximal-contact is conductively connected with the
element through a lead.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] FIG. 1 is a perspective view of a preferred depth probe
having a connector extending outward from the body in accordance
with this invention with cut-away sections to reveal and dashed
lines to represent otherwise unseen internal features.
[0035] FIGS. 2A and 2B are perspective views of the distal portions
of alternate preferred depth probes in accordance with this
invention with dashed lines to represent otherwise unseen internal
features.
[0036] FIG. 3 is a perspective view of another preferred depth
probe in accordance with this invention receiving an inner catheter
with cut-away sections to reveal and dashed lines to represent
otherwise unseen internal features.
[0037] FIG. 4 is a perspective view of an alternate embodiment of
the depth probe having a connector attached to the body in
accordance with this invention with a cut-away section.
[0038] FIG. 5A is a perspective view of a preferred depth probe
having a balloon shown deflated in accordance with this invention
with cut-away sections to reveal and dashed lines to represent
otherwise unseen internal features.
[0039] FIG. 5B is the distal end of the depth probe of FIG. 5A
showing the balloon inflated with cut-away sections to reveal and
dashed lines to represent otherwise unseen internal features.
[0040] FIG. 6 is a schematic view illustrating the depth probe of
FIGS. 5A and 5B positioned within the brain.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0041] The figures illustrate preferred embodiments of an improved
depth probe for intracranial treatment of a patient in accordance
with this invention. FIG. 1 is a perspective view of depth probe 10
having an elongated, tubular body 12 extending from proximal end 14
to distal end 16. Body 12 preferably has a diameter between about
0.6 and 3.0 millimeters, most preferably about 1.0 millimeter.
[0042] As seen in FIG. 1, body 12 includes elements 18 secured to
distal portion 20 at distal end 16. Body 12 is also provided with
lumen 22 extending from opening 24 at proximal end 14 and in
communication with aperture 26. Lumen 22 is a tubular channel
extending for some length within body 12, preferably having a
diameter of 0.5 millimeters or less. Body 12 is open at distal end
16 to form aperture 26. Opening 24 and aperture 26 are coaxial with
lumen 22 along central axis 28 of body 12.
[0043] Elements 18 are conductively connected by leads 30 (seen in
FIG. 1 running alongside lumen 22) to proximal-contacts 32. Leads
30 can be in the form of electrical wiring or a fiber-optic bundle.
Proximal-contacts 32 are mounted along proximal portion 34 of body
12. When depth probe 10 is inserted into the brain,
proximal-contacts 32 remain outside of the patient.
Proximal-contacts 32 are preferably formed from stainless steel or
similar alloys or materials that are non-corrosive conductors and
that can endure sterilization.
[0044] Depth probe 10 can be substantially flexible, formed from
bio-compatible materials such as polyurethane, silicone, or
polyimide. Body 12 can also be in the form of a cannula where body
12 is made from a substantially rigid material that is preferably
MRI safe/compatible. Such preferable materials are platinum,
titanium, polyimide-coated glass, and other non-ferrous alloys.
During surgery, when in the form of a cannula, depth probe 10 may
be used with a stereotatic frame or a frameless guidance system to
accurately position the catheter within the brain.
[0045] As seen in FIGS. 2A and 2B, preferred embodiments of depth
probe 10 can have a closed distal end 16 and a plurality of
apertures 26, each aperture 26 in communication with lumen 22.
Apertures 26 in FIG. 2A are positioned above distal end 16 and
spaced in axial alignment with axis 28 along distal portion 20.
Apertures 26 in FIG. 2B are shown axially and radially spaced about
axis 28. One skilled in the art will recognize that these
configurations can also include an aperture 26 forming an open
distal end 16 as depicted in FIG. 1.
[0046] Body 12 of depth probe 10 may also include a distal portion
20 having a reduced diameter as illustrated in FIG. 3. Such a
configuration for distal portion 20 allows for reduced injury to
the surrounding tissue regions during the insertion of depth probe
10 into the brain.
[0047] As depicted in FIG. 3, lumen 22 is preferably sized so as to
be able to receive an inner catheter 36, i.e., lumen 22 is provided
with a diameter slightly greater than the outside diameter of inner
catheter 36. After positioning the distal end 16 of depth probe 10
in a targeted region of the brain, inner catheter 36 can be
inserted into opening 24 and guided by lumen 22 to this tissue
area. Inner catheter 36 can be withdrawn and reinserted or
different inner catheters 36 can be inserted into depth probe 10
without reinserting or repositioning depth probe 10. Inner catheter
36 is preferably polyimide, polyimide-coated glass or other similar
material. Applicant notes that one such preferred catheter is
disclosed in U.S. patent application Ser. No. 10/423,587 filed by
Applicant on Apr. 25, 2003, the disclosure of which is incorporated
by reference herein.
[0048] Proximal end 14 of body 12 is provided with a tapered
fitting 38, preferably a male luer conical fitting, to provide for
a detachable fluid-tight coupling with some external device. The
proximal end of inner catheter 36 is provided with a tapered
coupler 40, preferably a luer coupler that has female luer fittings
at both of its ends. Tapered coupler 40 enables inner catheter 36
to form a liquid-tight joint with depth probe 10 when inner
catheter 36 is fully inserted into lumen 22 through opening 24.
Coupler 40 enables inner catheter 36 to be operatively connected by
tubing to an external piece of equipment such as a pump. One
skilled in the art will recognize that inner catheter 36 could also
be connected to internal instrumentation having pumping capability.
This process enables fluids such as drugs to be administered to the
brain through inner catheter 36.
[0049] Elements 18 provide for monitoring of brain activity, for
stimulating brain tissue or for serving as a location beacon to aid
in determining the precise position of distal portion 20 within the
brain. Elements 18 can take the form of contacts 42, as illustrated
in FIGS. 1-6. Contacts 42 comprise devices such as electrodes 44
designed to monitor brain activity in a selected tissue region of
the brain 46 through the sensing of electrical and/or
electrochemical changes within the brain as well as electrodes 48
designed to provide electrical stimulation to specific areas of the
brain. Electrodes serving as contacts 42 are preferably constructed
from platinum, platinum-iridium or other bio-compatible conductive
material. Electrodes can be macro-contacts 49 that circumscribe or
band body 12 or micro-contacts 50 capable of measuring electrical
changes at the level of a single neuron.
[0050] Elements 18 can also can take the form of a sensor 52 as
depicted in FIG. 3. Sensors 52 are designed to monitor brain
activity within select tissue regions through the sensing of
electrical, electrochemical, chemical, temperature or pressure
changes within the brain. Sensors 52 can be electrochemical and
optical transducers designed to measure chemical, pressure,
temperature, cerebral blood flow and other physiological changes in
the brain. Such devices are known in the art and are preferably
less than about 2 millimeters long. Sensor 52 is preferably in the
form of a chemical sensor.
[0051] Elements 18 may further be in the form of a location marker
54 as seen in FIGS. 5A and 5B. Location marker 54 is preferably a
structure comprised of a non-ferrous material known in the art such
as gold or tungsten that has an image signal intensity suitable for
proton magnetic resonance imaging (MRI) with most commercial
machines and is also sufficiently x-ray opaque for satisfactory
imaging using computed tomographic scanning (CT) or on X-ray.
Location marker 54 can also be comprised of a sensor capable of
measuring voltages induced by a transmitted magnetic field that can
be used to identify the position and orientation of the sensor
within that field.
[0052] Elements 18 may be positioned on both the distal and
proximal sides of apertures 26 along distal portion 20 as seen in
FIGS. 2A and 2B. This configuration allows for monitoring of
cellular function within the tissue region of the brain 46 being
targeted prior to treatment to verify the presence of diseased
brain cells. Upon verification of diseased tissue within the
targeted region, delivery of a drug or other treatment agent can
commence through depth probe 10 while monitoring of the tissue
region 46 continues concurrently with such treatment. This can have
particular value in the treatment of different tissue regions of
the brain for movement disorders such as Parkinson's Disease.
[0053] FIGS. 1, 2, 5A and 5B show that macro-contacts 49 are spaced
axially along distal portion 20. Micro-contacts 50 can be spaced
axially along distal portion 20 as illustrated in FIG. 4 or spaced
radially around body 12 as shown in FIG. 1.
[0054] FIGS. 5A and 5B illustrate a depth probe 10 having an
inflatable balloon 56 rigidly mounted to distal portion 20,
preferably above at least one element 18 and at least one aperture
26. As seen in FIG. 5A, a conduit 58 enters body 12 along proximal
portion 34 and runs alongside lumen 22, terminating at balloon 56.
Conduit 58 is preferably tubing made of polyurethane. Conduit 58
provides for the introduction of a fluid to inflate balloon 56 and,
if necessary to withdraw fluid from balloon 56 to cause deflation.
Conduit 58 originates at injection port 60 that can be operatively
connected to an external device 62 such as a pump to dispense or
receive fluid.
[0055] As depicted in FIG. 6, following placement of distal portion
20 of depth probe 10 within the brain, balloon 56 can be inflated
to block or occlude the insertion tract 64 created during the
insertion process so that any drug administered to the brain 46
through aperture 26 cannot migrate back through that tract. Balloon
56 is preferably made from an elastomeric material to achieve
complete deflation of balloon 56 when depth probe 10 is later
withdrawn from the brain.
[0056] In certain embodiments, balloon 56 is permeable. Balloon 56
in these embodiments can be inflated with a drug or other fluid
intended to be administered to the brain whereby the drug then
permeates through the wall of balloon 56 to treat the tissue region
of the brain 46 surrounding balloon 56. In this manner, a drug can
be introduced to one targeted tissue region of the brain delivered
by depth probe 10 through aperture 26 at the same time the same or
a different drug is transferred to another selected tissue region
through permeable balloon 56. Balloon 56 is preferably adapted to
administering a drug to the brain slowly over a period of time,
thereby allowing for the effective introduction of the drug to the
desired tissue region. This is especially desirable where there is
a void in the particular tissue region due to some structure such
as a tumor being removed. Inflating balloon 56 within the void
permits the medication to be more effectively transferred to all of
the affected tissue that surrounds the outside of the balloon.
[0057] One skilled in the art will recognize that balloon 56 can be
made permeable by forming balloon 56 from a naturally porous
material such as polytetrafluroethylene (PTFE) or from an
elastomeric material having perforations formed in the wall of the
balloon. The balloon wall is preferably from 0.5 to 5.0 mils in
thickness. Where the balloon wall is perforated, an array of minute
perforations, each having a diameter of 5 to 30 microns, is
preferably uniformly spaced apart and concentrated along a central
band circumscribing balloon 56. Concentration of the perforations
within such a region in the middle of balloon 56 provides for
focused delivery of the drug by limiting the area of permeation to
just the surface area of balloon 56 making conforming contact with
the surrounding brain tissue.
[0058] Tapered fitting 38 enables depth probe 10, as shown in FIG.
6, to form a liquid-tight seal with tubing or similar conduit
having a female luer connector. In this manner, opening 24 of body
12 is operatively connected by the tubing to an external instrument
such as pumping equipment 66. One skilled in the art will recognize
that depth probe 10 could also be connected to internal
instrumentation having pumping capability. Such equipment allows
fluids to be transferred to or from tissue region of the brain 46
through any aperture 26. Drugs can then be administered to the
brain, cerebral spinal fluid can be withdrawn, or both.
[0059] Depth probe 10, as illustrated in FIGS. 1 and 4, can also
include a connector 68. Connector 68 comprises a housing 69
mounting a linear array 70 of proximal-contacts. Connector 68 is
conductively connected via additional leads 30 to elements 18,
preferably micro-contacts 50, along distal portion 20. Connector 68
can be rigidly mounted to body 12 along its proximal portion 34 as
shown in FIG. 4.
[0060] Connector 68 can also extend outward from body 12 as seen in
FIG. 1. Connector 68 in this embodiment is secured to body 12 by
lead-conduit 72. Leads 30 that originate at connector 68 pass
through lead-conduit 72 before entering body 12 at a point along
proximate portion 34 to proceed along lumen 22 to the corresponding
elements 18.
[0061] One skilled in the art will readily recognize that
proximal-contacts 32 are in an axial alignment that adapts them to
being conductively connected to an external connector (not shown)
in operative communication with a computer or similar instrument
having a conventional output display and monitor with a suitable
power source. This enables the brain activity sensed by elements 18
linked to these proximal-contacts to be recorded and/or analyzed
and/or control over elements 18 to be exercised.
[0062] Although the invention has been described in conjunction
with specific embodiments thereof, it is evident that many
alternatives, modifications and variations will be apparent to
those skilled in the art. Accordingly, it is intended to embrace
all such alternatives, modifications and variations that fall
within the spirit and broad scope of the appended claims.
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