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Claims  |
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What is claimed is:
1. A permanently implantable guiding catheter for facilitating repeated
access to a body tissue site, the guiding catheter comprising:
a flexible, elongate catheter body having a substantially hollow
cylindrical configuration, the catheter body having a proximal end, and
having an openable distal end adapted to be disposed generally at the body
tissue site, the distal end having a seal;
a port assembly, coupled to the proximal end of the catheter body, for
retaining the catheter body in position, the port assembly including a
self-sealable septum for preventing seepage of body fluids into the
catheter body or from the openable distal end of the catheter body into
the adjacent subcutaneous tissue, the port assembly adapted to be
subcutaneously disposed;
wherein the catheter body has a sufficient internal diameter to allow
passage of a flexible elongate medical instrument therethrough, such that
a distal end of the medical instrument is provided access to the body
tissue site through the seal of the distal end of the catheter body.
2. A guiding catheter in accordance with claim 1, wherein the medical
instrument is a drug infusion catheter.
3. A guiding catheter in accordance with claim 1, wherein the guiding
catheter is made of PTFE.
4. A guiding catheter in accordance with claim 1, wherein the self-sealable
septum is made of silicone rubber.
5. A guiding catheter in accordance with claim 1, wherein the body tissue
site is located in the patient's epidural space, intrathecal space or
cranium, including but not limited to the ventricles of the brain or brain
tissue.
6. A guiding catheter in accordance with claim 1, wherein the catheter body
is made of a material that is biocompatible.
7. A guiding catheter in accordance with claim 1, wherein the catheter body
is made of a material that is radiopaque.
8. A guiding catheter in accordance with claim 1, wherein the catheter body
is made of a material that is detectable by a nuclear magnetic resonance
(NMR) device during a nuclear magnetic resonance procedure.
9. A guiding catheter in accordance with claim 1, wherein the seal
comprises a sealing valve attached to the distal end of the catheter body
to prevent body fluids from entering the catheter body.
10. A guiding catheter in accordance with claim 1, wherein the port
assembly includes a base portion with a central opening extending
therethrough for receiving a medical device.
11. A guiding catheter in accordance with claim 1, wherein the
self-sealable septum comprises a dome made of an elastomeric material.
12. A guiding catheter in accordance with claim 1, further comprising a
positive locking mechanism for retaining the medical instrument in the
catheter body.
13. A permanently implantable guiding catheter for facilitating repeated
access to a body tissue site, the guiding catheter comprising:
a flexible, elongate catheter body having a substantially hollow
cylindrical configuration, the catheter body having a proximal end, and
having an openable distal end adapted to be disposed generally at the body
tissue site, the distal end having a sealing valve attached to the distal
end of the catheter body to prevent body fluids from entering the catheter
body;
a port assembly, coupled to the proximal end of the catheter body, for
retaining the catheter body in position, the port assembly including a
base portion with a central opening extending therethrough for receiving a
medical device and a self-sealable septum for preventing seepage of body
fluids into the catheter body or from the openable distal end of the
catheter body into the adjacent subcutaneous tissue, the self-sealable
septum comprising a dome made of an elastomeric material, the dome
attached to and extending over the base to cover the central opening in
the base, the port assembly adapted to be subcutaneously disposed;
wherein the catheter body has a sufficient internal diameter to allow
passage of a flexible elongate medical instrument therethrough, such that
a distal end of the medical instrument is provided access to the body
tissue site through the sealing valve.
14. A system for facilitating repeated access to a body tissue site, the
system comprising:
a guiding catheter comprising:
a flexible, elongate catheter body having a substantially hollow
cylindrical configuration, the catheter body having a proximal end, and
having an open distal end adapted to be disposed generally at the body
tissue site;
a port assembly, coupled to the proximal end of the catheter body, for
retaining the catheter body in position, the port assembly including a
self-sealable septum for preventing seepage of body fluids into the
catheter body or from the open distal end of the catheter body into the
adjacent subcutaneous tissue, the port assembly adapted to be
subcutaneously disposed;
a hollow needle to access the guiding catheter, the needle having a
sharpened distal end to pass through the skin and into the septum of the
port assembly;
a flexible, elongate infusion catheter, the infusion catheter having a
substantially hollow cylindrical configuration, the catheter body having a
proximal end, and having an open distal end adapted to be disposed
generally at the body tissue site;
wherein the guiding catheter body has a sufficient internal diameter to
allow passage of the needle therethrough;
wherein the needle has a sufficient internal diameter to allow passage of
the infusion catheter therethrough, such that a distal end of the infusion
catheter is provided access to the body tissue site;
whereby, the guiding catheter is placed in position in a patient's body,
the needle placed through the guiding catheter and the drug infusion
catheter placed through the needle.
15. A system for facilitating repeated access to a body tissue site, the
system comprising:
a guiding catheter comprising:
a flexible, elongate catheter body having a substantially hollow
cylindrical configuration, the catheter body having a proximal end, and
having a distal end adapted to be disposed generally at the body tissue
site, the distal end having a seal;
a port assembly, coupled to the proximal end of the catheter body, for
retaining the catheter body in position, the port assembly including a
self-sealable septum for preventing seepage of body fluids into the
catheter body or from the open distal end of the catheter body into the
adjacent subcutaneous tissue, the port assembly adapted to be
subcutaneously disposed;
a flexible, elongate infusion catheter, the infusion catheter having a
substantially hollow cylindrical configuration, the catheter body having a
proximal end, and having an open distal end adapted to be disposed
generally at the body tissue site;
wherein the guiding catheter body has a sufficient internal diameter to
allow passage of the infusion catheter therethrough, such that a distal
end of the infusion catheter is provided access to the body tissue site;
whereby, the guiding catheter is placed in position in a patient's body and
the drug infusion catheter placed through the guiding catheter to the body
tissue site through the seal of the distal end of the catheter body. |
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Claims |
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Description |
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FIELD OF THE INVENTION
This invention relates generally to the field of caterers, and more
particularly to a permanently implantable guiding catheter for
facilitating access to body tissue.
BACKGROUND OF THE INVENTION
In current medical practice, there are numerous instances where therapeutic
agents are delivered to a specific organ or tissue area within the
patient's body. One example of this is the infusion of chemotherapy agents
into a central vein on a recurring basis over a lengthy treatment period
for treatment of malignant tumors. Without an infusion device for
intravenous drug infusion, multiple vein punctures over a lengthy period
can result in progressive thrombosis, venous sclerosis, and destruction of
small-diameter peripheral vessels. In other cases, it may be desired to
infuse chemotherapy agents or other substances to a localized site, for
example, to brain or liver tissue. In these situations, it can be
difficult to deliver an agent specifically to such a localized site on a
regular, repetitive basis without surgically implanting or otherwise
introducing an infusion system.
Similarly, repeated arterial access is occasionally needed for injection of
substances like X-ray dye or contrast agents into an artery for diagnostic
purposes. In other situations, there is a need to remove body fluid
repetitively from a remote body site, for analysis. Sensing and
physiological measuring devices incorporated into small-diameter catheters
and small-diameter optical fibers are increasingly being utilized for
monitoring body processes, and could more easily be implemented through an
access device with an adequate internal diameter.
In the prior art, it has been common medical practice to use percutaneous
catheters for providing vascular or organ access for drag therapy or
removing body fluids. Although such systems generally function in a
satisfactory manner, numerous problems have been perceived by such
approaches, including the substantial patient care requirements--e.g.,
dressing changes with sterile techniques--the significant risk of
infection of the catheter due to its transcutaneous position, and the high
risk of venous thrombosis, particularly if the catheter is located within
an extremity vein.
Implantable infusion devices or "ports" have been proposed in the prior art
as representing an advance over transcutaneous catheters. Presently
available infusion ports have a number of common design features. The
ports themselves typically comprise a housing which forms a reservoir
which can be constructed from a variety of materials. A surface of the
reservoir is enclosed by a high-density, self-sealing septum, typically
made of silicone rubber. Connected to the port housing is an outflow
catheter which communicates with a vein or other site within the patient
where it is desired to infuse a therapeutic agent or to which access is
otherwise necessary. Implantation of such devices generally involves
making a small subcutaneous pocket in the patient under local anesthesia.
The internal outflow catheter is tunneled to the desired infusion site and
is connected to the infusion port. When the physician desires to access
the site, for example, to infuse or remove material through the port, a
hypodermic needle is used to pierce the skin over the port, and to pierce
the septum.
Although presently available infusion systems have generally been deemed
satisfactory, there are a number of potential shortcomings in practical
application. Since these devices rely upon a compressed rubber septum for
sealing, there can be limitations on the diameter of needles used to
penetrate the septum, (large diameter needles can damage the septum and
hinder proper sealing of the port). Moreover, the needles used for this
purpose must be of special design which minimizes septum damage. These
limitations can seriously restrict the flow rate of fluids passing through
the port.
For prolonged infusion using a conventional port, the infusion needle may
be taped to the patient's skin to hold it in position. Conventional ports
do not allow the needle to penetrate deeply into the port, leading to the
possibility that a small displacement of the needle can cause it to be
pulled from the port. In cases where locally toxic materials are being
infused, extravasation of such materials can cause local tissue damage
making corrective surgery, e.g., skin grafting, necessary.
A further perceived disadvantage of prior art infusion ports is that they
can be difficult to clear if thrombosis occurs within them or within the
implanted outflow catheter, since it can be difficult to feed a cleaning
wire through the penetrating hypodermic needle in a manner which will
clear the infusion device and internal outflow catheter. Moreover, prior
infusion ports typically have had a retained volume beneath the
self-sealing septum, increasing the volume of agent which must be
administered to enable a desired quantity to reach the infusion site. This
can also pose problems when a physician wishes to deliver different,
potentially incompatible, agents to the same infusion site. In addition,
when it is desired to withdraw body fluid from through the port, the
retained volume of prior art infusion ports is an area where blood
clotting can occur, thus interfering with future access to the infusion
site. Also, withdrawing fluid can require a large volume to fill the
catheter and ports.
The introduction of infusion port and catheter systems as described above
into the ventricular system of the human brain forms a large part of
modern neurosurgical clinical practice. Procedures which involve the
introduction of ventricular catheters include intracranial pressure
monitoring, draining or shunting of cerebral-spinal fluid, and the
infusion of pharmacological therapeutic agents. Catheters are also
commonly introduced to access the heart, liver, subarachnoid space, or
peritoneum.
Catheters can be introduced and positioned using a variety of standard
surgical techniques, including direct observation, observation with
imaging systems, and stereotactic placement,, Each of the known techniques
relies heavily upon the skill of the surgeon, and are relatively expensive
and time-consuming. In the case of neurological catheter introduction,
which is usually preceded by a CT scan or other imaging, the neurosurgeon
first forms a burr hole in the skull, and then guides the catheter through
the hole toward landmarks on the opposite side of the head. It is
necessary that the neurosurgeon be able to accurately visualize the
internal tomography of the brain when performing such a procedure, and it
is presumed that the catheter is properly located when fluid is returned
through the catheter. In some cases, however, the surgeon desires to check
the location of the catheter, typically by subjecting the patient to
another CT scan in order to verify proper location of the catheter. This
can be costly, time consuming, and inconvenient.
Stereotactic placement of neurological catheters is generally regarded as
an acceptable method of introducing neurological instruments. See, e.g.,
U.S. Pat. No. 5,300,080 to Clayman eta., entitled "Stereotactic Instrument
Guide Placement." Stereotactic placement involves the use of an apparatus
adapted to direct the neurological instrument, e.g., catheter, in three
planes, to reach a specific site within the brain. A stereotactic
procedure is a long and expensive operation. As such, it may not always be
practical or desirable to perform the procedure multiple times on the same
patient.
Stereotactic procedures may not be suitable for placement of extremely
delicate neurological instruments which could be damaged by the
stereotactic frame. In addition, stereotactic procedures cannot typically
be used for placement of small diameter instruments or instruments which
cannot accept a stiffening guide wire therein.
A further consideration with regard to the introduction of catheter and
infusion port systems into a patient relates to the material from which
the catheter is made. On the one hand, it is typically desirable for a
catheter to be relatively thin and flexible; of course, the catheter
material must also be compatible with the tissue in which it is intended
to be implanted. On the other hand, however, the catheter material is
preferably strong, particularly if stereotactic placement is used. In
addition, the catheter must be compatible with whatever agent is to be
conducted through it. Sometimes, the forgoing factors come into conflict.
For example, a catheter material which is biocompatible with brain tissue,
for example, might not be compatible with the drugs to be introduced with
the catheter. Similarly, a material that is suitably flexible and thin may
not be rugged enough to withstand the placement procedure.
The fact that few if any biocompatible materials are compatible with all
drugs and other agents that may be introduced into a patient by means of a
catheter can complicate situations in which it is desired to deliver
multiple agents serially into a patient. One solution to this dilemma is
to introduce a separate catheter for each agent to be delivered. This may
not be acceptable or practical, however, particularly in view of the
complexities of catheter introduction and the difficulties associated with
achieving the desired placement of the catheter, as previously discussed.
SUMMARY OF THE INVENTION
In view of the foregoing considerations, the present invention is directed
to a method and apparatus for performing surgical techniques, such as drug
infusion, which conventionally involve the introduction of a catheter into
a patient's body.
In accordance with one aspect of the present invention, a guiding catheter
is permanently implanted in a patient's body. The guiding catheter can be
positioned using conventional surgical techniques, including direct
observation, observation by imaging systems, and/or stereotactic
placement. The guiding catheter is made of biocompatible material and is
preferably radiopaque. The guiding catheter may also be made of a material
that is detectable during a nuclear magnetic resonance (NMR) imaging
procedure.
In accordance with another aspect of the present invention, a needle or
introducer is used to access the guiding catheter. The needle or
introducer is placed through the skin and into a reseatable septum
disposed on the proximal end of the guiding catheter. Once the needle or
introducer is in place, another catheter, for example a drug infusion
catheter, can be inserted through the needle or introducer, into the
guiding catheter, and then to the target site.
In accordance with still another aspect of the invention, the permanently
implanted guiding catheter can be used to guide catheters and other
instruments to various sites in the body. For neurological applications,
the guiding catheter in accordance with the present invention is designed
for placement using a stereotactic frame. The guiding catheter is
constructed from a material that is strong enough to withstand
stereotactic placement and not be damaged during the surgical procedure,
and which is biocompatible with brain tissue. Advantageously,
compatibility with various drugs or other agents is not necessary for the
guiding catheter, through which another catheter, for example a drug
infusion catheter, extends during subsequent catheterization procedures.
In one embodiment of the invention, a permanently implanted guiding
catheter is used as a guide for temporary drug infusion catheters and the
like. For example, chemotherapy agents may be delivered periodically to a
site at which the guiding catheter's distal end is positioned. In this
embodiment, an access port is disposed upon the proximal end of the
guiding catheter. The access port can be placed either in the skull or
further down the body, at the neck or chest.
The guiding catheter in accordance with the present invention is preferably
implanted once during a single surgical procedure using any conventional
catheter insertion technique, such as stereotactic placement. Once the
distal tip of the guiding catheter is confirmed to be accurately placed at
the desired site, a drug infusion catheter may thereafter inserted into
the guiding catheter, by accessing the septum of the access port with a
needle introducer. The drug infusion catheter may be advanced through the
guiding catheter to be guided to the desired site at the distal end of the
guiding catheter. After drug is infused for the desired period of time,
the drug infusion catheter is removed, leaving the guiding catheter in
place for subsequent use.
The guiding catheter in accordance with the present invention allows for
multiple agents to be used at different times for the same infusion site.
This eliminates one problem with prior art catheter configurations, namely
that few if any catheter materials are compatible with all agents.
In accordance with another aspect of the invention, a permanently implanted
guiding catheter can serve as a surgical aid for permanently implanted
systems, for example, an implanted pump or access port.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other aspects of the present invention may perhaps be
best appreciated with reference to a detailed description of a specific
embodiment of the invention, when read in conjunction with the
accompanying drawings, wherein:
FIG. 1 is a cross-sectional view of a guiding catheter and port assembly in
accordance with one embodiment of the invention, implanted in a patient
and having an introducer needle percutaneously piercing the port assembly;
and
FIG. 2 is a cross-sectional view of the guiding catheter and port assembly
from FIG. 1 having an elongate medical instrument extending therethrough.
FIG. 3 is a cross-sectional view of the distal end of the guiding catheter
with a sealing valve attached and with an infusion catheter within the
guiding catheter.
FIG. 4 is a cross-sectional view of the distal end of the guiding catheter
with a sealing valve attached of FIG. 3 and with the infusion catheter
removed from within the guiding catheter.
FIG. 5 is a cross-sectional view of the guiding catheter and port assembly
of FIGS. 1 and 2 with a positive locking mechanism in place within the
guiding catheter and port assembly and with an infusion catheter extending
through the positive locking mechanism.
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