U.S. patent application number 10/514600 was filed with the patent office on 2005-11-03 for connector for catheter attachment to an implantable pump.
Invention is credited to Bright, Jeffrey D., Burke, Paul, Calder, Stephen D., Gailey, Robert N..
Application Number | 20050242579 10/514600 |
Document ID | / |
Family ID | 29778981 |
Filed Date | 2005-11-03 |
United States Patent
Application |
20050242579 |
Kind Code |
A1 |
Bright, Jeffrey D. ; et
al. |
November 3, 2005 |
Connector for catheter attachment to an implantable pump
Abstract
A catheter system for locking a catheter to an implantable pump
and for effectively flushing a catheter after implantation within a
body. A locking component comprises an extension boot and catheter
lock that together fluidly connect the catheter to the pump in a
secure, safe and effective manner. A catheter component comprises a
design having kink-resistant walls and a unique tip. A flushing
component comprises a hub and stylet combination characterized by a
hydrophilic coating on the stylet and a flush through hub to allow
flushing of the stylet while inside the catheter.
Inventors: |
Bright, Jeffrey D.; (Salt
Lake City, UT) ; Gailey, Robert N.; (Farmington,
UT) ; Calder, Stephen D.; (Farmington, UT) ;
Burke, Paul; (Bellingham, MA) |
Correspondence
Address: |
NIELDS & LEMACK
176 EAST MAIN STREET, SUITE 7
WESTBORO
MA
01581
US
|
Family ID: |
29778981 |
Appl. No.: |
10/514600 |
Filed: |
May 9, 2005 |
PCT Filed: |
June 26, 2003 |
PCT NO: |
PCT/US03/20600 |
Current U.S.
Class: |
285/256 |
Current CPC
Class: |
A61M 2039/1072 20130101;
F16L 47/12 20130101; A61M 2039/1044 20130101; A61M 39/12 20130101;
A61M 39/1011 20130101; F16L 33/30 20130101; A61M 5/14276 20130101;
A61M 39/0208 20130101; F16L 33/2071 20130101 |
Class at
Publication: |
285/256 |
International
Class: |
F16L 033/00; F16L
047/00; F16L 049/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 26, 2002 |
US |
10/180,708 |
Claims
We claim:
1. A connection device for attaching a catheter to an implantable
port or pump, wherein the catheter is in fluid communication with
said port or pump, comprising: a coupling device extending from
said port or pump, comprising an arm portion and a stem, wherein
the shape of the arm portion is substantially similar to an outer
contour of said port or pump, and wherein the stem comprises a base
portion and a tip portion; and a locking device slideable along a
length of the catheter, comprising varying diameter portions that
communicate directly with diameters of the base portion and tip
portion of the stem, wherein a locking connection is established
therebetween.
2. The connection device according to claim 1, wherein the base
portion of the stem comprises a body portion and an engaging
portion, wherein the engaging portion has a diameter that is
greater than a diameter of the body portion.
3. The connection device according to claim 2, wherein the diameter
of the body portion is constant.
4. The connection device according to claim 2, wherein the diameter
of the engaging portion tapers down to the diameter of the body
portion.
5. The connection device according to claim 1, wherein the tip
portion of the stem comprises a barbed end, having a diameter
larger than a lumen of the catheter.
6. The connection device according to claim 1, wherein an audible
confirmation is provided upon establishment of said locking
connection.
7. The connection device according to claim 1, wherein a tactile
confirmation is provided upon establishment of said locking
connection.
8. The connection device according to claim 1, wherein the arm
portion is comprised of a flexible material and is biased to a
resting position in close proximity to said port or pump, wherein
said arm portion is movable to a connecting position away from said
port or pump, and wherein said arm portion retracts to said resting
position upon release from said connecting position.
9. The connection device according to claim 1, wherein said stem
further comprises a rear portion.
10. The connection device according to claim 9, wherein said rear
portion comprises a barbed end.
11. The connection device according to claim 9, further comprising
a sleeve attached to said stem, covering said rear portion.
12. The connection device according to claim 11, further comprising
a collar positioned around said sleeve, said collar securing said
sleeve to said stem.
13. The connection device according to claim 12, wherein said
collar is positioned between said base portion and a barbed end of
said rear portion.
14. The connection device according to claim 1, wherein the stem is
comprised of titanium.
15. The connection device according to claim 1, wherein the stem is
comprised of stainless steel.
16. The connection device according to claim 1, wherein the locking
device is comprised of plastic.
17. The connection device according to claim 1, wherein the locking
device comprises a radiopaque portion.
18. The connection device according to claim 17, wherein the
radiopaque portion comprises a metal ring.
19. The connection device according to claim 17, wherein the
radiopaque portion comprises radiopaque ink.
20. A connection device for attaching a catheter to an implantable
port or pump, comprising: a coupling device extending from the
implantable port or pump, comprising an arm portion and a stem,
wherein the shape of the arm portion is substantially similar to an
outer contour of the implantable port or pump, and wherein the stem
comprises a base portion and a tip portion; and a locking device
slideable over the catheter, comprising varying diameter portions
that communicate directly with diameters of the base portion and
tip portion, wherein a locking connection is established
therebetween, wherein the base portion of the stem comprises a body
portion and an engaging portion, wherein the engaging portion has a
diameter that is greater than a diameter of the body portion, and
wherein the tip portion of the stem comprises a barbed end, having
a diameter larger than a lumen of the catheter.
21. The connection device according to claim 15, wherein the
locking device comprises a first diameter portion that is
approximately equivalent to the diameter of the barbed end.
22. The connection device according to claim 16, wherein the
locking device further comprises a second diameter portion adjacent
the first diameter portion that is approximately equivalent to the
diameter of the tip portion of the stem.
23. The connection device according to claim 17, wherein the
locking device further comprises a third diameter portion adjacent
the second diameter portion that is approximately equivalent to the
diameter of the body portion of the base portion.
24. The connection device according to claim 18, wherein the
locking device further comprises a fourth diameter portion adjacent
the third diameter portion that is approximately equivalent to the
largest diameter of the engaging portion.
25. The connection device according to claim 19, wherein the
locking device further comprises a fifth diameter portion adjacent
the fourth diameter portion, wherein the diameter of the fifth
diameter portion is less than the diameter of the fourth diameter
portion.
26. A locking device for securing a catheter to a stem of an
extension device, wherein the stem comprises a base portion and a
tip portion, the base portion comprising a body portion and an
engaging portion and the tip portion comprising a barbed end,
comprising: a first diameter portion that is approximately
equivalent to the diameter of said barbed end; a second diameter
portion adjacent the first diameter portion that is approximately
equivalent to the diameter of said tip portion; a third diameter
portion adjacent the second diameter portion that is approximately
equivalent to the diameter of said body portion; a fourth diameter
portion adjacent the third diameter portion that is approximately
equivalent to the largest diameter of the engaging portion; and a
fifth diameter portion adjacent the fourth diameter portion having
a diameter less than the diameter of the fourth diameter
portion.
27. A coupling device for attachment of an implantable port or pump
to a catheter, comprising: an arm portion having a proximal end
that is fixedly attached to said port or pump and a distal end,
said arm portion comprising a flexible material and shaped
substantially similar to an outer contour of said implantable port
or pump, said arm portion being biased to a resting position in
close proximity to said port or pump, wherein said arm portion is
movable to a connecting position away from said port or pump, and
wherein said arm portion retracts to said resting position upon
release from said connecting position; and a stem positioned at a
distal end of said arm portion.
28. The coupling device according to claim 27, wherein said stem
comprises a rear portion, a base portion and a tip portion, wherein
said rear portion is substantially covered by said arm portion.
29. The coupling device according to claim 28, further comprising a
sleeve attached to said stem, covering said rear portion.
30. The coupling device according to claim 29, further comprising a
collar positioned around said sleeve, said collar securing said
sleeve to said stem.
31. The coupling device according to claim 30, wherein said collar
is positioned between said base portion and a barbed end of said
rear portion.
32. The coupling device according to claim 29, wherein said arm
portion and said sleeve are comprised of silicone.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a catheter system and more
particularly to a catheter flushing and locking system for use with
an implantable pump.
BACKGROUND OF THE INVENTION
[0002] Use of implantable pumps for treating chronic pain
conditions has become widely accepted practice when more
conservative means of relieving pain have failed. Implantable pump
technology can be divided into two primary categories, namely
constant flow and programmable. Both technologies incorporate an
indwelling catheter to establish a fluid path from a pump disposed
subcutaneously to a desired anatomical site, including but not
limited to, arterial or venous locations, the epidural space and
the intrathecal space of the spine. Some of the reported
complications with implanted pumps deal with the connection between
the pump and the catheter, including leaks, disconnect and reduced
flow. Other reported complications involve the catheter itself,
which include but are not limited to, kinking, occlusion,
disconnect, malposition, migration and reduced flow. Thus, the
success of an implanted pump system is dependent in large part on a
successful and dependable connection between the pump and the
catheter as well as the design of the catheter and the introduction
techniques utilized.
[0003] Prior art implantable pumps employ relatively tedious and
often complicated means for attaching the catheter to the pump,
which also may promote problems for the entire pump and catheter
system. For example, screw driven clamping connections are both
complicated and unreliable as the required clamping action on the
outer diameter of an unsupported catheter increases the risk of
collapsing the inner lumen of the catheter. Stent based designs
that do utilize internal support solve the problem of internal
collapse, but require the additional step of attachment involving
multiple sutures around the connection area. The suturing process,
as well as the sutures themselves, can lead to broken or severed
catheters at the suture site where the suture cuts through the
catheter or surrounding support members. Also, variability in
suture tying and force applied by the user leads to variability in
attachment. Thus, a prior art approach to attaching the catheter to
the pump has been to utilize a barbed stem connector. The pump is
fit with a barbed or flared outer stem for the catheter to be
placed therearound. The problem with these designs, which are
common in subcutaneous access ports, is a connection that is
relatively unsecured and potential damage to the catheter caused by
the barbed section. Another related problem is that it is often
difficult to ascertain whether a positive connection between the
pump and catheter has been established. This can lead to catheter
and/or pump damage as undue force is placed on the attachment
system in order to get verification of the connection.
[0004] In addition to these drawbacks of the prior art systems, one
of the primary concerns to overcome in developing a successful and
reliable attachment system is that the catheters are generally very
small in diameter while the pumps to which they are connected are
relatively large. Thus, it is often physically difficult to make
the connection between the pump and the catheter.
[0005] Accordingly, it is an object of the present invention, in a
system involving an implantable pump and catheter, to provide a
catheter system for use with implantable pumps and other known
catheter-based systems that will maintain the effectiveness and
longevity of the connection and system following implantation
thereof.
[0006] It is also an object of the present invention to provide a
connection between the catheter and the pump which eliminates the
need for suturing around the catheter, avoids potential collapse of
the catheter or other attendant damage thereto.
[0007] It is a further object of the present invention to provide a
connection system for an implantable pump and catheter that
overcomes the difficulty arising from the size difference between
the catheter and pump.
[0008] It is yet a further object of the present invention to
provide a flexible interface between the catheter and pump body to
facilitate attachment of the catheter and minimize strains on the
connection.
[0009] It is still a further object of the present invention to
provide a connection system for an implantable pump and catheter,
which is very easy and quick to implement.
[0010] It is also an object of the present invention to provide a
connection system for an implantable pump and catheter that
confirms a secure connection.
[0011] It is another object of the present invention to provide a
connection system for an implantable pump and catheter that is
reliable and long-lasting.
[0012] It is yet another object of the present invention to provide
a catheter with minimal contained dead space at the tip to minimize
possible complications from static fluid in the system.
[0013] It is still another object of the present invention to
provide a stiffening stylet to facilitate positioning of the
catheter that is easy to remove and minimizes bunching and
displacement of the catheter tip during removal of the stylet.
[0014] Further objects and advantages of the present invention will
become apparent from the ensuing description and drawings.
BRIEF SUMMARY OF THE INVENTION
[0015] In accordance with the present invention, a catheter system
for locking a catheter to an implantable pump and for effectively
flushing a catheter after implantation within a body is provided. A
locking component comprises an extension boot and catheter lock
that together fluidly connect the catheter to the pump in a secure,
safe and effective manner. A catheter component comprises a design
having kink-resistant walls and a unique tip. A flushing component
comprises a hub and stylet combination characterized by a
hydrophilic coating on the stylet and a flush through hub to allow
flushing of the stylet while inside the catheter.
[0016] What is claimed is a connection device for attaching a
catheter to an implantable port or pump, wherein the catheter is in
fluid communication with said port or pump, comprising a coupling
device extending from said port or pump, comprising an arm portion
and a stem, wherein the shape of the aim portion is substantially
similar to an outer contour of said port or pump, and wherein the
stem comprises a base portion and a tip portion and a locking
device slideable along a length of the catheter, comprising varying
diameter portions that communicate directly with diameters of the
base portion and tip portion of the stem, wherein a locking
connection is established therebetween.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a perspective view of an implantable pump with
attached boot and stem according to the present invention.
[0018] FIG. 2 is a side view of the boot and stem according to the
present invention.
[0019] FIG. 3 is an enlarged view of the stem in FIG. 2.
[0020] FIG. 4 is a cross-sectional view of a stem according to the
present invention.
[0021] FIG. 5 is a cross-sectional view of a subassembly according
to the present invention, including the stem of FIG. 4.
[0022] FIG. 6 is a cross-sectional view of a boot according to the
present invention, including the subassembly of FIG. 5.
[0023] FIG. 7 is a longitudinal cross-sectional view of a catheter
lock according to the present invention.
[0024] FIG. 8 is an end view of the catheter lock in FIG. 4.
[0025] FIG. 9 is a side view of a catheter and flushing hub of the
present invention.
[0026] FIG. 10 is a side view of a hub and stylet of the present
invention.
[0027] FIG. 11 is perspective view of the hub, stylet and catheter
of FIGS. 6 and 7.
[0028] FIG. 12 is a cross-sectional view of the hub and stylet of
FIG. 7.
[0029] FIG. 13 is a cut away view of a distal end of a catheter of
the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0030] The following detailed description illustrates the invention
by way of example, not by way of limitation of the principles of
the invention. This description will clearly enable one skilled in
the art to make and use the invention, and describes several
embodiments, adaptations, variations, alternatives and uses of the
invention, including what we presently believe is the best mode of
carrying out the invention.
[0031] The present invention is directed to a novel attachment
device for securely connecting a catheter to a pump, which can be
used in a variety of applications to optimize efficiency and
effectiveness. The present invention is also directed to a unique
catheter configuration, along with means for introduction and
positioning thereof within the body, which offers several
advantages over prior art catheters and introducing systems and can
be used in various applications.
[0032] One example of a suitable pump for use with the present
invention can be seen in FIG. 1 as implantable pump 10. Implantable
pump 10 could be any medical device that is implanted
subcutaneously to deliver a steady stream of drugs or other fluids
to the body. Generally, the implanted medical device will contain a
septum through which an inner chamber to hold and dispense the drug
or fluid can be accessed via a needle. The medical device will also
have some type of mechanism to release the drug or fluid at
predetermined intervals or in a steady stream at a given flow rate.
This timed interval or flow rate can be regulated via mechanism
within the medical device or outside of the body using other known
means.
[0033] Examples of implantable medical devices that would be
suitable for use in conjunction with the present invention can be
found in U.S. application Ser. No. 09/481,298, filed Jan. 11, 2000,
entitled "Implantable refillable infusion device and septum
replacement kit" and in U.S. Pat. Nos. 6,287,293, entitled "Method
and apparatus for locating the injection point of an implanted
medical device;" 6,213,973, entitled "Vascular access port with
elongated septum;" 6,086,555, entitled "Dual reservoir vascular
access port with: two-piece housing and compound septum;"
5,833,654, entitled "Longitudinally aligned dual reservoir access
port;" 5,049,141, entitled "Programmable valve pump;" and
4,838,887, entitled "Programmable valve pump," all of which are
incorporated by reference herein.
[0034] The implantable pump 10 is shown in FIG. 1 with an inventive
boot 20 containing a stem 30 according to the present invention,
which is shown in more detail in FIGS. 2 and 3. The boot 20 has an
arm 24 that is curved to conform to the outside of the pump 10 so
that the overall profile thereof is minimized to facilitate
implantation and compatibility within the body. While the boot 20
is shown as curved to conform to the shape of the pump 10, in an
alternate embodiment a boot would take on any shape of the outer
contour of a port or pump to realize the advantages mentioned
above. The boot 20 attaches to the implantable pump 10 via
connector tube 22, which has a lumen 26 that fluidly connects the
inner chambers of the implantable pump 10 (not shown) with the stem
outlet 38. Of course, the boot 20 can be adapted further to connect
to various shapes and sizes of pumps other than implantable pump
10. For instance, in the case of a conventional port with a
straight stem, the boot 20 could be fashioned to replace the
straight stem to reduce port profile, or in the case of a dual port
system, the boot could likewise be fashioned to accommodate the
shape of the housing to reduce the overall space occupied by the
port or pump.
[0035] Among the many advantages of the conformal shape of the boot
are less tissue trauma and reduced force on the catheter and
catheter interface with the port or pump (i.e. a stem). Also, in a
preferred embodiment of the present invention, the boot is made of
a flexible material (such as silicone or a compliant polymer) so
that it can be pulled away from the port or pump to which it is
attached. This is important because in many applications, the
catheters are extremely small, meaning that a physician or medical
technician can often find it very difficult to push the catheter
onto a stem extending from the port or pump. By providing a
flexible boot, the physician or medical technician can pull the
boot away from the port or pump, thereby facilitating attachment of
the catheter to the stem. After the catheter is sufficiently
attached and the boot is released, it will snap back into place,
conforming once again to the shape of the port or pump.
[0036] In a preferred embodiment of the present invention, the stem
30 contains a base portion 32 and a tip portion 34 and is made of
titanium. As shown in more detail in FIG. 3, the base portion 32
includes a forward portion 36 and an engaging lock portion 33. The
engaging lock portion 33 is shown as a larger diameter in a wing
configuration near a connecting portion 35 that attaches to the arm
24 of the boot 20. The engaging lock portion 33 is configured to
communicate with the geometry of a locking mechanism (see FIG. 4)
to secure the catheter 120 to the boot 20. Of course, the engaging
lock portion 33 can take on various shapes and sizes and is not
confined to the embodiment shown Indeed, other types of engaging
devices could be employed that would certainly be within the scope
of the present invention, including twist locks, spring locks,
etc.
[0037] The tip 34 is configured to receive the catheter 120 such
that the lumen 122 of the catheter 120 fits over the tip 34 and is
expanded by a tip end 39. Depending on the size of the catheter
120, the size of the tip 34 can vary, but generally, the diameter
of a main body 37 of the tip 34 will be slightly larger than the
lumen of the catheter so that a tight friction fit between the two
is realized. In addition to the friction fit between the main body
37 of the tip 34 and the catheter 120, tip end 39 has a conical
shape with a base portion attached to the main body 37 to further
ensure a tight fit between the catheter 120 and the tip 34. The
diameter of the base portion of the tip end 39 is larger than the
diameter of the main body 37 to make disengagement difficult, but
not so large that undue stress and resultant damage occurs to the
catheter 120 as a result of compression to the wall thereof. The
tip end 39 can also take on different forms other than the conical
shape shown that will permit the catheter 120 to slide onto the
stem 34, while ensuring that sliding off of the stem is
unlikely.
[0038] In one embodiment of the present invention, a subassembly
comprising a sleeve and a collar is attached onto a rear of the
stem. FIG. 4 shows a stem 230 prior to attachment of a subassembly.
Stem 230 has a rear portion 240 with a barbed end 242 that extends
from a base portion 232. Stem 230 also contains a lumen
therethrough, having three different sections. The first and
largest diameter lumen section 222 is at barbed end 242, which is
connected to a second diameter lumen section 224 by transition
region 223, which in turn is connected to a third diameter lumen
section 226 by transition region 225. As is apparent from FIG. 4,
the lumen sections decrease in diameter from the first to the third
section. However, as should be appreciated, other possibilities
exist which would be equally within the scope of the present
invention (e.g., the sections increase in size, the sections remain
constant in size, or the sections have varying diameters).
[0039] FIG. 5 illustrates subassembly 250 in cross-section,
including the stem 230, a sleeve 260 and a collar 270. In this
embodiment, the sleeve 260 is made of silicone or like material,
while the collar 270 is made of stainless steel. Certainly,
however, other materials are possible and would be equally within
the scope of the present invention. The sleeve 260 has a length
262, which in one embodiment is in the range of approximately 0.5
in to 1.0 in. Of course, a length shorter than 0.5 in and longer
than 1.0 in would also be within the scope of the present
invention. The subassembly is constructed by sliding the sleeve 260
over the rear portion 240 of the stem 230 until a proximal end of
the sleeve 260 abuts a flange 234 of the base portion 232. The
collar 270 is then crimped into place around the sleeve 260 between
the barb 242 and the flange 234 to secure the sleeve 260 to the
stem 230. The length of the collar 270 in this embodiment should be
long enough to tightly secure the sleeve 260 to the stem 230 to
prevent relative movement, but short enough to lie in its crimped
state between the barb 242 and the flange 234. It should be
appreciated, however, that the length of the collar 270 can vary
depending on the application and materials involved. It should also
be appreciated that sleeve 260 could be secured to stem 230 in
other ways, such as through the use of adhesives, etc.
[0040] Referring to FIG. 6, a boot 280 is illustrated in
cross-section, including the subassembly 250. In this embodiment,
the subassembly 250 is overmolded to form the boot 280, using a
molding process as is well-known and understood in the art
(although other means of forming a boot around subassembly 250 are
also possible). While certainly many different materials are
possible for the boot 280, in this embodiment, the boot 280 is made
of silicone. It is important to note that by utilizing a silicone
or like material, a silicone to silicone bond is formed along a
majority of the overmolded segment, providing a superior mechanical
bond in which stem 230 is secured within boot 280. Such a
construction prevents the possibility of delamination of the stem
230 from the boot 280 and leaks associated therewith.
[0041] Referring now to FIGS. 7 and 8, a catheter lock 40 is shown.
FIG. 7 illustrates a longitudinal cross-sectional view of the
catheter lock 40, which in the preferred embodiment is made of a
hard shell construction (for example, polyacetal resin,
polycarbonate or polysulfones) to positively fit over the catheter
120 to secure in place and provide an audible and tactile lock and
to provide added security against inadvertent needle sticks. FIG. 8
shows an end view of the catheter lock 40 from the locking end
thereof, which is the end that engages with the base portion 32 of
the stem 30. Not shown in either view is an optional radiopaque
feature, which can be a metal ring, ink or other material on the
distal end of the catheter lock 40, providing easy visualization
under x-ray or fluoroscopy to verify lock engagement and position.
Of course, a radiopaque section could be added to many different
portions of the catheter lock 40 for accomplishing the same
objective. The catheter lock of the present invention provides an
easy, one-step connection mechanism to secure a catheter to an
extension of a port or pump, eliminating the need for cumbersome
suturing, which may cause damage to the catheter and/or the
connection. While a preferred embodiment of the catheter lock is
described herein, it should be appreciated that many configurations
are possible that would certainly be within the scope of the
present invention.
[0042] Referring again to FIGS. 7 and 8, the catheter lock 40 has
five distinct diameter portions each having a particular function
with respect to the locking of the catheter 120 to the stem 30. A
middle portion 42 of the catheter lock 40 contains the smallest
diameter d.sub.1, which is sized slightly larger than the outside
diameter of the catheter 120 so that the catheter lock 40 can slide
freely along the length thereof. A distal portion 44 of the
catheter lock 40 has a slightly larger diameter d.sub.2 to allow
the catheter 120 to move freely after the catheter lock 40 is
secured to the boot 20. The front portion of the catheter lock has
three diameter portions 46, 48 and 49, having respective diameters
d.sub.3 d.sub.4 and d.sub.5, designed to mate with the base portion
32 of the stem 30, and thereby providing a secondary tactile
locking mechanism as will be explained in more detail below. Also
positioned in the front portion of the catheter lock 40 are slits
50 positioned on opposite sides thereof to facilitate the movement
of the diameter portion 49 of the catheter lock 40 over the
engaging portion 33 of the stem 30 and the subsequent locking
action therebetween.
[0043] The advantage of the catheter boot and locking system as
described herein is the ease of connection in combination with the
difficult disengagement of the catheter after assembly is complete
(will not disengage at clinical loads/extensions). With reference
to FIGS. 3 and 7, a catheter connection in a preferred embodiment
will be described. After the catheter 120 has been established
within the body, for example having an end established in the spine
as described above, and is tunneled or otherwise delivered to the
location of the pump or port, the catheter connection thereto takes
place. As mentioned, the catheter lock 40 is configured to slide
freely along the catheter 120 and therefore can be threaded onto
the end of the catheter 120 quite easily just prior to connection
to the boot 20.
[0044] The lumen 122 of the catheter 120 is first slid onto the tip
portion 34 of the stem 30 until the catheter 120 is midway along
the section 37. The catheter lock 40 is then slid onto the stem 30
and pressed in a direction toward the boot 20 until an audible
clicking sound is heard and a positive connection is felt The slits
50 enable the catheter lock 40 to flex outward slightly when
pressed over the engaging portion 33 to facilitate the connection.
After connection has been established between the catheter lock 40
and the stem 30, the forward portion 36, having a diameter
substantially equal to d.sub.3 is within portion 46 and the
engaging portion 33, having its largest diameter substantially
equal to d.sub.4 is within portion 48. Because portion 49 has a
diameter d.sub.5 slightly smaller than that of the largest diameter
of the engaging portion 33, once a connection has been established,
the catheter lock cannot be pulled off of the stem 30. Portion 42,
having diameter d.sub.1, is superimposed over the catheter on
section 37 of the stem 30, preventing movement of the catheter
within the lock due to the compression applied thereon and
providing a primary obstacle for removal of the catheter 120 from
the stem 30. In addition, this arrangement acts to seal the
connection against fluid leakages between the various interfaces.
Portion 49 with diameter d.sub.5 provides a secondary obstacle by
preventing movement of the catheter lock in a direction away from
the boot
[0045] The inventive catheter lock can be used in conjunction with
various pumps and ports as mentioned, as well as with a host of
different catheters and catheter systems. Examples of intended uses
for the catheter system described herein is to deliver pain
medicating drug(s) to a patient at locations in the body including
the intrathecal space, the epidural space, arterial and venous
areas and directly into tissue. A preferred embodiment of the
catheter system of the present invention can be seen in FIGS.
9-13.
[0046] Referring to FIG. 9, a catheter system 110 has a flushing
hub 140 for flushing a catheter 120 during placement thereof in a
patient's body, including a main hub body 154. At a proximal end of
the flushing hub 140, an opening 158 provides access to an inner
lumen 152 (see FIG. 12). At a distal end of the flushing hub 140, a
cannula 156 extends therefrom and is in communication with the
inner lumen 152. The cannula 156 surrounds a stylet 160, which can
be seen in phantom within the catheter 120, and which is attached
to the main hub body 154. The relation between the stylet 160 and
the cannula 156 and main hub body 154 can be better seen in FIGS.
10 and 11.
[0047] FIG. 11 shows the flushing hub 140 and stylet 160 along the
length of the catheter 120. The flushing hub 140 allows catheter
flushing without removal of the stylet 160 as well as the
withdrawal of bodily fluid to confirm catheter location. The stylet
160 provides internal rigidity to the catheter 120 and allows for
maneuverability via torque transmission down the stylet 160 from
the proximal end of the catheter system 100 to facilitate precise
placement of the tip. In the preferred embodiment, the stylet 160
is coated with a hydrophillic coating for ease of removal from the
catheter 120. The coating reduces catheter bunching that can
compromise the physical properties of the catheter 120 by leading
to destructive forces on the catheter 120. The coating further
reduces traction internal to the catheter 120 during stylet
withdrawal and reduces the potential of tip and/or catheter
malposition.
[0048] The catheter 120 is closely fitted over the cannula 156 to
provide a continuous pathway from the inner lumen 152 of the
flushing hub 140 into the lumen 122 of the catheter 120, thereby
allowing for the flushing of fluid from the cannula 156 through the
lumen of the catheter 120 around the stylet 160 to wet the stylet
surface before exiting from the holes 126 at the distal end of the
catheter 120 (see FIG. 13).
[0049] FIG. 12 shows a cross-sectional view of the flushing hub
140. From this view, the inner lumen 152 of the main hub body 154
can be seen, with opening 158 at the proximal end thereof. In this
particular embodiment, the stylet 160 is shown affixed to the body
154 and extends through the inner lumen 152, leaving a channel 153
on either side of the stylet 160 for fluid flow. Of course, the
stylet 160 could be affixed in other locations not directly within
the center of the inner lumen 152 of the main hub body 154. Also,
the inner lumen 152 could be differently configured, depending on
the features desired in a given catheter system.
[0050] Turning now to FIG. 13, a cut-away view of a distal end of
the catheter 120 is shown In the preferred embodiment, catheter 120
has a lumen 122 and walls 124 made of high durometer silicone for
kink resistance and its beneficial properties with regard to
biocompatibility and biodurability, though other materials are
certainly possible that would similarly afford the advantages of
the preferred material, such as polyethylene and polyurethane. The
walls 124 in the preferred embodiment are relatively thick to
further the goal of kink resistance, together comprising
approximately half of the external diameter of the catheter (ie.,
if the catheter 120 had an outside diameter of nominally 0.055
inches, each wall 124 in cross-section would have a thickness of at
least 0.014 inches). At the distal end of the catheter 120, a tip
130 is rounded in the form of a bullet and made of a highly
radiopaque material to provide a dual advantage of a geometry that
is less traumatic to bodily tissues and anatomical structures and
an enhanced visibility, which facilitates location determination
during and after introduction to the patient's body. The radiopaque
material utilized for the tip 130 in a preferred embodiment is a
combination of cured liquid silicone and tungsten powder in
approximately 50% by weight of each component.
[0051] In the walls 124 of the catheter 120, a set of side holes
126 are provided to allow passage of fluid to and from the lumen
122. The side holes are drilled perpendicular to the surface
thereof to limit surface area anomolies that may result in tissue
trauma and/or catheter damage upon placement. A catheter segment
128 between the tip 130 and a side hole 126 is filled with similar
material as the tip 130 to form plug 132. This feature, combined
with the closed-ended geometry of the catheter 120 eliminates dead
space that can host proteinaceous material and the like, which, if
present within a catheter lumen, can propogate into an occlusion
thereof.
[0052] As mentioned, one application of the present invention is
for use along with an implantable pump to deliver medication to the
intrathecal space in a patient's spine. An indwelling catheter,
such as catheter 120, is utilized to establish a fluid path from a
subcutaneous pump through the dura membrane. The procedure
generally consists first of embedding the catheter in the spine (5
to 10 cm). A drop of the spinal fluid is then allowed to form at
the proximal end of the catheter 120 to confirm catheter location,
after which the catheter is clamped. A tunnel is formed from the
spine to the area of the abdomen, where the pump will be implanted,
and the catheter is pulled through and cut to length. The catheter
is then attached to the pump as described above through the use of
an inventive boot and catheter lock. The pump is placed in a
previously created pocket in the area of the abdomen and the pocket
is closed. Implantation of the described system is relatively quick
and easy and provides for prolonged delivery of drugs or medication
to the spine.
[0053] The present invention has been described above in terms of a
presently preferred embodiment so that an understanding of the
present invention can be conveyed However, there are many
alternative arrangements for a catheter system not specifically
described herein but with which the present invention is
applicable. For example, there are many different applications and
configurations for a catheter locking system that would be within
the scope of the present invention and similarly, there are many
applications for a catheter and flushing system other than those
specifically described. Although specific features have been given,
the catheter system for locking a catheter to an implantable pump
and for effectively flushing a catheter after implantation within a
body of the present invention would equally be embodied by other
configurations not specifically recited herein. The scope of the
present invention should therefore not be limited by the
embodiments illustrated, but rather it should be understood that
the present invention has wide applicability with respect to
catheter systems generally. All modifications, variations, or
equivalent elements and implementations that are within the scope
of the appended claims should therefore be considered within the
scope of the invention.
* * * * *