U.S. patent application number 17/583100 was filed with the patent office on 2022-05-12 for sleeve for delivery of embolic coil.
This patent application is currently assigned to ENDOSHAPE, INC.. The applicant listed for this patent is ENDOSHAPE, INC.. Invention is credited to Steve Choi, Gregory Edwin Mirigian, Jessi Watson.
Application Number | 20220142649 17/583100 |
Document ID | / |
Family ID | 1000006096415 |
Filed Date | 2022-05-12 |
United States Patent
Application |
20220142649 |
Kind Code |
A1 |
Choi; Steve ; et
al. |
May 12, 2022 |
SLEEVE FOR DELIVERY OF EMBOLIC COIL
Abstract
An endovascular treatment system includes a delivery sleeve that
is insertable into an intravascular catheter. A therapeutic device
is housed coaxially within the delivery sleeve and both are
advanced within the catheter in combination. An advancement
mechanism is connected to the therapeutic device to advance the
therapeutic device out of the delivery sleeve and into a patient.
The delivery sleeve includes a stop positioned on the proximal end.
The stop contacts the proximal end of the catheter, limiting the
distance the delivery sleeve is inserted into a catheter.
Inventors: |
Choi; Steve; (Lafayette,
CO) ; Watson; Jessi; (Denver, CO) ; Mirigian;
Gregory Edwin; (Dublin, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ENDOSHAPE, INC. |
Boulder |
CO |
US |
|
|
Assignee: |
ENDOSHAPE, INC.
Boulder
CO
|
Family ID: |
1000006096415 |
Appl. No.: |
17/583100 |
Filed: |
January 24, 2022 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16641988 |
Feb 25, 2020 |
11253266 |
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PCT/US2016/048715 |
Aug 25, 2016 |
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17583100 |
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62209736 |
Aug 25, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 17/12109 20130101;
A61B 2017/00845 20130101; A61B 2017/1205 20130101; A61B 2017/0023
20130101; A61B 17/1214 20130101; A61B 2017/12054 20130101; A61B
2017/00336 20130101 |
International
Class: |
A61B 17/12 20060101
A61B017/12 |
Claims
1. An endovascular apparatus comprising a delivery sleeve having a
longitudinal lumen extending between a proximal end and a distal
end; a therapeutic device housed within and extending substantially
an entire length of the delivery sleeve; wherein the therapeutic
device includes one or more detachable polymer endovascular
embolization coils; and a stop positioned on the proximal end of
the delivery sleeve which is operable to limit a distance the
delivery sleeve is inserted into a catheter; wherein an outside
diameter of the delivery sleeve is sufficiently small such that the
delivery sleeve is insertable into the catheter.
2. The endovascular apparatus of claim 1, further comprising an
advancement mechanism configured to engage the therapeutic device
to advance the therapeutic device into a patient.
3. The endovascular apparatus of claim 2, a diameter of the lumen
is sufficiently large such that the lumen is able to coaxially
receive the therapeutic device and the advancement mechanism
therein but sufficiently small that the delivery sleeve adds
longitudinal strength to the therapeutic device.
4. The endovascular apparatus of claim 3 further comprising: a
connection mechanism that connects the advancement mechanism to the
therapeutic device, wherein the connection mechanism is sized
relative to the delivery sleeve such that the connection mechanism
is compressed by the delivery sleeve and remains connected while in
the delivery sleeve, but once the connection mechanism exits the
delivery sleeve the compression, and thereby the connection, is
released; and wherein the therapeutic device is located coaxially
within the delivery sleeve; and the advancement mechanism is
connected to a proximal end of the therapeutic device.
5. The endovascular apparatus of claim 1, wherein both an inner
surface and an outer surface of the delivery sleeve are composed of
a material with a low coefficient of friction.
6. The endovascular apparatus of claim 1, wherein the therapeutic
device extends approximately to the distal end of the delivery
sleeve.
7. The endovascular apparatus of claim 1, wherein the stop is a
luer connection operable to engage an opposing luer connection on a
proximal end of the catheter.
8. An endovascular system comprising: a catheter having a proximal
catheter end and a distal catheter end with a longitudinal catheter
lumen extending therebetween; a delivery sleeve having a proximal
end and a distal end with a longitudinal lumen extending
therebetween, wherein the delivery sleeve is coaxial with and
movable within the catheter lumen; a therapeutic device located
coaxially within the lumen of the delivery sleeve and movable
therein; an advancement mechanism connected to the therapeutic
device and configured to advance the therapeutic device into a
patient; and a stop positioned on the proximal end of the delivery
sleeve which contacts the proximal catheter end, limiting the
distance the delivery sleeve is inserted into the catheter; and a
connection mechanism that connects the advancement mechanism to the
therapeutic device, wherein the connection mechanism is sized
relative to the delivery sleeve such that the connection mechanism
is compressed by the delivery sleeve and remains connected while in
the delivery sleeve, but once the connection mechanism exits the
delivery sleeve the compression, and thereby the connection, is
released.
9. The endovascular system of claim 8, wherein the therapeutic
device extends substantially an entire length of the delivery
sleeve.
10. The endovascular system of claim 8, wherein the delivery sleeve
is made of polytetrafluoroethylene.
11. The endovascular system of claim 8 further comprising: a
catheter extender having a proximal extender end and a distal
extender end with a longitudinal extender lumen extending
therebetween, wherein the distal extender end is attached to the
proximal catheter end, and wherein the delivery sleeve is longer
than the catheter.
12. The endovascular system of claim 11, wherein the catheter
extender has a length that is approximately a difference in length
between an entire length of the delivery sleeve and an entire
length of the catheter, so that when the proximal end of the
delivery sleeve is connected to the proximal extender end, the
delivery sleeve and the catheter are generally coextensive to the
distal catheter end.
13. The endovascular system of claim 8, wherein the therapeutic
device is a detachable endovascular embolization coil formed of a
polymer.
14. The endovascular system of claim 8, wherein the therapeutic
device is located coaxially within the delivery sleeve; and the
advancement mechanism is connected to a proximal end of the
therapeutic device.
15. The endovascular system of claim 8, wherein: the advancement
mechanism is further connected to a distal end of the therapeutic
device; and the therapeutic device extends approximately to the
distal end of the delivery sleeve.
16. A method for delivering a therapeutic treatment to a patient
comprising: providing a catheter having a proximal catheter end and
a distal catheter end with a longitudinal catheter lumen extending
therebetween; providing a therapeutic delivery device apparatus
comprising: a delivery sleeve having a proximal end and a distal
end with a longitudinal lumen extending therebetween, wherein the
delivery sleeve is coaxial and longitudinally movable within the
catheter lumen; a therapeutic device enclosed coaxially within the
lumen of the delivery sleeve and longitudinally movable therein; an
advancement mechanism connected to the therapeutic device and
configured to advance the therapeutic delivery device into a
patient; a stop positioned on the proximal end of the delivery
sleeve which contacts the proximal catheter end of the catheter,
limiting a distance the delivery sleeve is inserted into the
catheter; inserting the therapeutic delivery device into the
catheter until the stop comes into contact with the proximal
catheter end; and wherein the therapeutic delivery device is a
detachable polymer endovascular embolization coil.
17. The method of claim 16, wherein the therapeutic device extends
substantially an entire length of the delivery sleeve.
18. The method of claim 16 further comprising attaching a catheter
extender to the catheter in response to the delivery sleeve being
longer than the catheter, wherein the catheter extender includes a
proximal extender end and a distal extender end with a longitudinal
extender lumen extending therebetween which is attached to the
proximal catheter end via the distal extender end.
19. The method of claim 18 further comprising: determining a
difference in length between an entire length of the delivery
sleeve and an entire length of the catheter; and selecting the
catheter extender such that a length of the catheter extender is
approximately equal to the difference in length so that in response
to the proximal end of the delivery sleeve being connected to the
proximal extender end, the delivery sleeve and the catheter are
generally coextensive to the distal catheter end.
20. The method of claim 16, wherein, in the method, the therapeutic
delivery device further comprises a connection mechanism; and the
method further comprises: connecting the advancement mechanism to
the therapeutic device; compressing the connection mechanism within
the delivery sleeve such that the connection mechanism remains
connected while in the delivery sleeve; releasing the connection
mechanism from the delivery sleeve once the connection mechanism
exits the delivery sleeve; pushing the therapeutic device out the
end of the delivery sleeve until the compression of the delivery
sleeve on the connection mechanism is released and the therapeutic
device disconnects from the advancement mechanism; and withdrawing
the delivery sleeve from the catheter and repeating the process
with a second therapeutic delivery device.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of priority of U.S.
provisional application No. 62/209,736 filed 25 Aug. 2015 entitled
"Sleeve for delivery of embolic coil," which is hereby incorporated
herein by reference in its entirety for the purposes of PCT Rules
4.18 and 20.6.
TECHNICAL FIELD
[0002] The disclosure herein relates generally to medical devices
used with intravascular catheters. More particularly, it relates to
a sleeve that contains embolic devices for delivery through the
catheters.
BACKGROUND
[0003] Intravascular catheters are common medical devices that are
manufactured by numerous companies. The various companies provide
catheters that have different physical performance attributes that
physicians find attractive for the purposes of accessing a targeted
vessel in the highly tortuous/varied vascular anatomy of each
patient. The various catheters are provided in numerous length
options and are provided with numerous pre-curved tip shapes and
mechanical structure (e.g., bending stiffness/softness and
"torqueability" to orient the tip shape remotely). Additionally,
catheters are provided with variations in their internal lumen in
both diameter size and surface material. In some medical
procedures, the vascular catheter is routinely used to deliver
embolic devices such as endovascular embolization coils to a
particular target location in the vasculature to conduct vascular
occlusions or embolizations to stop the blood flow in a vessel or
isolate a vascular area from blood flow.
[0004] The various differences in physical attributes of the
catheters, for example, relative roughness or friction coefficient
of the material forming the interior surface, impacts the potential
compatibility of using certain catheters with different
manufacturers' embolic devices. For example, Boston Scientific
contraindicates the use of its Interlock embolic coil products with
any polyurethane, soft-tip catheter, for example, Terumo Glide
catheters or AngioDynamics Soft-Vu catheters. These limitations
detrimentally impact the ability of the embolic coil manufacturer
to gain clinical use of their coil when the physician wants to use
one of these catheters due to the feature benefits of the catheter
in accessing the target vessel. In some instances, the physician
may be forced to "exchange" one catheter for another over the
guidewire to achieve a compatible catheter for deployment of the
embolic device, which is a costly and inefficient method.
[0005] With current technology, embolic devices (such as coils) use
an introducer tube to advance the coil into the catheter. The
function of the introducer tube is to hold the device straight
(i.e., in an uncoiled form) outside of the catheter and facilitate
"introducing" the device into the catheter. In this structure, the
embilic device is fed directly into the catheter, necessitating
compatibility between the embolic device and the catheter, e.g.,
compatibility between outer diameter of the embolic device and
inner diameter and surface of the catheter lumen and material
compatibility between the material forming the embolic device and
the catheter material to ensure smooth advancement of the embolic
device through the catheter lumen. Thus, cost is increased and
physician alternatives are reduced.
[0006] Clinicians utilize various imaging modalities such as
fluoroscopy to direct the embolic device to the end of the catheter
and into the targeted area for treatment. However, this reliance on
the imaging modalities while the embolic device travels through the
catheter requires additional cost and time, which results in
heightened risk to the patient. As such, these risks and costs
represent the insufficiency of typical solutions and room for
improvements in the industry.
[0007] The information included in this Background section of the
specification, including any references cited herein and any
description or discussion thereof, is included for technical
reference purposes only and is not to be regarded subject matter by
which the scope of the invention is to be bound.
SUMMARY
[0008] In order to address the shortcomings of the status quo, the
following disclosure presents device that may be used in
conjunction with catheters to aid in the delivery of a therapeutic
device, e.g., one or more embolic coils, through a catheter which
might otherwise be contraindicated for such delivery due to an
incompatibility as discussed above. The device may take the form of
a sleeve made, in part, of a material having a low coefficient of
friction in which the device is housed or otherwise retained until
delivery. The sleeve may provide a more appropriate environment for
delivery of the therapeutic device than the lumen of the catheter.
For example, the delivery sleeve may provide a lower friction
interface with the therapeutic device allowing the therapeutic
device to easily slide as it is pushed through the sleeve to the
end of the deliver catheter instead of possibly getting caught on
or damaged by the wall of the delivery catheter. The delivery
sleeve may further provide structural support, radial compressive
or resistive force along the length of the therapeutic device,
thereby providing longitudinal strength and support to the therapy
device such that it can be advanced along the catheter 60 without
bucking, kinking, or crushing.
[0009] In one implementation, an endovascular apparatus includes a
delivery sleeve, a therapeutic device, an advancement mechanism,
and a stop. The delivery sleeve has a longitudinal lumen extending
between a proximal end and a distal end. The therapeutic device may
be housed within and extend substantially an entire length of the
delivery sleeve. The advancement mechanism may be configured to
engage the therapy device to advance the therapy device into a
patient. A stop may be positioned on the proximal end of the
delivery sleeve and is operable to limit a distance the delivery
sleeve is inserted into a catheter. An outside diameter of the
delivery sleeve is sufficiently small such that the delivery sleeve
may be inserted into a catheter and a diameter of the lumen is
sufficiently large such that the lumen is able to coaxially receive
the therapeutic device and the advancement mechanism therein but
sufficiently small that the delivery sleeve adds longitudinal
strength to the therapeutic device.
[0010] In another implementation, an endovascular system includes a
catheter, a delivery sleeve, a therapy device, an advancement
mechanism, and a stop. The catheter may have a proximal catheter
end and a distal catheter end with a longitudinal catheter lumen
extending therebetween. The delivery sleeve may have a proximal end
and a distal end with a longitudinal lumen extending therebetween.
The delivery sleeve may be coaxial with and movable within the
catheter lumen. The therapeutic device may extend substantially an
entire length of the delivery sleeve, or even slightly beyond the
distal length, and may be located coaxially within the lumen of the
delivery sleeve and movable therein. The advancement mechanism may
be connected to the therapy device and configured to advance the
therapy device into a patient. The stop may be positioned on the
proximal end of the delivery sleeve which contacts the proximal end
of the catheter to limit the distance the delivery sleeve is
inserted into a catheter. The stop may be part of a deployment
handle that controls advancing the therapy device into a
patient.
[0011] In a further implementation, a method for delivering a
therapeutic treatment to a patient is disclosed. A catheter may be
provided having a proximal catheter end and a distal catheter end
with a longitudinal catheter lumen extending therebetween. A
therapeutic delivery device apparatus may be provided including a
delivery sleeve, a therapeutic device, an advancement mechanism,
and a stop. The delivery sleeve may have a proximal end and a
distal end with a longitudinal lumen extending therebetween. The
delivery sleeve may be coaxial with and longitudinally movable
within the catheter lumen. The therapeutic device may extend
substantially an entire length of the delivery sleeve, or even
slightly beyond the distal end, and may be enclosed coaxially
within the lumen of the delivery sleeve and longitudinally movable
therein. The advancement mechanism may be connected to the
therapeutic device and configured to advance the therapy delivery
device into a patient. The stop may be positioned on the proximal
end of the delivery sleeve which contacts the proximal catheter end
of the catheter, limiting a distance the delivery sleeve is
inserted into the catheter. The method may further include
inserting the therapeutic delivery device into the catheter until
the stop comes into contact with the proximal end of the
catheter.
[0012] This Summary is provided to introduce a selection of
concepts in a simplified form that are further described below in
the Detailed Description. This Summary is not intended to identify
key features or essential features of the claimed subject matter,
nor is it intended to be used to limit the scope of the claimed
subject matter. A more extensive presentation of features, details,
utilities, and advantages of the present invention as defined in
the claims is provided in the following written description of
various embodiments and implementations and illustrated in the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 illustrates an exploded view of an endovascular
system in accordance with various embodiments.
[0014] FIG. 2A illustrates a perspective view of an endovascular
system in accordance with various embodiments.
[0015] FIG. 2B illustrates a detailed cross-section view of the
endovascular system of FIG. 2A taken along section 2B-2B.
[0016] FIG. 3A illustrates a perspective view of a delivery sleeve
with a therapeutic device positioned therein in accordance with
various embodiments.
[0017] FIG. 3B illustrates a detailed cross-section view of the
endovascular system of FIG. 3A taken along section 3B-3B.
[0018] FIG. 4A illustrates an exploded view of an endovascular
system with a plurality of parallel embolic coils in accordance
with various embodiments.
[0019] FIG. 4B illustrates a perspective view of an endovascular
system with a plurality of parallel embolic coils in accordance
with various embodiments.
[0020] FIG. 4C illustrates a detailed cross-section view of the
endovascular system of FIG. 4B taken along section 4C-4C.
[0021] FIG. 5 illustrates a flow chart of a method of using an
endovascular system in accordance with various embodiments.
DETAILED DESCRIPTION
[0022] Various embodiments related to systems and methods for
treating patients via intravascular catheters are disclosed herein.
However, in contrast to traditional catheter configurations, a
temporary, disposable sleeve may be used to separate the catheter
from the particular therapy device being delivered through the
catheter. The sleeve may minimize the effects of the inner lumen
characteristics of different catheter materials, geometries, and
construction on devices or instruments passed through the catheter
to provide the desired therapy. The sleeve may reduce variability
between different catheter designs and provide a stable, regular
lumen of known physical and performance characteristics. This may
enable development of therapeutic products without the limitation
and complexity of having to design for use with all catheters and
minimizes the limitations of indicating (or contra-indicating)
specific catheters for use. Such devices or instruments may include
embolic devices and, in particular, examples may be embolic coils
for administering a vascular embolization or occlusion.
[0023] The sleeve may be formed from a flexible tube made up of a
bio-compatible material or constructed of multiple layers of
biocompatible materials. The sleeve may have a thin-wall, flexible
structure formed of a material operable to slide easily through the
lumen of a catheter. The sleeve may have a construction, such as
including a wire or fiber braid, that provides mechanical support
such as radial or longitudinal rigidity, or both. Similarly, a
lumen of the sleeve may be formed of a material that allows a
therapeutic device to slide easily along the length of the sleeve.
The therapeutic device is loaded into the sleeve ex-vivo, for
example, by the manufacturer of the therapeutic device at the time
of manufacture. The sleeve may function to hold the therapeutic
device in a state for delivery through the catheter, e.g., in a
restrained state, that changes to an unrestrained state upon
delivery from the sleeve and the catheter in vivo. For example, the
sleeve may contain an embolic coil in a stretched, linear form
while within the sleeve, which converts to a coil shape upon
delivery from the sleeve and catheter. The sleeve with the
therapeutic device housed therein may be inserted into and line the
inner wall of the catheter. The therapeutic device may then be
delivered through a lumen extending along the longitudinal length
of the sleeve.
[0024] As shown in the exploded view of FIG. 1, an exemplary
endovascular system 10 may include a therapy delivery device 20 and
a catheter 60. The therapy delivery device 20 may include a therapy
device 30. The therapy device 30 may be connected to an advancement
device 40 via a connection mechanism 37. The therapy device 30 may
be insertable and movably positioned within a delivery sleeve 50.
The therapy delivery device 20 may be movably positioned within the
catheter 60. The delivery sleeve 50 may be connected to the
catheter 60. The endovascular system 10 may include an extension 70
that is positioned on a proximal end of the catheter 60 to
accommodate a delivery sleeve 50 that is longer in length than the
catheter 60.
[0025] The catheter 60 may be any type of intravascular catheter
known in the industry suitable to be placed in the body of a
patient. For example, the catheter 60 may include a single lumen 66
(see FIG. 2B) or the catheter 60 might include multiple lumens (not
shown). The catheter 60 may be operable to follow a tortuous path
to reach a target site. The catheter 60 may have a first distal end
63 with respect to the user. The distal end 63 may include an
outlet 64 operable to deliver the therapy device 30 near the target
therapy site within the patient. The catheter 60 may have a
proximal end 61 with respect to the user. The proximal end 61 may
include an attachment mechanism 62. The attachment mechanism 62 may
be in the form of a luer fitting operable to connect with other
medical devices.
[0026] As indicated above, the therapy delivery device 20 may
include the therapy device 30 and a delivery sleeve 50. The
delivery sleeve 50 is a component that may be used in conjunction
with the therapy device 30. The delivery sleeve 50 may include a
single lumen 56 (see FIG. 3B) extending between a distal end 53 and
a proximal end 51. The delivery sleeve 50 may be sufficiently
flexible to follow the lumen 66 of the catheter 60. The distal end
53 of the delivery sleeve 50 may include an outlet 54 configured to
be positioned near the distal end 63 of the catheter 60 adjacent to
the target therapy site and allow the therapy device 30 to exit
both the outlet 54 of the delivery sleeve 50 and the outlet 64 of
the catheter 60 proximal to the target therapy site within the
patient.
[0027] The proximal end 51 of the delivery sleeve 50 may include a
stop 52 that is positioned to limit the travel of the delivery
sleeve 50 into the lumen 66 of the catheter 60. In some
embodiments, the stop 52 may be an attachment mechanism suitable to
connect to the proximal end 61 of the catheter 60. In one example,
the attachment mechanism of the stop 52 may be a luer fitting
operable to connect with the luer fitting attachment mechanism 62
on the catheter 60 or operable to connect to other medical devices.
As shown in FIG. 2A, the therapy delivery device 20 may be
positioned within the catheter 60 (the advancement device and the
sleeve cap are the portions of the delivery device 20 shown in FIG.
2A.) The positioning may be coaxial. In this configuration, the
delivery sleeve 50 may extend through the lumen 66 of the catheter
60.
[0028] The delivery sleeve 50 may be made of a flexible,
low-friction material suitable to glide easily through the lumen 66
of the catheter 60. The low-friction material may be, for example,
a bio-compatible material such as a polytetrafluoroethylene (PTFE)
material formed as a tube defining the lumen 56. The material is
not limited to PTFE, but may include any other bio-compatible
materials with sufficient lubricity such as other flouropolymers or
modified polymers having a lubrication agent or lubricating
coatings. For the purposes of this disclosure, materials with a low
coefficient of friction suitable for forming, lining, or coating
the lumen of the delivery sleeve 50 may have a coefficient of
friction .ltoreq.0.1. In various embodiments, the material provides
a lubricious surface on both the outside and inside of the delivery
sleeve 50. The outside surface of the delivery sleeve 50 interacts
with the interior lumen 66 of the catheter 60 during deployment of
the delivery sleeve 50. The inside surface defining the lumen 56 of
the delivery sleeve 50 interacts with the exterior of the therapy
device 30. In one exemplary embodiment, the delivery sleeve 50 may
be an unreinforced, natural, single-wall PTFE tube. In another
exemplary embodiment, the delivery sleeve 50 may be a reinforced,
composite structure incorporating a PTFE inner lumen, a stainless
steel wire braid, and a polyimide outer jacket.
[0029] In some exemplary embodiments, the inner and outer surfaces
of the delivery device 50 may be made of different material to
optimize the interaction with the opposing surface (catheter 60 or
therapy device 30). The thickness of the wall of the delivery
sleeve 50 may be from about 0.001 to about 0.01 inches (about 0.025
mm to about 0.25 mm) thick. More particularly, the wall of the
delivery sleeve 50 may be about 0.002 inches (about 0.05 mm) thick.
The wall of the delivery sleeve 50 may be sufficiently fluid tight
to allow fluid flushing through the length of the delivery sleeve
50. The material forming the delivery sleeve 50 may be made kink
resistant, including by reinforcing the tubing utilizing coils,
braids, spirals, fibers, or composite materials such as
co-polymers. Other materials may be used as reinforcement of the
wall of the delivery sleeve 50 as well including metallic ones.
While the delivery sleeve 50 is sufficient flexible for
endovascular travel, it is also sufficiently strong such that is
can be advanced through the catheter 60 as a column.
[0030] The delivery sleeve 50 may be manufactured in a number of
diameters depending on the vascular application. In one example,
the delivery sleeve 50 may have about a 0.04 inch (about 1.02 mm)
outside diameter and about a 0.036 inch (about 0.91 mm) inside
diameter resulting in a wall thickness of about 0.002 inch (0.0508
mm). Such sizes may provide suitable compatibility with 4 French to
5 French catheter applications. In various other examples, the
sleeve may include about 0.035-0.038 inch (about 0.09 mm-0.1 mm)
inside diameters and/or 0.039-0.042 inch (about 0.1 mm-0.11 mm)
outside diameters. While these various examples may be used, it may
be preferable to size the delivery sleeve 35 according to the
preferred catheter/therapy device combination.
[0031] The inside diameter of the delivery sleeve 50 may also be
sized to add longitudinal compressive strength to the therapy
device 30 such that it can be advanced along the catheter 60 easier
without kinking or crushing. The delivery sleeve 50 may provide a
homogeneous and consistent surface for delivery of the therapy
device 30 through the catheter. In contrast, the inner surface of
the catheter varies from catheter to catheter and manufacturer to
manufacturer.
[0032] As noted above, the therapy delivery device 20 may include
an advancement mechanism 40 that connects to the therapy device 30
to push the therapy device 30 through the lumen 56 of the delivery
sleeve 50. The therapy device 30 may be coupled with the
advancement mechanism 40 by a connection system 37. The connection
system 37 may comprise any of a number of known systems with
opposing features 32, 42 that interconnect a therapy device 30 to
an advancement mechanism 40 (e.g., an embolic coil device to a
pusher wire). The internal diameter of the lumen 56 of the delivery
sleeve 50 may be sized to assist in maintaining engagement between
the opposing features 32, 42 of the connection system 37 by
providing a consistent cross-sectional area within and along the
lumen 56 of the delivery sleeve 50. The diameter of the lumen 56 of
the delivery sleeve 50 may thus be optimized to maintain sufficient
pressure on the connection system 37 to limit premature release.
The delivery sleeve 50 thus provides an advantage, which is not
provided by the various catheters on the market.
[0033] The delivery sleeve 50 may extend through the catheter lumen
66 until the stop 52 engages with the proximal end 61 of the
catheter 60. This engagement may be configured to position the
distal end 51 of the delivery sleeve 50 at a desired location
within the catheter 60. For example, in some embodiments, the
delivery sleeve 50 may have a length that extends approximately to
the distal end 63 of the catheter 60 when the stop 52 engages the
proximal end 61 of the catheter 60. As shown in FIG. 2B, the distal
end 53 of the delivery sleeve 50 may extend approximately the same
distance as the distal end 63 of the catheter 60. Any difference in
length may be nominal such as caused by a difference in tolerances
of the two devices or use of catheter or therapeutic device
accessories.
[0034] The distal end 33 of the therapy device 30 may likewise
extend to the distal end 53 of the delivery sleeve 50. Preferably,
the distal end 33 of the therapy device 30 is adjacent and proximal
to the distal end 53 of the delivery sleeve 50, which extends to a
point immediately proximal to the distal end 63 of the catheter 60.
In some exemplary embodiments, the length of the therapy device 30
may be coextensive with the length of the delivery sleeve 50. In
various exemplary embodiments, the stop 52, which limits the
distance that the distal end 53 of the delivery sleeve 50 extends
within the catheter 60, may be a female luer fitting 5. The stop 52
may removably connect to the attachment mechanism 62, which may be
a male luer fitting. The distal end 53 of the delivery sleeve 50
may extend from the stop 52 approximately to the distal end 63 of
the catheter 60. By sizing the delivery sleeve 50 in accordance
with the catheter 60 such that the distal ends 53, 63 extend to
approximately the same length, the delivery sleeve 50 may be
inserted into the catheter 60 and extended to the distal end 63
without the use of an imaging modality such as fluoroscopy to
determine its location. For example, a 100 cm delivery sleeve
length would be designed for use with a 100 cm catheter length,
enabling the precise placement of the distal end 53 of the delivery
sleeve 50 without need for using an imaging modality.
[0035] In accordance with another exemplary embodiment, the
delivery sleeve 50 may be longer than the catheter 60. In such an
embodiment, the precise placement of the distal end 53 of the
delivery sleeve 50 relative to the distal end 63 of the catheter
may still be accomplished by pairing the delivery sleeve 50 with an
extender 70. If a user desired to use a catheter 60 that is shorter
than the length of the delivery sleeve 50, when the stop 52 on the
delivery sleeve 50 abuts the attachment mechanism 62 on the
proximal end 61 of the catheter 60, the distal end 53 of the
delivery sleeve 50 would extend outward beyond the distal end 63 of
the catheter 60 and into the patient. Such a situation could
increase the procedural risk of damaging a vessel, thereby harming
the patient and require that the clinician use fluoroscopy to
navigate the distal end 53 of the delivery sleeve 50 through the
length of the catheter 60 to ensure that it does not enter into the
vessel, thus increasing the time needed to perform the
procedure.
[0036] However, it is possible for the longer delivery sleeve 50 to
be used with a desired shorter catheter by using the extender 70.
The extender 70 may include a distal end 73 with respect to the
user and a proximal end 71 with respect to the user. Each end of
the extender 70 may have an attachment mechanism 72, 74 such as a
luer fitting. In various embodiments the attachment mechanism 72 at
the proximal end 71 may be a male luer as shown and the attachment
mechanism 74 at the distal end 73 may be a female luer fitting
(although each end may use ether type of fitting, male or female as
long as the opposing fitting mates). The extender 70 defines a
lumen extending between the proximal end 71 and the distal end 73
that is sized similarly or the same as the lumen 66 of the catheter
60. The extender 70 may have a length that is about equal to the
length that the delivery sleeve 50 extends beyond the catheter 60
in response to the delivery sleeve stop 52 (e.g., a luer fitting)
engaging the proximal end 61 of the catheter 60.
[0037] It should be appreciated that when using the extender 70,
the delivery sleeve stop 52 does not directly engage the proximal
end 61 of the catheter 60. Instead, the delivery sleeve stop 52 may
engage the proximal end 71 of the extender 70. For example, the
stop 52 in the form of a luer fitting may engage the attachment
mechanism 72 (e.g., and opposing luer fitting) with the delivery
sleeve 50 extending through the extender 70 lumen. The distal end
73 of the extender 70 may then be connected to the proximal end 61
of the catheter 60. The distal attachment mechanism 74 of the
extender 70 may connect to the attachment mechanism 62 at the
proximal end 61 of the catheter 60.
[0038] For example, if the user desires to use a shorter catheter
60 (e.g., a 65 cm catheter) with a longer delivery sleeve 50 (e.g.,
a 100 cm delivery sleeve), then the delivery sleeve 50 will be too
long for the catheter 60 without increasing the aforementioned
risks. However, by connecting an extender 70 sized to the
difference between the catheter length and the delivery sleeve
length, the extender 70 takes up the additional length required by
the shorter catheter 60 and the longer delivery sleeve 50. Pursuant
to this example, the 65 cm catheter can be connected to a 35 cm
extender 70, which in combination form a 100 cm delivery device for
the delivery sleeve 50 (i.e., 35 cm+65 cm=100 cm). Thus, the
extender-catheter combination has a length about the same as the
delivery sleeve 50. In this way, the delivery sleeve 50 may be
inserted into the extender 70 and further through the attached
catheter 60 until the proximal end 61 of the delivery sleeve
connects to the proximal end 71 of the extender and the distal end
53 of the delivery sleeve 50 will be located approximately at the
distal end 64 of the catheter 60. The location of the distal end 53
of the delivery sleeve 50, and thus the distal end 33 of the
therapeutic device 30 contained therein, is positioned adjacent the
distal end 63 of the catheter 60 without need for fluoroscopy or
other imaging to guide the therapeutic device 30 to that point.
[0039] In accordance with various embodiments, multiple different
lengths of extenders 70 may be provided with the therapy delivery
device 20 to allow compatibility with different length catheters
60. For example, for a 100 cm length delivery sleeve, a 35 cm
length extender can be used for 65 cm length catheter
compatibility. Alternatively, for a 100 cm length delivery sleeve,
a 55 cm length extender can be used for 45 cm length catheter
compatibility. Other lengths of extenders 70 can be provided to
create similar combinations of extenders 70 and catheters 60 to
accommodate the desired use of catheters 60 of various lengths with
desired lengths of therapeutic devices 30 housed in delivery
sleeves 50.
[0040] The extender 70 may be made of a low-friction tubing. The
low-friction tube may be formed, for example, of a
polytetrafluoroethylene (PTFE) material in the tube structure
forming the lumen. The tube may be securely attached to attachment
mechanisms 72, 74 at either or both ends. As indicated above, the
attachment mechanisms 72, 74 may be luer fittings. However, any
suitable connection mechanism, particularly medically suitable
mechanisms, may be used. The tubing may be reinforced for better
kink-resistance. The extender 70 may have an inside diameter
slightly larger than the outside diameter of the delivery sleeve 50
to allow for easy insertion of the delivery sleeve 50 therethrough.
The extender 70 may have a wall thickness anywhere from 0. 01 mm to
0.10'' mm. This diameter and wall thickness may be the same as or
larger than the wall thickness of catheter 60 since the extender 70
does not enter the catheter lumen 66. While the extender 70 may be
specifically configured to maximize its accommodation of the
delivery sleeve 50, the extender 70 may also or alternatively be
configured to accommodate specific catheters that a physician may
use. In this way, the extender 70 may be formed to match the
diameter and structure of the catheter 60 it is used with so there
is conformity of parts. Thus, the extender 70 not only provides
compatibility with multiple catheter lengths, but also facilitates
all procedural, performance, and safety advantages of the delivery
sleeve 50.
[0041] As indicated above, the therapy delivery device 20 may
include the delivery sleeve 50 and a therapeutic device 30. The
therapeutic device 30 may include any of a variety of endovascular
medical devices. The therapeutic device 30 may be preloaded into
the lumen 56 of the delivery sleeve 50 during manufacturing or
before the catheterization procedure. In this way, the physician
can remove the combination of the delivery sleeve 50 preloaded with
the therapeutic device 30 from its packaging and insert the
delivery sleeve 50 and therapeutic device 30 combination into the
catheter 60 together. The combination may then be advanced along
the catheter 60 together until the delivery sleeve 50 hits its stop
52.
[0042] Having a delivery sleeve 50 of known length commensurate
with the length of the catheter 60 can minimize procedure time by
reducing or eliminating fluoroscopic or other angiographic
requirements until the therapeutic device 30 is deployed from the
outlet 64 of the catheter 60. The delivery sleeve 50, and the
therapeutic device 30 positioned therein, can be positioned quickly
and accurately because the physician does not need to monitor where
the distal end of either the delivery sleeve 50 or the therapeutic
device 30 is located until the stop 52 on the delivery sleeve 50
engages the proximal end 61 of the catheter 60. From that point,
fluoroscopy (or like technique) may be used to advance only the
therapeutic device 30 to the target region.
[0043] While the therapeutic device 30 may be any endovascular
medical device, as illustrated in FIGS. 1-5, the therapeutic device
30 may be an embolic device configured to form vascular occlusions
within a patient. More specifically, the embolic device may be an
embolic coil. In accordance with the various embodiments described
herein, one or more embolic coils may be delivered through the
catheter 60 by advancing the embolic coil(s) (shown in FIGS. 1-5 as
therapeutic device 30) and delivery sleeve 50 combination into the
catheter 60 until the stop 52 on the delivery sleeve 50 engages the
proximal end 61 of the catheter 60. This process positions the
embolic coil 30 for deployment into the patient. The embolic coil
30 may extend within the lumen 56 of the delivery sleeve 50 in a
restrained form as a linear shape and then take on a complex shape
as originally formed after being deployed into the area of
interest, such as an aneurysm.
[0044] The advancement mechanism 40 may be configured to advance
the embolic coil 30 via a variety of different ways. The
advancement mechanism 40 does not need to rely on a structural
interlock. For example, the advancement mechanism 40 may function
as an injection device thereby injecting the coil out of the
sleeve. In other embodiments, a more structural interface may be
incorporated. For example, as shown in FIG. 3B, a connection
mechanism 37 may be provided between the embolic coil 30 and the
advancement mechanism 40 (shown as a pusher wire). Any connector
configuration or coupling mechanism may be used. In the exemplary
embodiment of FIG. 3B, the proximal end 31 of the embolic coil 30
may include a receiving feature 32 (such as a recess, slot,
aperture, or the like) and is operable to engage a linking feature
42 (such as a protrusion, hook, clasp, or the like) positioned at
the distal end of the advancement mechanism 40 used. The receiving
feature 32 and the linking feature 42 may be positioned on
overlapping tabs that extend from the therapeutic device 30 and the
advancement mechanism 40, respectively. The tabs may overlap such
that the connection mechanism 37 is not larger than the outside
diameters of each of the therapy device 30 and the advancement
mechanism 40. To release the therapeutic device 30 from the
advancement mechanism 40, the advancement mechanism 40 merely
extends the connection mechanism 37 out of the delivery sleeve 50.
With the external pressure from the sleeve 50 removed, there is
insufficient force to hold the connection mechanism 37 together and
the therapeutic device 50 is released from the advancement
mechanism 40. As shown in FIG. 2A, the advancement mechanism 40 may
be longer than and extend out of the proximal end of the lumen 56
of the delivery sleeve 50.
[0045] Ordinarily, using prior art devices and techniques for
placement of embolic coils, to complete an occlusion procedure, the
physician must sequentially reload the catheter with several
additional coils through an introducer that abuts the proximal end
of the catheter until it is determined the occlusion is sufficient.
This procedure is traditionally performed using typical medical
imaging techniques to monitor the position of the embolic coils
along the entire length of the catheter. However, by prepackaging
one or more embolic coils 30 within a delivery sleeve 50 of known
length, the delivery sleeve 50 may be advanced down the catheter 60
until the stop 52 at the proximal end 51 of the delivery sleeve 50
engages the proximal end 61 of the catheter 60 without need for
imaging. Further, if additional embolic coils are needed beyond the
embolic coil(s) 30 deployed from the initial delivery sleeve 50,
the initial delivery sleeve 50 may be removed from the catheter 60
and a new delivery sleeve 50 with additional embolic coils 30 may
be inserted into and advanced down the catheter 60 without need for
angiography. This procedure makes the transition between additional
embolic coils much quicker, cheaper, and safer.
[0046] There are many known variations of embolic coils, including
many different types of metallic and polymer coils. Various coils
are made from different materials and are designed with different
means of controlling various characteristics such as enhancing
thrombogenic response. Coils may be formed as a singular coil or
the coils may comprise multiple coil devices packaged together and
stored inside the sleeve together. By way of Example, FIGS. 4A-4C
illustrate an endovascular system with a plurality of parallel
embolic coils in accordance with various embodiments. FIG. 4A shows
the endovascular system 10 in an exploded view. Similar to other
embodiments discussed herein, this endovascular system 10 may
include an advancement mechanism 40 and the therapeutic device 30.
This therapeutic device 30 in such an embodiment includes a
plurality of embolic coils. The plurality of embolic coils can be
inserted into the delivery sleeve 50, which in turn is insertable
into and through the catheter 60. The plurality of embolic coils
can then be delivered from the distal end 64 of the catheter as
illustrated in FIG. 4B. As illustrated in the detailed cross
section of FIG. 4C, the plurality of coils forming the therapeutic
device remains organized within the delivery sleeve 50 until
dispensed from the end.
[0047] In accordance with various embodiments, as illustrated in
FIG. 4C the plurality of coils may include separate coils 30a, 30b,
30c, and 30d. As illustrated in FIGS. 4A-4C, the coils may be bound
on each end by retaining feature 15a, 15b. The advancement
mechanism may include one or more separate members. For example, as
shown in FIGS. 4A-4C, an inner advancement member 40b may extend
the distal retaining feature 15b. An outer advancement member 40a
may extend the proximal retaining feature 15a. Each of the separate
coils 30a, 30b, 30c, and 30d, the proximal advancement feature 15a,
the distal advancement feature 15b, inner advancement member 40b
and outer advancement member 40a may all be contained within the
delivery sleeve 50. The outer and inner advancement members 40a,
40b and related proximal and distal retaining features 15a, 15b may
be configured as any of the types of pusher systems providing both
proximal and distal control of delivery of the therapeutic device
30 as disclosed and described in U.S. Patent Application
Publication No. US20140039542A1, which is hereby incorporated by
reference herein in its entirety. Further, such pusher systems with
proximal and distal control can be used to deliver a therapeutic
device 30 such as an embolic coil composed of only a single length
of coil within the delivery sleeve 50 rather than a plurality of
separate coils delivered in parallel as depicted in this
example.
[0048] The various embodiments and examples disclosed herein may be
used with any of the known embolic coils and coils of similar
purpose. Each and every therapeutic device, however, will not be
discussed herein, but exemplary processes, devices, embodiments are
known, and examples of some of these devices include embolic coils
that may be used with embodiments of the delivery sleeve disclosed
herein, which are described in U.S. Patent Application Publication
No. 2012/0046687, U.S. Patent Application Publication No.
US20130085518A1, Patent Cooperation Treaty international
application Publication No. WO/2013/109784, and Patent Cooperation
Treaty international application Publication No. WO/2014/160320.
Each of these publications is hereby incorporated by reference in
its entirety. Each of the various types of embolic devices
described therein may be used with the delivery sleeve disclosed
herein.
[0049] For the purpose of further description herein, examples will
be directed to detachable embolic coils, i.e., embolic coils that
can be advanced or retracted by an advancement mechanism (e.g., a
pusher wire) until the embolic coil exits the catheter. In some
exemplary implementations, a number of embolic coils may be
attached to each other end to end within the delivery sleeve 50
with the proximal end of the proximal embolic coil attached to the
pusher wire. More particularly detachable polymer coils (DPC) are
discussed herein as an example of the therapeutic device 30, but,
as indicated, this is not limiting as a person of ordinary skill in
the art may apply the concepts provided herein to other types of
coils in addition to those incorporated by reference.
[0050] In accordance with various embodiments, the therapeutic
device 30 may be a single, long detachable polymer coil (DPC) or a
series of shorter DPCs attached to each other within the delivery
sleeve 50. The DPC may have a lubricious surface to aid in travel
through the tighter fit of the delivery sleeve 50 as opposed to
traveling through the much larger catheter lumen 66.
[0051] In one exemplary implementation, the proximal end 31 of the
embolic coil 30 may have a connection mechanism 32 and the distal
end 33 may be configured to engage the targeted treatment area to
begin creating the occlusion structure. The embolic coil 30 may
have a length commensurate with the length of the sleeve 50. To
provide more material at the treatment area, longer coil lengths
may be desirable (e.g., longer than 100 cm). To accommodate this,
longer delivery sleeve lengths may be used such that the entire
length of the embolic coil 30 along with the connection mechanism
37 and a portion of the advancement mechanism 40 is contained
within the lumen 56 of the delivery sleeve 50.
[0052] As indicated above, appropriate lengths of extenders 70 can
also be incorporated into the system so that embolic coil lengths
can be increased. Longer embolic coils 30 may be retained within
commensurately longer sleeves 50. However, physicians are still
able to use desired catheters 60 of shorter lengths by using
extenders 70 of appropriate lengths in conjunction with the shorter
catheters 60. For example, if a 200 cm DPC coil is desired,
accordingly it would be provided in a 200 cm length delivery sleeve
50. If the longest catheter length used will be 100 cm, then the
luer attachment mechanism 62 of the catheter 60 would be around the
midpoint length of the delivery sleeve 50 (i.e., at about 100 cm).
This delivery sleeve 50 configuration would be undesirable with the
100 cm catheter length, but with an extender of 100 cm the system
would be modified to thereby match the sleeve 50 length of 200 cm
with the combination length of catheter 60 at 100 cm and the
extension tube at 100 cm. Alternatively, if the user wanted to use
a 65 cm catheter length, then a longer extender 70 of 135 cm would
need to be attached to the delivery sleeve 50 to provide
compatibility with the shorter catheter. The delivery sleeve length
is preferably as long as (or longer than) the longest coil 30. When
these factors are known, then the appropriate extension tube
lengths can be calculated and provided.
[0053] The endovascular system 10 may include accessories operable
to provide additional therapeutic benefits to the patient. For
example, the endovascular system 10 may include medical device
accessories that allow sending a flushing fluid or liquid therapy
treatment (e.g., saline or medication) through the catheter in
conjunction with the therapy device 40. Such flushing devices could
include dual port luer access attachment mechanisms. The delivery
sleeve 50 may also be configured for use with a flushing system.
For example, the wall of the delivery sleeve 50 may be perforated
to allow flushing solution to pass through the delivery sleeve 50
such that fluid may be introduced into the delivery sleeve 50 but
also reach and flush the catheter 60. It may be noted, that the
addition of a medical device accessory like the dual port luer
access may cause a length change to the catheter or sleeve. The
difference in length may be considered minimal as discussed above
or the difference length could be significant warranting the use of
the extender 70 discussed above.
[0054] In accordance with the various embodiments discussed herein,
the delivery sleeve 50 may improve the treatment of a patient
because the user can advance the delivery sleeve 50 into the
catheter lumen 66 without using fluoroscopy, as the length of the
delivery sleeve 50 may be sized relative to the length of the
catheter. Additionally, the delivery sleeve 50 may be secured to
the catheter 60, increasing the stability of the system with the
delivery sleeve 50 positioned inside the catheter 60, particularly
during advancement of the therapy device 30, such as situations in
which the therapy device 30 is an embolic coil system. Also, by
connecting the delivery sleeve 50 to the catheter 60, continuous
flush can be maintained through both the delivery sleeve 50 and the
catheter 60, reducing delivery friction of the therapy device 30
within the delivery sleeve 50 and catheter 60.
[0055] FIG. 5 illustrates a flow chart of a method of using an
endovascular system in accordance with various embodiments
disclosed herein. A method for delivering a therapeutic treatment
to a patient may include providing a catheter having a proximal
catheter end and a distal catheter end with a longitudinal catheter
lumen extending therebetween (1000). The catheter may be positioned
proximal to the target treatment area within the patient (1100). An
endovascular therapeutic apparatus having a delivery sleeve, a
therapy device, and an advancement device may be provided (1200).
The delivery sleeve may have a proximal end and a distal end with a
longitudinal lumen extending therebetween. The delivery sleeve may
be positioned to be coaxial and movable within the catheter lumen.
The therapy device may be located coaxially within the lumen of the
delivery sleeve and movable therein. The advancement device may be
connected to the therapy device to advance the therapy delivery
device through the delivery sleeve into the patient. If the
delivery sleeve is longer than the catheter, a catheter extender
may be positioned on the proximal end of the catheter (1500). The
catheter extender may have a proximal extender end and a distal
extender end with a longitudinal extender lumen extending
therebetween. The catheter extender may be attached to the proximal
catheter end at the distal extender end. The catheter extender may
have a length that is approximately equal to the difference in
length between the delivery sleeve and the catheter length. When
the proximal end of the delivery sleeve is connected to the
proximal extender end, the delivery sleeve and the catheter are
generally coextensive to the catheter distal end.
[0056] The delivery sleeve may include a stop positioned on the
proximal end. The stop may be positioned to limit the distance the
delivery sleeve is inserted into the catheter. The endovascular
therapeutic apparatus may be inserted into the catheter until the
stop comes into contact with the proximal end of the catheter
(1400). The method may include extending the therapy device out the
distal end of the delivery sleeve and further out distal end of the
catheter (1500).
[0057] The therapy device may be an endovascular embolization coil.
The endovascular embolization coil may be detachable coil. The
detachable coil may be a polymer coil. The advancement mechanism
may be connected to the detachable coil with a connection mechanism
that is sized to be compressed or restrained by the delivery
sleeve. The detachable coil may remain connected to the advancement
mechanism within the delivery sleeve, but once it exits the
delivery sleeve, the compression, and thereby the connection, may
be released. The detachable coil may be pushed out of the end of
the delivery sleeve until the detachable coil disconnects from the
advancement mechanism (1600). The delivery sleeve may be withdrawn
from the catheter (1700). The process may be repeated by inserting
a second endovascular therapeutic apparatus into the catheter
(1800).
[0058] All directional references (e.g., proximal, distal, upper,
lower, upward, downward, left, right, lateral, front, back, top,
bottom, above, below, vertical, horizontal, clockwise, and
counterclockwise) are only used for identification purposes to aid
the reader's understanding of the present invention, and do not
create limitations, particularly as to the position, orientation,
or use of the invention as claimed. Connection references (e.g.,
attached, coupled, connected, and joined) are to be construed
broadly and may include intermediate members between a collection
of elements and relative movement between elements unless otherwise
indicated. As such, connection references do not necessarily infer
that two elements are directly connected or are in fixed relation
to each other. The exemplary drawings are for purposes of
illustration only and the dimensions, positions, order, and
relative sizes reflected in the drawings attached hereto may
vary.
[0059] The above specification, examples, and data provide a
complete description of the structure and use of exemplary
embodiments of the invention as claimed. Although various
embodiments of the invention as claimed have been described above
with a certain degree of particularity, or with reference to one or
more individual embodiments, those skilled in the art could make
numerous alterations to the disclosed embodiments without departing
from the spirit or scope of the invention as claimed. Other
embodiments are therefore contemplated. It is intended that all
matter contained in the above description and shown in the
accompanying drawings shall be interpreted as illustrative only of
particular embodiments and not limiting. Changes in detail or
structure may be made without departing from the basic elements of
the invention as defined in the following claims.
* * * * *