U.S. patent application number 17/147124 was filed with the patent office on 2021-05-06 for tracheal stent.
This patent application is currently assigned to BOSTON SCIENTIFIC SCIMED, INC.. The applicant listed for this patent is BOSTON SCIENTIFIC SCIMED, INC.. Invention is credited to Sean P. Fleury, Gary J. Leanna, Seamus F. O'Shaughnessy, Dane T. Seddon, Jason Weiner.
Application Number | 20210128329 17/147124 |
Document ID | / |
Family ID | 1000005331757 |
Filed Date | 2021-05-06 |
United States Patent
Application |
20210128329 |
Kind Code |
A1 |
Leanna; Gary J. ; et
al. |
May 6, 2021 |
TRACHEAL STENT
Abstract
Tracheal stents may include a plurality of wave form structures
each extending radially about the support structure, a plurality of
axial loop members extending axially between adjacent wave form
structures and a polymeric covering disposed thereover. Tracheal
stents may include an expandable metal structure and a plurality of
spacer fins extending above an outer surface of the expandable
metal structure. The plurality of spacer fins may be formed of a
material different than that of the expandable metal structure.
Inventors: |
Leanna; Gary J.; (Holden,
MA) ; Seddon; Dane T.; (Boston, MA) ; Weiner;
Jason; (Grafton, MA) ; O'Shaughnessy; Seamus F.;
(Chelmsford, MA) ; Fleury; Sean P.; (Brighton,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
BOSTON SCIENTIFIC SCIMED, INC. |
Maple Grove |
MN |
US |
|
|
Assignee: |
BOSTON SCIENTIFIC SCIMED,
INC.
Maple Grove
MN
|
Family ID: |
1000005331757 |
Appl. No.: |
17/147124 |
Filed: |
January 12, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
16268659 |
Feb 6, 2019 |
10898354 |
|
|
17147124 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2210/0004 20130101;
A61F 2002/91558 20130101; A61F 2/04 20130101; A61F 2/07 20130101;
A61F 2002/91583 20130101; A61F 2210/0014 20130101; A61F 2002/91575
20130101; A61F 2/89 20130101; A61F 2002/043 20130101; A61F 2/844
20130101; A61F 2002/91566 20130101; A61F 2220/0008 20130101; A61F
2002/046 20130101; A61F 2/915 20130101 |
International
Class: |
A61F 2/89 20060101
A61F002/89; A61F 2/04 20060101 A61F002/04; A61F 2/07 20060101
A61F002/07; A61F 2/844 20060101 A61F002/844; A61F 2/915 20060101
A61F002/915 |
Claims
1. A medical stent extending from a first end to a second end, the
medical stent comprising: an expandable metal structure extending
from the first end to the second end, the expandable metal
structure convertible between a compressed configuration for
delivery and an expanded configuration once deployed, the
expandable metal structure including an inner surface defining a
stent lumen and an outer surface; and a plurality of spacer fins
extending above the outer surface of the expandable metal
structure; wherein the plurality of spacer fins are formed of a
material different than that of the expandable metal structure.
2. The medical stent of claim 1, wherein the plurality of spacer
fins are formed of a biodegradable or bioabsorbable material.
3. The medical stent of claim 2, wherein the plurality of spacer
fins include a therapeutic agent.
4. The medical stent of claim 1, further comprising a polymer
coating disposed over the expandable metal structure.
5. The medical stent of claim 4, wherein a base of each of the
plurality of spacer fins is encapsulated within the polymer coating
and an apex of each spacer fin is exposed radially above the
polymer coating.
6. The medical stent of claim 4, wherein the plurality of spacer
fins are separately formed with each having an end, and the ends of
the plurality of spacer fins are encapsulated in the polymer
coating.
7. The medical stent of claim 1, wherein the plurality of spacer
fins comprise a cap secured to high spots formed within the
expandable metal structure.
8. The medical stent of claim 7, wherein the cap is biodegradable
or bioresorbable.
9. The medical stent of claim 7, wherein the expandable metal
structure is formed from a plurality of struts, wherein each high
spot is an apex of a stent strut.
10. The medical stent of claim 1, wherein the plurality of spacer
fins are aligned parallel to a longitudinal axis of the expandable
metal structure.
11. The medical stent of claim 1, wherein the plurality of spacer
fins are formed from a filament that is interlaced within the
expandable metal structure.
12. The medical stent of claim 11, wherein the expandable metal
structure is cut from a metal tube and the plurality of spacer fins
are formed from the filament extending in and out of apertures in
the expandable metal structure, wherein the filament forms high
spots protruding radially outward from the metal tube.
13. The medical stent of claim 11, wherein the filament is
biodegradable or bioresorbable.
14. A medical stent extending from a first end to a second end, the
medical stent comprising: an expandable metal structure extending
from the first end to the second end, the expandable metal
structure convertible between a compressed configuration for
delivery and an expanded configuration once deployed, the
expandable metal structure including an inner surface defining a
stent lumen and an outer surface, wherein the expandable metal
structure is formed from a plurality of struts; and a plurality of
high spots extending above the outer surface of the expandable
metal structure, each high spot formed at an apex of a strut; a
plurality of caps secured to the plurality of high spots, the
plurality of caps forming spacer fins, wherein the caps are formed
of a material different than that of the expandable metal
structure.
15. The medical stent of claim 14, wherein the caps are
biodegradable or bioresorbable.
16. The medical stent of claim 14, further comprising a polymer
coating disposed over the expandable metal structure.
17. The medical stent of claim 16, wherein a base of each of the
plurality of spacer fins is encapsulated within the polymer coating
and an apex of each spacer fin is exposed radially above the
polymer coating.
18. The medical stent of claim 14, wherein the plurality of spacer
fins are aligned parallel to a longitudinal axis of the expandable
metal structure.
19. The medical stent of claim 11, wherein the expandable metal
structure is cut from a metal tube and the plurality of spacer fins
are formed from a filament extending in and out of apertures in the
expandable metal structure, wherein the filament forms the high
spots protruding radially outward from the metal tube.
20. A medical stent extending from a first end to a second end, the
medical stent comprising: an expandable metal structure extending
from the first end to the second end, the expandable metal
structure convertible between a compressed configuration for
delivery and an expanded configuration once deployed, the
expandable metal structure including an inner surface defining a
stent lumen and an outer surface; a plurality of spacer fins
extending above the outer surface of the expandable metal
structure; and a polymer coating disposed over the expandable metal
structure; wherein the plurality of spacer fins are formed of a
material different than that of the expandable metal structure;
wherein a base of each of the plurality of spacer fins is
encapsulated within the polymer coating and an apex of each spacer
fin is exposed radially above the polymer coating.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 16/268,659, filed Feb. 6, 2019, which is a continuation of U.S.
application Ser. No. 14/932,407, filed Nov. 4, 2015, which claims
priority under 35 U.S.C. .sctn. 119 to U.S. Provisional Application
Ser. No. 62/076,181, filed Nov. 6, 2014, the entirety of which is
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure pertains to medical devices, and
methods for manufacturing medical devices. More particularly, the
present disclosure pertains to endoprostheses such as tracheal
stents.
BACKGROUND
[0003] An endoprosthesis may be configured to be positioned in a
body lumen for a variety of medical applications. For example, an
endoprosthesis may be used to treat a stenosis in a blood vessel,
used to maintain a fluid opening or pathway in the vascular,
urinary, biliary, tracheobronchial, esophageal or renal tracts, or
to position a device such as an artificial valve or filter within a
body lumen, in some instances. Bare or partially covered
endoprostheses allow tissue ingrowth through the structure of the
endoprosthesis to prevent migration of the endoprosthesis. However,
if it is desired to remove the endoprosthesis at some later time,
the ingrown tissue must be cut away, causing significant trauma to
the body lumen. Fully covered stents, on the other hand, prevent
tissue ingrowth to facilitate removal. However, fully covered
endoprostheses are prone to migrate through the body lumen.
[0004] Accordingly, it is desirable to provide endoprostheses that
exhibit anti-migration features, while reducing the trauma to the
body lumen of the patient if removal of the endoprosthesis is
desired.
BRIEF SUMMARY
[0005] The disclosure is directed to several alternative designs,
materials and methods of manufacturing medical device structures
and assemblies, and uses thereof.
[0006] In one example, a medical stent, such as a tracheal stent,
extends from a first end to a second end and includes a support
structure extending from the first end to the second end. The
support structure includes a plurality of wave form structures each
extending circumferentially about the support structure and a
plurality of axial loop members extending axially between adjacent
wave form structures and a polymeric covering disposed over the
support structure. At least some of the plurality of axial loop
members are configured to include an extended configuration in
which the at least some of the plurality of axial loop members
extend radially outward from an outer surface defined by the
plurality of wave form structures.
[0007] Alternatively, or additionally, at least some of the wave
form structures extend circumferentially about 360 degrees about
the support structure and form closed rings.
[0008] Alternatively, or additionally, at least some of the wave
form structures include a nickel-titanium alloy.
[0009] Alternatively, or additionally, at least some of the wave
form structures are formed from nitinol wire.
[0010] Alternatively, or additionally, at least some of the wave
structures are defined by a wire diameter that is in the range of
about 0.2 millimeters (mm) to about 0.5 mm. Alternatively, or
additionally, at least some of the wave form structures are defined
by a wave frequency in the range of about 0.5 to about 4 waves per
centimeter (cm) and a wave amplitude in the range of about 0.25 cm
to about 1 cm.
[0011] Alternatively, or additionally, at least some of the
plurality of axial loop members extend from a peak, a valley or a
transition region of a wave form structure of the plurality of wave
form structures to a peak, a valley or a transition region of an
adjacent wave form structure of the plurality of wave form
structures.
[0012] Alternatively, or additionally, the plurality of axial loop
members provide the only direct connection between adjacent wave
form structures of the plurality of wave form structures.
[0013] In another example, a support structure for an
endoprosthesis has a first end, a second end and a lumen extending
therebetween. The support structure includes a first wave form
structure extending circumferentially about the support structure
and defining a first closed ring, the first wave form structure
formed of a first wire oscillating in a wave form having a first
wave frequency and a first wave amplitude. The support structure
includes a second wave form structure extending circumferentially
about the support structure and defining a second closed ring, the
second wave form structure formed of a second wire oscillating in a
wave form having a second wave frequency and a second wave
amplitude. An axial loop member extends from the first wave form
structure to the second wave form structure and provides a
connection between the first wave form structure and the second
wave form structure and is configured to include an extended
configuration in which the axial loop member extends radially
outward from an outer surface defined by the first and second wave
form structures.
[0014] Alternatively, or additionally, the first wave form
structure and the second wave form structure are formed from
nitinol wire.
[0015] Alternatively, or additionally, at least some of the wave
structures are defined by a wire diameter that is in the range of
about 0.2 mm to about 0.5 mm.
[0016] Alternatively, or additionally, at least some of the wave
form structures are defined by a wave frequency in the range of
about 0.5 to about 4 waves per cm and a wave amplitude in the range
of about 0.25 cm to about 1 cm.
[0017] Alternatively, or additionally, in another example, the
axial loop member extends from a peak, a valley or a transition
region of the first wave form structure to a peak, a valley or a
transition region of the second wave form structure.
[0018] In another example, a method of forming a support structure
for an endoprosthesis having a first end, a second end and a lumen
extending therebetween includes forming a first wave form structure
from a first wire, the first wave form structure undulating side to
side while extending circumferentially around to form a first
closed ring. A second wave form structure is formed from a second
wire, the second wave form structure undulating side to side while
extending circumferentially around to form a second closed ring. An
axial loop member having a first end and a second end is secured,
the first end secured to the first wave form structure and the
second end secured to the second wave form structure.
[0019] Alternatively, or additionally, the first wave form
structure is formed on a mandrel.
[0020] Alternatively, or additionally, the second wave form
structure is formed on a mandrel.
[0021] Alternatively, or additionally, the method further includes
forming a plurality of additional wave form structures from a
plurality of wires, each of the plurality of additional wave form
structures undulating side to side while extending
circumferentially around to form a plurality of additional closed
rings.
[0022] Alternatively, or additionally, the method further includes
securing a plurality of axial loop members between adjacent wave
form structures of the plurality of additional wave form
structures.
[0023] Alternatively, or additionally, the first wire and the
second wire include a nitinol wire.
[0024] Alternatively, or additionally, the first end of the axial
loop member is secured to the first wave form structure via
welding.
[0025] In another example, a medical stent, such as a tracheal
stent, extending from a distal end to a proximal end includes an
expandable metal structure extending from the distal end to the
proximal end, the expandable metal structure convertible between a
compressed configuration for delivery and an expanded configuration
once deployed, the expandable metal structure including an inner
surface defining a stent lumen and an outer surface. A plurality of
spacer fins extends above the outer surface of the expandable metal
structure and are formed of a material different than that of the
expandable metal structure.
[0026] Alternatively, or additionally, the plurality of spacer fins
are formed of a biodegradable or bioabsorbable material.
[0027] Alternatively, or additionally, the plurality of spacer fins
are formed from a filament that is interlaced within the expandable
metal structure.
[0028] Alternatively, or additionally, the plurality of spacer fins
are separately formed each having an end, and the ends of the
plurality of spacer fins are encapsulated in a polymeric coating
that is disposed over the expandable metal structure.
[0029] Alternatively, or additionally, the plurality of spacer fins
include a cap secured to high spots formed within the expandable
metal structure.
[0030] Alternatively, or additionally, at least some of the
plurality of spacer fins are triangular in shape, with a base
secured relative to the expandable metal structure and an apex
extending above the base.
[0031] Alternatively, or additionally, the expandable metal
structure comprises a laser cut expandable metal structure.
[0032] Alternatively, or additionally, the expandable metal
structure includes a woven or braided expandable metal
structure.
[0033] In another example, a medical stent, such as a tracheal
stent, extending from a distal end to a proximal end includes an
expandable metal structure extending from the distal end to the
proximal end, the expandable metal structure convertible between a
compressed configuration for delivery and an expanded configuration
once deployed, the expandable metal structure including an inner
surface defining a stent lumen and an outer surface. A
biodegradable filament is interwoven through the expandable metal
structure to form a plurality of biodegradable spacer fins
extending above the outer surface of the expandable metal
structure.
[0034] Alternatively, or additionally, the expandable metal
structure includes a laser cut expandable metal structure.
[0035] Alternatively, or additionally, the expandable metal
structure includes a woven or braided expandable metal
structure.
[0036] Alternatively, or additionally, the biodegradable filament
includes square or round shaped protruding caps.
[0037] Alternatively, or additionally, the biodegradable filament
has a diameter in the range of about 0.1 cm to about 1 cm.
[0038] Alternatively, or additionally, at least some of the
plurality of spacer fins are triangular in shape.
[0039] In another example, a medical stent, such as a tracheal
stent, extending from a distal end to a proximal end includes an
expandable metal structure extending from the distal end to the
proximal end, the expandable metal structure convertible between a
compressed configuration for delivery and an expanded configuration
once deployed, the expandable metal structure including an inner
surface defining a stent lumen and an outer surface. A polymeric
coating is disposed over the expandable metal structure and a
plurality of biodegradable spacer fins are secured relative to the
polymeric coating, the plurality of biodegradable spacer fins
extending above the outer surface of the expandable metal
structure.
[0040] Alternatively, or additionally, at least some of the
plurality of spacer fins are triangular in shape, with a base
secured relative to the expandable metal structure and an apex
extending above the base.
[0041] Alternatively, or additionally, the plurality of
biodegradable spacer fins are separately formed each having an end,
and the ends of the plurality of biodegradable spacer fins are
encapsulated in the polymeric coating.
[0042] Alternatively, or additionally, the plurality of
biodegradable spacer fins are formed of a biodegradable material
comprising poly-l-lactide acid (PLLA) and/or
poly(lactide-co-Glycoside 8515) (PLGA 8515).
[0043] Alternatively, or additionally, the plurality of
biodegradable spacer fins have an average height, relative to the
outer surface of the expandable metal structure, ranging from about
0.1 cm to about 0.5 cm.
[0044] Alternatively, or additionally, the polymeric coating
includes silicone.
[0045] The above summary of some embodiments is not intended to
describe each disclosed embodiment or every implementation of the
present disclosure. The Figures, and Detailed Description, which
follow, more particularly exemplify these embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] The disclosure may be further understood in consideration of
the following detailed description in connection with the
accompanying drawings, in which:
[0047] FIG. 1 is a schematic illustration of a patient, showing a
trachea stent disposed within the patient's right main bronchus in
accordance with an embodiment of the disclosure;
[0048] FIG. 2 is an illustration of a trachea stent in accordance
with an embodiment of the disclosure;
[0049] FIG. 3 is a schematic illustration of a portion of the
trachea stent of FIG. 2 in accordance with an embodiment of the
disclosure;
[0050] FIG. 4 is a schematic illustration of a portion of the
trachea stent of FIG. 2 in accordance with an embodiment of the
disclosure;
[0051] FIG. 5 is a perspective illustration of a trachea stent in
accordance with an embodiment of the disclosure;
[0052] FIG. 6 is a schematic cross-sectional illustration of the
trachea stent of FIG. 5 in accordance with an embodiment of the
disclosure;
[0053] FIG. 7 is a schematic illustration of a portion of a trachea
stent in accordance with an embodiment of the disclosure; and
[0054] FIG. 8 is a schematic cross-sectional illustration of a
portion of a trachea stent in accordance with an embodiment of the
disclosure.
[0055] While the disclosure is amenable to various modifications
and alternative forms, specifics thereof have been shown by way of
example in the drawings and will be described in detail. It should
be understood, however, that the intention is not to limit the
invention to the particular embodiments described. On the contrary,
the intention is to cover all modifications, equivalents, and
alternatives falling within the spirit and scope of the
disclosure.
DETAILED DESCRIPTION
[0056] For the following defined terms, these definitions shall be
applied, unless a different definition is given in the claims or
elsewhere in this specification.
[0057] All numeric values are herein assumed to be modified by the
term "about", whether or not explicitly indicated. The term "about"
generally refers to a range of numbers that one of skill in the art
would consider equivalent to the recited value (e.g., having the
same function or result). In many instances, the terms "about" may
include numbers that are rounded to the nearest significant
figure.
[0058] The recitation of numerical ranges by endpoints includes all
numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3,
3.80, 4, and 5).
[0059] As used in this specification and the appended claims, the
singular forms "a", "an", and "the" include plural referents unless
the content clearly dictates otherwise. As used in this
specification and the appended claims, the term "or" is generally
employed in its sense including "and/or" unless the content clearly
dictates otherwise.
[0060] It is noted that references in the specification to "an
embodiment", "some embodiments", "other embodiments", etc.,
indicate that the embodiment described may include one or more
particular features, structures, and/or characteristics. However,
such recitations do not necessarily mean that all embodiments
include the particular features, structures, and/or
characteristics. Additionally, when particular features,
structures, and/or characteristics are described in connection with
one embodiment, it should be understood that such features,
structures, and/or characteristics may also be used connection with
other embodiments whether or not explicitly described unless
clearly stated to the contrary.
[0061] The following detailed description should be read with
reference to the drawings in which similar elements in different
drawings are numbered the same. The detailed description and the
drawings, which are not necessarily to scale, depict illustrative
embodiments and are not intended to limit the scope of the
disclosure. The illustrative embodiments depicted are intended only
as exemplary. Selected features of any illustrative embodiment may
be incorporated into an additional embodiment. It will be
appreciated that while the disclosure describes an airway or
trachea stent, the features and elements described herein may be
applied to any variety of endoprosthesis.
[0062] FIG. 1 provides a schematic illustration of the torso of a
patient 10. The patient 10 includes a trachea 12, a left main
bronchus 14 and a right main bronchus 16 (relative to the patient's
perspective). An endoprosthesis 18 may be seen in phantom, disposed
within the right main bronchus 16. It will be appreciated that this
placement is merely for illustrative purposes, as the
endoprosthesis 18 may be deployed elsewhere in the trachea 12 or
even down into the bronchia (not illustrated). It will also be
appreciated that while the endoprosthesis 18 is described herein as
an airway stent, the endoprosthesis 18 may be deployed in a variety
of other bodily lumens, including but not limited to the vascular,
urinary, biliary, tracheobronchial, esophageal or renal tracts.
Although illustrated as a stent, the endoprosthesis 10 may be any
of a number of devices that may be introduced endoscopically,
subcutaneously, percutaneously or surgically to be positioned
within an organ, tissue, or lumen, such as a heart, artery, vein,
urethra, esophagus, trachea, bronchus, bile duct, or the like.
[0063] A difficulty in placing an endoprosthesis in the trachea 12
is that the patient 10 may have a tendency to try and cough out the
endoprosthesis 18. The human respiratory system is designed, when
encountering an obstacle or other foreign object, to try to move
the obstacle out of the way. This may mean pushing the object
farther down, to a position of relative safety. This may also mean
trying to cough it out. The human body may try to forcibly eject
the object. Accordingly, and in some embodiments, the
endoprosthesis 18 may be configured to help hold the endoprosthesis
18 in place within the trachea 12.
[0064] Another difficulty in placing an endoprosthesis in the
trachea 12 is that the presence of a foreign object such as an
endoprosthesis triggers an inflammatory response that produces
mucus. Mucus can become trapped between the body of an
endoprosthesis and the wall of the trachea 12. Trapped mucus can
stimulate or facilitate the growth of bacteria. Accordingly, and in
some embodiments, the endoprosthesis 18 may be configured to
provide air channels or voids by spacing at least a part of the
endoprosthesis 18 away from the wall of the trachea 12.
[0065] FIG. 2 provides an illustration of a trachea stent 20 that
may be deployed as shown with respect to the endoprosthesis 18 of
FIG. 1. In FIG. 2, the trachea stent 20 is shown on a mandrel 30.
The trachea stent 20 may include a support structure 22 extending
from a first end 24 to a second end 26. The support structure 22
may include one or more (a plurality are illustrated) wave form
structures 28 that extend circumferentially about the support
structure 22. In some embodiments, the wave form structures 28
extend about 360 degrees about the support structure 22 and thus
each of the wave form structures 28 may form closed loops. In some
embodiments, each wave form structure 28 is formed independently of
any other wave form structure 28. The wave form structures 28 may
be arranged axially adjacent one another along the length of the
support structure 22. In some embodiments, each wave form structure
28 may be formed on the mandrel 30, by forming a wire into the
sinusoidal pattern shown, having peaks oriented toward the first
end 24 of the support structure 22 and valleys oriented toward the
second end 26 of the support structure 22.
[0066] The wave form structures 28 are joined together via
connectors, such as one or more axial loop members 32. In some
embodiments, the axial loop members 32 (two are illustrated in FIG.
2) are the only physical connection between adjacent wave form
structures 28. It will be appreciated that, while not illustrated,
the trachea stent 20 may include a polymeric coating or covering to
prevent tissue ingrowth into the interior of the trachea stent 20.
The polymeric coating or covering, if present, may be disposed
about an exterior of the support structure 22, for example. The
axial loop members 32 are shown in an extended configuration in
which they extend radially outward from an outer surface 34 that is
defined by the wave form structures 28 and the polymeric coating or
covering, if present. While not illustrated, it will be appreciated
that the support structure 22 may have a compressed configuration
for delivery in which the axial loop members 32 flatten against the
outer surface 34.
[0067] The connectors or axial loop members 32 may be configured to
engage a wall of a body lumen in the expanded state to inhibit
migration of the endoprosthesis 18 subsequent to implanting the
endoprosthesis 18 in the body lumen. For example, the connectors or
axial loop members 32 may engage the tissue between cartilage rings
within the tracheal anatomy to provide anti-migration support for
the endoprosthesis 18.
[0068] A space or opening may be defined between the connectors or
axial loop member 32 and the outer circumference of the wave form
structures 28 and/or overlaying polymeric coating or covering as
viewed along the central longitudinal axis of the support structure
22, as a result of the connectors or axial loop members 32
extending radially outward of or above the outer circumference of
the wave form structures 28 and/or overlaying polymeric coating or
covering. The space or opening may be unobstructed by any other
structure of the endoprosthesis 18. Accordingly, tissue ingrowth
through these spaces or openings subsequent to implanting the
endoprosthesis 18 may further secure the endoprosthesis 18 in place
in the anatomy and prevent migration of the endoprosthesis 18.
[0069] The support structure 22 may be formed of any suitable
material. In some embodiments, the support structure 22 may be
formed of a nickel-titanium alloy such as nitinol. In some
embodiments, at least some of the wave form structures 28 may be
formed of a nitinol or other wire having a wire diameter that is in
the range of about 0.2 mm to about 0.5 mm. In some embodiments, at
least some of the axial loop members 32 may be formed of a nitinol
or other wire having a wire diameter that is in the range of about
0.25 mm to about 0.4 mm, which may be the same or different from
the wire diameter used to form at least some of the wave form
structures 28.
[0070] FIG. 3 provides an illustration of a portion of a wave form
structure 28. In some embodiments, at least some of the wave form
structures 28 may be considered as undulating back and forth in a
sinusoidal pattern. A sinusoidal pattern may be defined, at least
in part, by a frequency and an amplitude. As illustrated, the wave
form structure 28 may be considered as having a frequency that is
in the range of about 0.5 to about 4 waves per cm. A wave may be
defined as the distance or wavelength F between adjacent peaks. The
wave form structure 28 may be considered as having an amplitude A,
measured as the distance between peak and valley. In this, it will
be appreciated that peaks and valleys are a matter of perspective.
What appears as a peak from one side looks like a valley if viewing
from the opposite side.
[0071] FIG. 4 provides an illustration of two adjacent wave form
structures 28. One of the wave form structures (i.e., the first
wave form structure) is labeled as 28a and the adjacent wave form
structure (i.e., the second wave form structure) is labeled as 28b.
To avoid confusion, each wave form structure 28a, 28b are labeled
as having peaks P and valleys V. It will be appreciated that in
connecting the axial loop members 32 to adjacent wave form
structures 28, there are a variety of different relative locations
at which the axial loop members 32 may be connected. Each axial
loop member 32 may be considered as having a first end 36 connected
to the first wave form structure 28a and a second end 38 connected
to the adjacent second wave form structure 28b.
[0072] In FIG. 4, an axial loop member 32a is shown having its
first end 36 secured to a peak P on the wave form structure 28a and
its second end 38 secured to a peak P on the wave form structure
28b. An axial loop member 32b is shown extending from an
intermediate position I on the wave form structure 28a to an
intermediate position I on the wave form structure 28b. An axial
loop member 32c is shown extending from a valley V on the wave form
structure 28a to a valley V on the wave form structure 28b. An
axial loop member 32d is shown extending from a peak P on the wave
form structure 28a to a valley V on the wave form structure 28b. It
will be appreciated that these axial loop members 32a, 32b, 32c and
32d, are illustrative only, and are intended merely to illustrate
the variety of available connection points. In alternative
embodiments, the first end 36 of the axial loop member 32 may be
secured at any desired location along the first wave form structure
28a while the second end 38 of the axial loop member 32 may be
secured at any desired location along the second wave form
structure 28b.
[0073] FIG. 5 provides a perspective illustration of a trachea
stent 40 having a first end 42 and a second end 44. The trachea
stent 40 has an inner surface 46 defining a lumen 48 and an outer
surface 50. In some embodiments, as illustrated, the outer surface
50 includes a plurality of spacer fins 52 that extend above the
outer surface 50. In some embodiments, the spacer fins 52 are
formed of a different material. In some embodiments, the spacer
fins 52 are formed of a biodegradable or bioabsorbable material
that will break down or dissolve over time once implanted.
Accordingly, the spacer fins 52 may provide migration resistance
upon implantation of the trachea stent 40 within a body lumen. Over
time, the spacer fins 52, which are formed of a biodegradable or
bioabsorbable material, will break down or dissolve once implanted.
Thereafter, if it is desired to remove the trachea stent 40 at a
later time, the degradation or absorption of the spacer fins 52
will reduce the trauma experienced by the patient in removing the
trachea stent 40 from the body lumen.
[0074] Illustrative but non-limiting examples of suitable
biodegradable or bioabsorbable materials include polymers, such as
poly-L-lactide (PLLA), polyglycolide (PGA), polylactide (PLA),
poly-D-lactide (PDLA), polycaprolactone, polydioxanone,
polygluconate, polylactic acid-polyethylene oxide copolymers,
modified cellulose, collagen, poly(hydroxybutyrate), polyanhydride,
polyphosphoester, poly(amino acids), and combinations thereof.
[0075] In some embodiments, the spacer fins 52 could also provide
drug elution. The terms "therapeutic agents," "drugs," "bioactive
agents," "pharmaceuticals," "pharmaceutically active agents", and
other related terms may be used interchangeably herein and include
genetic therapeutic agents, non-genetic therapeutic agents, and
cells. Therapeutic agents may be used singly or in combination. A
wide range of therapeutic agent loadings can be used in conjunction
with the devices of the present invention, with the
pharmaceutically effective amount being readily determined by those
of ordinary skill in the art and ultimately depending, for example,
upon the condition to be treated, the nature of the therapeutic
agent itself, the tissue into which the dosage form is introduced,
and so forth.
[0076] Some specific beneficial agents include anti-thrombotic
agents, anti-proliferative agents, anti-inflammatory agents,
anti-migratory agents, agents affecting extracellular matrix
production and organization, antineoplastic agents, anti-mitotic
agents, anesthetic agents, anti-coagulants, vascular cell growth
promoters, vascular cell growth inhibitors, cholesterol-lowering
agents, vasodilating agents, and agents that interfere with
endogenous vasoactive mechanisms.
[0077] More specific drugs or therapeutic agents include
paclitaxel, sirolimus, everolimus, tacrolimus, Epo D,
dexamethasone, estradiol, halofuginone, cilostazole, geldanamycin,
ABT-578 (Abbott Laboratories), trapidil, liprostin, Actinomcin D,
Resten-NG, Ap-17, abciximab, clopidogrel, Ridogrel, beta-blockers,
bARKct inhibitors, phospholamban inhibitors, and Serca 2
gene/protein, resiquimod, imiquimod (as well as other
imidazoquinoline immune response modifiers), human apolioproteins
(e.g., AI, AII, AIII, AIV, AV, etc.), vascular endothelial growth
factors (e.g., VEGF-2), as well as derivatives of the forgoing,
among many others.
[0078] Numerous additional therapeutic agents useful for the
practice of the present invention may be selected from those
described in paragraphs [0040] to [0046] of commonly assigned U.S.
Patent Application Pub. No. 2003/0236514, the entire disclosure of
which is hereby incorporated by reference.
[0079] While the spacer fins 52 are illustrated as being generally
aligned along an axial length of the trachea stent 40 (i.e.,
generally parallel to a central longitudinal axis of the trachea
stent 40), it will be appreciated that in some embodiments, the
spacer fins 52 could be aligned perpendicular or at an acute angle
relative to an axial length of the trachea stent 40 (i.e.,
generally non-parallel to a central longitudinal axis of the
trachea stent 40, such as perpendicular to or at an acute angle to
the central longitudinal axis of the trachea stent 40), in order to
limit migration in a particular direction, for example. Moreover,
while the spacer fins 52 are shown as being generally triangular in
shape, it will be appreciated that in some cases the spacer fins 52
may have other shapes, such as round or square.
[0080] FIG. 6 provides a schematic cross-sectional view of the
trachea stent 40, illustrating that the trachea stent 40 may, in
some embodiments, include an expandable metal structure 54 and a
polymeric coating or sleeve 56 disposed over the expandable metal
structure 54. The expandable metal structure 54 is generically
illustrated, as the expandable metal structure 54 may have any
desired design and configuration. For example, in some embodiments,
the expandable metal structure 54 may represent a laser cut
structure that can be laser cut from a tube. In some embodiments,
the expandable metal structure 54 may represent a wound metal
structure. In some embodiments, the expandable metal structure 54
may represent a braided metal structure. In some embodiments, as
shown in FIG. 6, the spacer fins 52 may be secured relative to the
trachea stent 40 by encapsulating the spacer fins 52 within the
polymeric coating or sleeve 56. In some embodiments, the spacer
fins 52 may have a base and an opposing apex positioned radially
outward from the base, and the base of each of the spacer fins 52
may be encapsulated within the polymeric coating or sleeve 56 and
the apex of each of the spacer fins is exposed from and extends
radially outward from the polymeric coating or sleeve 56 such that
the biodegradable material forming the spacer fins 52 are exposed
after implantation.
[0081] In some embodiments, the spacer fins 52 may be formed by
placing a biodegradable cap directly on a portion of the expandable
metal structure 54. As schematically illustrated in FIG. 7, an
expandable metal structure 54a may include high spots 54b, such as
an apex of a stent strut. A spacer fin 52a may be formed by
securing a biodegradable cap 52b onto the high spot 54b or
protruding portion of the expandable metal structure 54a. In some
embodiments, while not illustrated, a polymeric covering or sleeve
could cover the expandable metal structure 54a prior to securing
the biodegradable cap 52b onto the high spot 54b or protruding
portion.
[0082] Another method for creating the spacer fins 52 is
illustrated in FIG. 8, which shows a schematic cross-sectional view
of an expandable metal structure 54c. As discussed above with
respect to the expandable metal structure 54, the expandable metal
structure 54c may generically represent a laser cut structure, a
wound structure or a braided metal structure. A filament 58 may be
wrapped around the expandable metal structure 54c, in and out of
apertures formed within the expandable metal structure 54c such
that the filament 58 forms high spots 60 or radially outwardly
protruding portions. The high spots 60 or protruding portions may
form spacer fins. While a single filament 58 is shown, it will be
appreciated that a plurality of filaments 58 may be wrapped around
the expandable metal structure 54c. The filament 58 may be formed
of any desired biodegradable or bioabsorbable material, as
discussed above with respect to the spacer fins 52, and may have
any desired diameter such as about 0.5 cm.
[0083] In some embodiments, as noted, the expandable metal
structure 54, 54b and 54c may be cut from a metal tube using any
desired technique, including but not limited to micro-machining,
saw-cutting (e.g., using a diamond grit embedded semiconductor
dicing blade), electron discharge machining, grinding, milling,
casting, molding, chemically etching or treating, or other known
methods, and the like. Some example embodiments of appropriate
micromachining methods and other cutting methods, and structures
for tubular members including slots and medical devices including
tubular members are disclosed in U.S. Pat. Publication Nos.
2003/0069522 and 2004/0181174-A2; and U.S. Pat. Nos. 6,766,720; and
6,579,246, the entire disclosures of which are herein incorporated
by reference. Some example embodiments of etching processes are
described in U.S. Pat. No. 5,106,455, the entire disclosure of
which is herein incorporated by reference.
[0084] In at least some embodiments, a laser cutting process may be
used. The laser cutting process may include a suitable laser and/or
laser cutting apparatus. For example, the laser cutting process may
utilize a fiber laser. Utilizing processes like laser cutting may
be desirable for a number of reasons. For example, laser cutting
processes may allow for a number of different cutting patterns in a
precisely controlled manner. Furthermore, changes to the cutting
pattern can be made without the need to replace the cutting
instrument (e.g., blade).
[0085] The materials that can be used for the expandable metal
structure 54, 54b, 54c may include those commonly associated with
medical devices. For simplicity purposes, the following discussion
makes reference to the expandable metal structure 54. However, this
is not intended to limit the devices and methods described herein,
as the discussion may be applied to other similar structures.
[0086] The expandable metal structure 54, 54b, 54c, may be made
from a metal, metal alloy, polymer (some examples of which are
disclosed below), a metal-polymer composite, ceramics, combinations
thereof, and the like, or other suitable material. Some examples of
suitable metals and metal alloys include stainless steel, such as
304V, 304L, and 316LV stainless steel; mild steel; nickel-titanium
alloy such as linear-elastic and/or super-elastic nitinol; other
nickel alloys such as nickel-chromium-molybdenum alloys (e.g., UNS:
N06625 such as INCONEL.RTM. 625, UNS: N06022 such as HASTELLOY.RTM.
C-22.RTM., UNS: N10276 such as HASTELLOY.RTM. C276.RTM., other
HASTELLOY.RTM. alloys, and the like), nickel-copper alloys (e.g.,
UNS: N04400 such as MONEL.RTM. 400, NICKELVAC.RTM. 400,
NICORROS.RTM. 400, and the like), nickel-cobalt-chromium-molybdenum
alloys (e.g., UNS: R30035 such as MP35-N.RTM. and the like),
nickel-molybdenum alloys (e.g., UNS: N10665 such as HASTELLOY.RTM.
ALLOY B2.RTM.), other nickel-chromium alloys, other
nickel-molybdenum alloys, other nickel-cobalt alloys, other
nickel-iron alloys, other nickel-copper alloys, other
nickel-tungsten or tungsten alloys, and the like; cobalt-chromium
alloys; cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such
as ELGILOY.RTM., PHYNOX.RTM., and the like); platinum enriched
stainless steel; titanium; combinations thereof; and the like; or
any other suitable material.
[0087] As alluded to herein, within the family of commercially
available nickel-titanium or nitinol alloys, is a category
designated "linear elastic" or "non-super-elastic" which, although
may be similar in chemistry to conventional shape memory and super
elastic varieties, may exhibit distinct and useful mechanical
properties. Linear elastic and/or non-super-elastic nitinol may be
distinguished from super elastic nitinol in that the linear elastic
and/or non-super-elastic nitinol does not display a substantial
"superelastic plateau" or "flag region" in its stress/strain curve
like super elastic nitinol does. Instead, in the linear elastic
and/or non-super-elastic nitinol, as recoverable strain increases,
the stress continues to increase in a substantially linear, or a
somewhat, but not necessarily entirely linear relationship until
plastic deformation begins or at least in a relationship that is
more linear that the super elastic plateau and/or flag region that
may be seen with super elastic nitinol. Thus, for the purposes of
this disclosure linear elastic and/or non-super-elastic nitinol may
also be termed "substantially" linear elastic and/or
non-super-elastic nitinol.
[0088] In some cases, linear elastic and/or non-super-elastic
nitinol may also be distinguishable from super elastic nitinol in
that linear elastic and/or non-super-elastic nitinol may accept up
to about 2-5% strain while remaining substantially elastic (e.g.,
before plastically deforming) whereas super elastic nitinol may
accept up to about 8% strain before plastically deforming. Both of
these materials can be distinguished from other linear elastic
materials such as stainless steel (that can also can be
distinguished based on its composition), which may accept only
about 0.2 to 0.44 percent strain before plastically deforming.
[0089] In some embodiments, the linear elastic and/or
non-super-elastic nickel-titanium alloy is an alloy that does not
show any martensite/austenite phase changes that are detectable by
differential scanning calorimetry (DSC) and dynamic metal thermal
analysis (DMTA) analysis over a large temperature range. For
example, in some embodiments, there may be no martensite/austenite
phase changes detectable by DSC and DMTA analysis in the range of
about -60 degrees Celsius (.degree. C.) to about 120.degree. C. in
the linear elastic and/or non-super-elastic nickel-titanium alloy.
The mechanical bending properties of such material may therefore be
generally inert to the effect of temperature over this very broad
range of temperature. In some embodiments, the mechanical bending
properties of the linear elastic and/or non-super-elastic
nickel-titanium alloy at ambient or room temperature are
substantially the same as the mechanical properties at body
temperature, for example, in that they do not display a
super-elastic plateau and/or flag region. In other words, across a
broad temperature range, the linear elastic and/or
non-super-elastic nickel-titanium alloy maintains its linear
elastic and/or non-super-elastic characteristics and/or
properties.
[0090] In some embodiments, the linear elastic and/or
non-super-elastic nickel-titanium alloy may be in the range of
about 50 to about 60 weight percent nickel, with the remainder
being essentially titanium. In some embodiments, the composition is
in the range of about 54 to about 57 weight percent nickel. One
example of a suitable nickel-titanium alloy is FHP-NT alloy
commercially available from Furukawa Techno Material Co. of
Kanagawa, Japan. Some examples of nickel titanium alloys are
disclosed in U.S. Pat. Nos. 5,238,004 and 6,508,803, which are
incorporated herein by reference. Other suitable materials may
include ULTANIUM.TM. (available from Neo-Metrics) and GUM METAL.TM.
(available from Toyota). In some other embodiments, a superelastic
alloy, for example a superelastic nitinol can be used to achieve
desired properties.
[0091] In at least some embodiments, portions or all of the trachea
stents 20 and 40 described herein may also be doped with, made of,
or otherwise include a radiopaque material. Radiopaque materials
are understood to be materials capable of producing a relatively
bright image on a fluoroscopy screen or another imaging technique
during a medical procedure. Some examples of radiopaque materials
can include, but are not limited to, gold, platinum, palladium,
tantalum, tungsten alloy, polymer material loaded with a radiopaque
filler, and the like.
[0092] In some embodiments, a degree of Magnetic Resonance Imaging
(MRI) compatibility is imparted into the trachea stents 20, 40. For
example, the trachea stents 20, 40, or portions thereof, may be
made of a material that does not substantially distort the image
and create substantial artifacts (e.g., gaps in the image). Certain
ferromagnetic materials, for example, may not be suitable because
they may create artifacts in an MRI image. Trachea stents 20, 40,
or portions thereof, may also be made from a material that the MRI
machine can image. Some materials that exhibit these
characteristics include, for example, tungsten,
cobalt-chromium-molybdenum alloys (e.g., UNS: R30003 such as
ELGILOY.RTM., PHYNOX.RTM., and the like),
nickel-cobalt-chromium-molybdenum alloys (e.g., UNS: R30035 such as
MP35-N.RTM. and the like), nitinol, and the like, and others.
[0093] As noted, the trachea stents 20, 40 may include a sheath or
covering thereover. Suitable polymeric material include but are not
limited to polytetrafluoroethylene (PTFE), ethylene
tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP),
polyoxymethylene (POM, for example, DELRIN.RTM. available from
DuPont), polyether block ester, polyurethane (for example,
Polyurethane 85A), polypropylene (PP), polyvinylchloride (PVC),
polyether-ester (for example, ARNITEL.RTM. available from DSM
Engineering Plastics), ether or ester based copolymers (for
example, butylene/poly(alkylene ether) phthalate and/or other
polyester elastomers such as HYTREL.RTM. available from DuPont),
polyamide (for example, DURETHAN.RTM. available from Bayer or
CRISTAMID.RTM. available from Elf Atochem), elastomeric polyamides,
block polyamide/ethers, polyether block amide (PEBA, for example
available under the trade name PEBAX.RTM.), ethylene vinyl acetate
copolymers (EVA), silicones, polyethylene (PE), Marlex high-density
polyethylene, Marlex low-density polyethylene, linear low density
polyethylene (for example REXELL.RTM.), polyester, polybutylene
terephthalate (PBT), polyethylene terephthalate (PET),
polytrimethylene terephthalate, polyethylene naphthalate (PEN),
polyetheretherketone (PEEK), polyimide (PI), polyetherimide (PEI),
polyphenylene sulfide (PPS), polyphenylene oxide (PPO), poly
paraphenylene terephthalamide (for example, KEVLAR.RTM.),
polysulfone, nylon, nylon-12 (such as GRILAMID.RTM. available from
EMS American Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene
vinyl alcohol, polyolefin, polystyrene, epoxy, polyvinylidene
chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (for
example, SIBS and/or SIBS 50A), polycarbonates, ionomers,
biocompatible polymers, other suitable materials, or mixtures,
combinations, copolymers thereof, polymer/metal composites, and the
like.
[0094] In some embodiments, the exterior surfaces of the expandable
metal structures 22, 52 may be sandblasted, beadblasted, sodium
bicarbonate-blasted, electropolished, etc. In these as well as in
some other embodiments, a coating, for example a lubricious, a
hydrophilic, a protective, or other type of coating may be applied
thereover portions. Alternatively, the expandable metal structures
22, 52 may include a lubricious, hydrophilic, protective, or other
type of coating. Hydrophobic coatings such as fluoropolymers
provide a dry lubricity which improves guidewire handling and
device exchanges. Lubricious coatings improve steerability and
improve lesion crossing capability. Suitable lubricious polymers
are well known in the art and may include silicone and the like,
hydrophilic polymers such as high-density polyethylene (HDPE),
polytetrafluoroethylene (PTFE), polyarylene oxides,
polyvinylpyrrolidones, polyvinylalcohols, hydroxy alkyl
cellulosics, algins, saccharides, caprolactones, and the like, and
mixtures and combinations thereof. Hydrophilic polymers may be
blended among themselves or with formulated amounts of water
insoluble compounds (including some polymers) to yield coatings
with suitable lubricity, bonding, and solubility. Some other
examples of such coatings and materials and methods used to create
such coatings can be found in U.S. Pat. Nos. 6,139,510 and
5,772,609, which are incorporated herein by reference.
[0095] It should be understood that this disclosure is, in many
respects, only illustrative. Changes may be made in details,
particularly in matters of shape, size, and arrangement of steps
without exceeding the scope of the disclosure. This may include, to
the extent that it is appropriate, the use of any of the features
of one example embodiment being used in other embodiments. The
invention's scope is, of course, defined in the language in which
the appended claims are expressed.
* * * * *