U.S. patent application number 10/864665 was filed with the patent office on 2005-12-15 for overlapped stents for scaffolding, flexibility and mri compatibility.
This patent application is currently assigned to SCIMED LIFE SYSTEMS, INC.. Invention is credited to Gregorich, Daniel.
Application Number | 20050278017 10/864665 |
Document ID | / |
Family ID | 34969867 |
Filed Date | 2005-12-15 |
United States Patent
Application |
20050278017 |
Kind Code |
A1 |
Gregorich, Daniel |
December 15, 2005 |
Overlapped stents for scaffolding, flexibility and MRI
compatibility
Abstract
A tubular insert for a vessel comprises an inner stent and an
outer stent. At least a portion of the inner stent is disposed
within the outer stent. The outer stent has a longitudinal axis and
is constructed to be free of any closed loops which are
electrically conductive and which are disposed about the
longitudinal axis such that the longitudinal axis passes through
the closed loop. The inner stent has a longitudinal axis and is
constructed so as to be free of any closed loops which are
electrically conductive and which are disposed about the
longitudinal axis such that the longitudinal axis passes through
the closed loop. There is a substantially electrically
non-conductive connection between the inner and outer stents.
Desirably, a wall surface is defined by the outer and inner stents,
and there are no closed, electrically conductive loops in the wall
surface of the tubular insert.
Inventors: |
Gregorich, Daniel; (Mound,
MN) |
Correspondence
Address: |
VIDAS, ARRETT & STEINKRAUS, P.A.
6109 BLUE CIRCLE DRIVE
SUITE 2000
MINNETONKA
MN
55343-9185
US
|
Assignee: |
SCIMED LIFE SYSTEMS, INC.
Maple Grove
MN
|
Family ID: |
34969867 |
Appl. No.: |
10/864665 |
Filed: |
June 9, 2004 |
Current U.S.
Class: |
623/1.44 |
Current CPC
Class: |
A61F 2230/0013 20130101;
A61F 2250/0067 20130101; A61F 2230/0054 20130101; A61F 2250/0063
20130101; A61F 2/89 20130101; A61F 2/915 20130101; A61F 2002/91533
20130101; A61F 2/885 20130101; A61F 2002/91591 20130101; G01R
33/285 20130101; A61F 2250/0045 20130101; A61F 2/90 20130101; A61F
2/852 20130101; A61F 2/88 20130101; A61F 2/91 20130101; A61F
2210/0076 20130101; A61F 2250/0062 20130101; A61F 2002/91508
20130101; A61F 2002/91558 20130101; A61F 2002/9155 20130101; A61F
2002/91516 20130101 |
Class at
Publication: |
623/001.44 |
International
Class: |
A61F 002/06 |
Claims
1. A tubular insert for a bodily vessel comprising an inner stent,
and an outer stent, at least a portion of the inner stent disposed
within the outer stent, the outer stent having a longitudinal axis
and constructed so as to be free of any closed loops which are 1)
electrically conductive; and 2) disposed about the longitudinal
axis such that the longitudinal axis passes through the closed
loop; the inner stent having a longitudinal axis and constructed so
as to be free of any closed loops which are 1) electrically
conductive; and 2) disposed about the longitudinal axis such that
the longitudinal axis passes through the closed loop; wherein there
is a substantially electrically non-conductive connection between
the inner stent and the outer stent.
2. The tubular insert of claim 1 wherein there are a plurality of
substantially electrically non-conductive connections between the
inner stent and the outer stent.
3. The tubular insert of claim 2 wherein the inner stent is a
helical stent and the outer stent is a helical stent.
4. The tubular insert of claim 1 wherein the inner stent is a
helical stent and the outer stent is a helical stent.
5. The tubular insert of claim 1 wherein the electrically
non-conductive connection comprises plastic.
6. The tubular insert of claim 1 wherein the electrically
non-conductive connection comprises adhesive.
7. The tubular insert of claim 1 wherein the electrically
non-conductive connection comprises ceramic.
8. The tubular insert of claim 3 wherein the electrically
non-conductive connections comprise plastic.
9. The tubular insert of claim 3 wherein the electrically
non-conductive connection comprise adhesive.
10. The tubular insert of claim 3 wherein the electrically
non-conductive connection comprise ceramic.
11. The tubular insert of claim 3 wherein one of the outer stent
and inner stent extends generally clockwise about the longitudinal
axis of the stent from one end of the stent to another and the
other of the outer stent and inner stent extends in a generally
counterclockwise direction about the longitudinal axis of the
stent.
12. The tubular insert of claim 1 wherein at least one of the outer
stent and the inner stent is made from a magnetic resonance
compatible material.
13. The tubular insert of claim 1 wherein the outer stent and the
inner stent are made from a magnetic resonance compatible
material.
14. The tubular insert of claim 4 wherein the outer stent and the
inner stent are made from a magnetic resonance compatible
material.
15. The tubular insert of claim 1 wherein the outer stent includes
a plurality of interconnected loops which extend at an oblique or
perpendicular angle relative to the longitudinal axis of the outer
stent, the loops extending only part of the way about the
longitudinal axis of the outer stent and the inner stent includes a
plurality of interconnected loops which extend at an oblique or
perpendicular angle relative to the longitudinal axis of the inner
stent, the loops extending only part of the way about the
longitudinal axis of the inner stent.
16. The tubular insert of claim 2 having a plurality of cells, each
cell defined by a portion of the outer stent, a portion of the
inner stent and at least two connections between the outer stent
and the inner stent.
17. The tubular insert of claim 2 wherein the inner and outer
stents are both made of a conductive material with an electrically
non-conductive material disposed thereabout.
18. The tubular insert of claim 1 wherein a wall surface is defined
by the outer and inner stents, there being no closed, electrically
conductive loops in the wall surface of the tubular insert.
19. The tubular insert of claim 2 wherein a wall surface is defined
by the outer and inner stents, there being no closed, electrically
conductive loops in the wall surface of the tubular insert.
20. The tubular insert of claim 1 wherein portions of the inner and
outer stents are made of metal.
21. A method of imaging a tubular medical device, the tubular
medical device being in the form of an outer stent and an inner
stent, at least a portion of the inner stent disposed within the
outer stent, the outer stent having a longitudinal axis and
constructed so as to be free of any closed loops which are 1)
electrically conductive; and 2) disposed about the longitudinal
axis such that the longitudinal axis passes through the closed
loop; the inner stent having a longitudinal axis and constructed so
as to be free of any closed loops which are 1) electrically
conductive; and 2) disposed about the longitudinal axis such that
the longitudinal axis passes through the closed loop; wherein there
is a substantially electrically non-conductive connection between
the inner stent and the outer stent, the method comprising the
steps of: a) disposing the tubular medical device within a magnetic
resonance imager; b) using the magnetic resonance imager to obtain
a magnetic resonance image of the tubular medical device; and c)
removing the tubular medical device from the magnetic resonance
imager.
22. The method of claim 21 wherein the tubular medical device is
located within a living body when it is disposed within the
magnetic resonance imager.
23. The method of claim 21 wherein the tubular medical device is
not located within a living body when it is disposed within the
magnetic resonance imager.
24. The method of clam 22 wherein the inner stent is a helical
stent and the outer stent is a helical stent.
25. The method of clam 23 wherein the inner stent is a helical
stent and the outer stent is a helical stent.
26. The method of claim 24 wherein one of the inner stent and the
outer stent extends in a generally clockwise direction about the
longitudinal axis of the stent and the other stent extends in a
generally counterclockwise direction about the longitudinal axis of
the stent.
27. The method of claim 25 wherein one of the inner stent and the
outer stent extends in a generally clockwise direction about the
longitudinal axis of the stent and the other stent extends in a
generally counterclockwise direction about the longitudinal axis of
the stent.
28. The method of claim 22 wherein the connection between the outer
stent and the inner stent comprises a material selected from the
group consisting of ceramic materials, plastic materials and
adhesive materials.
29. The method of claim 21 wherein the outer stent includes a
plurality of interconnected loops which extend at an oblique or
perpendicular angle relative to the longitudinal axis of the outer
stent, the loops extending only part of the way about the
longitudinal axis of the outer stent and the inner stent includes a
plurality of interconnected loops which extend at an oblique or
perpendicular angle relative to the longitudinal axis of the inner
stent, the loops extending only part of the way about the
longitudinal axis of the inner stent.
30. The method of claim 21 having a plurality of cells, each cell
defined by a portion of the outer stent, a portion of the inner
stent and at least two connections between the outer stent and the
inner stent.
31. The method of claim 21 wherein the inner and outer stents are
both made of a conductive material with an electrically
non-conductive material disposed thereabout.
32. The method of claim 21 wherein a wall surface is defined by the
outer and inner stents, there being no closed, electrically
conductive loops in the wall surface of the tubular medical
device.
33. A method of manufacturing a tubular medical device, comprising
the steps of: a) providing a first stent, the first stent having a
longitudinal axis and constructed so as to be free of any closed
loops which are 1) electrically conductive; and 2) disposed about
the longitudinal axis such that the longitudinal axis passes
through the closed loop; b) providing a second stent, the second
stent having a longitudinal axis and constructed so as to be free
of any closed loops which are 1) electrically conductive; and 2)
disposed about the longitudinal axis such that the longitudinal
axis passes through the closed loop; wherein there is a
substantially electrically non-conductive connection between the
first stent and the second stent; c) disposing at least a portion
of the second stent within the first stent; d) connecting the first
stent and the second stent together via a connection which is
substantially electrically non-conductive.
34. The method of claim 33 wherein the first stent is a helical
stent and the second stent is a helical stent.
35. The method of claim 33 wherein the first stent includes a rib
which runs along the length of the first stent and a plurality of
first arms extending therefrom, the first arms extending only part
of the way about the circumference of the first stent and the
second stent includes a rib which runs along the length of the
second stent and a plurality of second arms extending therefrom,
the second arms extending only part of the way about the
circumference of the second stent.
36. The method of claim 33 wherein the first stent includes a
plurality of interconnected loops which extend at an oblique or
perpendicular angle relative to the longitudinal axis of the first
stent, the loops extending only part of the way about the
longitudinal axis of the first stent and the second stent includes
a plurality of interconnected loops which extend at an oblique or
perpendicular angle relative to the longitudinal axis of the second
stent, the loops extending only part of the way about the
longitudinal axis of the second stent
37. The method of claim 33 wherein the tubular medical device has a
plurality of cells, each cell defined by a portion of the first
stent, a portion of the second stent and at least two connections
between the first stent and the second stent.
38. The method of claim 33 wherein the first and second stents are
both made of a conductive material with an electrically
non-conductive material disposed thereabout.
39. The method of claim 33 wherein a wall surface is defined by the
first and second stents, there being no closed, electrically
conductive loops in the wall surface of the tubular medical
device.
40. An expandable member for implantation in a bodily vessel, the
expandable member comprising a multilayer tubular wall surface
formed of a plurality of interconnected struts disposed at
different distances from a centerline which runs along a
longitudinal axis of the stent, the struts defining a plurality of
interconnected cells, each cell including an electrically
conducting portion and an electrically non-conductive portion, the
tubular member including pathways which form closed paths about the
circumference of the stent, each closed path including at least one
substantially electrically non-conducting portion and one
electrically conducting portion.
41. An expandable member comprising a first stent and a second
stent, the first stent formed of a member which winds from a
proximal end of the first stent to a distal end of the first stent
and back again to the proximal end, the second end formed of a
member which winds from a distal end of the second stent to a
proximal end of the second stent and back again to the distal end,
whereon one of the first and second stents is disposed within the
other of the first and second stents.
Description
BACKGROUND OF THE INVENTION
[0001] A stent is a generally tubular device that is used to
support a bodily lumen. A stent is typically delivered to a desired
bodily location via a catheter.
[0002] Magnetic resonance imaging (MRI) has been widely used to
image various parts of the body. One of the uses of MRI has been to
image blood flow. It is, therefore, desirable for stents to be MRI
compatible to allow for imaging of vessels in the region of a
stent. Although there has been a great deal of activity focusing on
the choice of materials for MRI compatible stents, other factors in
the design of the stent must be considered as well.
[0003] For example, a stent that is made from an electrically
conductive material that is formed in electrically conductive loops
which extend fully around the longitudinal axis of the stent, as
shown by way of example at 50 in FIG. 1, may facilitate the
formation of eddy currents when the region of the body in which the
stent is located is imaged. Similarly, the presence of closed,
electrically conductive loops which extend in a longitudinal
direction in the wall, as shown by way of example at 54 in FIG. 1,
also may result in eddy currents. Eddy currents, however, are know
to cause distortions in MRI images.
[0004] While many helical stents avoid the problem of electrically
conductive loops which extend fully about the longitudinal axis,
helical stents may have less compression resistance as compared
with stents having circumferential bands which extend fully about
the longitudinal axis. The scaffolding provided by helical stents
is also less than that provided by many of the stents having closed
circumferential bands.
[0005] Generally, there is a tradeoff between scaffolding and side
branch access. A stent with a larger, more open geometry will have
an improved side branch access and expandability but poorer
scaffolding. Smaller, tight geometry results in better scaffolding,
but poor side branch access and expandability.
[0006] There remains a need for MRI compatible stents with
innovative designs which combine excellent scaffolding, compression
resistance and side branch access while at the same time providing
reduced MRI distortions.
[0007] All US patents, applications and all other published
documents mentioned anywhere in this application are incorporated
herein by reference in their entirety.
[0008] Without limiting the scope of the invention a brief summary
of some of the claimed embodiments of the invention is set forth
below. Additional details of the summarized embodiments of the
invention and/or additional embodiments of the invention may be
found in the Detailed Description of the Invention below.
[0009] A brief abstract of the technical disclosure in the
specification is provided as well only for the purposes of
complying with 37 CFR 1.72.
BRIEF SUMMARY OF EMOBIDMENT(S) OF THE INVENTION
[0010] In one embodiment, the invention is directed to a tubular
insert for a bodily vessel. The insert comprises an inner stent and
an outer stent. At least a portion of the inner stent is disposed
within the outer stent. The outer stent has a longitudinal axis and
is constructed so as to be free of any closed loops which are
electrically conductive and which are disposed about the
longitudinal axis such that the longitudinal axis passes through
the closed loop. The inner stent has a longitudinal axis and is
constructed so as to be free of any closed loops which are
electrically conductive and which are disposed about the
longitudinal axis such that the longitudinal axis passes through
the closed loop. There is a substantially electrically
non-conductive connection between the inner stent and the outer
stent. Desirably, where a wall surface is defined by the outer and
inner stents, there are no closed, substantially electrically
conductive loops in the wall surface of the tubular insert.
Typically, at least portion of both the inner and outer stents will
be made of metal.
[0011] The invention is also directed to a method of imaging a
tubular medical device where the tubular medical device is in the
form of an outer stent and an inner stent. At least a portion of
the inner stent is disposed within the outer stent. The outer stent
has a longitudinal axis and is constructed so as to be free of any
closed loops which are electrically conductive and are disposed
about the longitudinal axis such that the longitudinal axis passes
through the closed loop. The inner stent has a longitudinal axis
and is constructed so as to be free of any closed loops which are
electrically conductive; and are disposed about the longitudinal
axis such that the longitudinal axis passes through the closed
loop. There is a substantially electrically non-conductive
connection between the inner stent and the outer stent. Desirably,
where a wall surface is defined by the outer and inner stents,
there are no closed, substantially electrically conductive loops in
the wall surface of the tubular insert. The method comprises the
steps of disposing the tubular medical device within a magnetic
resonance imager; using the magnetic resonance imager to obtain a
magnetic resonance image of the tubular medical device and removing
the tubular medical device from the magnetic resonance imager.
[0012] In one embodiment, the inventive method of imaging a tubular
medical device is carried with the tubular medical device located
within a living body when it is disposed within the magnetic
resonance imager. In another embodiment, the tubular medical device
is not located within a living body when it is disposed within the
magnetic resonance imager.
[0013] The invention is also directed to a method of manufacturing
a tubular medical device comprising the steps of providing a first
stent and a second stent, disposing at least a portion of the
second stent within the first stent and connecting the first stent
and the second stent together via a connection which is
substantially electrically non-conductive. The first stent has a
longitudinal axis and is constructed so as to be free of any closed
loops which are electrically conductive and disposed about the
longitudinal axis such that the longitudinal axis passes through
the closed loop. The second stent has a longitudinal axis and is
constructed so as to be free of any closed loops which are
electrically conductive and disposed about the longitudinal axis
such that the longitudinal axis passes through the closed loop.
There is a substantially electrically non-conductive connection
between the first stent and the second stent. Desirably, where a
wall surface is defined by the first and second stents, there are
no closed, substantially electrically conductive loops in the wall
surface of the tubular medical device.
[0014] In any of the inventive devices and methods described above
and below, desirably there are a plurality of substantially
electrically non-conductive connections between the inner stent and
the outer stent or between the first stent and the second
stent.
[0015] Typically, the inner stent or first stent will be a helical
stent and the outer stent or second stent will be a helical stent.
Where helical stents are used, one of the outer stent (or first
stent) and inner stent (or second stent) extends generally
clockwise about the longitudinal axis of the stent from one end of
the stent to another and the other of the outer stent (or first
stent) and inner stent (or second stent) extends in a generally
counterclockwise direction about the longitudinal axis of the
stent.
[0016] It is within the scope of the invention to use other types
of stent as well for the outer (or first) and inner (or second)
stents. For example, the outer or first stent may include a rib
which runs along the length of the stent and a plurality of outer
arms extending therefrom where the outer arms extend only part of
the way about the circumference of the stent. The inner or second
stent may include a rib which runs along the length of the stent
and a plurality of inner arms extending therefrom where the inner
arms extend only part of the way about the circumference of the
stent.
[0017] As another example, the outer or first stent may include a
plurality of interconnected loops which extend at an oblique or
perpendicular angle relative to the longitudinal axis of the stent
with the loops extending only part of the way about the
longitudinal axis of the stent. The inner or second stent may
include a plurality of interconnected loops which extend at an
oblique or perpendicular angle relative to the longitudinal axis of
the stent with the loops extending only part of the way about the
longitudinal axis of the stent.
[0018] Desirably, the tubular medical device or insert will have a
plurality of cells where each cell is defined by a portion of the
outer or first stent, a portion of the inner or second stent and at
least two connections between the outer or first stent and the
inner or second stent.
[0019] The non-conductive connection(s) between stents will
typically comprise one or more plastics, adhesives, composites,
ceramic or combinations thereof.
[0020] Desirably, at least one and more desirably both the outer
(or first) stent and the inner (or second) stent are made from a
magnetic resonance compatible material. The inner or second and
outer or first stents may both be made of a conductive material
with a non-conductive material disposed thereabout.
[0021] These and other embodiments which characterize the invention
are pointed out with particularity in the claims annexed hereto and
forming a part hereof. However, for a better understanding of the
invention, reference should be made to the drawings which form a
further part hereof and the accompanying descriptive matter, in
which there is illustrated and described embodiments of the
invention.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0022] A detailed description of the invention is hereafter
described with specific reference being made to the drawings in
which:
[0023] FIG. 1 shows a prior art stent.
[0024] FIG. 2a shows a stent which has been cut open along a line
parallel to the longitudinal axis of the stent and laid flat. The
stent is for use as a component of the inventive tubular
inserts.
[0025] FIG. 2b shows a stent which has been cut open along a line
parallel to the longitudinal axis of the stent and laid flat. The
stent is for use as a component of the inventive tubular
inserts.
[0026] FIG. 2c shows an inventive tubular insert which has been cut
open along a line parallel to the longitudinal axis of the stent
and laid flat.
[0027] FIG. 2d is an inset of FIG. 2c showing a highlighted
cell.
[0028] FIG. 2e shows an inventive tubular stent.
[0029] FIG. 3a shows a stent which has been cut open along a line
parallel to the longitudinal axis of the stent and laid flat. The
stent is for use as a component of the inventive tubular
inserts.
[0030] FIG. 3b shows a stent which has been cut open along a line
parallel to the longitudinal axis of the stent and laid flat. The
stent is for use as a component of the inventive tubular
inserts.
[0031] FIG. 3c shows an inventive tubular insert which has been cut
open along a line parallel to the longitudinal axis of the stent
and laid flat.
[0032] FIG. 3d shows one inventive configuration of connections
between inner and an outer stents.
[0033] FIG. 4a shows a stent which has been cut open along a line
parallel to the longitudinal axis of the stent and laid flat. The
stent is for use as a component of the inventive tubular
inserts.
[0034] FIG. 4b shows a stent which has been cut open along a line
parallel to the longitudinal axis of the stent and laid flat. The
stent is for use as a component of the inventive tubular
inserts.
[0035] FIG. 4c shows an inventive tubular insert which has been cut
open along a line parallel to the longitudinal axis of the stent
and laid flat.
[0036] FIG. 5a shows a stent which has been cut open along a line
parallel to the longitudinal axis of the stent and laid flat. The
stent is for use as a component of the inventive tubular
inserts.
[0037] FIG. 5b shows a stent which has been cut open along a line
parallel to the longitudinal axis of the stent and laid flat. The
stent is for use as a component of the inventive tubular
inserts.
[0038] FIG. 5c shows an inventive tubular insert which has been cut
open along a line parallel to the longitudinal axis of the stent
and laid flat.
[0039] FIG. 5d shows another inventive tubular insert which has
been cut open along a line parallel to the longitudinal axis of the
stent and laid flat.
[0040] FIG. 6a shows a stent which has been cut open along a line
parallel to the longitudinal axis of the stent and laid flat. The
stent is for use as a component of the inventive tubular
inserts.
[0041] FIG. 6b shows a stent which has been cut open along a line
parallel to the longitudinal axis of the stent and laid flat. The
stent is for use as a component of the inventive tubular
inserts.
[0042] FIG. 6c shows an inventive tubular insert which has been cut
open along a line parallel to the longitudinal axis of the stent
and laid flat.
[0043] FIG. 7a shows a stent which has been cut open along a line
parallel to the longitudinal axis of the stent and laid flat. The
stent is for use as a component of the inventive tubular
inserts.
[0044] FIG. 7b shows a stent which has been cut open along a line
parallel to the longitudinal axis of the stent and laid flat. The
stent is for use as a component of the inventive tubular
inserts.
[0045] FIG. 7c shows an inventive tubular insert which has been cut
open along a line parallel to the longitudinal axis of the stent
and laid flat.
[0046] FIG. 8a shows a stent which has been cut open along a line
parallel to the longitudinal axis of the stent and laid flat. The
stent is for use as a component of the inventive tubular
inserts.
[0047] FIG. 8b shows a stent which has been cut open along a line
parallel to the longitudinal axis of the stent and laid flat. The
stent is for use as a component of the inventive tubular
inserts.
[0048] FIG. 8c shows an inventive tubular insert which has been cut
open along a line parallel to the longitudinal axis of the stent
and laid flat.
[0049] FIG. 9 shows another stent for use in the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0050] While this invention may be embodied in many different
forms, there are described in detail herein several specific
embodiments of the invention. This description is an
exemplification of the principles of the invention and is not
intended to limit the invention to the particular embodiments
illustrated.
[0051] For the purposes of this disclosure, like reference numerals
in the figures shall refer to like features unless otherwise
indicated.
[0052] In one embodiment, the invention is directed to a tubular
insert for a bodily vessel. The insert, as shown generally in the
flat at 100 in FIG. 2c, comprises an inner stent 104 and an outer
stent 108. At least a portion of inner stent 104 is disposed within
the outer stent 108. The outer stent has a longitudinal axis 110
and is constructed so as to be free of any closed loops which are
electrically conductive and which are disposed about the
longitudinal axis such that the longitudinal axis passes through
the closed loop. The inner stent has a longitudinal axis 110 and is
constructed so as to be free of any closed loops which are
electrically conductive and which are disposed about the
longitudinal axis such that the longitudinal axis passes through
the closed loop. There is at least one and desirably, a plurality
of substantially electrically non-conductive 112 connections
between the inner stent and the outer stent. Desirably, where a
wall surface is defined by the outer and inner stents, there are no
closed, substantially electrically conductive loops in the wall
surface of the tubular insert.
[0053] Typically, the inner stent or first stent will be a helical
stent, as shown schematically in FIG. 2a and the outer stent or
second stent will be a helical stent as shown schematically in FIG.
2b. Inner helical stent 104 has a proximal end 105 and a distal end
107 and a plurality of proximal turns 109 and distal turns 111.
Outer helical stent 108 has a proximal end 113 and a distal end 115
and a plurality of proximal turns 117 and distal turns 119.
[0054] Where helical stents are used, one of the outer stent (or
first stent) and inner stent (or second stent) extends generally
clockwise about the longitudinal axis of the stent from one end of
the stent to another, as shown in FIG. 2a and the other of the
outer stent (or first stent) and inner stent (or second stent)
extends in a generally counterclockwise direction about the
longitudinal axis of the stent, as shown in FIG. 2b.
[0055] Other variants of the stents of FIGS. 2a and 2b may be used
as well. For example, the stents may have loops which are oriented
at an oblique angle relative to the longitudinal axis.
[0056] An example of an inventive device is shown in tubular form
generally at 100 in FIG. 2e. The device includes an inner stent
104, an outer stent 108 and a plurality of connections 112.
[0057] It is within the scope of the invention to use other types
of stents for the outer (or first) and inner (or second) stents.
For example, the stent of U.S. Pat. No. 4,800,882 may be used. That
stent includes a plurality of interconnected loops which extend at
a perpendicular angle relative to the longitudinal axis of the
stent with the loops extending only part of the way about the
longitudinal axis of the stent. Two such stents may be used, each
of wind in opposing directions.
[0058] Helical stents having cells may also be used for the inner
stent and/or outer stent. In such a case, however, it is desirable
that the helical stent with the cells not have a closed,
electrically conductive pathway. Such a stent could be made by
including non-conductive material, for example any of the
non-conductive materials disclosed herein, in each cell of a metal
stent so as to prevent the formation of an electrically conductive
pathway. Desirably, the electrically non-conducting materials will
be provided in portions of the stent which are subjected to
compressive stress on expansion of the stent rather than in those
portions of the stent which will experience tension on expansion of
the stent. As such, the straight segments of a stent will be more
desirable locations for the non-conductive materials than the turns
of the stent.
[0059] Desirably, the tubular medical device or insert will have a
plurality of cells where each cell is defined by a portion of the
outer or first stent, a portion of the inner or second stent and at
least two connections between the outer or first stent and the
inner or second stent. An example of such a cell is highlighted in
FIG. 2d, an inset of FIG. 2c. Cell 130 is formed by a portion of
inner stent 104 and a portion of outer stent 108, joined together
by two connections 112. The cell lies partially in the tubular
envelope of the outer stent and partially in the tubular envelope
of the inner stent. Cells 130 do not form a continuous, closed
electrically conductive loop because the connection between the two
portions of the cells is substantially electrically
non-conductive.
[0060] Another embodiment of an inventive device is shown at 100 in
FIG. 3c. Tubular medical device or insert 100, shown in the flat in
FIG. 3c, comprises an inner stent 104 and an outer stent 108, shown
in FIGS. 3a and 3b, respectively. At least a portion of inner stent
104 is disposed within the outer stent 108. The outer stent has a
longitudinal axis 110 and is constructed so as to be free of any
closed loops which are electrically conductive and which are
disposed about the longitudinal axis such that the longitudinal
axis passes through the closed loop. The inner stent has a
longitudinal axis 110 and is constructed so as to be free of any
closed loops which are electrically conductive and which are
disposed about the longitudinal axis such that the longitudinal
axis passes through the closed loop. There is at least one and
desirably, a plurality of substantially electrically non-conductive
112 connections between the inner stent and the outer stent.
Desirably, where a wall surface is defined by the outer and inner
stents, there are no closed, substantially electrically conductive
loops in the wall surface of the tubular insert.
[0061] Inner stent 104 and outer stent 108 spiral in opposing
directions and have a steeper pitch than that shown in FIG. 2.
Desirably, as shown in FIGS. 3a and 3b, the stents are mirror
images of one another. The stents are arranged to overlap so as to
provide one or more large openings 164 in the regions in-between
where the inner and outer stents overlap with one another.
[0062] Desirably, the inner and outer stents will be provided with
substantially electrically non-conductive connectors therebetween.
An example of a suitable pattern of substantially electrically
non-conductive connectors 112 is shown in FIG. 3d. In the example
of FIG. 3d, connectors 112 are arranged about the periphery of
large openings 164. In the example of FIG. 3c, the connectors are
evenly spaced from one-another along the inner stent and are evenly
spaced from one-another along the outer stent. In general, the
connectors may be evenly spaced from one another or may be unevenly
spaced from one another on the inner and outer stents. In both
arrangements, the connectors are desirably distributed so that the
resulting device lacks electrically conductive closed loops.
[0063] Yet another embodiment of the invention is shown in FIG. 4c.
The insert of FIG. 4c is formed of two helical stents, inner stent
104 and outer stent 108 shown in FIGS. 4a and 4b. Desirably, the
inner and outer stents will be mirror images of one another, as
shown in FIGS. 4a and 4b. The stents of FIGS. 4a and 4b each have a
plurality of sections where the regular pattern of bends is
interrupted by a substantially straight, long segment 166. The
inner and outer stents are arranged such that the substantially
straight, long segments 166 of the inner and outer stents cross one
another. Typically, the straight, long segments will be
non-parallel to the longitudinal axis of the stent. As shown in
FIG. 4c, the segments cross one another to form a structure that
resembles an `X`. The inner and outer stents are desirably
connected one to the other in areas of overlap via substantially
non-electrically conduction connectors. Desirably, the stents are
interconnected at least in the area where the straight, long
segments cross one another. The stent of FIG. 4c includes a
plurality of substantially electrically non-conductive connections
112. It is also within the scope of the invention for there to be
fewer connections or for there to be more connections.
[0064] In yet another embodiment of the invention, as shown in FIG.
5a-5c, the pattern of bends in one of the stents is interrupted by
a straight section 166a which extends in a substantially
circumferential direction (shown in FIG. 5a) and the pattern of
bend in the other stent (FIG. 5b) is interrupted by a section which
includes a portion 166b which extends substantially in the
longitudinal direction. The inner and outer stents are arranged
such that the substantially straight, long segments 166a of one
stents crosses the portion 166b of the other stent which extends
substantially in the longitudinal direction. The crossing portion
defines a plurality of right angles between the circumferential and
longitudinal sections of the two stents. The inner and outer stents
are desirably connected one to the other in areas of overlap via
substantially non-electrically conduction connectors. In the device
of FIG. 5c, it is noted that the inner and outer stents are not
mirror images of one another. Desirably, the stents are
interconnected at least in the area where the straight, long
segments cross one another, as shown in FIG. 5c. Optionally, the
stents may be connected at regions of overlap so as to avoid the
presence of electrically conductive loops. As shown in FIG. 5c,
there are a series of connections on one side of the device and
another series of connections opposite the first series of
connections. Another pattern of connections is shown in FIG. 5d.
The device of FIG. 5d includes additional connections in between
the lines of connections which are opposite one another in the
device of FIG. 5c. The devices of FIGS. 5c and 5d as well as the
other devices disclosed herein may have fewer or more connections
than shown in FIGS. 5c and 5d.
[0065] Yet another embodiment is shown in FIG. 6c. The device of
FIG. 6c is similar to that of FIG. 4c, although the exact pattern
of overlap between inner stent 104 and outer stent 108 differs with
the regions of overlap more evenly spaced. In the device of FIG.
4c, there are fewer connections. A first line of connections 112a
extends up one side of the stent and a second line of connections
112b extends along the device opposite the first line of
connections.
[0066] The inventive medical devices or inserts may also be made
using overlapping stents which are not helical. An example of such
a device is shown in FIG. 7c. Stents 104, shown in FIG. 7a, winds
upward in a first helical direction and then winds helically
downward. The upward and downward pattern is optionally repeated
one or more times, as shown in FIG. 7a. The stent of FIG. 7b is a
mirror of the stent of FIG. 7a. Desirably, the inner and outer
stents will be connected one to the other via substantially
non-electrically conducting connectors in the areas where they
overlap one another, as shown in FIG. 7c, so as to avoid the
presence of electrically conductive loops. In the device of FIG.
7c, the connections may be seen as forming as plurality of lines of
connections which extend along the longitudinal axis.
[0067] Yet another inventive stent is shown in FIG. 8c. The stent
of FIG. 8c is made from inner stent 104, shown in FIG. 8a, and
outer stent 108, shown in FIG. 8b. Each of the inner stent and the
outer stent consists of a single member which winds from one end of
the stent to the other end of the stent and back again. Outer stent
108 is a mirror image of inner stent 104 about an axis that is
perpendicular to the longitudinal axis of the stent. Desirably, the
inner stent and the outer stent will be interconnected at a
plurality of locations with connectors that are substantially
electrically non-conductive so as to avoid the presence of
electrically conductive loops. The pattern of conections 112 as
shown in FIG. 8c includes a plurality of lines of connections which
extend longitudinally, The stent may also be prepared with more
connections or with fewer connections.
[0068] Other arrangements of inner and outer stents are also within
the scope of the invention.
[0069] Morover, the inner stent can have more undulations than the
outer stent or vice versa. In those cases where the undulations may
be characterized as having a frequency and an amplitude, the inner
stent and outer stent may have different frequencies and/or
amplitudes, or the same frequencies and/or amplitudes. The inner
stent may be made of a thicker or a thinner material than the outer
stent or vice versa, or they may be of the same thickness. The
inner and outer stents may be made of the same material or a
different material. The material of the inner stent may be wider or
narrower than the material of the outer stent or of the same
width.
[0070] Another example of a stent that is suitable for use as an
inner stent and/or an outer stent is illustrated in FIG. 9.
Connectors 205, shown as shaded, may be made of a substantially
electrically non-conductive material, such as, for example, a
polymeric material and at least a portion 211 (shown as hatched) of
each circumferential band may include an electrically
non-conductive material. More details about the use of polymeric
connectors in a stent such as that shown in FIG. 1 are disclosed in
U.S. Pat. No. 6,409,754. Thus, each cell 215 (shown as hatched) has
at least one electrically non-conducting portion 211 and/or 205 and
an electrically conductive portion 219. Similarly, each closed
circumferential path about the stent includes at least one
electrically non-conducting portion 211 and/or 205 and an
electrically conductive portion 219. Desirably, the electrically
non-conductive portions will be provided in portions of the stent
which are subjected to compressive stress on expansion of the stent
rather than in those portions of the stent which will experience
tension on expansion of the stent. As such, the straight segments
of a stent will be more desirable locations for the non-conductive
materials than the turns of the stent.
[0071] Two such stents may be coupled one to another at one or more
locations using an electrically non-conductive material, in an
arrangement similar to that disclosed with respect to FIG. 1. The
connectivity between the inner and outer stents is such as to avoid
providing any electrically conductive closed loops.
[0072] The invention is also directed to an expandable member for
implantation in a bodily vessel where the expandable member
comprises a multilayer tubular wall surface formed of a plurality
of interconnected struts disposed at different distances from a
centerline which runs along a longitudinal axis of the stent. The
struts define a plurality of interconnected cells, each cell
including an electrically conducting portion and an electrically
non-conductive portion. The tubular member includes pathways which
form closed paths about the circumference of the stent, each closed
path including at least one substantially electrically
non-conducting portion and one electrically conducting portion. An
example of such a tubular member is shown in FIG. 2e. The inventive
tubular member may also be formed from a single stent which has
multiple layers of struts.
[0073] In any of the inventive tubular medical devices and inserts
disclosed herein as well as in any of the inventive methods
disclosed herein, the substantially electrically non-conductive
connection(s) between stents will typically comprise one or more
plastics, adhesives, composites or ceramics or combinations
thereof. In the case of a plastic, any suitable biocompatible
plastic may be used. Examples of suitable plastics include but are
not limited to suitable polymeric materials such as thermotropic
liquid crystal polymers (LCP's). In the case of adhesives, the
adhesive may be biocompatible. In the case of ceramics, the
ceramics should be biocompatible. Examples of suitable ceramics
include without limitation, hydroxyapatite, alumina and pyrolytic
carbon. Desirably, the ceramic will be curable. Suitable materials
include nitrides, oxides, silicides, and carbides. It is also with
the scope of the invention for the connections to be in the form of
substantially electrically non-conductive metals which are
biocompatible. Additionally, any or all materials may be
non-biocompatible, as long as a biocompatible coating encases the
entire geometry.
[0074] Desirably, at least one and more desirably both the outer
(or first) stent and the inner (or second) stent are made from a
magnetic resonance compatible material. Examples of magnetic
resonance compatible materials include non-ferromagnetic metals
such as Elgiloy and other alloys of cobalt, chromium and nickel,
Nitinol and other nickel based materials, Phynox, MP35N, titanium,
titanium alloy, tantalum and tantalum alloy. The inner or second
and outer or first stents may both be made of a conductive material
with an electrically non-conductive material disposed
thereabout.
[0075] The isolation between the first and second stents may also
be achieved by providing drug and/or polymeric and/or ceramic
coatings to a portion of the stents or to the entirety the stent.
Where the coating(s) are provided only to portions of the stent,
the coating(s) would be provided at least in the regions of contact
between the two stents. Of course, the coating need be applied to
only one of the two stents but it may optionally be provided to
both stents. Suitable drugs and polymeric coatings include those
disclosed elsewhere in this disclosure.
[0076] The invention is also directed to a method of delivering any
of the inventive medical devices disclosed herein to a desired
location in the body comprising disposing the medical device, for
example, the tubular inserts disclosed herein, about a catheter,
delivering the medical device to the desired bodily location using
the catheter and deploying the medical device. Methods of
deployment include allowing the medical device to self-expand in
the case of self-expanding tubular inserts and using a medical
balloon to expand the medical device in the case of balloon
expandable tubular inserts. Balloon catheters are well known in the
art. An example of a balloon catheter is disclosed in U.S. Pat. No.
6,506,201. An example of a self-expanding stent delivery catheter
is disclosed in U.S. Pat. No. 6,120,522.
[0077] The inventive stents may also be used to stent bifurcated
regions. A more detailed discussion of stenting bifurcated regions
may be found in U.S. application Ser. No. 10/084,766 as well as in
U.S. Pat. No. 5,749,825 to Fischell. To that extent, the invention
is also directed to a method of stenting a bifurcated region of a
vessel comprising the steps of providing any of the inventive
stents disclosed herein, disposing them about a catheter,
delivering the stent to a bifurcated region and deploying the
stent. An additional stent may be deployed through one of the cells
of an inventive stent into one of the branch vessels using any
suitable technique including that disclosed in U.S. Pat. No.
5,749,825.
[0078] The invention is also directed to a method of imaging a
tubular medical device where the tubular medical device is in the
form of an outer stent and an inner stent. At least a portion of
the inner stent is disposed within the outer stent. The outer stent
has a longitudinal axis and is constructed so as to be free of any
closed loops which are electrically conductive and are disposed
about the longitudinal axis such that the longitudinal axis passes
through the closed loop. The inner stent has a longitudinal axis
and is constructed so as to be free of any closed loops which are
electrically conductive; and are disposed about the longitudinal
axis such that the longitudinal axis passes through the closed
loop. There is a substantially non-electrically conductive
connection between the inner stent and the outer stent. Desirably,
where a wall surface is defined by the outer and inner stents,
there are no closed, substantially electrically conductive loops in
the wall surface of the tubular insert. The method comprises the
steps of disposing the tubular medical device within a magnetic
resonance imager; using the magnetic resonance imager to obtain a
magnetic resonance image of the tubular medical device and removing
the tubular medical device from the magnetic resonance imager.
[0079] In one embodiment, the inventive method of imaging a tubular
medical device is carried with the tubular medical device located
within a living body when it is disposed within the magnetic
resonance imager. In another embodiment, the tubular medical device
is not located within a living body when it is disposed within the
magnetic resonance imager.
[0080] The invention is also directed to a method of manufacturing
a tubular medical device comprising the steps of providing a first
stent and a second stent, disposing at least a portion of the
second stent within the first stent and connecting the first stent
and the second stent together via a connection which is
substantially non-electrically conductive. The first stent has a
longitudinal axis and is constructed so as to be free of any closed
loops which are electrically conductive and disposed about the
longitudinal axis such that the longitudinal axis passes through
the closed loop. The second stent has a longitudinal axis and is
constructed so as to be free of any closed loops which are
electrically conductive and disposed about the longitudinal axis
such that the longitudinal axis passes through the closed loop.
There is a substantially non-electrically conductive connection
between the first stent and the second stent. Desirably, where a
wall surface is defined by the first and second stents, there are
no closed, substantially electrically conductive loops in the wall
surface of the tubular medical device which form a loop about the
longitudinal axis. More desirably, there are no closed,
substantially electrically conductive loops in the wall surface of
the tubular medical device regardless of whether they extend about
a longitudinal axis or a radial axis.
[0081] The stents disclosed herein may be self-expanding or balloon
expandable or a hybrid of the two. In the case of a self-expanding
stent, the device will be made from spring steel, a shape-memory
metal such as nitinol, a shape memory polymer or any other suitable
material. In the case of a balloon expandable stent, the stent may
be made of metals such as stainless steel, titanium, tantalum or
any other suitable material.
[0082] The invention has been discussed in particular with respect
to stents. It is directed more generally to other tubular inserts
as well including distal protection devices and vena cava filters.
Also, the stents disclosed herein may serve as frameworks for
grafts.
[0083] Any of the inventive medical devices disclosed herein may
include one or more coatings and/or other delivery mechanisms which
comprise one or more therapeutic agents, cellular materials,
polymeric agents, drugs, etc. The coating and/or other delivery
mechanism may be provided on the outer (first) stent or portions
thereof, on the inner (second) stent or portions thereof or both
stents or portions thereof.
[0084] The therapeutic agent may be non-genetic or genetic.
Suitable non-genetic therapeutic agents include anti-thrombogenic
agents such as heparin, heparin derivatives, urokinase, and PPack
(dextrophenylalanine proline arginine chloromethylketone),
anti-proliferative agents such as enoxaprin, angiopeptin, or
monoclonal antibodies capable of blocking smooth muscle cell
proliferation, hirudin, and acetylsalicylic acid, anti-inflammatory
agents such as dexamethasone, prednisolone, corticosterone,
budesonide, estrogen, sulfasalazine, and mesalamine,
antineoplastic/antiproliferative/anti-miotic agents such as
paclitaxel, 5-fluorouracil, cisplatin, vinblastine, vincristine,
epothilones, endostatin, angiostatin and thymidine kinase
inhibitors, anesthetic agents such as lidocaine, bupivacaine, and
ropivacaine, anti-coagulants such as D-Phe-Pro-Arg chloromethyl
keton, an RGD peptide-containing compound, heparin, antithrombin
compounds, platelet receptor antagonists, antithrombin antibodies,
anti-platelet receptor antibodies, aspirin, prostaglandin
inhibitors, platelet inhibitors and tick antiplatelet peptides,
vascular cell growth promoters such as growth factor inhibitors,
growth factor receptor antagonists, transcriptional activators, and
translational promoters, vascular cell growth inhibitors such as
growth factor inhibitors, growth factor receptor antagonists,
transcriptional repressors, translational repressors, replication
inhibitors, inhibitory antibodies, antibodies directed against
growth factors, bifunctional molecules consisting of a growth
factor and a cytotoxin, bifunctional molecules consisting of an
antibody and a cytotoxin, cholesterol-lowering agents; vasodilating
agents; and agents which interfere with endogenous vascoactive
mechanisms.
[0085] Suitable genetic materials include anti-sense DNA and RNA,
DNA coding for anti-sense RNA, tRNA or rRNA to replace defective or
deficient endogenous molecules, angiogenic factors including growth
factors such as acidic and basic fibroblast growth factors,
vascular endothelial growth factor, epidermal growth factor,
transforming growth factor .alpha. and .beta., platelet-derived
endothelial growth factor, platelet-derived growth factor, tumor
necrosis factor .alpha., hepatocyte growth factor and insulin like
growth factor, cell cycle inhibitors including CD inhibitors,
thymidine kinase ("TK") and other agents useful for interfering
with cell proliferation, the family of bone morphogenic proteins
("BMP's"), BMP-2, BMP-3, BMP-4, BMP-5, BMP-6 (Vgr-1), BMP-7 (OP-1),
BMP-8, BMP-9, BMP-10, BMP-11, BMP-12, BMP-13, BMP-14, BMP-15, and
BMP-16. Any of BMP-2, BMP-3, BMP-4, BMP-5, BMP-6 and BMP-7 are
particularly desirable. These dimeric proteins can be provided as
homodimers, heterodimers, or combinations thereof, alone or
together with other molecules. Alternatively or, in addition,
molecules capable of inducing an upstream or downstream effect of a
BMP can be provided. Such molecules include any of the "hedgehog"
proteins, or the DNA's encoding them.
[0086] Suitable cellular materials include cells of human origin
(autologous or allogeneic) or from an animal source (xenogeneic),
genetically engineered if desired to deliver proteins of interest
at the transplant site. The delivery media can be formulated as
needed to maintain cell function and viability.
[0087] Suitable polymer coating materials include polycarboxylic
acids, cellulosic polymers, including cellulose acetate and
cellulose nitrate, gelatin, polyvinylpyrrolidone, cross-linked
polyvinylpyrrolidone, polyanhydrides including maleic anhydride
polymers, polyamides, polyvinyl alcohols, copolymers of vinyl
monomers such as EVA, polyvinyl ethers, polyvinyl aromatics,
polyethylene oxides, glycosaminoglycans, polysaccharides,
polyesters including polyethylene terephthalate, polyacrylamides,
polyethers, polyether sulfone, polycarbonate, polyalkylenes
including polypropylene, polyethylene and high molecular weight
polyethylene, halogenated polyalkylenes including
polytetrafluoroethylene, polyurethanes, polyorthoesters, proteins,
polypeptides, silicones, siloxane polymers, polylactic acid,
polyglycolic acid, polycaprolactone, polyhydroxybutyrate valerate
and blends and copolymers thereof, coatings from polymer
dispersions such as polyurethane dispersions (BAYHDROL.RTM., etc.),
fibrin, collagen and derivatives thereof, polysaccharides such as
celluloses, starches, dextrans, alginates and derivatives,
hyaluronic acid, squalene emulsions. Desirably, polyacrylic acid,
available as HYDROPLUS.RTM. (Boston Scientific Corporation, Natick,
Mass.), and described in U.S. Pat. No. 5,091,205, the disclosure of
which is hereby incorporated herein by reference, may be used. Also
desirably, the polymer may be a copolymer of polylactic acid and
polycaprolactone. Other materials include selected medical-grade
biodegradable materials such as PGA-TMC, Tyrosine-Derived
Polycarbonates and arylates, polycaprolactone co butyl acrylate and
other co polymers, Poly-L-lactic acid blends with DL-Lactic Acid,
Poly(lactic acid-co-glycolic acid), polycaprolactone co PLA,
polycaprolactone co butyl acrylate and other copolymers,
Tyrosine-Derived Polycarbonates and arylate, poly amino acid,
polyphosphazenes, polyiminocarbonates,
polydimethyltrimethylcarbonates, biodegradable CA/PO4's,
cyanoacrylate, 50/50 DLPLG, polydioxanone, polypropylene fumarate,
or polydepsipeptides.
[0088] Other suitable coatings include macromolecules such as
chitosan and Hydroxylpropylmethylcellulose. Surface erodible
materials may also be used. Coatings may also comprise maleic
anhydride copolymers, zinc-calcium phosphate and amorphous
polyanhydrides.
[0089] The inventive medical devices may also be provided with a
sugar or more generally a carbohydrate and/or a gelatin to maintain
the inventive medical devices on a balloon during delivery of the
medical device to a desired bodily location. Other suitable
compounds for treating the inventive medical devices include
biodegradable polymers and polymers which are dissolvable in bodily
fluids. Portions of the interior and/or exterior of the inventive
medical devices may be coated or impregnated with the compound.
Mechanical retention devices may also be used to maintain the
inventive medical devices on the balloon during delivery.
[0090] The inventive medical devices may also be provided in whole
or in part with one or more of the above therapeutic agents,
polymeric coatings or the like. Where multiple therapeutic agents
are provided, different coatings and/or mechanisms may release the
drugs at different rates. For example, one therapeutic agent may be
released at a fast rate and another therapeutic agent may be
released at a slow rate. Where multiple polymeric coatings are
provided, the coatings may degrade or erode at different rates.
[0091] The inventive medical devices disclosed herein may also be
provided with radiopaque markers. The radiopacity may be provided
through any suitable process known in the art including but not
limited to using a radiopaque coating, for example a noble metal
coating such as gold, affixing a radiopaque marker to the stent or
providing an area of the stent with an enlarged mass of metal as
compared with the remainder of the stent.
[0092] The above disclosure is intended to be illustrative and not
exhaustive. This description will suggest many variations and
alternatives to one of ordinary skill in this art. All these
alternatives and variations are intended to be included within the
scope of the claims where the term "comprising" means "including,
but not limited to". Those familiar with the art may recognize
other equivalents to the specific embodiments described herein
which equivalents are also intended to be encompassed by the
claims.
[0093] Further, the particular features presented in the dependent
claims can be combined with each other in other manners within the
scope of the invention such that the invention should be recognized
as also specifically directed to other embodiments having any other
possible combination of the features of the dependent claims. For
instance, for purposes of claim publication, any dependent claim
which follows should be taken as alternatively written in a
multiple dependent form from all prior claims which possess all
antecedents referenced in such dependent claim if such multiple
dependent format is an accepted format within the jurisdiction
(e.g. each claim depending directly from claim 1 should be
alternatively taken as depending from all previous claims). In
jurisdictions where multiple dependent claim formats are
restricted, the following dependent claims should each be also
taken as alternatively written in each singly dependent claim
format which creates a dependency from a prior
antecedent-possessing claim other than the specific claim listed in
such dependent claim below.
[0094] This completes the description of the preferred and
alternate embodiments of the invention. Those skilled in the art
may recognize other equivalents to the specific embodiment
described herein which equivalents are intended to be encompassed
by the claims attached hereto.
* * * * *