U.S. patent application number 17/397150 was filed with the patent office on 2022-01-27 for catheter curve shape strut.
The applicant listed for this patent is St. Jude Medical, Atrial Fibrillation Division, Inc.. Invention is credited to Sameer Pai.
Application Number | 20220023594 17/397150 |
Document ID | / |
Family ID | 1000005898525 |
Filed Date | 2022-01-27 |
United States Patent
Application |
20220023594 |
Kind Code |
A1 |
Pai; Sameer |
January 27, 2022 |
CATHETER CURVE SHAPE STRUT
Abstract
Catheter curve shape struts for steerable medical devices such
as catheters are disclosed. These struts may not only help shape a
steerable portion of a medical device (e.g., a distal portion of a
catheter), but also may help to return a steered or deflected
portion of the medical device to an uncurved configuration when it
is no longer desirable or necessary to steer or deflect the medical
device. These struts may include first and second pluralities of
complementary, staggered cutout regions. When used in a catheter
that is deployed via an introducer, at least some configurations of
the catheter curve shape strut can enable the catheter to be
rotated about its longitudinal axis, even when the distal
deflectable section is in a curved configuration and inside of the
introducer.
Inventors: |
Pai; Sameer; (Plymouth,
MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
St. Jude Medical, Atrial Fibrillation Division, Inc. |
St. Paul |
MN |
US |
|
|
Family ID: |
1000005898525 |
Appl. No.: |
17/397150 |
Filed: |
August 9, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15103723 |
Jun 10, 2016 |
11116941 |
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PCT/US2014/066579 |
Nov 20, 2014 |
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17397150 |
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61914346 |
Dec 10, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 25/0147 20130101;
A61B 2218/002 20130101; A61M 2205/0266 20130101; A61M 25/0138
20130101; A61B 18/1492 20130101; A61B 1/0055 20130101; A61B
2018/00577 20130101 |
International
Class: |
A61M 25/01 20060101
A61M025/01 |
Claims
1-39. (canceled)
40. A deflectable insert component comprising the following: a
longitudinally-extending body configured to facilitate planar
deflection of the deflectable component, the
longitudinally-extending body having an inner surface and an outer
surface and extending along a body longitudinal axis, the
longitudinally-extending body comprising three
longitudinally-extending lumens, including a central lumen
straddled by a pair of offset pull wire lumens, wherein the central
lumen is symmetrically disposed about a first imaginary plane of
symmetry extending through the central lumen and through each of
the pull wire lumens, and wherein the body longitudinal axis lies
in the first imaginary plane of symmetry, wherein the offset pull
wire lumens are diametrically-opposed, and wherein each of the pair
of wire lumens inwardly displaces a section of the inner surface of
the longitudinally-extending body.
41. The deflectable insert component of claim 40, wherein the outer
surface of the longitudinally-extending body has a cylindrical
configuration.
42. The deflectable insert component of claim 40, wherein the outer
surface of the longitudinally-extending body is circular in cross
section.
43. The deflectable insert component of claim 40, wherein the first
imaginary plane of symmetry divides the longitudinally-extending
body into a first hemicylindrical half-body and a second
hemicylindrical half-body.
44. The deflectable insert component of claim 40, wherein the inner
surface of the longitudinally-extending body circumscribes the
central lumen.
45. The deflectable insert component of claim 40, wherein the first
imaginary plane of symmetry divides the central lumen into a first
complementary lobed region and a second complementary lobed region,
and wherein the first complementary lobed region is a mirror image
of the second complementary lobed region.
46. The deflectable insert component of claim 45, wherein the first
complementary lobed region of the central lumen is partially
circumscribed by a first convex section of the inner surface of the
longitudinally-extending body; and wherein the second complementary
lobed region of the central lumen is partially circumscribed by a
second convex section of the inner surface of the
longitudinally-extending body.
47. The deflectable insert component of claim 40, wherein the
central lumen is symmetrically disposed about a second imaginary
plane of symmetry that is perpendicular to the first imaginary
plane of symmetry, and wherein the second imaginary plane of
symmetry divides the central lumen into a first complementary,
concave region and a second complementary concave region.
48. The deflectable insert component of claim 47, wherein the pair
of offset pull wire lumens comprises a first pull wire lumen and a
second pull wire lumen, wherein the first complementary concave
region is adjacent to the first pull wire lumen, and wherein the
second complementary concave region is adjacent to the second pull
wire lumen.
49. The deflectable insert component of claim 47, wherein the first
complementary concave region is a mirror image of the second
complementary concave region, wherein the first complementary
concave region extends partially around the first pull wire lumen,
and wherein the second complementary concave region extends
partially around the second pull wire lumen.
50. The deflectable insert component of claim 40, wherein the
central lumen has a cross-sectional configuration comprising
centrally-located, concave regions adapted to accommodate the
offset pull wire lumens.
51. The deflectable insert component of claim 50, wherein the
concave regions comprise two diametrically-opposed concave regions,
and wherein each of the two diametrically-opposed concave regions
accommodates one of the two offset pull wire lumens between the
inner surface and the outer surface of the longitudinally-extending
body.
52. The deflectable insert component of claim 40, wherein the pull
wire lumens extend parallel to the body longitudinal axis and are
located between the inner surface and the outer surface of the
longitudinally-extending body.
53. The deflectable insert component of claim 40, wherein the pull
wire lumens are diametrically-opposed.
54. The deflectable insert component of claim 40, wherein the
longitudinally-extending body is formed from an extruded
polymer.
55. The deflectable insert component of claim 40, wherein the
longitudinally-extending body is configured to be inserted into a
catheter curve shape strut.
56. The deflectable insert component of claim 55, wherein the
combined longitudinally-extending body and catheter curve shape
strut are configured to be inserted into an outer body of a distal
deflectable section of a catheter.
Description
[0001] This application is a continuation of U.S. application Ser.
No. 15/103,723, filed 10 Jun. 2016 (the '723 application), which is
the national stage application of International application no.
PCT/US2014/066579, filed 20 Nov. 2014 (the '579 application) and
published under International publication no. WO/2015/088733 on 18
Jun. 2015. This application claims the benefit of U.S. provisional
application No. 61/914,346, filed 10 Dec. 2013 (the '346
application). The '723 application, '579 application and the '346
application are all hereby incorporated by reference in their
entirety as though fully set forth herein.
BACKGROUND
a. Field
[0002] The instant disclosure relates to components for steerable
medical devices. In one particular form, the disclosure relates to
a strut comprising part of a distal deflectable section of an
electrophysiology catheter to facilitate predictable and repeatable
asymmetric and symmetric deflection of the distal deflectable
section.
b. Background Art
[0003] Electrophysiology catheters are used in a variety of
diagnostic, therapeutic, and/or mapping and ablative procedures to
diagnose and/or correct conditions such as atrial arrhythmias,
including for example, ectopic atrial tachycardia, atrial
fibrillation, and atrial flutter. Arrhythmias can create a variety
of conditions including irregular heart rates, loss of synchronous
atrioventricular contractions, and stasis of blood flow in a
chamber of a heart, which can lead to a variety of symptomatic and
asymptomatic ailments and even death.
[0004] Typically, a catheter is deployed and manipulated through a
patient's vasculature to the intended site, for example, a site
within a patient's heart. The catheter typically carries one or
more electrodes that can be used for cardiac mapping or diagnosis,
ablation, and/or other therapy delivery modes, or both, for
example. Once at the intended site, treatment can include, for
example, radio frequency (RF) ablation, cryoablation, laser
ablation, chemical ablation, high-intensity focused
ultrasound-based ablation, microwave ablation, and/or other
ablation treatments. In some procedures, the catheter imparts
ablative energy to cardiac tissue to create one or more lesions in
the cardiac tissue. These lesions disrupt undesirable cardiac
activation pathways and thereby limit, corral, or otherwise prevent
errant conduction signals that can form the basis for
arrhythmias.
[0005] To position a catheter within the body at a desired site,
some type of navigation must be used, such as using mechanical
steering features incorporated into the catheter (or an introducer
sheath). In some examples, medical personnel may manually
manipulate and/or operate the catheter using the mechanical
steering features.
[0006] In order to facilitate the advancement of catheters through
a patient's vasculature, the simultaneous application of torque at
the proximal end of the catheter and the ability to selectively
deflect the distal tip of the catheter in a desired direction can
permit medical personnel to adjust the direction of advancement of
the distal end of the catheter and to selectively position the
distal portion of the catheter during an electrophysiological
procedure. The proximal end of the catheter can be manipulated to
guide the catheter through a patient's vasculature. The distal tip
can be deflected by a pull wire or other tension member attached or
anchored at the distal end of the catheter and extending proximally
to an actuator in a control handle that controls the application of
tension on the pull wire.
[0007] The foregoing discussion is intended only to illustrate the
present field and should not be taken as a disavowal of claim
scope.
BRIEF SUMMARY
[0008] It is desirable to be able to ensure that a deflectable
portion of a catheter shaft may be predictably deflected in a
preferentially-planer manner whenever desired throughout a medical
procedure. It is also desirable to be able to tailor total
deflectability of the catheter distal portion and the curve shape
of the deflectable portion throughout the full deflection of the
catheter shaft.
[0009] In one embodiment, a catheter curve shape strut comprises a
longitudinally-extending cylindrical wall, the wall having an outer
surface, an outer surface circumference, and an outer surface
length measured longitudinally. The wall comprises connected
end-to-end cylindrical sections including at least a first
cylindrical section and a second cylindrical section. There are a
plurality of first slots through the cylindrical wall and
sequentially arranged along a first line extending longitudinally
along the wall outer surface in both the first cylindrical section
and the second cylindrical section. There are a plurality of second
slots through the cylindrical wall and sequentially arranged along
a second line extending longitudinally along the wall outer surface
in both the first cylindrical section and the second cylindrical
section. The slots in the plurality of second slots are
longitudinally offset from the slots in the plurality of first
slot. Also, the plurality of second slots further comprises second
slots of a first type and second slots of a second type. The second
slots of the first type are sequentially arranged along the second
line only along the first cylindrical section, and the second slots
of the second type are sequentially arranged along the second line
only along the second cylindrical section. In some embodiments, the
second slots of the second type are longer in a circumferential
dimension than one-half of the outer surface circumference, whereby
at least some of the second slots of the second type
circumferentially overlap with at least some of the slots in the
first plurality of slots. An expansion gap may be present between
at least some of the end-to-end cylindrical sections.
[0010] In another embodiment, a catheter curve shape strut is
configured to facilitate preferentially-planar, asymmetric
deflection of a medical device. The catheter curve shape strut
comprises the following: (1) a longitudinally-extending cylindrical
wall, the wall having an outer surface, an outer surface
circumference, and an outer surface length measured longitudinally,
wherein a first line extends longitudinally along the outer
surface, wherein a second line extends longitudinally along the
outer surface, and wherein the second line is circumferentially
offset from the first line by 180 degrees; (2) a plurality of first
slots through the cylindrical wall and sequentially present along
the first line, wherein each first slot has a first slot length
measured circumferentially on the outer surface between first slot
ends, wherein each first slot has a first slot width measured
longitudinally on the outer surface, and wherein the first slot
length is greater than the first slot width; (3) a plurality of
first arches, wherein each first arch is present between a pair of
longitudinally-adjacent first slots, wherein each first arch has a
first arch length measured circumferentially on the outer surface,
wherein each first arch has a first arch width measured
longitudinally on the outer surface, and wherein the first arch
length is greater than the first arch width; (4) a plurality of
second slots through the cylindrical wall and sequentially present
along the second line, wherein each second slot has a second slot
length measured circumferentially on the outer surface between
second slot ends, wherein each second slot has a second slot width
measured longitudinally on the outer surface, and wherein the
second slot length is greater than the second slot width; and; (5)
a plurality of second arches, wherein each second arch is present
between a pair of longitudinally-adjacent second slots, wherein
each second arch has a second arch length measured
circumferentially on the outer surface, wherein each second arch
has a second arch width measured longitudinally on the outer
surface, and wherein the second arch length is greater than the
second arch width, wherein at least one of the first slot length
and the second slot length is greater than one-half of the outer
surface circumference. The catheter curve shape strut may further
comprise a plurality of bridges connecting the first arches to the
second arches. The plurality of bridges may define first and second
diametrically-opposed serpentine backbones. The catheter curve
shape strut may further comprise at least two alignment tabs on
each longitudinal end of the strut.
[0011] In yet another embodiment, a catheter curve shape strut
assembly comprises a curve shape strut, an outer body surrounding
the curve shape strut, and an insert component surrounded by the
curve shape strut. The outer body may comprise a single polymer
layer. The insert component may be formed from an extruded polymer
and may comprise three longitudinally-extending lumens, including a
central lumen straddled by a pair of pull wire lumens that may be
diametrically-opposed.
[0012] In another embodiment, a distal deflectable portion of an
ablation catheter comprises a catheter curve shape strut assembly,
a tip electrode affixed to the distal end of the catheter curve
shape strut assembly, a plurality of ring electrodes affixed to the
catheter curve shape strut assembly proximal to the tip electrode,
a pull ring affixed to the catheter curve shape strut assembly
proximal to the plurality of ring electrodes, a coupler affixed to
the proximal end of the catheter curve shape strut assembly, and
first and second pull wires, each pull wire having a distal end
affixed to the pull ring. The first pull wire may extend proximally
from the pull ring through the first pull wire management channel,
and the second pull wire may extend proximally from the pull ring
through the second pull wire management channel.
[0013] In a further embodiment, a catheter comprises an elongated
catheter shaft comprising a distal deflectable section, first and
second pull wires (each pull wire having a proximal end and a
distal end) extending along the elongated catheter shaft, an
actuator operatively coupled to the proximal ends of the first and
second pull wires and adapted selectively deflect the distal
deflectable section, a curve shape strut assembly comprising part
of the distal deflectable section and itself comprising a curve
shape strut mounted within an outer jacket, and a pull ring affixed
to the distal ends of the first and second pull wires.
[0014] The foregoing and other aspects, features, details,
utilities, and advantages of the present disclosure will be
apparent by reading the following description and claims, and from
reviewing the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 depicts a representative ablation catheter having a
distal deflectable section configured to create asymmetric curve
shapes when deflected in different directions, as represented by
the two curves shown in phantom.
[0016] FIG. 2 is a fragmentary, isometric view of a portion of the
distal deflectable section, with sections on each end broken away
to reveal various details.
[0017] FIG. 3 is a fragmentary, isometric view of the proximal end
of a strut assembly and pull wires, with a portion of an outer body
of the strut assembly removed to show various features of a strut
and of an insert component comprising part of the strut
assembly.
[0018] FIG. 4 is a cross-sectional view taken along line 4-4 of
FIG. 3.
[0019] FIG. 5 is an isometric view of a strut assembly, depicted
with a strut shown in phantom within the outer body of the strut
assembly, and with the pull wires removed.
[0020] FIG. 6 is a cross-sectional view of the strut assembly
depicted in FIG. 5, taken along line 6-6 of FIG. 5.
[0021] FIG. 7 is a cross-sectional view of the strut assembly
depicted in FIG. 5, taken along line 7-7 of FIG. 5.
[0022] FIG. 8 is an exploded, isometric, assembly view of the strut
assembly depicted in FIGS. 5-7, revealing details about the
components of the strut assembly.
[0023] FIG. 9 is a cross-sectional view of the insert component,
taken along line 9-9 of FIG. 8.
[0024] FIG. 10 is a side view of a strut according to one
embodiment.
[0025] FIG. 11 is an end view of the strut depicted in FIG. 10,
taken in the direction of line 11-11 in FIG. 10.
[0026] FIG. 12 is a planar view of a flat, two-dimensional cut
pattern that could be used to automate the production of the strut
depicted in, for example, FIG. 10.
[0027] FIG. 13 is an enlarged view of the circled portion of FIG.
12.
[0028] FIG. 14 is a greatly enlarged, fragmentary view of a portion
of a cut pattern such as the one depicted in FIG. 12, depicting
further details about the construction and components of a
strut.
[0029] FIG. 15 schematically depicts a representative view of an
arch compromising part of a strut, and provides details regarding
the parameters used to describe an arch configuration.
[0030] FIG. 16 is an isometric view of a strut according to another
embodiment.
[0031] FIG. 17 is an isometric view of another embodiment of a
strut, shown adjacent to a representative pull ring.
[0032] FIGS. 18-20 depict different embodiments of two-dimensional
cut patterns that could be used to form various strut embodiments,
each having stiffness that varies along the longitudinal axis of
the strut.
[0033] FIG. 21 is a fragmentary, isometric view of a representative
distal deflectable section of an ablation catheter having a
flexible, irrigation tip, a strut assembly, and a coupler for
attaching the distal deflectable section to a proximal catheter
shaft.
[0034] FIGS. 22 and 23 are enlarged, fragmentary views of the
distal portion of the distal deflectable section depicted in FIG.
21, and provide further details about the placement of various
components.
[0035] FIGS. 24 and 25 are enlarged, fragmentary, isometric views
of the proximal portion of the distal deflectable section depicted
in FIG. 21, and show the alignment tabs in position on a tab
alignment ring comprising part of one possible embodiment of a
coupler.
[0036] FIGS. 26 and 27 are enlarged, isometric views of the coupler
that is also depicted in FIGS. 21, 24, and 25.
[0037] FIGS. 28-30 schematically depict a distal deflectable
section comprising a strut assembly before a severe kink, while
having a severe kink, and after recovering from a severe kink.
DETAILED DESCRIPTION
[0038] FIG. 1 depicts a representative catheter 10 compromising a
catheter curve shape strut (not directly visible in FIG. 1). In
particular, this catheter includes a handle 12 and a catheter shaft
14. The handle 12 comprises a housing 16 that houses an actuator
(not shown). The catheter shaft comprises a proximal section 18 and
a distal deflectable section 20 connected at a juncture 22. As
shown in FIG. 1, the distal deflectable section 20 is mounted to
the distal end of the proximal catheter shaft and includes, in this
embodiment, three ring electrodes 24 and a tip electrode. As shown
in phantom in FIG. 1, the catheter curve shaped strut comprising
part of the distal deflectable section 20 facilitates the formation
of asymmetric curves upon deflection of the distal section in
different directions. Although the phantom lines in this figure
schematically depict the curves commencing from the same
longitudinal position along the catheter shaft, the curves could
each commence at a different longitudinal location along the
catheter shaft. Also, and as discussed further below, although FIG.
1 depicts asymmetric curves, the distal deflectable section could
be constructed to deflect symmetrically.
[0039] FIG. 2 is a fragmentary, isometric view of a portion of the
distal deflectable section depicted in FIG. 1. In FIG. 2, however,
the ring electrodes and tip electrode have been removed, and the
distal deflectable section 20 has been separated from the proximal
catheter shaft 18. In this figure, a portion of the outer body (or
outer jacket or outer layer) 28 of the distal deflectable section
has been broken away on the distal end (i.e., the left-hand end as
oriented in FIG. 2) of the distal deflectable section to reveal a
representative pull ring 30. Similarly, at the proximal end (i.e.,
the right-hand end as oriented in FIG. 2) of the distal deflectable
section 20, another fragment of the outer body has been broken away
to reveal first and second pull wires 32, 34, respectively,
entering the proximal end of the distal deflectable section on
their way to the pull ring. As shown in FIG. 2, first and second
tightly-wound compression coils 36, 38 may surround the first and
second pull wires 32, 34, respectively. Although these compression
coils are shown in FIG. 2 to terminate just proximal to the
proximal end of the distal deflectable section, these tightly-wound
compression coils, in reality, may extend through the entire length
of the proximal catheter shaft 18 to the handle 12.
[0040] FIG. 3 is an enlarged, fragmentary, isometric view of the
proximal end of the distal deflectable section, shown with a
portion of the outer body 28 removed to reveal a plurality of
cutout regions (or slots or channels or gaps), including a first
plurality of cutout regions 40 and a second plurality of cutout
regions 42, formed in the strut 44 comprising part of the strut
assembly (see element 46 in FIG. 5). As shown in FIG. 3, the strut
assembly includes the outer jacket 28, the strut 44, and an insert
component 48, which may be, for example, made from an extruded
polymer. The strut may be constructed from a super-elastic Nitinol
and, in one embodiment, the outer body comprises a single layer of
polymer material. The outer body 28 could, however, comprise
multiple layers, including layers of different types of materials.
As clearly shown in FIG. 3, the insert component 48 may comprise a
section of tri-lumen tubing, including a single central lumen 50
that is straddled by a pair of diametrically-opposed pull wire
lumens 52, 54 (see, e.g., FIG. 4). As discussed further below,
these pull wire lumens must be properly oriented relative to a cut
pattern (various representative cut patterns are depicted in FIGS.
12-14 and FIGS. 18-20) in the strut for the distal deflectable
section to deflect as desired. FIG. 4 is a cross-sectional view of
the strut assembly 46 depicted in FIG. 3, taken along line 4-4 of
FIG. 3. As clearly shown in FIG. 4, the insert component 48
includes a large central lumen 50 for wire management, for example,
and the two offset pull wire lumens 52, 54 (shown as diametrically
opposed from each other in this embodiment).
[0041] FIG. 5 is an isometric view of a strut assembly 46. In this
figure, the strut 44 comprising part of the strut assembly is
depicted in phantom below the outer body. FIG. 6 is a lateral
cross-sectional view of the strut assembly, taken along line 6-6 of
FIG. 5. FIG. 7 is a longitudinal cross-sectional view of the strut
assembly depicted in FIG. 5, taken along line 7-7 of FIG. 5.
[0042] FIG. 8 shows the components of the strut assembly 46
depicted in FIGS. 5-7 prior to assembly and a reflow process. As
represented by the staggered, serpentine dashed lines in FIG. 8,
the strut assembly 46 is constructed by placing the insert
component 48 into the strut 44, and then inserting the combined
strut and insert component into the outer body 28. That assembly of
the insert component, the strut, and the outer body would then be
subjected to a reflow process to help lock the components together
into a functional strut assembly. Also clearly visible for the
first time in FIG. 8 are alignment tabs (or pin) 56 on the
longitudinal ends of the strut. Although the strut embodiment shown
in FIG. 8 has two alignment tabs on each of its longitudinal ends
(note that only one of the two alignment tabs on the right-hand end
of the strut as oriented in FIG. 8 is visible), any number of
alignment tabs could be used. Two alignment tabs per end, each tab
being approximately 0.01 inches by 0.01 inches, has been found to
work well. As explained further below, the alignment tabs help
ensure that the pull wires ultimately end up correctly oriented
relative to the cutout pattern in the strut, so as to be able to
effectuate deflection of the distal deflectable section. The
alignment tabs also facilitate torque transfer along the catheter
shaft. FIG. 9 is a cross-sectional view taken along 9-9 of FIG. 8,
and clearly depicts the diametrically-opposed pull wire lumen (or
channels) 52, 54 and the large central wire management lumen
50.
[0043] FIG. 10 is a side view of a strut 44.sup.I according to an
embodiment. FIG. 11 is an end view of the strut depicted in FIG.
10, taken in the direction represented by the arrows on line 11-11
of FIG. 10. In this embodiment, the strut 44.sup.I includes a
distal part 58 and a proximal part 60 that meet at a location
represented by a vertical line 62. Each end of this strut again
includes a pair of diametrically-opposed alignment tabs 56, two of
which may be seen in FIG. 11. Again, although any number of
alignment tabs may be used, it works well to have two alignment
tabs that are diametrically opposed from each other as shown to
best advantage in FIG. 11. As shown in FIG. 10, in this embodiment
of the strut 44.sup.I, a first plurality of slots 40 are formed in
the upper surface of the strut and define a first plurality of
arches 64. A second plurality of slots 42 is cut in the bottom
surface of the strut 44.sup.I, creating a second plurality of
arches 66. These slots and arches are explained further below.
[0044] In the embodiment depicted in FIG. 10, each slot 40
comprising the first plurality of slots is the same, and each arch
64 comprising the first plurality of arches is the same. The second
plurality of slots 42, however, comprises two types of slots. In
particular, the proximal end of the strut (i.e., the right-hand end
of the strut as oriented in FIG. 10) includes a plurality of deep
(or tall), narrow cuts or slots 42a, and the distal portion of the
strut includes a plurality of relativity wider and more shallow
slots 42b. Also, the slots 40 in the top portion of the strut
44.sup.I are identical to the slots 42b in the bottom portion of
the strut along the distal portion 58 of the strut 44.sup.I. The
differences between the slot configurations in the top of the strut
versus the slot configurations in the bottom of the strut along the
proximal part of the strut, create asymmetric curves when the
catheter is deflected in different directions. In particular, if
the distal end of the distal deflectable section is deflected
downwardly (i.e., in the direction of arrow 68 depicted in FIG.
10), the deflection curve will tend to commence at the location
represented by the vertical line 62, which, as noted above, is at
the junction of the distal part 58 with the proximal part 60 of the
strut 44.sup.I. However, if the distal deflectable section is
deflected upwardly (i.e., in the direction of arrow 70 depicted in
FIG. 10), the resulting curve will tend to commence closer to the
proximal end 72 of the strut.
[0045] The strut 44.sup.I depicted in FIG. 10 could be created in
an automated process. In order to drive the automated process, a
cut pattern 74 may be defined from a CAD model of the strut and
then information about the design may be loaded into the guidance
system for a cutting machine (e.g., a laser cutter--not shown).
FIG. 12 depicts a two-dimensional, flat pattern 74 that could be
used to direct the cutting machine to create the strut depicted in
FIG. 10. In particular, if the flat pattern 74 were formed into a
cylindrical configuration (as shown in FIGS. 10 and 11), by joining
the top horizontal edge 76 of the pattern depicted in FIG. 12 with
the bottom edge 80 of the pattern, that body would have a
configuration similar to that shown in FIG. 10.
[0046] The pattern 74 depicted in FIG. 12 is symmetrical about a
longitudinally-extending line 78, which longitudinally divides the
pattern into symmetrical upper and lower halves. That is, the
portion of the pattern above the line 78 is a mirror image of the
portion of the pattern below the line. This pattern also defines
the proximal part 60 (which, in this embodiment, is an asymmetric
portion), which is the portion of the pattern to the left of a
vertical line 62; and the distal part 58 (which, in this
embodiment, is a symmetric portion), which is the portion of the
pattern to the right of the vertical line 62. In this embodiment,
the first plurality of elliptical slots is longitudinally-arranged
(or `stacked`) along the line of symmetry 78. Each elliptical slot
40 in the first plurality of slots is the same. In other words, in
the pattern 74 depicted in FIG. 12, the elliptical cutouts
comprising the first plurality of slots are the same from the
proximal end of the strut to the distal end of the strut.
[0047] The pattern depicted in FIG. 12 also comprises a second
plurality of cutout regions (or slots) 42. It should be kept in
mind that FIG. 12 depicts a `flat pattern.` Thus, half of each slot
in the second plurality of slots opens upwardly in the depicted
pattern, and the other half of each slot opens downwardly in the
depicted pattern. As may be clearly seen in FIG. 12, the second
plurality of slots 42 are not uniform from one end of the strut to
the other. In particular, on the proximal end of the strut pattern
(i.e., on the left-hand end of the strut pattern as oriented in
FIG. 12), along what will become the asymmetric portion of a strut
(i.e., the portion to the left of vertical line 62), the second
slots 42a are of a first type; and, on the distal end of the strut
pattern (i.e., on the right-hand end of the strut pattern as
oriented in FIG. 12), along the symmetric portion of the strut
pattern (i.e., the portion to the right of vertical line 62), the
second slots 42b are of a second type. The second slots of a first
type 42a are relatively narrow and relatively long compared to the
second slots of a second type 42b along the symmetric portion of
the strut. Further, in the symmetric section, the slots in the
first plurality of slots are identical to the second type of second
slots. That is, to the right of vertical line 62, the complementary
slots 40, 42b are the same and are merely staggered
longitudinally.
[0048] Moving distally from the proximal end of the strut to the
distal end of the strut depicted in FIG. 12, the second slots get
shorter and wider (e.g., compare slots 42a to slots 42b). In
particular, the second slots of the first type 42a are narrow and
deep compared to the second slots of the second type 42b. As a
direct result, the first arches 64 (discussed further below in
connection with FIG. 14) get longer as one transitions from the
asymmetric portion of the cut pattern to the symmetric portion.
Correspondingly, again moving from the proximal end of the strut to
the distal end of the strut, the second arches 66 get narrower
(e.g., compare arches 66a to arches 66b). Finally, as one moves
from the proximal end of the strut cut pattern 74 depicted in FIG.
12 to its distal end, the bridges 82 (see FIGS. 13 and 14) that
connect the first arches 64 to the second arches 66 get shorter.
That is, the bridges in the symmetric deflection portion are
shorter than the bridges in the asymmetric deflection portion.
Bridges are discussed in detail below in connection with FIG. 14.
In the configuration depicted in FIGS. 10 and 12, the first arches
64 match the second arches 66b, and the first slots 40 match the
second slots 42b in the symmetric portion 58 of the strut. Thus, in
the symmetric portion of a strut, deflection is symmetrical. FIG.
13 is an enlarged view of the circled portion of FIG. 12.
[0049] In order to better understand the cut patterns used to form
the struts, FIG. 14 depicts a greatly enlarged portion of the cut
pattern 74 depicted in FIG. 12. Each strut is formed from a series
of longitudinally-offset arches, including a first plurality of
arches 64 and a second plurality of arches 66. The arches
comprising the first plurality of arches are arranged in a
longitudinally-extending row (or series), as shown to good
advantage in FIG. 12. Similarly, the arches 64 comprising the
second plurality of arches are arranged in a complementary and
circumferentially-offset, second longitudinally-extending row.
Adjacent arches of said first plurality of arches 64 are separated
by circumferentially-extending cutout regions 40 (or slots or
channels or gaps). Similarly, adjacent arches 66 comprising the
second plurality of arches are separated by
circumferentially-extending cutout regions 42. Each cutout region
may have an elliptical configuration as shown in, for example, FIG.
12-14, or a cat-eye or almond configuration, such as shown in, for
example, FIG. 3. Other symmetrical and asymmetrical slot shapes are
contemplated, such as diamonds, rectangles, and triangles.
[0050] Again referring to FIG. 14, each of the first arches 64
extends circumferentially a distance L3 between a third
longitudinally-extending line 84 and a fourth
longitudinally-extending line 86. Each of these first arches has a
midpoint width 88. Further, each of the first arches is separated
from the next adjacent arch by a first cutout region 40. Each of
the these first cutout regions has its own midpoint width 90, and
extends circumferentially a distance L2+L3+L4 between a second
longitudinally-extending line 92 and a fifth
longitudinally-extending line 94, as clearly depicted in FIG. 14.
Referring briefly to FIG. 15, each arch (e.g., arch 64) shown in
FIG. 14 subtends an angle theta (.theta.) and has an arc length L
and a span S. Referring back to FIG. 14, the depicted cut pattern
74 further comprises a plurality of second arches 66, each having a
mid-point width 100, separated by a plurality of second cutout
regions 42, each having a mid-point width 102. Each of the second
arches extends circumferentially a distance L1+L5 from the second
longitudinally-extending line 92 in FIG. 14 to the fifth
longitudinally-extending line 94, keeping in mind that the cut
pattern 74 depicted in FIG. 14 is a flat, two-dimensional pattern.
Thus, the first longitudinally-extending line 96 and the sixth
longitudinally-extending line 98 shown in FIG. 14 comprise the same
line in the cylindrical strut 44.sup.I formed from the pattern
depicted in FIG. 14. Thus, the length of the second arches, as
discussed above, is the distance L1 from the second
longitudinally-extending line 92 downward (as depicted in FIG. 14)
to the first longitudinally-extending line 96, plus the distance L5
from the fifth longitudinally-extending line 94 upward (as depicted
in FIG. 14) to the sixth longitudinally-extending line 98. As also
shown in FIG. 14, the length of each second cutout region 42 in
this particular pattern is the sum of L1+L2+L4+L5.
[0051] FIG. 14 also clearly depicts the bridges 82 (or links or
connectors) that connect the first arches 64 to the second arches
66. These bridges flexibly interconnect the first plurality of
arches to the second plurality of arches. A first plurality of
adjacent bridges 82 form a first longitudinally-extending,
serpentine backbone (this backbone may be seen in, for example,
FIG. 10 running longitudinally along the vertical midline of the
strut 44.sup.I), which permits and facilitates
preferentially-planar deflection of the distal deflectable section
20, and restrains out-of-plane deflection. When the slots are
elliptical as shown in, for example, FIG. 14, the arches take the
shape of necked-in rectangles in the two-dimensional cut
pattern.
[0052] FIG. 16 is an isometric view of a strut 44.sup.II according
to another embodiment. In this figure, the distal end of the strut
is on the left, and the proximal end of the strut is on the right.
Similar to the strut discussed above, the strut depicted in FIG. 16
includes a section 58.sup.I of symmetric cuts and a section
60.sup.I of assymetric cuts. In the section 58.sup.I, the top cuts
40.sup.I and bottom cuts 42b.sup.I are the same. In contrast, in
60.sup.I, the top and bottom cuts are different. Looking more
carefully at FIG. 16, a first plurality of slots 40 separates a
first plurality of arches 64. In the section 58.sup.I of the strut,
each arch 64a.sup.I has a first width 88a. In section 60.sup.I,
each arch 64b.sup.I has a second width 88b that is larger than the
first width.
[0053] Looking now more carefully at the slots on the bottom of the
strut 44.sup.II depicted in FIG. 16, the slots 42a.sup.I in section
58.sup.I are shallower but wider than the slots 42b.sup.I in
section 60.sup.I. Thus, moving distally from the proximal end of
the strut to the distal end of the strut (i.e., from right to left
in FIG. 16), the first slots 40.sup.I remain constant, the first
arches get narrower and longer (i.e., arches 64a.sup.I are narrower
and longer than arches 64b.sup.I) after the transition from section
60.sup.I to section 58.sup.I (i.e., after crossing vertical line
62.sup.I), the second slots get shorter and wider (i.e., slots
42a.sup.I are shorter and wider than slots 42b.sup.I) after the
transition from section 60.sup.I to section 58.sup.I, the second
arches get narrower (compare width 100b of arches 66b.sup.I to
width 100a of arches 66a.sup.I), and the bridges get shorter
(compare longer bridges 82b to shorter bridges 82a).
[0054] FIG. 17 depicts yet another embodiment of a strut
44.sup.III. FIG. 17 also shows a pull ring 30 exploded away from
the distal end of the strut. The strut depicted in FIG. 17 has a
stiffer proximal portion 60.sup.II (i.e., the left end of the strut
as depicted in FIG. 17) and a softer distal portion 58.sup.II
(i.e., the right end of the strut as depicted in FIG. 17). The
strut again comprises a first plurality of arches 64a.sup.II,
64b.sup.II, a first plurality of slots 40.sup.II, a second
plurality of arches 66a.sup.II, 66b.sup.II and a second plurality
of slots 42a.sup.II, 42b.sup.II. The first plurality of slots and
the first plurality of arches are arranged along a first
longitudinally-extending line 104 in FIG. 17. In other words the
midpoints (or waists) of the first plurality of slots 40.sup.II and
of the first plurality of arches 64.sup.II, 64b.sup.II would be
aligned along the first longitudinally-extending line 104. In this
particular embodiment, the slots in the first plurality of slots
40.sup.II remain a constant size for the entire length of the strut
40.sup.I. The slots in the second plurality of slots 42a.sup.II,
42b.sup.II, however, are shorter and wider in the softer section
58.sup.II of the strut than they are in the stiffer section
60.sup.II of the strut. In this embodiment, the midpoints of the
second plurality of slots 42a.sup.II, 42b.sup.II and of the second
plurality of arches 64a.sup.II, 64b.sup.II would be aligned along a
second longitudinally-extending line (not shown in FIG. 17) that
would be circumferentially offset 180 degrees from the first
longitudinally-extending line 104. Since the second slots get
shorter in the distal, softer portion of the strut depicted in FIG.
17 (compare longer slots 42b.sup.II to shorter slots 42b.sup.II the
first arches get longer in the softer, distal portion 58.sup.II.
The second arches, however, remain the same size throughout the
length of the strut. Finally, as one moves distally and transitions
from the stiffer portion 60.sup.II to the softer portion 58.sup.II,
the bridges get shorter. That is, the bridges are shorter in the
softer portion of the strut.
[0055] Looking next at FIGS. 18-20, some relatively complex strut
cut patterns 74.sup.I, 74.sup.II, 74.sup.III, respectively, each
for creating a strut having longitudinally-varying stiffness, are
described next. Each of these cut patterns comprises twelve
sections (S1-S12--only labeled in FIG. 18) and eight different
sub-cut patterns (P1-P8--only labeled in FIG. 18), but any number
of sections and sub-cut pattern combinations could be used.
Further, each strut pattern depicted in FIGS. 18-20 includes a
proximal pattern portion 106 (to the left of vertical line 108) and
a distal pattern portion 110 (to the right of vertical line 108).
The proximal pattern portion 106 is the same for each of these
three strut cut patterns 74.sup.I, 74.sup.II, 74.sup.III, and
comprises six sections (namely, S1-S6) and five sub-cut patterns
(namely, P1-P5): [0056] Section S1 comprises sub-cut pattern P1;
[0057] Section S2 comprises sub-cut pattern P2; [0058] Section S3
comprises sub-cut pattern P3; [0059] Section S4 comprises sub-cut
pattern P4; [0060] Section S5 comprises sub-cut pattern P4; and
[0061] Section S6 comprises sub-cut pattern P5.
[0062] Each of the distal strut pattern portions 110 shown in FIGS.
18-20 is different from the other two, and each again comprises six
sections (namely S7-S12), but only three cut patterns (namely,
P6-P8): [0063] Section S7 comprises sub-cut pattern P6; [0064]
Section S8 comprises sub-cut pattern P7; [0065] Section S9
comprises sub-cut pattern P7; [0066] Section S10 comprises sub-cut
pattern P7; [0067] Section S11 comprises sub-cut pattern P7; and
[0068] Section S12 comprises sub-cut pattern P8.
[0069] Continuing to consider FIGS. 18-20, the following pairs of
adjacent sections are separated by a type one expansion gap (or
transition region), G1, or a type two expansion gap, G2 (these gaps
G1, G2 are only labeled in FIG. 18): [0070] Sections S3 and S4 are
separated by expansion gap G1; [0071] Sections S4 and S5 are
separated by expansion gap G1; [0072] Sections S5 and S6 are
separated by expansion gap G1; [0073] Sections S7 and S8 are
separated by expansion gap G2; [0074] Sections S8 and S9 are
separated by expansion gap G2; [0075] Sections S9 and S10 are
separated by expansion gap G2; [0076] Sections S10 and S11 are
separated by expansion gap G2; and [0077] Sections S11 and S12 are
separated by expansion gap G2. As noted above and as may be clearly
seen in these three figures, the G1 expansion gap is different from
the G2 expansion gap G2.
[0078] As already stated, section S1-S6, which together comprise
the proximal strut cut pattern portion 106, are the same in each of
the cut patterns 74.sup.I-74.sup.III depicted in FIGS. 18-20,
respectively. In particular, in the proximal strut cut pattern
portion 106, the slots straddling the longitudinal centerline 112
that bifurcates the pattern horizontally into symmetrical upper and
lower portions are long and narrow in the section S1 (see slots
114a), and then wider (longer midpoint width) and shorter in
remaining sections S2-S6 (see slots 114b). The slots 114b in
section S2-S6 are the same size in the depicted embodiment.
[0079] On the other hand, the distal portion 110 of the cut
patterns depicted in FIGS. 18-20 is different in each figure. In
FIG. 18, the first slots, which extend along the longitudinal
centerline 112 are the same size in all of sections S7-S12 (in
fact, in FIG. 18, the first slots are the same size in all of
sections S2-S12). In contrast, in FIGS. 19 and 20, the first slots
are not all the same size in sections S7-S12. In the FIG. 19 cut
pattern, the slots (which are part of the first plurality of slots)
in section S7 through section S12 are longer (i.e., taller in FIG.
19) than they are in sections S2-S6. Similarly, in the FIG. 20 cut
pattern, the slots (which are again part of the first plurality of
slots) in section S7 through S12 are even longer than the
corresponding slots in FIG. 19. Thus, a strut constructed from the
strut cut pattern 74.sup.I depicted in FIG. 18 would have the
stiffest distal strut portion, a strut constructed from the strut
cut pattern 74.sup.III depicted in FIG. 20 would have the least
stiff distal strut portion, and a strut constructed from the strut
cut pattern 74.sup.II depicted in FIG. 19 would have a stiffness
somewhere between the stiffness of the other two. As should be
apparent from reviewing the representative cut patterns depicted in
FIGS. 18-20, struts created from these patterns can flex
section-by-section, mitigating the tendency of the deflectable
section to come out of plane during deflection. These cut patterns
also result in a preferentially-planar performance.
[0080] FIG. 21 is a fragmentary, isometric view of a distal
deflectable section 20 of an ablation catheter, shown with portions
removed or displaced to reveal various internal components. In this
figure, a flexible, irrigated tip electrode 116 is shown distal of
three ring electrodes 24 and a pull ring 30. Also visible in this
figure, at the proximal end of the distal deflectable section 20,
is a coupler 118 that may be used to join the distal deflectable
section 20 to the proximal catheter shaft 18.
[0081] FIGS. 22 and 23 are enlarged, fragmentary isometric views of
part of the distal portion of the distal deflectable section shown
in FIG. 21. As shown on these two figures, the flexible irrigated
tip electrode includes a tip irrigation tube 120 with a barb 122 on
its proximal end for connection to a shaft irrigation tube (not
shown). Three ring electrodes 24 are shown `hovering` in
approximately the correct longitudinal position. A respective pull
ring 30 is visible in each of these two figures. Also highly
visible in each of these two figures are the alignment tabs 56
riding in corresponding tab slots 124 in the pull ring to ensure
that the pull wires 32, 34 and the pull wire management channels
52, 54 are properly aligned with the cut pattern in the strut.
[0082] Referring next to FIGS. 24-27, the coupler 118 that is also
depicted in FIG. 21 will be described. FIGS. 24 and 25 are
fragmentary, isometric views of the proximal end of the distal
deflectable section depicted in FIG. 21. In each of these two
figures, it is possible to see a coupler 118 extending from the
proximal end of the distal deflectable section. The distal end of
the coupler (not shown in FIGS. 24 and 25) would ride adjacent to
or against the proximal end of the strut comprising part of the
strut assembly. As clearly shown in these figures, the alignment
tabs 56 extending proximally from the proximal end of the strut
ride in tab slots 126 formed in a tab alignment ring 128 comprising
part of the coupler 118. These tab slots and the tab alignment ring
may be clearly seen in FIG. 26 as well. In FIGS. 24 and 25, the
pull wires 32, 34 are shown schematically entering the pull wire
channels 130, 132 comprising part of the shaft coupler 118. These
pull wires would be connected on their distal ends to, for example,
the pull ring 30, and would be connected on their proximal ends to
an actuator. The pull wire channels 130, 132 would align with the
similar pull wire channels 52, 54 comprising part of the insert
component 48 that is part of the strut assembly 46. Also clearly
visible in FIGS. 24-27 is a barbed section 134 (labeled in FIG. 27)
of the coupler 118. This barbed section comprises a plurality of
slopped annular sections 136 and flat annular sections 138. The
barbed section 134 would be inserted into the distal end of the
proximal catheter shaft 18 and then would be connected by adhesive
or sonic welding or some other means to the proximal catheter
shaft. The pull wire channels 130, 132 are offset 90 degrees from
the tab slots 126. The end of the coupler 118 opposite the barbed
section 134 comprises a smooth section 140. This smooth section 140
would ride in, and be attached to, the proximal end of the distal
deflectable section 20.
[0083] FIG. 28 schematically shows a distal deflectable section 20.
FIG. 29 schematically depicts the distal deflectable section of
FIG. 28 with a severe kink 142 formed in it. FIG. 30 shows that,
after the kink has been removed, the distal deflectable section
recovers from even such a severe kink when the strut assembly
described herein is in place.
[0084] The strut described above, whether constructed from a laser
cut Nitinol tube or some other material, can be configured to give
control over the deflection characteristics of a catheter,
especially asymmetric deflection, while maintaining the orientation
of internal components. The design of the cut pattern can be
altered to create various shapes, planar behavior, desired curve
sizes, and desired catheter shaft stiffness.
[0085] One of the benefits of this curve strut is that it makes
manufacturing of, for example, the distal deflectable section of a
catheter easy and repeatable. Current manufacturing practices may
introduce potentially undesirable variability in outgoing
assemblies due to the difficult and labor-intensive process
required to produce a given deflection behavior. The strut describe
about is designed to have an inherent deflection behavior that is
easy to assemble and lacks the variation in other assembly methods.
The strut helps the catheter take that shape in each deflection.
This takes much of the variability out of creating a distal
deflectable section by creating a structure with which to create
the deflection behavior. Additionally, this component provides
excellent durability in the body due to the fact that it does not
degrade under in vivo conditions and the super elastic nature of
the Nitinol provides excellent return to straight ability in a
catheter application.
[0086] Embodiments are described herein of various apparatuses,
systems, and/or methods. Numerous specific details are set forth to
provide a thorough understanding of the overall structure,
function, manufacture, and use of the embodiments as described in
the specification and illustrated in the accompanying drawings. It
will be understood by those skilled in the art, however, that the
embodiments may be practiced without such specific details. In
other instances, well-known operations, components, and elements
have not been described in detail so as not to obscure the
embodiments described in the specification. Those of ordinary skill
in the art will understand that the embodiments described and
illustrated herein are non-limiting examples, and thus it can be
appreciated that the specific structural and functional details
disclosed herein may be representative and do not necessarily limit
the scope of all embodiments.
[0087] Reference throughout the specification to "various
embodiments," "some embodiments," "one embodiment," or "an
embodiment," or the like, means that a particular feature,
structure, or characteristic described in connection with the
embodiment(s) is included in at least one embodiment. Thus,
appearances of the phrases "in various embodiments," "in some
embodiments," "in one embodiment," or "in an embodiment," or the
like, in places throughout the specification, are not necessarily
all referring to the same embodiment. Furthermore, the particular
features, structures, or characteristics may be combined in any
suitable manner in one or more embodiments. Thus, the particular
features, structures, or characteristics illustrated or described
in connection with one embodiment may be combined, in whole or in
part, with the features, structures, or characteristics of one or
more other embodiments without limitation given that such
combination is not illogical or non-functional.
[0088] It will be appreciated that the terms "proximal" and
"distal" may be used throughout the specification with reference to
a clinician manipulating one end of an instrument used to treat a
patient. The term "proximal" refers to the portion of the
instrument closest to the clinician and the term "distal" refers to
the portion located furthest from the clinician. It will be further
appreciated that for conciseness and clarity, spatial or
directional terms such as "vertical," "horizontal," "up," "down,"
"clockwise," and "counterclockwise" may be used herein with respect
to the illustrated embodiments. However, medical instruments may be
used in many orientations and positions, and these terms are not
intended to be limiting and absolute.
[0089] Joinder references (e.g., affixed, attached, coupled,
connected, and the like) are to be construed broadly and may
include intermediate members between a connection of elements and
relative movement between elements. As such, joinder references do
not necessarily infer that two elements are directly connected and
in fixed relation to each other. As used herein, joinder references
may also include two components that are molded as a single or
unitary piece. Changes in detail or structure may be made without
departing from the spirit of the disclosure as defined in the
appended claims.
* * * * *