U.S. patent application number 15/375027 was filed with the patent office on 2017-07-20 for steerable medical devices, systems, and methods of use.
The applicant listed for this patent is Marc Bitoun, Christopher T. Cheng, Jean-Pierre Dueri, Emma Lepak, Jonah Lepak, Colin Mixter, Richard Joseph Renati, Amr Salahieh, Tom Saul, Joseph Creagan Trautman. Invention is credited to Marc Bitoun, Christopher T. Cheng, Jean-Pierre Dueri, Emma Lepak, Jonah Lepak, Colin Mixter, Richard Joseph Renati, Amr Salahieh, Tom Saul, Joseph Creagan Trautman.
Application Number | 20170203077 15/375027 |
Document ID | / |
Family ID | 57143642 |
Filed Date | 2017-07-20 |
United States Patent
Application |
20170203077 |
Kind Code |
A1 |
Salahieh; Amr ; et
al. |
July 20, 2017 |
STEERABLE MEDICAL DEVICES, SYSTEMS, AND METHODS OF USE
Abstract
Steerable medical devices and methods of use. In some
embodiments, the steerable medical devices can be steered
bi-directionally. In some embodiments the steerable medical devices
include a first flexible tubular member and a second flexible
tubular member secured together at a location distal to a steerable
portion of the steerable medical device.
Inventors: |
Salahieh; Amr; (Saratoga,
CA) ; Lepak; Jonah; (Santa Cruz, CA) ; Lepak;
Emma; (Santa Cruz, CA) ; Saul; Tom; (Moss
Beach, CA) ; Dueri; Jean-Pierre; (Los Gatos, CA)
; Trautman; Joseph Creagan; (Sunnyvale, CA) ;
Cheng; Christopher T.; (Los Altos, CA) ; Renati;
Richard Joseph; (Los Gatos, CA) ; Mixter; Colin;
(Santa Clara, CA) ; Bitoun; Marc; (Santa Cruz,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Salahieh; Amr
Lepak; Jonah
Lepak; Emma
Saul; Tom
Dueri; Jean-Pierre
Trautman; Joseph Creagan
Cheng; Christopher T.
Renati; Richard Joseph
Mixter; Colin
Bitoun; Marc |
Saratoga
Santa Cruz
Santa Cruz
Moss Beach
Los Gatos
Sunnyvale
Los Altos
Los Gatos
Santa Clara
Santa Cruz |
CA
CA
CA
CA
CA
CA
CA
CA
CA
CA |
US
US
US
US
US
US
US
US
US
US |
|
|
Family ID: |
57143642 |
Appl. No.: |
15/375027 |
Filed: |
December 9, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15138050 |
Apr 25, 2016 |
|
|
|
15375027 |
|
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|
|
62152741 |
Apr 24, 2015 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M 25/005 20130101;
A61M 25/0138 20130101; A61M 2025/0004 20130101; A61B 1/0055
20130101; A61M 25/0012 20130101; A61M 25/0141 20130101; A61B 1/0052
20130101; A61M 25/0136 20130101; A61B 1/00147 20130101; A61M
25/0147 20130101; A61M 25/0053 20130101 |
International
Class: |
A61M 25/01 20060101
A61M025/01; A61M 25/00 20060101 A61M025/00 |
Claims
1. A steerable medical device, comprising: an inner flexible
tubular member with an inner spine; an outer flexible tubular
member axially fixed to the inner flexible tubular member at a
fixation location distal to a steerable portion, the outer tubular
member having an outer spine that is offset from the inner spine,
and a linear reinforcing member extending within the outer spine;
and an external controller operatively interfacing with the inner
and outer flexible tubular members to put one of the inner and
outer tubular members in tension and the other in compression, to
steer the steerable portion.
2. The steerable medical device of claim 1 wherein the inner
tubular member further comprises an inner linear reinforcing member
extending within the inner spine.
3. The steerable medical device of claim 2 wherein the linear
reinforcing member and the inner linear reinforcing member are 180
degrees away around the steerable medical device.
4. The steerable medical device of claim 1 wherein linear
reinforcing member is 180 degrees away from the inner spine around
the steerable medical device.
5. The steerable medical device of claim 1 wherein the outer spine
comprises a linear segment of first material extending less than
180 degrees around the outer tubular member.
6. The steerable medical device of claim 5 wherein the first
material has a durometer greater than a second segment of material
extending more than 180 degrees around the outer tubular
member.
7. The steerable medical device of claim 1 wherein the outer
tubular member further comprises a braided reinforcing member in
the steerable portion.
8. The steerable medical device of claim 7 wherein the linear
reinforcing member is woven into the braided reinforcing
member.
9. The steerable medical device of claim 1 wherein a distal end of
the linear reinforcing member is further distally than a distal end
of the steerable portion.
10. The steerable medical device of claim 9 wherein a distal end of
the linear reinforcing member extends substantially to a distal end
of the outer tubular member.
11. The steerable medical device of claim 1 wherein a distal end of
the linear reinforcing member extends to a location where the inner
tubular member and outer tubular member are axially secured
together.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 15/138,050, filed Apr. 25, 2016, which application claims the
priority of U.S. Provisional App. 62/152,741, filed Apr. 24, 2015,
both of which are incorporated by reference herein.
INCORPORATION BY REFERENCE
[0002] All publications and patent applications mentioned in this
specification are herein incorporated by reference to the same
extent as if each individual publication or patent application was
specifically and individually indicated to be incorporated by
reference.
BACKGROUND
[0003] Steerable medical devices can be used in any application
when a medical device needs to be steered, or bent. For example,
steerable delivery devices can be used to deliver, or guide,
medical devices or instruments to a target location within a
subject. The delivery devices provide access to target locations
within the body where, for example, diagnostic, therapeutic, and
interventional procedures are required. Access via these devices is
generally minimally invasive, and can be either percutaneous, or
through natural body orifices. The access can require providing a
guiding path through a body lumen, such as, for example without
limitation, a blood vessel, an esophagus, a trachea and adjoining
bronchia, ducts, any portion of the gastro intestinal tract, and
the lymphatics. Once a delivery device has provided access to the
target location, the delivery device is then used to guide the
medical device or instrument to perform the diagnostic,
therapeutic, or interventional procedure. An example of such a
delivery device is a guide catheter, which may be delivered by
steering it to its required destination, tracking it along a
previously delivered guide wire, or both. The list of components
being delivered for use percutaneously is large and rapidly
growing.
[0004] Minimal outer dimensions of delivery devices can be
important for minimizing the injury associated with delivery.
Minimizing the wall thickness of a delivery device provides
additional space for the medical device to be guided, while
minimizing the injury associated with entry into the subject and
the closure needed. Flexibility of a delivery device is important
in allowing the guiding device to track or be steered to its target
destination along tortuous paths while minimizing injury to the
intervening tissues. A delivery device may also need to have
compressive and tensile properties sufficient to support its
delivery to the target site. When tracking around bends in the
body, any kinks created in a guiding device can create an
obstruction to the delivery of the medical device. When used as a
steerable device, the distal end of a delivery device is preferably
deflectable over a range of bend radii and responsive to the
steering controls. A delivery device may also need to support
torque transmitted from the handle to the distal region.
[0005] Once a delivery device is in place the delivery device
preferably also supports torque around a distal bend such that the
medical device may be rotated into position while sustaining some
contact loads. Additionally, once in place the guiding device
preferably is sufficiently stiff to support and guide the medical
device to its target destination. A guiding device may also remain
stable and not shift from one state of equilibrium to another
either spontaneously or under the influence of forces being
imparted to it from the delivery of the medical device or its own
control mechanisms. As a delivery device often travels down
fluid-filled lumens such as, for example without limitation, blood
vessels, it should additionally incorporate a seal against fluids
impinging upon its periphery and another at its distal end which
interfaces with the medical device to maintain a seal around the
delivery device.
[0006] There exists a need for improved steerable medical devices,
such as steerable delivery devices.
SUMMARY OF THE DISCLOSURE
[0007] One aspect of the disclosure is a steerable medical device,
comprising an inner flexible tubular member with an inner spine; an
outer flexible tubular member axially fixed to the inner flexible
tubular member at a fixation location distal to a steerable
portion, the outer tubular member having an outer spine that is
offset from the inner spine, and a linear reinforcing member
extending within the outer spine; and an external controller
operatively interfacing with the inner and outer flexible tubular
members to put one of the inner and outer tubular members in
tension and the other in compression, to steer the steerable
portion.
[0008] In some embodiments the inner tubular member further
comprises an inner linear reinforcing member extending within the
inner spine. The linear reinforcing member and the inner linear
reinforcing member can be 180 degrees away around the steerable
medical device.
[0009] In some embodiments the linear reinforcing member is 180
degrees away from the inner spine around the steerable medical
device.
[0010] In some embodiments the outer spine comprises a linear
segment of first material extending less than 180 degrees around
the outer tubular member. The first material can have a durometer
greater than a second segment of material extending more than 180
degrees around the outer tubular member.
[0011] In some embodiments the outer tubular member further
comprises a braided reinforcing member in the steerable portion.
The linear reinforcing member can be woven into the braided
reinforcing member.
[0012] In some embodiments a distal end of the linear reinforcing
member is further distally than a distal end of the steerable
portion. A distal end of the linear reinforcing member can extend
substantially to a distal end of the outer tubular member.
[0013] In some embodiments a distal end of the linear reinforcing
member extends to a location where the inner tubular member and
outer tubular member are axially secured together.
[0014] One aspect of the disclosure is a steerable medical
apparatus, comprising: an external controller comprising an
actuator and a driving member; and an elongate steerable device
including first and second tubular members axially fixed to one
another at a location distal to a steerable portion, one of the
first and second tubular members within the other, a proximal end
of the first tubular member operatively fixed to the driving member
such that axial movement of the driving member causes axial
movement of a proximal end of the first tubular member, the
actuator operatively interfaced with the driving member such that
in response to actuation of the actuator in a first direction, the
driving member moves proximally, the first tubular member is put in
tension and the second tubular member is put in compression, and
the steerable portion is steered in first direction, and in
response to actuation of the actuator in a second direction
opposite the first direction, the driving member moves distally,
the first tubular member is put in compression and the second
tubular member is put in tension, and the steerable portion is
steered in a second direction different than the first
direction.
[0015] In some embodiments the first tubular member is an outer
tubular member, the second tubular member being an inner tubular
member within the tubular member.
[0016] In some embodiments the actuator is coupled to a nut, and
the nut interfaces the driving member.
[0017] In some embodiments the driving member comprises an external
thread, the actuator operatively interfaced with the external
thread. The actuator can be coupled to a nut, and wherein the nut
can interface the external thread. In some embodiments the actuator
operatively interfaces with the external thread at a location
axially spaced from a proximal-most end and a distal-most end of
the thread. The proximal end of the first tubular member can be
fixed to the driving member within a lumen of the driving member.
The second tubular member can be disposed within the lumen of the
driving member.
[0018] In some embodiments a proximal end of the second tubular
member is axially fixed to a component of the external controller
that is not configured to move axially when the driving member
moves axially. In some embodiments the proximal end of the second
tubular member is axially fixed to a valve body.
[0019] In some embodiments the driving member interfaces a handle
shell with a female and male interface that prevents rotation of
the driving member in response to actuation of the actuator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a perspective view of a steerable portion of a
steerable medical device.
[0021] FIGS. 2A, 2B, and 2C illustrate steering of exemplary
steerable portions of steerable medical devices.
[0022] FIG. 3 illustrates a flattened view showing an exemplary
slot pattern for use in a steerable portion of a device.
[0023] FIG. 4 illustrates a flattened view showing an exemplary
slot pattern for use in a steerable portion of a device.
[0024] FIG. 5 illustrates a flattened view showing an exemplary
slot pattern for use in a steerable portion of a device.
[0025] FIG. 6 illustrates a flattened view showing an exemplary
slot pattern for use in a steerable portion of a device.
[0026] FIGS. 7A and 7B illustrate flattened views showing exemplary
slot patterns for use in a steerable portion of a device.
[0027] FIG. 8 illustrates an exemplary steerable portion including
an outer slotted tubular member and an inner slotted tubular
member, with an intermediate tubular element therebetween.
[0028] FIG. 9 illustrates an exemplary steerable portion including
an outer slotted tubular member and an inner non-slotted tubular
member.
[0029] FIG. 10 illustrates an exemplary steerable portion including
an inner slotted tubular member and outer non-slotted tubular
member.
[0030] FIG. 11A is a representation of a pattern for use in a
steerable portion capable of being cut from a tube or created by
winding a ribbon into a tube.
[0031] FIG. 11B illustrates a section of a ribbon for use in the
tube of FIG. 11A.
[0032] FIGS. 12A and 12B are different views of a groove pattern
for use in a steerable portion.
[0033] FIGS. 13A, 13B, and 13C are various views of a cut pattern
for use in a guide catheter.
[0034] FIG. 14 illustrates an outer guide member and a steerable
device therein.
[0035] FIG. 15 illustrates a discontinuous cut pattern for use on a
tubular member that is most steerable in compression.
[0036] FIGS. 16A and 16B illustrate a portion of a tubular member
formed with the cut pattern from FIG. 15, while FIG. 16C
illustrates compressive and tensile forces acting thereon.
[0037] FIG. 17 is a graph illustrating Force v. Displacement
behavior associated with the application of loads or displacements
at various points around the tubular member shown in FIGS.
15-16C.
[0038] FIG. 18 illustrates a continuous cut pattern for use on a
tubular member that is most steerable in tension.
[0039] FIG. 19 illustrates a discontinuous cut pattern for use on a
tubular member most steerable in tension.
[0040] FIG. 20 illustrates a continuous cut pattern for use on a
tubular member most deflectable in tension.
[0041] FIG. 21 illustrates a discontinuous cut pattern for use on a
tubular member with a substantially straight, continuous spine.
[0042] FIG. 22 illustrates a discontinuous cut pattern for use on a
tubular member with a helical, continuous spine.
[0043] FIG. 23 is a flattened view of an exemplary tubular member
with more than one spines.
[0044] FIG. 24 is a flattened view of an exemplary member with a
single substantially straight spine.
[0045] FIG. 25 illustrates a flattened portion of an exemplary
tubular member. The slots create a relatively neutral pattern.
[0046] FIG. 26 illustrates a flattened portion of an exemplary
tubular member including interlocking features with complimentary
curved surfaces that are adapted to support rotation of the tubular
member.
[0047] FIG. 27 illustrates an exemplary steerable delivery device
including a floating tubular member disposed therein.
[0048] FIG. 28 illustrates an exemplary steerable medical
system.
[0049] FIGS. 29, 30, 31, 32, 33 and 34 illustrate different views
of an exemplary steerable medical device.
[0050] FIG. 35 illustrates a representation of the performance of
the device in FIGS. 29-34.
[0051] FIG. 36 illustrates an embodiment of a cut-out pattern
incorporating both controlled variation in bending stiffness and
features which enhance torsional stiffness.
[0052] FIG. 37 illustrates inner and outer tubular members rotated
relatively to one another thereby causing the bent distal end of
the sheath to rotate in a generally circular arc.
[0053] FIG. 38 illustrates an exemplary steerable device with an
external actuator.
[0054] FIGS. 39, 40 and 41 illustrate different views of an
exemplary external controller.
[0055] FIGS. 42A-42G illustrate an exemplary embodiment of a
portion of a steerable device that includes materials with
different durometers.
[0056] FIGS. 43A-43D illustrate an exemplary embodiment of a
portion of a steerable device that includes materials with
different durometers.
[0057] FIGS. 44A-44C illustrate an exemplary inner tubular member.
FIG. 44A is a top view. FIG. 44B is a view rotated 90 degrees
relative to the FIG. 44A view, and FIG. 44C is a view rotated 180
degrees relative to the view in FIG. 44A (and 90 degrees relative
to the view in FIG. 44B).
[0058] FIGS. 45A-45C illustrate an exemplary outer tubular that is
part of a steerable device and is disposed outside of and around an
inner tubular member from FIGS. 44A-44C. FIG. 45A is a top view.
FIG. 45B is a view rotated 90 degrees from the view in FIG. 45A,
and FIG. 45C is a view rotated 180 degrees from the view in FIG.
45A (and 90 degrees from the view in FIG. 45B).
[0059] FIGS. 46A-46E illustrate views of an assembly including the
inner and outer tubular members from FIGS. 44 and 45.
[0060] FIGS. 47A-47I illustrate an exemplary inner tubular
member.
[0061] FIGS. 48A-48D illustrate an exemplary outer tubular
member.
[0062] FIGS. 49A-49D illustrate a steerable device comprising the
inner and outer tubular members from FIGS. 47A-47I and FIGS.
48A-48D.
[0063] FIGS. 50A and 50B are side views of an exemplary inner
tubular member, including an exemplary angled seam.
[0064] FIG. 50C is a side view of an exemplary inner tubular
member, with cut out at select portions to illustrate some
components of the inner tubular member.
[0065] FIG. 50D is a side view of a portion of an exemplary inner
tubular member.
[0066] FIG. 50E is a section view of an exemplary inner tubular
member shown in FIG. 50D.
[0067] FIGS. 51A and 51B illustrate flexing, or bending, of an
exemplary steerable medical device.
[0068] FIG. 52A is a side view showing a portion of an exemplary
steerable medical device.
[0069] FIG. 52B is a section view of a portion of an exemplary
steerable medical device shown in FIG. 52A.
[0070] FIG. 52C is a section view of an exemplary steerable medical
device shown in FIG. 52A.
[0071] FIG. 52D shows a detail view of a distal end of an exemplary
steerable medical device.
[0072] FIG. 53A is a perspective view of an exemplary steerable
medical device, including a steerable sheath and an external
controller.
[0073] FIG. 53B is an exploded view of the exemplary external
controller shown in FIG. 53A.
[0074] FIGS. 54A, 54B, and 54C illustrate an exemplary outer
tubular member.
[0075] FIGS. 55A, 55B, 55C, and 55D illustrate exemplary bonding of
inner and outer tubular members.
[0076] FIGS. 56A, 56B, 56C, 56D, 56E, 56F, 56G, and 56H illustrate
an exemplary handle that can impart bi-directionality to a
steerable medical device.
DETAILED DESCRIPTION
[0077] The disclosure relates generally to steerable medical
devices, including steerable guide devices, and their methods of
use. When a steerable medical "delivery" device is described herein
it is merely an example of the steerable medical devices described
herein. Steerable delivery devices can be used to deliver, or
guide, any type of suitable medical device or instrument
therethrough to a target location within a patient's body. For
example, a steerable delivery device can be used to deliver, or
guide, a medical device into bodily lumens or cavities such as, for
example without limitation, a blood vessel, an esophagus, a trachea
and possibly adjoining bronchia, any portion of the
gastrointestinal tract, an abdominal cavity, a thoracic cavity,
various other ducts within the body, the lymphatics, one or more
chambers of the heart, etc. Once a steerable delivery device has
gained access to a target location within the subject, one or more
medical devices or instruments is delivered, or guided, to the
target location to carry out one or more medical interventions. In
some methods of use steerable delivery device described herein are
tracked along a previously positioned guide wire, the positioning
of which is known in the art. In some embodiments the steerable
concepts described herein can be applied to steerable medical
devices such as catheters that have any diagnostic and/or
therapeutic functionality, and which are advanced through a
separate guide device.
[0078] FIG. 1 is a perspective view of a distal portion of an
exemplary steerable delivery device. Steerable device 10 includes
steerable portion 12 and has distal end 15. Steerable portion 12
includes an outer tubular member 14 and inner tubular member 16.
Outer tubular member 14 has an inner surface defining a lumen
therein, and inner tubular member 14 is sized to be disposed within
the inner lumen of outer tubular member 14. Outer tubular member 14
and inner tubular member 16 are permanently axially fixed relative
to one another at fixation location 18 along the length of
steerable device 10. That is, at fixation location 18, the inner
and outer tubular members are not adapted to move distally or
proximally relative to one another and are permanently axially
fixed to one another. "Permanent" fixation as used herein generally
refers to fixation that occurs during manufacture of the device
such that one or more components are not adapted or intended to be
disengaged from one another during use of the device. As used
herein, when the tubular members or components are described as
being axially fixed relative to one another at a certain location,
the fixation can be permanent fixation or temporary fixation unless
specifically indicated to be one or the other. Fixation location 18
is located distal to steerable portion 12. At locations proximal to
fixation location 18, inner tubular member 16 and outer tubular
member 14 are axially movable relative to one another. That is,
along steerable portion 12, inner tubular member 16 and outer
tubular member 14 are adapted to move axially relative to another,
which provides for the steering of the device, described below.
Outer tubular member 14 has slots 22 formed therein, which define
spine 20. Spine 20 extends along a length of steerable portion 12.
Slots 22 are shown substantially perpendicular to the longitudinal
axis "L" of steerable portion 12, when steerable portion 12 is in a
straightened configuration as shown in FIG. 1. Inner tubular member
16 also has slots formed therein (not shown) in the steerable
portion, which define a spine (not shown).
[0079] FIGS. 2A and 2B illustrate an exemplary embodiment of a
steerable delivery device. Steerable device 30 has a distal end 37
and includes outer tubular element 34 and inner tubular element 36
which are axially immovable relative to one another at fixation
location 38, but are axially movable proximal to fixation location
38. Outer tubular element 34 includes a plurality of slots 42
formed therein to define spine 40. Inner tubular element 36 also
includes a plurality of slots formed therein (not shown) to define
a spine (not shown). In FIGS. 2A and 2B, the spines are disposed
substantially 180 degrees apart from one another. FIG. 2A
illustrates steerable portion 32 deflected, or steered, into a
first bent configuration, while FIG. 2B illustrates steerable
portion 32 steered into a second bent configuration different than
the first bent configuration. To steer the steerable portion into
the configuration shown in FIG. 2A, a proximal portion of outer
tubular member 34 is moved axially, and specifically proximally,
relative to inner tubular member 36, while the tubular elements 34
and 36 are axially fixed relative to one another at fixation
location 38. This can be accomplished by pulling outer tubular
member 23 in a proximal "P" direction while maintaining the
position of inner tubular member 36, by pushing inner tubular
member 36 in a distal "D" direction while maintaining the position
of outer tubular member, or by a combination thereof. The relative
axial movement of the inner and outer tubular members as shown in
FIG. 2A applies substantially opposing compressive and tensile
forces to the spines of the tubular members, thus deflecting, or
steering, the device in the direction of spine 40 of outer tubular
member 34, as is shown in FIG. 2A. FIG. 2B illustrates a step of
steering device 30 in the substantially opposite direction from
that shown in FIG. 2A. To steer device 30 into the configuration
shown in FIG. 2B, inner tubular member is moved proximally relative
to outer tubular member 34. This can be performed by moving the
outer tubular member distally, moving the inner tubular member
proximally, or a combination thereof. This relative axial movement
applies substantially opposing compressive and tensile forces to
the spines in steerable portion 32 of device 30, thereby deflecting
the device in a direction substantially opposite that of spine 40
of outer tubular member 34.
[0080] FIG. 2C shows a sectional view of the steerable portion from
FIG. 2B, including optional floating tubular member 505 disposed
within inner tubular member 504. Steerable portion 500 includes
inner tubular member 504 and outer tubular member 502. Inner
tubular member 504 has interrupted slots 512 formed therein to
define spine 506. Outer tubular member 502 has interrupted slots
510 formed therein to define spine 508. The steerable portion is
bent along the axis of spine 506. Spine 508 and spine 506 are
substantially 180 degrees apart from one another (i.e., they are on
substantially opposite sides of steerable portion 500).
[0081] To steer steerable portion 500 into the configuration shown
in FIG. 2C (also shown in FIG. 2B), inner tubular member 504 is
pulled in the proximal direction relative to outer tubular member
502, as is illustrated in FIG. 2B. Pulling on the inner member 504
applies a tensile force to inner spine 506. Because inner and outer
tubular members 504 and 502 are axially fixed relative to one
another at a location distal to the steerable portion, pulling on
inner member 504 relative to outer tubular member 502 results in a
compressive force applied to the distal end of the steerable
portion of outer tubular member 502. The compressive force begins
to compress slots 510 on outer tubular member 502. Compression of
outer slots 510 causes outer tubular member to bend in the
direction shown in FIG. 2C, and the bending stops when inner slots
510 are closed. Thus, outer slots 510 limit the degree of the bend
of steerable portion 500. The same type of bending that is shown in
FIGS. 2B and 2C would occur if outer tubular element 502 were
pushed distally relative to inner tubular member 504.
[0082] If outer tubular member 502 were pulled proximally relative
to inner tubular member 504 (or if inner tubular member 504 were
pushed distally relative to outer tubular member 502), steerable
portion 500 would bend in the manner shown in FIG. 2A. The degree
of the bend would be limited by inner slots 512.
[0083] FIG. 2C illustrates an embodiment of a medical device
including a floating tubular member, which may be referred to
herein as a floating liner. In general, a floating liner is
disposed within an outer structure. In the exemplary embodiment in
FIG. 2C, the outer structure includes the inner and outer tubular
members. The outer structure generally provides structural and
mechanical properties for the delivery device, and the floating
liner provides lubricity for a medical device or instrument to be
advanced therethrough. A floating liner is generally impermeable as
well. A floating liner "floats" with a portion of the outer
structure. That is, the floating liner is not fixed to a portion of
the outer structure in which it floats. In the exemplary embodiment
in FIG. 2C, the floating liner floats within the steerable portion
(i.e., is not attached to the steerable portion). In general, a
floating liner is attached to the outer structure at a location
proximal to the steerable or bendable portion of the device. For
example, in the embodiment in FIG. 2C, the floating liner is
attached to the outer structure at a location proximal to the
steerable portion. A floating liner doesn't impede the ability of
the outer structure to move as it is steered, bent, actuated,
receives forces applied thereto, etc.
[0084] In some embodiments the floating liner is a lubricious
polymer tube. In some embodiments the floating liner includes wire
windings and/or axially laid wires.
[0085] The outer structure in which the floating liner floats can
be any suitable tubular member. For example, the outer structure
can be a catheter, guiding device, a steerable device, etc. In some
embodiments the outer structure has a neutral bending preference
but is not intended to be steered. In this embodiment the outer
structure provides axial and radial stiffness thereby limiting the
likelihood of kinks while the floating liner provides lubricity and
is additionally restrained from kinking by the outer structure.
[0086] FIGS. 2A and 2B also show proximal portion 35 of device 30,
which is proximal to steerable portion 32, having a substantially
neutral portion designed to have no preferential bending axis while
at the same time transmitting axial force and torque applied at a
proximal end of the device (not shown).
[0087] In some embodiments, the inner and outer tubular members are
adapted to have opposing compressive and tensile loads applied
thereto to steer the steerable portion. In some embodiments at
least one of the tubular members has a neutral bending axis. A
neutral bending axis, as used herein, generally refers to an axis
of the tubular member along which there is substantially no axial
displacement in response to a compressive and/or tensile force
applied thereto. Axial displacement along the neutral bending axis,
in response to a compressive and/or tensile force applied thereto,
is less than axial displacement of structures elsewhere in the
tubular member. In particular, axial displacement along the neutral
bending axis is minimal relative to axial displacement of
structures elsewhere in the tubular member. Examples of a neutral
bending axis include spine 382 in FIG. 21 and spines 412 and 414 in
FIG. 23.
[0088] In some embodiments at least one of the tubular members is
adapted to offset the neutral bending axis relative to the opposite
tubular member. The neutral bending axes of the tubular members can
be offset to be approximately tangent to opposite sides of the
opposing members, making the neutral bending axis offset equal to
the diameter of the device, thus providing the highest possible
bending leverage ratio for a given device diameter.
[0089] The tubular members described herein may exhibit
preferential or neutral bending behavior. Neutral bending behavior
implies that the displacement for a given radially applied load
(from the edge of the tubular member through the longitudinal axis
of the tubular member) will be independent of the radial angle from
which the load was applied. In contrast, in a non-neutral structure
the displacement associated with a radial load will change as a
function of the radial angle. An exemplary tubular member tending
towards neutral bending behavior is shown in FIG. 25 or the
uninterrupted spiral pattern of FIG. 25 which is essentially a
spring.
[0090] In some embodiments the inner and outer tubular elements are
adapted to be rotated relative to one another to enhance the
steerability of the steerable portion. The tubular elements can
rotate relative to one another yet remain axially fixed relative to
one another at a location distal to the steerable portion. In these
embodiments, in addition to axial forces being applied to one or
more tubes, one or more tubular members are also rotated with
respect to each other to steer the steerable portion.
[0091] In some embodiments only one of the inner and outer tubular
members has at least one slot defining a spine along the steerable
portion, while the other does not have any slots along the
steerable portion. For example, in FIGS. 2A and 2B, outer tubular
member 34 can have a slot and a spine while inner tubular member 36
does not have a slot formed therein. Alternatively, inner tubular
member 36 can have at least one slot and a spine while outer
tubular member 34 does not have a slot formed therein. The
steerable portion can be steered as described herein if at least
one of the inner and outer tubular members is adapted to
preferentially bend in a first direction.
[0092] In the embodiment in FIGS. 1 and 2 the slots in both tubular
members are substantially perpendicular to the longitudinal axis of
the steerable portion. The slots in one or both of the tubular
members can be, however, at an angle relative to the longitudinal
axis that is other than substantially 90 degrees.
[0093] In some embodiments the steerable device also includes a
tubular element disposed between the inner and outer tubular
members. The intermediate member can be, for example without
limitation, a flexible polymeric material. The intermediate member
can be encasing one or both of the tubular members, or comprising
one or both of the members. The intermediate member can be adapted
to provide a fluid barrier and/or a low friction surface.
[0094] Slots as described herein can be formed in a tubular member
by laser machining or other machining processes. Forming the slots
creates at least one spine in a tubular member. A spine as used
herein can be considered a region of the steerable portion that
imparts axial stiffness in compression or tension, or both, and may
additionally include features that provide torsional stiffness.
When a single spine is created in a tubular member, the neutral
bending axis of the tubular member is moved to the spine of the
tubular member.
[0095] In some embodiments, a tubular member includes at least two
spines, the combination of which moves the neutral bending axis of
the tubular member to an axis parallel to, or tangent to when bent,
the longitudinal axis of the tubular device and passing through the
spines.
[0096] In some embodiments a liner, such as a flexible polymer
liner, is bonded on the inner surface of the inner tubular member.
In some embodiments a flexible polymer is bonded or otherwise
disposed over the outer surface of the outer tubular member. A
liner can also be disposed such that it is encasing the inner
tubular member.
[0097] In some embodiments the steerable portion is comprised of a
first tubular member that is adapted to bend preferentially in a
first direction and a second tubular member that is not adapted to
bend preferentially in one direction. In some instances of these
embodiments, the second tubular member is a flexible polymer
material with or without a braided or wire support. In some
instances, a wire or other structural support is included in the
first tubular member in the deflectable area to increase
compressive and tensile stiffness along one side of the tubular
member, thus moving the neutral bending axis from the longitudinal
axis of the tubular member to the side of the tubular member that
includes the structural support. In some instances wires are laid
longitudinally and distributed evenly to increase axial stiffness
in tension without creating a preferential bending.
[0098] In some embodiments the device includes three tubular
members, having three offset neutral bending axes approximately 120
degrees radially spaced apart, thus providing the steerable device
with universal steering in any direction.
[0099] FIG. 3 illustrates, for ease of description, a flattened, or
unrolled, portion of exemplary tubular member 50, which can be an
inner or an outer tubular member. Tubular member 50 includes
fixation region 52, steerable portion 54, and a proximal neutral
portion 58. Steerable portion 54 includes a plurality of slots 56
formed therein to define spine 55 extending along the steerable
portion. Slots 56 are sinuous-shaped slots, and spine 55 has a
generally straight configuration along the length of steerable
portion 54. That is, spine 55 is substantially parallel with the
longitudinal axis of the tubular member. Fixation region 52
includes a plurality of holes 57 to facilitate bonding to provide
for axial fixation relative to a second tubular member (not shown).
Proximal portion 58 includes a plurality of multiple overlapping
slots 60 to provide the desired flexibility, axial force
transmission, and torque transmission characteristics.
[0100] FIG. 4 illustrates a flattened, or unrolled, portion of
exemplary tubular member 61, which can be an inner or an outer
tubular member of a steerable portion. Tubular member 61 includes
fixation region 62, steerable portion 64, and proximal neutral
bending portion 68. Neutral bending portion 68 will exhibit minimal
bending preference upon a compressive or tensile force applied
thereto. Tubular member 61 is similar to tubular member 50 shown in
FIG. 3, but includes linking elements 72, which can be flexible.
Each linking element extends from one side of a slot to the other
side. Each linking element includes two arm portions extending from
one side of the slot to the other side of the slot. The two arms
meet at the point at which they are connected to one side of the
slot. The linking elements extend along steerable portion 64 on
substantially the opposite side as spine 65. Linking elements 72
enhance and/or control torque response and bending of steerable
portion 64. As steerable portion 64 is bent about spine 65, linking
elements 72 bend and stretch under tension. As steerable portion 64
is twisted, or put in torque, linking elements 72 are put in
compression. In torque, the gap between a given linking element and
the section of the tubular member proximally adjacent to the given
linking element collapses, effectively increasing the torsional
stiffness of steerable portion 64.
[0101] FIG. 5 illustrates a flattened portion of exemplary tubular
member 80, including fixation portion 82, steerable portion 84, and
proximal neutral portion 86. The embodiment in FIG. 5 is similar to
the outer tubular member as shown in FIGS. 2A and 2B. Steerable
portion 84 includes substantially straight slots 90 that are
substantially perpendicular to the longitudinal axis of tubular
member 80. Spine 88 is substantially straight in configuration,
extending along the length of steerable portion 84 substantially
parallel to the longitudinal axis of the tubular member 80.
Fixation portion 82 includes holes 92 therethrough (four shown) to
facilitate bonding. Proximal portion 86 has multiple overlapping
slots 94 to give the desired flexibility, axial force and torque
transmission.
[0102] FIG. 6 illustrates a flattened portion of exemplary tubular
member 96, including fixation portion 98, steerable portion 100,
and proximal neutral portion 102. Steerable portion 100 includes
substantially straight slots 108 that are substantially
perpendicular to the longitudinal axis of tubular member 96, but
each is offset relative to the adjacent slot so that spine 106 has
a sinuous shape extending along the length of steerable portion
100. Fixation portion 98 includes holes 104 therethrough (four
shown) to facilitate bonding. Proximal portion 102 includes
multiple overlapping slots 110 to give the desired flexibility,
axial force and torque transmission characteristics.
[0103] FIGS. 7A and 7B illustrate exemplary portions of flattened
first and second tubular members 112 and 128. First tubular member
112 can be an inner tubular member and second tubular member 128
can be an outer tubular member, or first tubular member 112 can be
an outer tubular member and second tubular member 128 can be an
inner tubular member. Tubular members 112 and 128 can be assembled
as part of a steerable delivery device. That is, one of the first
and second tubular members can be disposed within the other. First
tubular member 112 includes fixation portion 114, steerable portion
116, and proximal neutral portion 118. Fixation portion 114
includes holes 120. Steerable portion 116 has slots 124 formed
therein to define spine 122. Spine 122 has a generally sinuous
shape. Proximal portion 118 includes a plurality of overlapping
slots 126. Second tubular member 128 includes fixation portion 130,
steerable portion 132, and proximal neutral portion 134. Fixation
portion 130 includes holes 136. Steerable portion 132 has slots 140
formed therein to define spine 138. Spine 138 has a generally
sinuous shape. Proximal portion 134 includes a plurality of
overlapping slots 142.
[0104] In FIGS. 7A and 7B, the slots in each of tubular members 112
and 128 are offset relative to the adjacent slot, interrupted, and
have a general helical configuration. Spines 122 and 138 have
generally sinuous configurations. The slots in the tubular members
are at the same angle relative to the longitudinal axis of the
tubular member, but are formed in opposite helical patterns. An
advantage of having inner and outer tubular members with slots that
are not in alignment (as opposed to inner and outer tubular members
that have slots perpendicular to the longitudinal axis of the
tubular member) is that the slots are less likely to get caught up
on one another as the steerable portion is steered. The angled
slots shown in FIGS. 7A and 7B also provide for an increased torque
response based on a torque applied at the proximal end of the
device.
[0105] FIG. 8 illustrates a portion of an exemplary steerable
delivery device. Steerable device 150 includes outer tubular member
152, inner tubular member 154, and intermediate tubular member 156.
A portion of outer tubular member 152 and intermediate member 156
are cut away to show inner tubular member 154. Intermediate tubular
member 156 can be a flexible polymeric tube. Inner and outer tubes
152 and 154 have slots 160, 164 formed therein to define spines 158
and 162. The spines are substantially 180 degrees apart, as shown.
The slots formed in the respective tubular members are at an angle
relative to the longitudinal axis of the steerable portion and are
formed in opposite helical patterns.
[0106] FIG. 9 illustrates a portion of an exemplary steerable
delivery device. Steerable device 166 includes outer tubular member
168 and inner tubular member 170. Inner tubular member 170 can be a
flexible polymeric tubular element. Outer tubular member 168 has a
plurality of slots 174 formed therein to define spine 172. Inner
tubular member 170 has no preferential bending axis. Inner tubular
member 170 could alternatively have a modified bending axis offset
by having, for example, a stiffening element incorporated into the
wall of inner tubular member 170 approximately 180 degrees from
spine 172. In some embodiments inner tubular member 170 may
incorporate wire braids and or axially-laid wires which reduce
kinkability and increase axial stiffness as is common in braided
catheters or other similar known tubular medical devices.
[0107] FIG. 10 illustrates a portion of an exemplary steerable
delivery device. Steerable delivery device 178 includes outer
tubular member 180 and inner tubular member 182. Outer tubular
member 180 can be, for example, a flexible polymeric tubular
member. Inner tubular member 182 has a plurality of slots 186
formed therein to define spine 184, which is substantially parallel
to the longitudinal axis of the steerable portion. Outer tubular
member 180 has no preferential bending axis. Alternatively, outer
tubular member 180 can have a preferential bending axis. For
example, a structural support element can be incorporated into the
wall of outer tubular member 180 approximately 180 degrees from
spine 184. Outer tubular member 180 can be substantially the same
as inner tubular element 170 in FIG. 9, but for any lubricity
enhancing feature. In some embodiments inner tubular member 170 may
incorporate wire braids and or axially laid wires which reduce
kinkability and increase axial stiffness as is common in braided
catheter or other similar known tubular medical device.
[0108] In an alternative embodiment, the device includes inner and
outer slotted tubes, and additionally includes an outermost tubular
member similar to 180 shown in FIG. 10. The outermost tubular
member can be, for example without limitation, a polymeric tubular
member.
[0109] FIG. 11A illustrates a portion of an exemplary embodiment of
a first tubular member that can be included in a steerable delivery
device. Tubular member 190 is a tubular member formed from a ribbon
wire. Tubular member 190 has spine 192 formed by coiling a ribbon
shaped with interlocking elements 194 and 196, which together form
an interlocking feature along spine 192. Interlocking elements 194
and 196 may be press-fit to interlock the two. The interlocking
elements can be encased with a tubular member, such as a polymer
tubular member, to secure them in place. The interlocking elements
can also, or alternatively, have a polymer tubular member disposed
therein to help secure them in place. In addition to the
interlocking features, the ribbon wire has sections of decreased
width 198 which once wound into a tubular structure create the
steerable portion for flexibility. A second tubular member of the
steerable delivery device can be created in a similar manner to the
tubular member in FIG. 11A. FIG. 11B illustrates an embodiment of
the ribbon with interlocking elements 196 and decreased width
regions 200 between elements 196. The angle of interlocking
elements 196 relative to the longitudinal axis of the tubular
element can be varied based on the pitch of the coil. Such a
pattern can additionally be fabricated by laser machining.
[0110] FIGS. 12A and 12B illustrate an exemplary embodiment of a
tubular member. Tubular member 210 comprises a tube 214 with
grooves 212 formed therein on the outer surface of tube 214.
Grooves 212 do not extend all the way through tube 214. Tubular
member can be, for example, a stiff polymeric tubular member. FIG.
12A shows a sectional view of a portion of tubular 210 showing the
depth of grooves 212 in the steerable portion. FIG. 12B illustrates
a flattened view of tubular member 210 showing grooves 212 formed
in tube 214. Grooves 212 define a single substantially straight
spine 216. Grooves 212 cut into tube 214 increase flexibility of
the steerable portion to allow the steerable portion to be steered.
Spine 216 provides for the application of compressive and tensile
forces to steer the device. Because the cut does not go all the way
through the wall of the tube, it inherently creates a fluid tight
barrier and a lubricious liner. In some embodiments tubular member
210 can be an inner or outer tubular member of a steerable device,
and the other of the inner and outer tubular elements can also
include a tubular element with grooves formed thereon. In some
embodiments the steerable device can also have a polymeric sleeve
to encapsulate the outer tube to create a smooth outer surface.
[0111] FIG. 13A illustrates a portion of an exemplary introducer
sheath reinforcement member 220. Member 220 is formed by laser
cutting a tubular member to slots or gaps therein. A helical slot
222 defines interlocking T-shaped patterns 224 formed in
reinforcement member 220. The helical path is shown generally in
helical path 226. Flexibility slots 228 are formed in member 220 to
provide flexibility to member 220. Member 220 also includes bonding
slots 230 formed therein to allow for bonding to one or more
components of the device. FIG. 13B illustrates member 220 from FIG.
13A in a flattened pattern showing the interlocking T-shaped
pattern along helical path 226, flexibility slots 228, and bonding
slots 230. FIG. 13C shows a close-up of the section shown in FIG.
13B.
[0112] In some embodiments a guide catheter includes a relatively
rigid metal or polymer reinforcement member (an example of which is
shown in FIGS. 13A-13C) layered between an inner and an outer
flexible polymer tube. The rigid reinforcement member can be laser
machined or otherwise cut in a pattern in order to enhance
flexibility along the longitudinal axis of the tube, to allow some
limited radial compliance, and to allow bonding of the inner and
outer flexible polymers. The slot pattern can include an
interlocking T-shaped pattern arranged helically around the tube
for flexibility and radial compliance, a slot pattern where the
slots are substantially perpendicular to the tube longitudinal
axis, and are patterned along the tube longitudinal axis to further
enhance flexibility and bonding of said layers.
[0113] FIG. 14 illustrates an exemplary embodiment of a guide
system adapted to guide and deliver a therapeutic, diagnostic,
interventional, or any other type of medical device 260
intraluminally to a target location within a body. Guide system 250
includes outer guide member 252 and steerable delivery device 256,
a portion of which is disposed within outer guide member 250.
Steerable delivery device 256 can be, for example, any of the
steerable delivery devices described herein. Outer guide member 252
has a preset bend 254 that can be formed by, for example, heat
setting. Steerable delivery device 256 includes steerable portion
258, which can be formed as, for example, any of the steerable
portions described herein. For example, steerable delivery device
can include outer and inner tubular members, wherein at least one
of the tubular members is adapted to preferentially bend in a first
direction. In the embodiment shown in FIG. 14, steerable portion
258 is comprised of a single steerable tubular member steered into
the configuration shown in FIG. 14 by actuating pull wire 264.
Alternatively, steerable delivery device 256 can be comprised of
the embodiment described in FIG. 2, and steered by relative axial
movement of inner and outer tubular members, as described
herein.
[0114] Alternatively, outer guide member 252 can be adapted to be
bent using optional pull wire 262, shown in FIG. 14. In such an
embodiment bend 254 may or may not preset. Guide member 250
comprises a tubular member incorporating a pattern of slots as
described for steering portions herein. When located in position
pull wire 262 is tensioned and the axial and torsional stiffness of
bend 254 is thereby increased. A steerable outer guide member 252
in its delivery configuration (non-bent) is generally loose and
compliant, but is tensioned or compressed to reconfigure it into a
pre-set shape. Its stiffness in the bent configuration is a
function of the amount of tension or compression applied and the
particular slot pattern chosen.
[0115] Bend 254 in outer guide member 252 is compliant enough to be
straightened for delivery, for example advanced on a guide wire,
but rigid enough to be able to guide steerable delivery device 256
around bend 254. Steerable delivery device 256 is steerable and
transmits torque.
[0116] The structural properties of the inner and outer tubular
members of the steerable delivery device will determine the manner
in which they respond to force applied thereon. The structural
properties of the inner and/or outer tubes will depend on the
tubing material and the design, or characteristics, of the slots
created in the tubular members (unless one of the inner and outer
tubular members does not have any slots therein). The design of the
slot pattern is therefore a function of the required structural
properties of the tubular member. For example, structural
properties of the tubular member that can be modified by changing
the design of the slots or slot patterns include flexural
stiffness, torque transmission, steerability, radius of curvature,
and allowable wall thickness of the steerable assembly.
[0117] FIG. 15 is a flattened view and illustrates a portion of an
exemplary steerable portion of a tubular member. Tubular member 290
can be an inner or an outer tubular member as described herein.
Steerable portion 290 is typically a laser-cut tubular member, but
may in fact be fabricated by any technique capable of creating the
appropriate widths of cuts required (e.g., water jet, wire EDM,
etc.) wherein first cut, or slot, 292 is made, defined by first
surface 294 and second surface 296. Slot 292 extends almost all the
way around tubular member 290, and defines spine 308. Slots 282 are
thickest, along the tubular longitudinal axis, along compression
axis C which allows tubular member to be compressed along
compression axis C, which changes the configuration of tubular
member 290. Tubular member 290 also includes interlocking features
298 (only one of which is labeled), which include first
interlocking element 300 and second interlocking element 302. Slot
292 includes slot portion 304, which is defined by the first and
second interlocking elements 300 and 302 and allows for movement
between the two interlocking elements 300 and 302 in the axial
direction. Tubular member 290 also includes stress relief slots
306, which extend across spine 308 and provide stress relief for
spine 308. Stress relief slots 306 can be considered to be axially
in-between slots 292. Slots 292 are not connected with slots 306.
Slots 306 are substantially thinner than slots 292. As will be
described in detail below, tubular member 290 is adapted to be
compressed along compression axis C, which is substantially 180
degree from spine 308.
[0118] FIGS. 16A and 16B illustrate a portion of tubular member 290
shown in FIG. 15. FIG. 16B illustrates tubular member 290 with slot
292, with a greatest thickness along compression axis C. Slot 292
includes slot 304, which is defined by interlocking elements 300
and 303. Slot 292 and slot 304 allow for compression of tubular
member 290, shown in FIG. 16A. When a compressive force A is
applied along compressive axis C surfaces 294 and 296 are brought
closer towards another, as are surfaces 300 and 302. Slots 292 and
304 therefore allow for axial compression of tubular member 290,
until surfaces 294 and 296 engage one another, or until surfaces
300 and 302 engage one another, whichever happens first. Slots 292
and 304 can be designed such that the slots close at the same time.
Once the surfaces engage, they behave substantially like a solid
tube and can no longer be compressed along the engagement points.
In this configuration, the first and second interlocking elements
are adapted to prevent movement therebetween at least along a first
axis, in this embodiment along compression axis C. Upon a
compressive force to tubular member 290, tubular member will
therefore be steered into the configuration shown in FIG. 16A.
[0119] Similarly, when a tensile force is applied to tubular member
290 shown in FIG. 16A, tubular member 290 will straighten to the
configuration shown in FIG. 16B. Particularly, tubular member 290
will straighten until the interlocking features engage one another
and prevent further movement. FIG. 16C illustrates the tubular
member from FIGS. 16A and 16B and indicates points of load
application including those illustrated in FIGS. 16B and 16C.
Torsional force T indicates a torsional force acting on tubular
member 290 upon the application of torque at a proximal end of the
device. Tensile and compressive forces are listed as "a" or "b"
depending on the behavior exhibited by the tubular member as
described below.
[0120] FIG. 17 is a graph illustrating Force v. Displacement
behavior associated with the application of loads or displacements
at various points around tubular member 290 shown in FIGS. 15-16C.
The Force/Displacement behavior of tubular member 290 for loads
applied in planes passing through the longitudinal axis of the
tubular member, ranges between the lines A and B in FIG. 17. Curve
A illustrates the behavior along a compliant axis on the surface of
the tubular member and parallel to the longitudinal axis of the
tubular member where the slots are widest, while curve B
illustrates the behavior where the slots are very narrow. As the
tubular member is bent about spine 308 in a fashion which closes
slots 292, the forces required to bend the tubular member are low
and the Force/Displacement curve has a small slope. The tubular
member is compliant in this region. When the width of the slots
decreases to zero the structure becomes much stiffer as indicated
by the second much higher slope region of curve A. The amount of
displacement associated with closing the slots is essentially
indicated by point D where the slope of the Force/Displacement
curve changes. Curve A indicates the behavior expected from forces
applied at a point along compressive axis C, illustrating that a
large amount of axial displacement follows from minimal compressive
force on tubular member 290. Upon closing slots, the compressive
axis becomes stiff (indicated by the large increase in Force at
point D in the curve). Curve B in the graph indicates compression
along the axis running through spine 308. Due to stress relief
slots 306, a small amount of compressive displacement occurs before
spine 308 stiffens and begins to act substantially like a solid
tube, as indicated by point E in the graph. The structure will
exhibit the behavior of curve B for tensional loads applied to the
top of the structure on the compressive axis C as the gaps closed
under this loading are very narrow. Curve B also represents the
behavior of the structure to torsional loads, as the gaps impacted
most by these loads are narrow.
[0121] FIG. 18 illustrates a flattened view of exemplary tubular
member 320. Slot 330, or cut, formed therein has a spiral (also
referred to herein as helical) pattern and is uninterrupted.
Tubular member 320 is shown in an as-cut compressed configuration,
and is adapted to be expanded the greatest amount along expansion
axis EA upon the application of a tensile force thereto. Tubular
member 320 includes interlocking features 332, which include
surfaces 322 and 324, and surfaces 326 and 328. Slot 330 includes
the slot defined by surfaces 326 and 328, and by surfaces 322 and
324. In this embodiment the slot, or gap, defined by surfaces 326
and 328 is larger than the gap defined by surfaces 322 and 324.
That is, the gap that is closer to expansion axis EA is larger than
the gap that is further from expansion axis EA. Tubular member 334
also includes spine 334, which is interrupted by small slots 336.
As illustrated in FIG. 16C, tubular member 320, upon the
application of axial loads applied thereto, will exhibit
Force/Displacement curves as follows: a compressive force
(downwards) applied at EA will exhibit curve B, while a tensile
load at EA (upwards) will exhibit curve A. A torsional load will
exhibit curve B.
[0122] FIG. 19 is a flattened view and illustrates a portion of a
tubular member. Tubular member 270 can be an inner or an outer
tubular member as described herein. Steerable portion 270 is a
laser-cut tubular member wherein first cut, or slot, 274 is made to
define spine 276. Cut 274 is made almost all the way around tubular
member 270. Cut 274 also defines interlocking features 278 (only
one of them is labeled), which are comprised of a first
interlocking element 280 and a second interlocking element 282. Cut
274 includes cut 284, which creates the interlocking features and
allows for movement between the two interlocking elements. Tubular
member 270 also includes stress relief 272, which extend across
spine 276 and provide stress relief for spine 276. Stress relief
slots 272 can be considered to be axially in-between slots 274.
Slots 274 are not connected with slots 272. Tubular member 270 is
adapted to be expanded along expansion axis EA, and is adapted to
be minimally compressible upon the application of compressive
forces thereto. Spine 276 is substantially static. Upon the
application of tensile forces to tubular member 270 along expansion
axis EA, tubular member 270 will deflect from a straightened
configuration into a bent configuration.
[0123] FIG. 20 illustrates an embodiment similar to that shown in
FIG. 18 and only differences in the structure between the two will
be described. All other features can be considered the same.
Tubular member 350 includes interlocking features including
interlocking elements 354 and 356. Slot 360 created in tubular
member 350 includes the gap defined by surfaces of interlocking
elements 354 and 356.
[0124] FIG. 21 illustrates a flattened portion of an exemplary
tubular member 380 including interrupted cuts 390 that define spine
382. Tubular member 380 includes interlocking features 384, which
include interlocking elements 386 and 388. Interlocking features
384 allow for expansion along expansion axis EA upon the
application of a tensile force thereto. Tubular member 380, like
all tubular members described herein unless specifically stated
otherwise, can be incorporated into a steerable portion as an inner
or an outer tubular member.
[0125] FIG. 22 illustrates a flattened portion of an exemplary
tubular member 400. Interrupted slots 404 define spine 402, which
has a spiral shape. Tubular member 400 does not have static
axis.
[0126] FIG. 23 illustrates a flattened portion of an exemplary
tubular member 410. Tubular member 410 includes interrupted helical
slots 418, which define spines 412 and 414. Tubular member 410 has
two spines, 180 degrees around the periphery of the device from one
other. The helical cut pattern repeats itself every 180 degrees to
define substantially straight spines. Tubular member 410 also
includes a plurality of interlocking features 420 which provide
torsional stiffness. The maximal expansion/compression is at axis
416.
[0127] FIG. 24 illustrates a flattened portion of an exemplary
tubular member 430, which is similar to the embodiment in FIG. 23
but rather than repeating every 180 degrees, the cut pattern
repeats every 360 degrees. Slots 434 have an interrupted helical
design, and tubular member 430 has a single spine 432. Feature 436
provides additional torsional stiffness. Tubular member 430
exhibits maximal expansion/compression along axis 438.
[0128] FIG. 25 illustrates a flattened portion of an exemplary
tubular member 440. Tubular member 440 includes slots 448, which
repeat every 190 degrees to define spines 442 and 446. The slots
have an interrupted helical pattern, and create a relatively
neutral pattern.
[0129] FIG. 26 illustrates a flattened portion of an exemplary
tubular member 450. Tubular member 450 has uninterrupted slot 456
formed therein, which repeats every 360 degrees. Tubular member 450
also includes interlocking features 454 comprised of at least two
interlocking elements as described herein. In this embodiment, the
interlocking elements have complimentary curved surfaces and are
adapted to support rotation. Slot 456 defines spines 452, while
slot 456 allows compression and/or expansion along axes A.
[0130] FIG. 27 illustrates an exemplary steerable delivery device
including steerable portion 520. Steerable delivery device includes
outer tubular member 522, inner tubular member 524, and floating
inner member 534. Inner tubular member 524 is disposed within and
coaxial to outer tubular member 522, and floating inner member 534
is disposed within and coaxial with inner tubular member 524.
Floating inner member 534 is axially fixed relative to inner
tubular member 524 at a location proximal to steerable portion 520.
The device shown in FIG. 27 can also include a liner member
disposed between the outer and inner tubular members.
[0131] FIG. 28 illustrates an exemplary steerable delivery system
600. System 600 includes control device 602 that is adapted to
steer steerable portion 610 of a steerable delivery device. The
steerable delivery device includes outer tubular member 606 and
inner tubular member 608 disposed within outer tubular member 606.
Control device 602 includes housing 612 with a slot therein adapted
to allow for movement of actuator 604. Actuator 604 is coupled to
inner tubular member 608, and is adapted to be moved axially,
either distally D or proximally P to control the axial movement of
inner tubular member 608. Any other suitable type of actuator can
also be used including actuators incorporating mechanical
advantage. Actuation of actuator 604 causes inner tubular member
608 to move axially relative to outer tubular member, which causes
steerable portion 610 to bend. The control device is therefore
adapted to steer steerable portion 610 inside of a subject. System
600 also includes a floating liner member 616 and hemostatic valve
614.
[0132] One aspect of the disclosure is a guide device that is
adapted to be maintained, or locked, in a specific configuration to
provide access for a medical device or instrument to be passed
therethrough, but may or may not be steerable. In FIGS. 2A-2C,
steerable portion 32 is adapted to be steered or deflected into any
configuration between those shown in FIGS. 2A and 2B. Steerable
portion is adapted to be steered to, for example, navigate bends or
turns within a bodily lumen. In that specific embodiment,
compressive and/or tensile forces are applied to the inner and/or
outer tubular members to steer the steerable portion. In some
embodiments, once steerable portion 32 is steered into a curved
configuration, the forces applied thereto (e.g., compressive,
tensile, torsional) can be released, and yet a medical device or
instrument can be passed through the tubular members. In some
embodiments, however, the bent configuration of the steerable
portion can be maintained by maintaining the application of the
forces thereto. For example, in FIGS. 2A-2C, steerable portion 32
can be maintained, or locked, in the bent configurations shown by
maintaining the application of the compressive and/or tensile
forces. By maintaining the application of the forces to the
steerable portion or locking the relative displacements of the
inner and outer tubes, the inner and outer tubes are substantially
axially fixed relative to one another along the length of the
steerable portion.
[0133] In an exemplary method of use, multiple bend portions may be
incorporated and adapted to have a locked configuration that
closely mimics, or resembles, a portion of the subject's anatomy.
The bend portion can be advanced through the subject (e.g., over a
guide wire) to a desired location, and can then be actuated into a
curved configuration, such as by the application of compressive
and/or tensile forces thereto. The curved configuration can be
adapted to resemble the path of the anatomical lumen in which the
device is positioned. Application of the actuation force maintains,
or stiffens, the bend portions in the desired curved configuration.
A medical device or instrument can then be advanced through the
curved portion to a target location within the subject.
[0134] The device shown in FIG. 14 can alternatively be configured
to be operated in this manner. For example, steerable delivery
device 256 in FIG. 14 can be actuated to have a first bend or
curved region 254 and a second bend or curved region 258. The
curves, or bends, form a general S-shaped portion of the device.
The delivery device 256 can be maintained, or locked, in the
general S-shape to guide a medical device or instrument
therethrough. The S-shape of the delivery device 256 can be used if
it resembles a portion of the anatomy into which it is placed, but
any other type of preformed configuration can be used, depending on
the anatomical requirements. In the alternative to FIG. 14, the
delivery device can be actuated into the configuration shown by the
application of compressive and/or tensile forces to inner and outer
tubular members, as is described herein.
[0135] FIGS. 29-34 show an alternative embodiment of a steerable
delivery device. FIGS. 29-34 illustrate steerable delivery sheath
900 capable of bending in one direction with torqueability and bend
retention enhancements. FIG. 34 is an enlarged view of a
distal-most portion of sheath 900. Sheath 900 includes inner
tubular member 930 and outer tubular member 920, respectively.
Cross sections of sheath 900 are represented in FIGS. 30-33.
Locations of cross sections are indicated as sections A-A, B-B,
C-C, and D-D as indicated in FIG. 29. Construction of sheath 900 in
proximal portion 913, shown in cross section D-D shown in FIG. 33,
is similar to the proximal portion for sheath 810. Table 1
describes component properties for an exemplary embodiment of the
sheath shown in FIGS. 29-34. As in sheath 810, the distal-most
portions of the inner and outer tubular members 930 and 920 are
merged together, as is shown in section A-A in FIG. 30. In section
A-A they are thus permanently axially fixed. Inner tubular member
930 includes three discrete components--inner layer 931, braided
layer 932, and outer layer 933. In this embodiment inner layer 931
is a lubricious liner, layer 932 is a braided material embedded in
PEBAX outer layer 933. Outer tubular member 920 includes inner
layer 921, intermediate layer 922, and outer layer 923. In this
embodiment, inner layer 921 is a lubricious liner, intermediate
layer 922 is a braided material embedded in outer PEXAX layer
923.
[0136] In contrast to sheath 810, however, inner sheath 930
incorporates an additional stiffening element 945 that provides
stiffness, only in tension, along the axis falling on the plane
within which the distal end of the sheath bends. The proximal end
of stiffening element 945 is embedded in the outer polymer layer
933 of the inner tubular member 930 at a location in a distal
portion of the proximal portion 913 of the inner tubular member
930, as shown in FIG. 33. Stiffening element 945 is free floating
in the annular space 943 between inner tubular member 930 and outer
tubular member 920 throughout the remaining portion of proximal
portion 913, as well as in distal bendable portion 914 of sheath
900 up to a point at the distal end of distal portion 914 where the
distal portion of stiffening element 945 is embedded in outer
polymer layer 923, which is shown in section A-A in FIG. 30.
Stiffening element 945 is located in the plane through which the
distal end of sheath 900 bends and is located on the inside radius
of the bend. In some embodiments stiffening element 945 is a
multi-stranded Kevlar line. In some embodiments the proximal end of
stiffening element is secured to the outer layer of the inner
tubular member at a location that is closer to the steerable
portion of the device than a proximal end of the inner tubular
member.
[0137] Distal portion 914 is the steerable portion of sheath 900
and is constructed as follows. In the proximal region of distal
portion 914 (section C-C), the braid in layer 922 is replaced by a
tubular structure with cutouts, and can be a metal tubular
structure. The cutouts allow for the controlled variation in the
bending stiffness of the outer tubular member in different planes
which extend through the longitudinal axis. The cutout pattern may
additionally incorporate features to enhance torsional
stiffness.
[0138] In this embodiment element 925 is a part of the spine of
pattern cut tube 922 and 927 is an aperture passing through all
layers of the device.
TABLE-US-00001 TABLE 1 1-way steerable sheath Proximal
Central/Middle Distal Inner sheath Liner 1 to 2 mil PTFE 1 to 2 mil
PTFE 1 to 2 mil PTFE Braided Diamond Diamond Diamond Material PEBAX
70 to 80 50 to 70 20 to 40 (Durometer) Outer Sheath Liner 1 to 2
mil PTFE 1 to 2 mil PTFE 1 to 2 mil PTFE Braided Herring Herring
None Material Cut Tube None None Patterned PEBAX 70 to 80 50 to 70
20 to 40 (Durometer)
[0139] A representation of the performance of such a tube with
cutouts is depicted in FIG. 35 where curve 951 represents the
stiffness in compression along axis on the periphery of the tube
parallel to the longitudinal axis of the cut tube. The stiffness is
represented on a polar plot where r represents the stiffness and
theta the angle around the longitudinal axis pointing at the
measurement axis. One embodiment of a cut-out pattern incorporating
both controlled variation in bending stiffness and features which
enhance torsional stiffness is represented as a flat pattern in
FIG. 36.
[0140] Bending in the steerable portion 914 of steerable sheath 900
occurs by axially translating the inner and outer tubular members
relative to each other along the longitudinal axis. In some
embodiments this is accomplished by fixing the outer sheath 920 to
a handle or external controller incorporating an internal mechanism
that is adapted to translate inner tubular member 930. As inner
tubular member 930 is translated distally relative to outer sheath
920, compressive forces are applied to outer sheath 920. These
compressive forces cause distal portion 914 of sheath 900 to bend
in the direction of its most compliant axis, indicated by 929 in
FIGS. 34, 35 and 36. As illustrated stiffening element 945 is
adjacent to axis 929 and provides additional tensional stiffness to
inner sheath 930 on this axis while allowing the opposed axis 928
to stretch. Sheath 900 in FIG. 34 additionally incorporates a radio
opaque marker 927 at its distal end. 926 is a cut out in layer 922
through which polymer can pass, as shown in FIG. 31. The section
with the square cutouts is completely embedded in polymer, hence
all of the material is secured together at the distal end in FIG.
34 allows for the delivery of fluid from within the sheath to
outside the sheath when the distal end of the sheath is plugged as
might occur when the device is used to deliver a balloon which is
inflated after delivery through the sheath and pulled back against
the distal end.
[0141] In the embodiments shown in FIGS. 29-34, the inner and outer
tubular members may be rotated relatively to one another, thereby
causing the bent distal end of the sheath to rotate in a generally
circular arc as shown in FIG. 37. This allows for more control of
the distal tip by very finely torqueing just the distal end. This
type of control minimizes whipping to an even greater degree.
[0142] FIG. 38 illustrates an exemplary steerable device that can
be controlled as described herein. The device includes an exemplary
external actuatable component incorporated into a handle at its
proximal end. The handle includes a first actuator at its distal
end that is adapted to be actuated (e.g., rotation) to deflect, or
steer, the tip as described herein. The handle also includes a
second actuator at its proximal end that is adapted to be actuated
(e.g., rotation) for fine tune torque adjustment as described in
FIG. 37.
[0143] FIGS. 39-41 illustrate an exemplary external controller, in
the form of a handle, that is adapted to deploy and actuate the
steerable devices described herein. The external controller is
adapted, or can be adapted to control other steerable devices not
specifically described herein. FIGS. 39 and 40 illustrate the
proximal portion of an exemplary steerable sheath system 1000 that
includes steerable sheath 1100, such as those described above, and
handle portion 1200 for actuating steerable sheath 1100. Handle
portion 1200 includes sheath flexure adjustment knob 1210, grip
1220, guide wire port 1230, inner lumen purge port 1240 leading
into central lumen 1150. Flexure, or steering, of the steerable
sheath is facilitated by twisting control knob 1210 relative to
handle grip 1220. The amount of flexure of the sheath is related to
the amount of rotation of adjustment knob 1210. In some embodiments
there will be a relatively linear correspondence between the
degrees of rotation of control knob 1210 and the angle of flexure
for the sheath steerable section. In such an embodiment each unit
of incremental rotation of the control knob 1210 substantially
equals or "maps" into a corresponding and constant unit of
incremental flexure for the sheath steerable portion, independent
of the starting flexure of the steerable sheath. In alternate
embodiments there can be a nonlinear correspondence. For example,
in an exemplary configuration when the steerable section is at
minimal flexure, control knob 1210 can impart twice as much flexure
as when it is at about 50% of its allowable flexure.
[0144] Other mappings are considered here although not described in
detail. FIG. 40 illustrates a cross-sectional view of handle
portion 1200 of FIG. 39 at a midline plane. Situated at the
proximal end is guide wire pass-through 1230 which sits proximal to
guide wire seal 1250 leading into central lumen 1150.
[0145] Additional features comprising the control mechanism 1330
are also shown. Control knob 1210 sits over drive nut 1330 and is
constrained against rotation relative to the drive nut by drive nut
feature 1380. Control knob 1210 and drive nut 1330 in turn are
positioned concentrically around drive screw 1310. Outer sheath
interface tube 1340 sits concentrically within the drive nut
1330.
[0146] Outer shaft 1110 is anchored to the outer sheath interface
tube at 1140. Anchoring may be accomplished with adhesives,
ultrasonic welding, heat staking or other suitable means. Inner
shaft 1120 is anchored at 1130 to inner sheath interface tube 1370
via any of the mechanisms described for the outer sheath.
[0147] Handle housing 1220 feature 1320 passes through a proximal
end of outer sheath interface tube 1340 constraining it from both
rotation and axial displacement. Pins 1320 additionally ride in the
drive screw stabilizing slot feature 1350 of drive screw 1310
pictures in FIG. 41. FIG. 41 depicts a portion of control mechanism
1300 with housing features removed. As control knob 1210 is
rotated, drive nut 1330 is constrained to rotate with it via
features 1380 and corresponding feature within the control knob,
not shown. Since drive screw 1310 is constrained against rotation
by the drive screw stabilizing pin 1320 riding in slot 1350,
rotation of drive nut 1330 is translated into a linear motion for
drive screw 1310. Drive screw thread 1360 may comprise a constant
pitch or a variable pitch. Since the inner shaft is anchored to the
inner sheath interface tube which in turn is constrained from
moving axially relative to screw 1310, this in turn will be
translated into axial motion of the inner sheath relative to the
outer sheath and result in flexure, or steering, of the steerable
portion of the device.
[0148] An exemplary aspect of the disclosure includes embodiments
that facilitate the visualization of portions of the steerable
sheath when used in a navigation system, such as the St. Jude NavX
Navigation & Visualization Technology, or other impedance-based
methods associated with identifying relative positions of system
components within a living or deceased body.
[0149] When a steerable device includes one or more tubular
members, as in the embodiments described above, the distal section
of one or more of the tubular member can sometimes compress, or
shorten, when it is actuated to straighten the tip of the steerable
device. For example, in the embodiments above which include an
inner tubular member disposed within an outer tubular member, the
distal section of the inner tubular member may sometime compress,
or shorten, when it is pushed in relative to the outer tubular
member to straighten the steerable portion from a bent
configuration towards a straighter configuration. In some of these
embodiments, the proximal section of the inner tubular member has a
greater durometer (e.g., 72D) than the steerable portion (e.g.,
35D). The lower durometer allows the steerable portion to bend. The
shortening, when it occurs, is an inefficient use of the
displacement of the inner tubular member that is necessary to
deflect the steerable device.
[0150] FIGS. 42A-42G illustrate an exemplary embodiment that
reduces or eliminates the shortening. In this embodiment, the
region of the inner tubular member disposed on the inside of the
curve in the steerable portion and the distal tip has a higher
durometer than the rest of the inner tubular member in the
steerable portion and distal tip. FIGS. 42B-42D show cross-sections
through sections A-A, B-B, and C-C as indicated in FIG. 42A. Device
1650 includes inner tubular member 1652, outer tubular member 1654,
and tensioning element 1660. Outer tubular member 1654 has the same
durometer along the length of the outer tubular members. In section
C-C, the inner tubular member includes a first portion 1658 with a
first durometer. In sections B-B and A-A, the inner tubular member
includes first portion 1658 with the first durometer and a second
portion 1656 with a second durometer lower than the first
durometer. First portion 1658 makes up about 1/4 of the inner
tubular member in cross section. First portion 1658 is radially
within tensioning member 1660 that is used to transfer tension from
the proximal section of the tubular member to the tip of the
device. The higher durometer in the portion on the inside of the
curve prevents the shortening of the inner tubular member when
actuated. FIG. 42G shows section G-G of the distal section
indicated in FIG. 42E. First portion 1658 can be seen on the inside
of the curve radially within tensioning element 1660. In one
specific embodiment first portion 1658 is 72D PEBAX, and second
portion 1656 is 35D PEBAX. These numbers are exemplary and are not
intended to be limiting.
[0151] FIGS. 43A-43D illustrate an alternative embodiment in which
device 1700 includes inner tubular member 1702 and outer tubular
member 1704. Inner tubular member 1702 has first section 1708 with
a first durometer and a plurality of second sections 1706 with a
second durometer lower than the first durometer. In this
embodiment, the steerable portion (section B-B) and distal tip
(section A-A) of the inner tubular member include two higher
durometer sections 1708. In this embodiment neither of the higher
durometer sections 1708 is radially within tensioning member 1710,
and as such neither of sections 1708 is on the inside of the curve.
The two higher durometer sections 1708 are substantially opposite
each other around the circumference of the inner tubular member,
and are each about 90 degrees apart from tensioning element
1710.
[0152] The exemplary steerable devices described in FIGS. 44-46 are
similar to those shown in FIGS. 42A-G above. In particular, the
inner tubular member of the steerable devices in FIGS. 44-46 is
similar to inner tubular member 1652 described in reference to
FIGS. 42A-G above.
[0153] FIGS. 44A-44C illustrate exemplary inner tubular member
4100. FIG. 44A is a top view. FIG. 44B is a view rotated 90 degrees
relative to the FIG. 44A view, and FIG. 44C is a view rotated 180
degrees relative to the view in FIG. 44A (and 90 degrees relative
to the view in FIG. 44B).
[0154] Inner tubular member 4100 includes steerable distal section
4114 and a proximal section 4102. Proximal section 4102 includes a
proximal tubular element 4116 with a first durometer. In the
embodiment shown proximal tubular element 4116 has a durometer of
72D and is a Pebax/Vestamid material. Steerable distal section 4114
includes tubular element 4104 and spine 4106. Spine 4106 is similar
to first portion 1658 from FIGS. 42A-G herein. Tubular element 4104
has a lower durometer than proximal tubular element 4116. In this
embodiment tubular element 4104 has a durometer of 35D, and is
Pebax. Spine 4106 has optional proximal and distal cuff portions
that extend all the way around the device, and a spine section that
extends between the two cuff portions that does not extend all the
way around the device. In the spine section spine 4106 makes up
about 1/4 of inner tubular member 4100, and tubular element 4104
makes up about 3/4 of the inner tubular member 4100. Inner tubular
member 4100 also includes tensioning member 4108 that is secured to
the distal end 4110 of cuff portion and to the distal end 4112 of
proximal section 4102. Tensioning member 4108 is free floating in
between the two points at which it is secured. Tensioning member
4108 is directly adjacent to, and in alignment with, the spine
section of spine 4106 (as can be seen in FIG. 44C). In this
embodiment tensioning member 4108 is a Kevlar line. Spine 4106 has
a greater durometer than tubular element 4104, and in this
embodiment is 72D Pebax.
[0155] As is described in more detail above, the lower durometer of
tubular element 4104 relative to proximal tubular element 4116
allows the steerable distal section to bend. Spine 4106, however,
due to its higher durometer, reduces shortening in compression and
stretching in tension, as can occur in the distal section when it
is actuated. For example, the distal section of the inner tubular
member may sometimes compress, or shorten, when it is pushed in
relative to the outer tubular member to straighten the steerable
portion from a bent configuration towards a straighter
configuration. The durometers provided are not intended to be
limiting but merely illustrative.
[0156] FIGS. 45A-45C illustrate exemplary outer tubular 4200 that
is part of the delivery device and is disposed outside of and
around inner tubular member 4100. FIG. 45A is a top view. FIG. 45B
is a view rotated 90 degrees from the view in FIG. 45A, and FIG.
45C is a view rotated 180 degrees from the view in FIG. 45A (and 90
degrees from the view in FIG. 45B).
[0157] Outer tubular member 4200 includes a proximal section 4202
and steerable, or articulating, distal section 4214. Proximal
section 4202 has a proximal tubular element 4204 with a first
durometer. In this embodiment proximal tubular element 4204 is a
72D Pebax/Vestamid material. Distal articulating section 4214
includes spine 4206, which is structurally the same as the spine in
FIGS. 44A-44C. Spine 4206 includes distal and proximal cuffs and a
spine section extending between the two optional cuff portions. In
this embodiment spine 4206 is 72D Pebax. Articulating section 4214
also includes first section 4208, second section 4210, and third
section 4212, all of which have different durometers. In this
embodiment the durometers decrease towards the distal end of the
device. In this embodiment first section 4208 is 55D Pebax, second
section 4210 is 40D Pebax, and third section 4212 is 35D Pebax. The
multiple sections of different durometer materials (three in this
embodiment) in the outer tubular member are arranged so that, as
the steerable portion is steered, the radius of curvature changes
along the length of the steerable portion. In this embodiment, the
radius of curvature of the steerable portion decreases along the
length of the steerable portion, and thus is less in the distal
region than in more proximal sections. The steerable portion has a
tighter curvature in the distal region than in the proximal region.
The configuration of the steerable portion can be thought of as a
spiral in this embodiment. In contrast, in embodiments in which a
single durometer material extends the length of the steerable
portion (except for the spine), the radius of curvature of the
steerable portion is substantially the same along the length of the
steerable portion (i.e., regardless of the location along the
length of the steerable portion). In the single durometer design
the radius of curvature does decrease in response to continued
external actuation, but the radius of curvature remains
substantially the same along the length of the steerable portion.
The curve thus becomes tighter, but it has a substantially constant
radius of curvature along the steerable portion. The materials and
the arrangement of the materials in the steerable portion can thus
be selected depending on the desired application of the device. For
example, different degrees of desired bending, or steering, may
differ depending on the intended use of the device, including any
intended target location within the body.
[0158] Proximal tubular element 4204 has a greater durometer than
all three sections 4208, 4210, and 4212. The distal articulating
section 4214 also includes distal tip 4216. In this embodiment
distal tip 4216 is the lowest durometer material, and in this
embodiment is 20D Pebax.
[0159] The embodiments herein with the outer spine and the multiple
durometer steerable sections provides for advantages in
bidirectional use. For example, less force is required to bend the
multiple durometer arrangement, hence there is less foreshortening
or conversely less stretching when the element is used in tension.
This advantage would also hold true for unidirectional
steering.
[0160] As is described in more detail in the assembly shown in
FIGS. 46A-46C, the spines in the inner and outer tubular members
are offset 4180 degrees from one another. Tensioning member 4108 is
therefore also offset 180 degrees from the outer spine.
[0161] FIGS. 46A-46E illustrate views of assembly 4300 including
the inner and outer tubular members 4100 and 4200, respectively,
from FIGS. 44 and 45. As can be seen in FIGS. 46A and 46E,
tensioning member 4108 is offset 180 degrees from outer spine 4206.
The inner and outer spines are also offset by 180 degrees.
[0162] The assembly 4300 can be used as is described in the
applications incorporated by reference herein. For example, the
inner and outer tubular members can be axially moved relative to
one another to steer the distal steerable section. When a spine
from one tubular member is put in tension, the other spine is put
in compression. The dual spine embodiment reduces shortening in one
tubular member in compression and stretching in the other tubular
member in tension.
[0163] In some embodiments the inner or outer tubular members are
formed by positioning the different materials on a mandrel, placing
shrink wrap over the different materials, and increasing the
temperature, which causes the material to melt together, forming
the inner or outer tubular members. The optional cuffs described
above can be helpful in securing one or more components together
during the manufacturing process.
[0164] Any of the inner and outer tubular members described above
that comprise one or more slots or spines can be made of an
elastomeric or polymeric material. For example, the tubular members
shown in FIG. 2, 3, or 4 with slots and spines therein can be made
from Pebax or other polymeric materials.
[0165] The embodiment in FIGS. 47-49 describes alternative designs
for inner and outer shafts described herein. The assembly of the
inner and outer tubular member described in FIGS. 47-49 can be
actuated and thus steered in the same or similar manner as is
described above. For example, the tubular members in the example in
FIGS. 47-49 are axially fixed relative to one another distal to a
steerable portion, and the steerable portion can be steered by
actuating the inner or outer tubular member relative to the other
tubular member via actuation of an external device. Actuating the
external device (e.g., a handle) causes the tubular members to be
axially moved relative to one another proximal to the steerable
portion, which causes their relative axial movement in the
steerable portion, which thereby causes the steerable portion to be
steered. The amount of relative movement between the tubular
members decreases as the distance from the axial fixation location
decreases. Due to the axial fixation, when one tubular member is
put in tension, the other is under compression. For example, if the
inner shaft is moved proximally relative to the outer shaft via
actuation of the external control (and the proximal end of the
outer shaft is not moved proximally), the inner shaft is put in
tension. Because the shafts are axially fixed and the outer shaft
does not move proximally, the outer shaft will be under
compression. In alternative embodiments, details of the inner and
outer tubular members disclosed above may be incorporated into the
tubular members described in the embodiment in FIGS. 47-49, unless
this disclosure specifically indicates to the contrary.
[0166] FIGS. 47A-47I illustrate details of an exemplary inner
tubular member, which may also be referred to herein as an inner
shaft (or member) subassembly. FIGS. 48A-48E illustrate details of
an exemplary outer tubular member, which may be referred herein as
in outer shaft (or member) subassembly. FIGS. 49A-49D illustrate
details of the steerable device assembly comprising the inner and
outer tubular members from FIGS. 47A-47I and FIGS. 48A-48E,
respectively. Additionally, the assembly in FIGS. 49A-49D
illustrates a soft tip at the distal end, which can be added after
the inner and outer tubular members are assembled.
[0167] FIGS. 47A and 47B illustrate side views of the steerable
portion of an exemplary inner tubular member, with select portions
cut away to review additional detail. FIG. 47B is a side view that
is 90 degrees around the tubular member relative to the side view
in FIG. 47A. "Distal" is to the left in the figure, and "proximal"
is to the right in the figure. The steerable portion of the inner
tubular member includes three sections of material that are each
coupled with at least one adjacent section at a seam that is not
parallel to and not perpendicular to the longitudinal axis of the
tubular member, and can be an angled seam. As shown in FIGS. 47A
and 47B, the steerable portion includes, in a proximal-to-distal
direction (right-to-left in FIGS. 47A and 47B), three different
sections, the durometer of the sections decreasing in the
proximal-to-distal direction. For example, as shown in FIG. 47A,
the steerable portion includes section 473 (e.g., 72D Pebax),
intermediate section 472 (e.g., 55D Pebax), and proximal section
471 (e.g., 35D Pebax). These durometers are merely exemplary and
the other durometers can be used. In some embodiments the
durometers decrease in the proximal-to-distal direction, in others
the central durometer may be the greatest. The joint, or seam,
between section 473 and 472 is not parallel to and not
perpendicular to the longitudinal axis of the inner shaft, and in
some embodiments it is an angled seam. The joint between sections
472 and 471 is also not parallel to and not perpendicular to the
longitudinal axis of the inner shaft, and in some embodiments is an
angled seam. The joint may, however, not form a straight line
between adjacent sections and still be considered to be
non-parallel and non-perpendicular to the longitudinal axis. In
this embodiment the joints are non-parallel and non-perpendicular
to the longitudinal axis over substantially the entire joint.
"Substantially the entire joint" in this context includes joints
that have end sections that are perpendicular to the longitudinal
axis. "Substantially" in this context refers to joints wherein most
of the joint is non-parallel and non-perpendicular to the
longitudinal axis, such as at least eighty percent of its
length.
[0168] In this embodiment, the varying durometers in the three
sections of the inner shaft have similar functionality to those
described above in the context of FIGS. 45A-45C. The multiple
sections of different durometer materials (three in this
embodiment) in the inner tubular member are arranged so that, as
the steerable portion is steered, the radius of curvature changes
along the length of the steerable portion. In this embodiment, the
radius of curvature of the steerable portion decreases along the
length of the steerable portion, and thus is less in the distal
region than in more proximal sections. The steerable portion has a
tighter curvature in the distal region than in the proximal region.
The configuration of the steerable portion can be thought of as a
spiral in this embodiment. In contrast, in embodiments in which a
single durometer material extends the length of the steerable
portion (except for the spine), the radius of curvature of the
steerable portion is substantially the same along the length of the
steerable portion (i.e., regardless of the location along the
length of the steerable portion). In the single durometer design
the radius of curvature does decrease in response to continued
external actuation, but the radius of curvature remains
substantially the same along the length of the steerable portion.
The curve thus becomes tighter as it is steered, but it has a
substantially constant radius of curvature along the steerable
portion. The materials and the arrangement of the materials in the
steerable portion can thus be selected depending on the desired
application of the device. For example, different degrees of
desired bending, or steering, may differ depending on the intended
use of the device, including any intended target location within
the body.
[0169] In the embodiment in FIGS. 42A-42G above, the average
durometer in cross sections (perpendicular to the longitudinal axis
of the shaft) throughout the inner shaft in the steerable portion
remains constant. In an effort to allows for tighter bending curves
in the distal direction in the steerable portion during bending, at
least one of the shafts in the steerable portion can have an
average durometer, in cross sections through the steerable portion,
that varies along its length (i.e., is not constant along its
length). The varying average durometer can be incrementally (i.e.,
step-wise) varying (e.g., FIG. 45), or it can be continuously
varying (e.g., FIG. 47, via the non-parallel and non-perpendicular
seams). Any configuration of the seams can be chosen to control the
variance in the average durometer in the cross sections.
[0170] In other embodiments the outer shaft has a non-constant
(i.e., varying) average durometer in cross section along its
length. In some embodiments both of the shafts have varying average
durometers in cross section along their lengths.
[0171] In any of the embodiments, in either shaft, there can
alternatively be more than or fewer than three sections with
different durometers in the steerable portion.
[0172] In this embodiment the bending plane of the inner shaft is,
in FIG. 47B, the plane of the page. The bending plane in this
embodiment (and others herein) is a plane that includes the spine,
the longitudinal axis, and preferential bending axis. The spine
extends through the top of the shaft in FIG. 47B (although the
spine itself in some embodiments is not necessarily a linear
"axis." For example, a spine can have a midline parallel to the
longitudinal axis of the shaft that is an "axis"). The preferential
bending axis is in the plane of the page and extends through the
bottom of the shaft in FIG. 47B. When put under compression the
shaft will bend downward in the page in the bending plane. When
bent, the spine, the longitudinal axis, and the preferential
bending axis remain in the bending plane. With respect to the seam
between sections 473 and 472, the distal-most location of section
473 is in the spine, in the bending plane. The proximal-most
location of section 472 is along the preferential bending axis.
Thus, the distal-most location of the higher durometer material is
along the spine, and the proximal-most location of the relatively
lower durometer material is along the preferential bending axis. As
discussed above, the average durometer of the shaft, in cross
section perpendicular to the longitudinal axis, continuously varies
from the proximal-most location of section 472 and the distal-most
location of section 473.
[0173] In this embodiment the distal-most location of the seam
between sections 473 and 472 is along the spine, and the
proximal-most location of the seam is in the preferential bending
axis.
[0174] The inner member includes a proximal portion 474 that is
proximal to the steerable portion. Proximal portion 474 is
generally stiffer than the steerable portion. In some embodiments
proximal portion 474 is a polyamide, such as nylon or Vestamid.
FIG. 47E shows cross section F-F (from FIG. 47A) through proximal
portion 474.
[0175] FIG. 47C shows cross section G-G within the steerable
portion from FIG. 47A. The innermost layer is liner 476, which can
be a lubricious liner such as PTFE. Section G-G also shows a
portion of support member 475 (in this embodiment is a helical
coil) embedded in the inner member. Support member 475 can be a
stainless steel wire, and in section G-G is embedded in distal
section 471, which in this embodiment comprises 35D Pebax. Also
embedded in distal section 471 is reinforcing member 477, which can
be, for example, a Kevlar line. The length of reinforcing member
471 and coil 475 are shown in FIG. 47B.
[0176] FIGS. 47G-47I, respectively, show side views of distal
section 471, intermediate section 472, and proximal section 473
before they are assembled.
[0177] FIG. 47F shows section J-J of the distal end of the device
from FIG. 47A. The ends of coil 475 are embedded in a thin
polyamide such as Vestamid, and the distal of the two is labeled
478 in FIG. 47E. Reinforcing member 477 can also be seen, the
distal end of which is proximal to the distal end of the device.
Inner liner 476 extends all the way to the distal end of the
device.
[0178] As shown in FIGS. 47G-47I, and as described above in the
context of FIGS. 47A and 47B, adjacent sections in the steerable
portion meet at a joint that is not parallel with and not
perpendicular to the longitudinal axis of the shaft, which in some
embodiments can be very slightly radially overlapped. In some
embodiments it can be an angled joint. The slight overlap can help
diminish flaws associated with the kitting of the two materials. In
embodiments in which the joints are angled, exemplary angles for
the seams are shown in FIGS. 47G-47I, but these are merely
exemplary. One difference between the inner tubular member shown in
FIGS. 47A-47I and the inner members in the embodiments above is
that reinforcing member 477, which can be a Kevlar material, is
completely embedded in the inner tubular member, as opposed to
being free-floating at certain points along its length or embedded
in the outer surface of the outer member. A reinforcing member can
also be woven through a support member, such as a braided material.
The reinforcing member and the support member would then be
embedded in the inner member. In this embodiment the reinforcing
member is linearly aligned with the spine of the shaft. A
reinforcing member can thus be woven through a braided material,
extending in a generally linear direction, and still be considered
"linearly aligned" with a spine in this context.
[0179] FIGS. 48A-48D illustrate an exemplary outer tubular member.
FIGS. 48A and 48B are the same relative views of the outer tubular
member as are the views from FIGS. 47A and 47B of the inner tubular
member. The outer member includes a proximal portion 481 that is
disposed proximal to steerable portion 501. In an exemplary
embodiment proximal portion 481 can be a 72D Pebax material. Along
steerable portion 501, the outer tubular member includes sections
of material that have different durometer. In this embodiment
steerable portion 501 includes first section 487 with a high
durometer than a second section 488. First section 487 acts as a
spine along steerable portion 501. In a merely exemplary embodiment
first section 487 can be a 72D Pebax material and second section
488 can be a 35D Pebax material. First section 487 extends less
than 180 degrees around the outer shaft, and second section 488
extends more than 180 degrees around the outer shaft. The joints
between the two materials are parallel to the longitudinal axis (as
that term is used in the art) of the outer shaft. In other
embodiments, however, the joints between sections 487 and 488 can
be non-parallel to the longitudinal axis of the outer tubular
member, and may also be non-perpendicular to the longitudinal axis
of the outer tubular member. For example, the joint between
sections 487 and 488 can include an angled joint.
[0180] FIG. 48C shows section A-A shown in FIG. 48A. The outer
shaft includes an inner liner 484, which can be a lubricious liner
such as PTFE. Supporting member 489, in this embodiment in the form
of a braided material, is disposed around liner 484. The polymeric
outer shaft includes lower durometer section 488 and higher
durometer section 487. As can be seen, the supporting member 489 is
embedded in the polymeric tubular member.
[0181] FIG. 48D illustrates section C-C of outer shaft shown in
FIG. 48A (distal end towards the left in the figure). Immediately
distal to the section that includes first and second sections 487
and 488 is a section of material with higher stiffness than
steerable section 501. In some embodiments section 485 can be a 72D
Pebax material. Supporting member 489 extends into section 485.
Liner 484 also extends into section 485. Distal to section 485 is a
tip section of outer shaft, which includes an outer layer 482 and
an inner layer 486. Outer layer 482 is stiffer than inner layer
486. As an example outer layer 482 can be a 72D Pebax, and inner
layer 486 can be a 35D Pebax. The distal tip also include marker
band 483, which is radially within outer layer 482 and radially
outward relative to inner layer 486. The distal tip also includes a
braided material captured, or retained, by marker band 483. Marker
band 483 may be formed from a radiopaque material such that the
distal tip is visible under fluoroscopy. For example, marker band
483 may be formed from a radiopaque alloy, e.g., a platinum-iridium
alloy.
[0182] FIGS. 49A-49D illustrate views of an exemplary steerable
device that includes outer shaft 491 (from FIGS. 48A-48D) affixed
to inner shaft 492 (from FIGS. 47A-47I). The assembled steerable
device also includes a soft tip 493 at the distal end that is
affixed to the inner and outer shafts after they are affixed to one
another.
[0183] Components from FIGS. 47A-47I and FIGS. 48A-48D are again
labeled in FIGS. 49A-49D. As can be seen most clearly in FIG. 49C,
reinforcing member 477 (e.g., a Kevlar line) of the inner shaft 492
is 180 degrees opposite from the midpoint of higher durometer
section 487 (measure around the perimeter of device orthogonal to
the longitudinal axis) in the outer shaft 491.
[0184] FIG. 49D shows section E-E of the device from FIG. 49A.
There is a space 505 between inner shaft 492 and outer shaft 491 in
the steerable portion. As can be seen in FIG. 49D, inner shaft 492
and outer shaft 491 are affixed to one another at the interface
between section 47I of the inner shaft and inner layer 486 of the
outer shaft (see inner layer 486 in FIG. 48D). As can be seen in
FIG. 49D, inner shaft 492 extends further distally than outer shaft
491. The portion of inner shaft 492 that extends further distally
than outer shaft 491 includes section 471 and inner liner 476. Soft
tip 493 is disposed radially over the distal end of inner shaft
492, and is also axially interfaced with the distal end of outer
shaft 491, as shown in FIG. 49D. The polymeric components are
affixed to one another using known techniques. After soft tip 493
is affixed, vent holes 510 are made in the assembly, which are
aligned with the reinforcing member 477 of inner shaft 492 and the
spine of outer shaft 491. The steerable device can be assembled to
any of the handles herein and can be actuated to steer the
steerable portion in the manners described herein.
[0185] FIGS. 50A and 50B illustrate side views of a distal region
of an alternative inner tubular member 550, with the views in FIGS.
50A and 50B 90 degrees relative to one another. Inner tubular
member 550 can be used in combination with any of the outer tubular
members herein. In this exemplary embodiment, steerable portion 553
includes first segment 551 and second segment 552 interfacing at
seam 558. Steerable portion 553 is similar to the steerable portion
in the embodiment in FIGS. 47A and 47B, but in steerable portion
553 there are only two segments, 551 and 552, that interface at a
seam.
[0186] FIG. 50B illustrates that seam 558 comprises first and
second seams 559 and 560, which meat at seam distal-most location
563 and seam proximal-most location 562.
[0187] In this exemplary embodiment, seam 558 is angled along its
entire length, shown as length "L" in FIG. 50A. "Angled," when used
in this manner, describes a seam that is not parallel with and not
perpendicular to a longitudinal axis of the inner tubular member,
which may be the same as a longitudinal axis of a steerable medical
device of which the inner tubular member is a part. The seam may
also be angled along substantially its entire length, such as at
least 85% of its length. For example, the distal and/or the
proximal-most locations of the seam may include short straight
sections that are perpendicular to the longitudinal axis of the
inner tubular member, and the seam can still be angled along
substantially its entire length.
[0188] The angled seam 558 may also be described in terms of a
comparison of cross-sectional areas of the inner tubular member in
the longitudinal direction. For example, cross-sectional areas
taken at different locations between distal-most point 563 and
proximal-most point 562 of the steerable portion may include
C-shaped segments having different material durometer that mesh to
create a circular cross-section. By way of example, a first
cross-section taken several millimeters proximal from the
distal-most point 563 may include a first C-shaped segment having a
higher durometer and having a smaller arc length, and a second
C-shaped segment having a lower durometer and having a larger arc
length. By contrast, a second cross-section taken several
millimeters distal from the proximal-most point 562 may include a
first C-shaped segment having a higher durometer and having a
larger arc length, and a second C-shaped segment having a lower
durometer and having a smaller arc length. In the case of seam 558
angled linearly and at a continuous angle between the distal-most
point 563 and the proximal-most point 562, a third cross-section
taken at a medial location between the distal-most and
proximal-most points may having a first C-shaped segment having a
higher durometer and a second C-shaped segment having a lower
durometer, and the first and second C-shaped segments may have a
same arc-length, i.e., may be semi-circular.
[0189] Seam 558 may include an angle relative to the longitudinal
axis that varies over its length. For example, a seam that is
angled along substantially its entire length can still include one
or more relatively short perpendicular or parallel seam sections
along its length. That is, seam 558 may include discrete steps,
each of which includes a perpendicular and a parallel segment
relative to the longitudinal axis. Thus, the stepped profile of the
angled seam 558 may progress around a surface of steerable portion
553 at an angle, even though one or more segments of the seam are
not directed at an angle.
[0190] Seam 558 may include other profiles that progress around the
surface of steerable portion 553 at an angle. For example, the seam
profile may be continuous (as opposed to a discrete profile of a
stepped seam profile), but the angle of the seam may vary. In an
embodiment, the variably-angled seam profile may include a wavy
profile beginning at a distal-most location 563 and progressing
around the surface of steerable portion in a wavy manner to a more
proximal location that is circumferentially offset relative to
distal-most location 563.
[0191] While inner tubular member 550 includes a seam that is
angled along its entire length, inner tubular 550 is also an
example of a tubular member with a seam, at least a portion of the
seam being angled along its length.
[0192] First segment 551 (which can also be considered a distal
segment) has a durometer less than the durometer of second segment
552 (which can also be considered a proximal segment). In some
embodiments, first segment 551 has a durometer of 20D-55D, such as
25D-45D, and in a particular embodiment can be about 35D. In some
embodiments second segment has a durometer of 55D-85D, such as
65D-85D, and in a particular embodiment is about 72D.
[0193] In some embodiments the inner tubular member includes a
segment of tubular material 554 proximal to the steerable portion,
and segment of tubular material 555 proximal to segment 554. In
some exemplary embodiments section 554 can be a polyamide such as
Vestamid.RTM.. In some embodiments segment 555 has a durometer
between 55D-85D, such as 65D-85D, such as about 72D. In other
embodiments the inner tubular member excludes section 555, and thus
section 554 (e.g., a Vestamid material) extends all the way to a
handle assembly.
[0194] In some embodiments the difference in durometers between the
first and second segments is at least 10D, at least 15D, at least
20D, at least 25D, at least 30D, or even at least 35D. The one or
more angled portions of seam 558 create one or more transitioning
portions of the inner tubular member with a varying durometer along
the angled seam.
[0195] The length of seam L as a percentage of the length of
steerable portion "S" of inner tubular member 550 is, in this
embodiment, relatively high. In this embodiment the length L is at
least 80% of length S, but in some embodiment it can be at least
50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%. An exemplary
advantage of angled seam 558, and its relative length, is that it
can provide a more consistent, or smooth, curvature to the
steerable portion of the steerable medical device during steering.
The angled seam creates a continuously changing stiffness along the
length of the angled seam, due to the different durometers of the
two materials. For example, a stiffness of inner tubular member 550
may decrease, in a stepped or continuous manner, in a distal
direction from proximal-most location 562 to distal-most location
563. Some alternative designs may have steerable portions that have
a tendency to form "joints" along the steerable section during
steering (i.e., a less smooth curvature), and the exemplary angled
seam 558 can help reduce the likelihood of a "jointed" steerable
section, if desired.
[0196] In some embodiments the length of the seam L can be between
1 cm and 8 cm, such as between 2 cm and 7 cm, or between 3 cm and 6
cm.
[0197] In some embodiments the length of the steerable portion S is
from 3 cm to 9 cm, such as from 3 cm to 8 cm, or 4 cm to 7 cm, such
as, without limitation, 4.5 cm, 4.6 cm, 4.7 cm, 4.8 cm, 4.9 cm, 5.0
cm, 5.1 cm, 5.2 cm, 5.3 cm, 5.4 cm, 5.5 cm, 5.6 cm, 5.7 cm, 5.8 cm,
5.9 cm, 6.0 cm, 6.1 cm, 6.2 cm, 6.3 cm, or 6.4 cm.
[0198] In some embodiments the steerable medical device includes
inner tubular member 550 and, for example without limitation, the
outer tubular member in FIGS. 48A-D. The lengths of the steerable
portions of both the inner and outer tubular members are generally
the same, such as any of the exemplary lengths herein. Inner
tubular member 550 can be incorporated into the steerable medical
device such that the steerable portion is steered upon actuation of
an external actuator, examples of which are described herein. For
example, in some embodiments the outer tubular member is axially
fixed with respect to an external handle, and the inner tubular
member is operatively coupled with the external actuator on the
external handle such that actuation of the actuator causes relative
axial movement (e.g., proximal movement) of the inner tubular
member. A proximal force on the inner tubular member puts the inner
tubular member in tension, and because the inner and outer tubular
members are axially fixed distal to the steerable portion, the
outer tubular member is put into compression, thereby steering the
steerable portion.
[0199] Compression of the outer tubular member and tensioning of
the inner tubular member, or vice versa, may create length changes
of differing amounts on opposing sides of the respective tubular
members. Taking the inner tubular member as an example, tensioning
of the inner tubular member may stretch the side of the steerable
portion having the lower durometer material more than the side of
the steerable portion having the higher durometer material having
the higher durometer material. The difference in material strain
may translate into a radius of curvature of the tubular member. A
similar phenomenon may occur in the outer tubular member under
compression, in which the lower durometer material is compressed
more than the higher durometer material. In either case, it is
noted that a radius of curvature is achieved through different
strain rates of material along the solid walls, i.e., non-slotted,
sides of the tubular members. More particularly, the steerable
portion may be curved and steered using tubular members that do not
include slots, holes, or discontinuities in the walls of the
tubular members over the steerable portion. In alternative
embodiments, one or both of the inner and outer tubular members may
include a steerable portion that does not include a solid tube of
polymeric material. For example, one or both of the inner and outer
tubular members may have, in the steerable portion, one or more
discontinuities in the polymeric member. Discontinuities could be
in the form of, for example, one or more holes of any
configuration, or one or more slots of any configuration, and can
extend along any desired length of the steerable portion. One
exemplary function of such a discontinuity could be to act as a
strain relief in one or more portions of the one or both tubular
members. An exemplary method of creating a discontinuity could be
to create one or more, for example, holes in the polymeric material
after the tubular member has been formed.
[0200] The lengths of the steerable portion of the medical device,
as well as the configuration and properties of the different
segments of material in the steerable portion, will, generally,
influence the configuration that the steerable portion will assume
when steered. The configuration includes the tightness of the curve
of the steerable portion after it has been steered, or bent, to the
fullest extent. The lengths of the steerable section S set forth
immediately above can allow the steerable portion to achieve a
curve diameter 571 of 2.0 cm-3.5 cm, the dimension of which is
illustrated in FIG. 51B for an example steerable medical device.
Curve diameter 571 may also be expressed in terms of a radius. For
example, a reach length 570 may be a radius of curvature of the
steerable portion when the steerable portion does not bend over 180
degrees or more. Exemplary reach lengths 570 shown in FIG. 51A,
which is the dimension when the steerable portion is bent at 90
degrees, can be, for example without limitation, 2.7 cm-4.7 cm.
[0201] The proximal end of steerable portion 553 does not include
an angled seam, and includes only second segment of material 552.
Similarly, the distal end of steerable portion 553 does not include
an angled seam, and includes only first segment of material 551, as
can be seen in FIG. 50B. In an embodiment, however, one or more of
the distal end of steerable portion 553 or the proximal end of
steerable portion 553 may be coincident with distal section 556 or
proximal section 554. That is, a vertex of seam 558, i.e., a point
whether seam portions 559 and 560 meet, may coincide with a distal
or proximal end of the steerable portion.
[0202] In some embodiments the segments 551 and 552 have the same
length. The length of segments 551 and 552 will influence the
location of the distal most and proximal most location of the
seam.
[0203] First and second segments 551 and 552 have the same
configuration, but they are offset by 180 degrees and face opposite
directions. The first and second segments need not, however, have
the same configurations.
[0204] FIG. 50B illustrates seam portions 559 and 560 forming acute
angles (only distal angle 561 labeled) at both ends of seam 558.
The length of the seam can influence the angle formed by the two
seam portions 559 and 560. An "angle" as used in this context does
not require two straight lines defining what is generally referred
to as an angle. The general configuration of seam portions 559 and
560 can form an acute angle therebetween even if seam portions 559
and 560 are not perfectly straight lines in the side view (e.g.,
even if there is a slight curvature to one or both of them).
Furthermore, seam portions 559 and 560 may meet at a vertex as
described above, or alternatively, may terminate at a connecting
segment that joins the portions 559 and 560 together. For example,
linear or curved seam portions 559 and 560 may terminate at a
curved segment having a radius that connects the ends of the seams
together. Similarly, seam portions 559 and 560 may terminate at a
circumferentially directed segment, e.g., a line running
perpendicular to the longitudinal axis, that connects the ends of
the seam together. Accordingly, the angular vertex illustrated in
FIG. 50B is provided by way of example and not limitation.
[0205] The seams herein can be formed by interfacing different
segments of material in any manner, such as butt joints,
overlapping portions, non-overlapping portions, etc. The sections
of the steerable portion may thus be spliced together along the
seams and joined using known processes, such as welding or bonding
using heat, adhesives, etc.
[0206] The distal most and proximal most locations of seam 558 are
180 degrees from another around the inner tubular member. The
distal most and proximal most locations need not be defined by the
intersections of two lines, but could include, for example,
straight lines that are perpendicular to the longitudinal axis of
the inner tubular member.
[0207] Inner tubular member 550 also includes a reinforcing member
557 along its spine, which can be seen in FIG. 50C and shown in
phantom in FIG. 50B. Reinforcing member 557 extends from a proximal
end secured in section 554, to a distal end secured in steerable
section 553. Reinforcing member 557 is, in this embodiment, woven
in second reinforcing member 565, such as in an under-over pattern,
a portion of which can be seen in FIG. 50C with select cutouts.
Reinforcing member 557 can be woven in an under-over pattern such
that it is changes its over-under position relative to second
reinforcing member 565 every time it meets a new section of the
second reinforcing member 565. In this embodiment second
reinforcing member 565 is a braided material along at least a
portion of its length. Reinforcing member 557 can alternatively be
disposed on top of or below second reinforcing member 565.
Reinforcing member 557, even when woven into (e.g., any type of
over-under pattern) second reinforcing member 565, is disposed
parallel to the longitudinal axis of inner tubular member 550. The
distal end of reinforcing member 557 is everted, or folds back on
itself, as shown in FIG. 50C. The distal end folds back and wraps
around a segment of second reinforcing member 565, as shown in FIG.
50C. The distal end can fold back on top of, or below, the second
reinforcing member 565, depending on the relative location of the
reinforcing member 557. For example, in FIG. 50C, reinforcing
member 557 extends distally from under second reinforcing member
565, and everts, or is folded back, on top of second reinforcing
member 565. The everted length can be, for example, between 0.5 mm
and 5 mm, such as between 1 mm and 3 mm. In some embodiments the
length of the everted length is at least 0.5 mm, such as at least 1
mm. In an embodiment, the length of the everted section is a
minimum of 1.5 mm. One or both ends of the reinforcing member can
be everted in this manner. In some embodiments reinforcing member
557 is not woven in second reinforcing member 565 all of the way to
the proximal end of reinforcing member 557. For example,
reinforcing member 557 can be disposed over or under at least two
braided wire portions at its proximal end.
[0208] Everting the distal end of reinforcing member 557 provides
for a more secure anchoring of the reinforcing member 557 in the
inner tubular member 550. Accordingly, a likelihood of movement of
reinforcing member 557 relative to second reinforcing member 565,
which could cause a predetermined shape of the steerable portion to
be altered, may be reduced. The distal end of inner tubular member
550 is shown with a distal section 556, which is generally
relatively flexible, and has a durometer less than second segment
552. Distal section 556 can have a durometer between 15D and 50D,
such as between 25D and 45D, such as 35D.
[0209] FIG. 50D illustrates a distal region of inner tubular member
550, illustrating reinforcing member 557 disposed along the spine
of the inner tubular member 550. Section A-A from FIG. 50D is shown
in FIG. 50E, showing inner liner 564, relatively soft distal
section 556, everted distal end of reinforcing member 557, and
portions of first and second segments 551 and 552.
[0210] The inner and outer tubular members can be manufactured
individually in a number of ways. One exemplary process is that the
materials of the inner tubular member can be reflowed together on a
mandrel using heat shrink tubing.
[0211] Any of the coils in the devices herein can be replaced with
braided sections of material.
[0212] FIG. 52A illustrates a portion of exemplary steerable
medical device, including inner tubular member 550, outer tubular
member 580, which can be the same or similar to the outer tubular
member shown in FIGS. 48A-48D, and distal flexible section 582.
FIGS. 52B and 52C illustrate sections A-A and B-B, respectively,
shown in FIG. 52A. FIG. 52C illustrates inner tubular member 550,
outer tubular member 580, and reinforcing member 557 of the inner
tubular member being 180 degrees opposite the midpoint of the
higher durometer segment, 581, in outer tubular member 580. In this
design, and as described repeatedly throughout herein, the spines
of the inner and outer tubular member are offset by 180 degrees.
The relatively lower durometer material, segment 583, extends more
than 180 degrees around outer tubular member.
[0213] FIG. 52D shows Detail A from FIG. 52B, showing the distal
end of the steerable medical device. Inner tubular member 550
extends slightly further distally than outer tubular member 580 as
shown, and both engage distal flexible tip 582.
[0214] FIG. 53A is perspective view of an exemplary steerable
medical device, including external handle and actuator. FIG. 53B is
an exploded view of Detail A shown in FIG. 53A.
[0215] FIG. 53A shows, an exemplary external controller, in the
form of a handle, that is adapted to deploy and actuate the
steerable devices described herein. The external controller 5300 is
adapted, or can be adapted to control other steerable devices not
specifically described herein. In an embodiment, the external
controller 5300 controls steering of an exemplary steerable sheath
system 1000 that includes steerable tubular members, such as those
described above. Steerable sheath system 1000 may be actuated by
handle portion 1200.
[0216] Referring to FIG. 53B, an exploded view of handle portion
1200 is shown in accordance with an embodiment. Handle portion 1200
includes sheath flexure adjustment knob 1210, grip 1220, and guide
wire port 1230. Portions of handle portion 1200 are indicated by
similar numerals to those described above with respect to FIGS.
39-41 to indicate similar functionality of the components, however,
the portions may include structural differences. For example, guide
wire port 1230 may be integral to a valve cap 5302 that forms a
proximal end of external controller 5300. Guide wire port 1230 may
be internal to the controller, however. For example, guide wire
port 1230 may include an embossed cylindrical portion extending
between grip portions 1220 to direct a guidewire toward guide wire
seal 1250 within handle portion 1200. Adjustment knob 1210, grip
1220, and guide wire port 1230 may form a housing to contain an
actuation mechanism of external controller 5300 as described
below.
[0217] Flexure, or steering, of the steerable sheath is facilitated
by an actuation mechanism. More particularly, the actuation
mechanism may be actuated by twisting control knob 1210 relative to
handle grip 1220. Rotation of knob 1210 may in turn load portions
that are respectively attached to outer shaft 1110 and inner shaft
1120 to cause relative movement between the tubular members. The
method of steering the steerable medical devices herein using
external controller 5300 may be similar to the methods described
above with respect to FIGS. 39-41, and any suitable construction of
the external controller from FIGS. 39-41, or methods of using it,
may be part of external controller 5300, and its method of use.
[0218] In an embodiment, the amount of flexure of the sheath is
related to the amount of rotation of adjustment knob 1210. In some
embodiments there will be a relatively linear correspondence
between the degrees of rotation of control knob 1210 and the angle
of flexure for the sheath steerable section. In such an embodiment
each unit of incremental rotation of the control knob 1210
substantially equals or "maps" into a corresponding and constant
unit of incremental flexure for the sheath steerable portion,
independent of the starting flexure of the steerable sheath. In
alternate embodiments there can be a nonlinear correspondence. For
example, in an exemplary configuration when the steerable section
is at minimal flexure, control knob 1210 can impart twice as much
flexure as when it is at about 50% of its allowable flexure.
[0219] A portion of external controller 5300 coupled to outer
sheath 1110 may include an outer sheath interface tube 1340. Outer
sheath 1110 may be anchored to the outer sheath interface tube at
1340, e.g., via adhesives, ultrasonic welding, heat staking, or
other suitable ways. Outer sheath 1110 and outer sheath interface
tube 1340 are, in this embodiment, axially fixed relative to grip
1220.
[0220] A portion of external controller 5300 connected to inner
sheath 1120 may include an inner sheath interface tube 1370. Inner
sheath 1120 may be anchored to inner sheath interface tube 1370 via
any of the mechanisms described for the outer sheath. For example,
the inner sheath interface tube 1370 may be adhesively bonded to
inner sheath 1120 at a location proximal to a bond between outer
sheath interface tube 1340 and outer shaft 1110. The inner sheath
interface tube 1370 is secured to drive screw 1310. O-ring cap 5306
is secured to the proximal end of inner sheath interface tube 1370
by any suitable coupling mechanism, and with O-ring 5304 disposed
therebetween. Pins 5308 are positioned inside drive screw 1310 and
secure O-ring cap 5306, and thus inner sheath interface tube 1370,
to drive screw 1310. The drive screw 1310, inner sheath interface
tube 1370, and inner sheath 1120 therefore move axially together.
Furthermore, drive screw 1310 is axially movable relative to handle
grip 1220. Accordingly, in an embodiment, relative movement between
outer shaft 1110 and inner shaft 1120 is effected through the
movement of inner shaft 1120 relative to the handle, although
handle can be modified to work in different ways to cause
steering.
[0221] It will now be apparent that relative movement between
shafts to effect steering may depend on relative movement between
the respective portions of external controller 5300 that connect to
outer shaft 1110 and inner shaft 1120. That is, relative movement
between the shafts may be effected by relative linear motion
between inner sheath interface tube 1370 and outer sheath interface
tube 1340. In an embodiment, such relative linear motion is caused
by rotation of knob actuator 1210, which causes rotation of drive
nut 1330, which causes linear motion of drive screw 1310. More
particularly, drive nut 1330 may engage knob 1210 such that
rotation of knob 1210 produces rotation of drive nut 1330. In an
embodiment, the rotation of knob 1210 and drive nut 1330 is in a
1:1 relationship, i.e., knob 1210 is fixed to drive nut 1330. Thus,
control knob 1210 may sit over drive nut 1330 and may be
constrained against rotation relative to the drive nut 1330.
Control knob 1210 and drive nut 1330 may in turn be positioned
concentrically around drive screw 1310 and inner sheath interface
tube 1370, and outer sheath interface tube 1340 may sit
concentrically within the drive nut 1330.
[0222] In an embodiment, drive nut 1330 may be placed in a threaded
engagement with drive screw 1310. That is, an internal thread of
drive nut 1330 may mesh with an external thread of drive screw
1310. Since inner sheath interface tube 1370 is axially movable
relative to handle 1220, rotation of knob 1210 produces linear
motion of drive nut 1330 and inner sheath interface tube 1370, and
thus the inner sheath. Handle extensions 1320 (e.g., pins) ride in
the drive screw slot 1350, as described above, and prevent the
drive screw from rotation when the knob 1210 is rotated. The handle
extensions thus cause the axial movement of drive screw 1310, which
causes axial movement of the inner sheath. Axial movement of outer
sheath interface tube 1340 is prevented, relative to handle grip
1220, by handle extensions 1320 (e.g., pins), which extends into an
aperture in the proximal end of outer sheath interface tube 1340.
The position of outer sheath interface tube 1340 and thus the outer
sheath are axially fixed relative to handle grip 1220. Actuation of
actuator 1210 thus, in this embodiment, axially moves the inner
sheath but does not cause axial movement of the outer sheath. In
some embodiments the external controller is adapted such that, upon
actuation, the outer tubular member moves axially but the inner
tubular member does not.
[0223] FIGS. 54A-54C illustrate an exemplary outer tubular member
620 of a steerable medical device. Outer tubular member 620 can be
built into any of the steerable medical devices herein, and can be
used with any of the inner tubular members herein, or any of the
handle assemblies herein. In some embodiments a steerable medical
device includes outer tubular member 620 and inner tubular member
550 shown in FIGS. 50A-50E. In some regards outer tubular member
620 is similar to the outer tubular member shown and described with
respect to 48A-48D herein, but there are differences between the
two exemplary embodiments.
[0224] Outer tubular member 620 includes a steerable portion 622,
which includes first segment 623 and second segment 624. First
segment 623 has a higher durometer than second segment 624. First
segment 623 acts as a spine along steerable portion 624. In some
embodiments first segment 623 has a durometer between 45D and 90D,
such as between 55D and 85D, such as between 65D and 80D (e.g., 72D
Pebax), and second segment 624 has a durometer between 20D and 50D,
such as between 25D and 45D (e.g., 35D Pebax). First segment 623
extends less than 180 degrees around the outer tubular member, and
second segment 624 extends more than 180 degrees around the outer
tubular member. The joints between the two segments are parallel to
the longitudinal axis of the outer tubular member. In other
embodiments, however, the joints between segments 623 and 624 can
be non-parallel to the longitudinal axis of the outer tubular
member, and may also be non-perpendicular to the longitudinal axis
of the outer tubular member. For example, any portion of the joint
(or seam) between segments 623 and 624 can be angled as described
above with respect to inner tubular member 550. Outer tubular
member 620 includes a transitional proximal portion 625, which may
have a durometer between about 50D and 90D, such as between 60D and
80D (e.g., 72D Pebax). Outer tubular member 620 also includes
relatively longer proximal portion 626, which may extend all the
way to a handle assembly, such as any of the handle assemblies
described herein. More particularly, proximal portion 626 may
extend to a proximal end of outer tubular member 620. In a merely
exemplary embodiment proximal portion 626 is a polyamide, e.g.,
Vestamid, material.
[0225] FIG. 54B illustrates a view taken through Section H-H shown
in FIG. 54A.
[0226] FIG. 54C shows detail F shown in FIG. 54A, which is a distal
region of outer tubular member 620. Distal to steerable portion 622
is a section 627, which may be shorter than steerable portion 622,
and distal to section 627 is distal tip 628. FIG. 54 C also shows
that outer tubular member 620 also includes optional reinforcing
member 631 (in this embodiment a Kevlar strip) and second
reinforcing member 632 (in this embodiment a braided material). The
reinforcing strip may have a cross-sectional geometry having
uniform cross-sectional dimensions or non-uniform cross-sectional
dimensions. For example, the cross-sectional geometry may be
circular, such that the cross-sectional dimension is a uniform
diameter. Alternatively, the cross-sectional geometry may be
rectangular or elliptical, such that the cross-sectional dimensions
include a width greater than a height, or vice versa. Accordingly,
the cross-sectional geometry may result in higher reinforcement in
one direction, e.g., in the direction of a horizontal axis of the
strip, than in another direction, e.g., in the direction of a
vertical axis of the strip. Reinforcing member 631 is disposed
within the spine of outer tubular member 620, and specifically
within first segment 623. Reinforcing member 631 extends axially
(parallel to a longitudinal axis of outer tubular member 620) and
through a midpoint of first segment 623. Alternatively stated, a
plane containing reinforcing member 631 and a central axis of outer
tubular member 620 may divide first segment 623 into two
hypothetical symmetrical sections. In some embodiments reinforcing
member 631 is a Kevlar line.
[0227] Reinforcing member 631 can help prevent unwanted stretching
of the outer tubular member spine (e.g., segment 623) if it is
placed under tension during bending. For example, if outer tubular
member 620 is placed under tension via a handle assembly to steer
the steerable section, first segment 623 may stretch more than
desired, resulting in an increase in the travel of the outer
tubular member in the handle to steer the steerable section. The
unwanted stretching can thus lead to inefficient steering by
increasing the travel needed to steer the steerable portion to the
desired configuration. Reinforcing member 631 in the spine of outer
tubular member can reduce the stretching, and thus the travel, and
thus can increase the efficiency of the bending. In some
embodiments the steerable system may be adapted to put outer
tubular member 623 only in compression, and it may not be necessary
to include reinforcing member 631. Alternatively, even in systems
where the inner tubular member is put under tension, it may not be
necessary to include reinforcing member 631.
[0228] Reinforcing member 631 can be woven through second
reinforcing member 632 (e.g., a braided material) in any desired
pattern. Either of the ends of reinforcing member 631 can be
everted such as described above. More particularly, either end of
the reinforcing member 631 may be folded on itself, however, in
this embodiment neither end is everted.
[0229] The ends of reinforcing member 631 can be disposed over or
under second reinforcing member 632 along at least one wire. For
example, in an embodiment, a distal end of reinforcing member 631
is woven between the braided material and coincides with a distal
end of the braiding material. Furthermore, the reinforcing member
631 may extend to a distal end of the outer tubular member 620.
More particularly, the distal end of the reinforcing member 631 may
be located within a bonding region where the distal end of the
outer tubular member 620 is bonded to the inner tubular member 550.
Locating the distal end of the reinforcing member 631 within this
bonding region may minimize stretching of the outer tubular member
620 in some actuation modes, and thus, may reduce the range of
travel of the controller 650 required to achieve a particular
steering bend.
[0230] A proximal end of reinforcing member 631 may overlap the
wires of the braided material. More particularly, the proximal end
portion transitions from a triaxial braid configuration to overlap
either an outside surface or an inside surface of the wires. This
is similar to the manner of overlap described above with respect to
an embodiment of inner tubular member 550 above. More particularly,
an end section of the reinforcing member 631 may overlay or
underlay at least one turn of each braid wire.
[0231] The distal end of reinforcing member 631 extends into distal
tip section 628 of outer tubular member 620, and can extend all the
way to the end of the distal tip section 628. In some embodiments
the distal end of reinforcing member 631 is in section 627. The
proximal end of reinforcing member 631 is disposed proximal to
steerable portion 622, and in this embodiment is disposed in
transition section 625.
[0232] In this embodiment liner 633 does not extend to the distal
end of outer tubular member 620. Specifically, liner 633 extends to
the distal end of section 627, but not into tip section 628.
[0233] Distal tip section 628, from inside to outside, includes
inner layer 630, a layer that includes both reinforcing members 631
and 632 (631 woven in 632 along at least a portion of tip section
628), marker band 629, and outer layer 635. In some embodiments
inner layer 630 can have a durometer from 20D to 50D, such as 30D
to 40D (e.g., 35D). In some embodiments outer layer 635 has a
durometer from 40D to 70D, such as 45D to 65D (e.g., 55D).
[0234] In some embodiments the inner and outer tubular members have
linear reinforcing members (e.g., Kevlar lines), and are 180
degrees apart. The reinforcing members can be aligned with spines
of both inner and outer tubular members.
[0235] FIG. 55A illustrates a portion of an exemplary steerable
medical device 645, including inner tubular member 550, outer
tubular member 620, and flexible distal tip 640. FIG. 55B shows
section W-W shown in FIG. 55A. FIG. 55C shows section Z-Z shown in
FIG. 55B, and FIG. 55D shows detail A-A of the distal end shown in
FIG. 55C. As shown in FIG. 55B, the reinforcing members 631 and 557
are 180 degrees from each other. Reinforcing member 557 of the
inner tubular member is 180 degrees from the midpoint of the higher
durometer segment, 623, in outer tubular member 620. FIG. 55C
illustrates distal tip 640 secured to outer tubular member 620 and
inner tubular member 550, which are also secured to one another.
FIG. 55D highlights the bonded nature of inner tubular member 550
and outer tubular member 620, and flexible distal tip 640. Inner
tubular member 550 extends further distally than outer tubular
member 620, and both are secured to distal flexible tip 640. More
particularly, inner tubular member 550, outer tubular member 620,
and distal flexible tip 640 may be fused together using, e.g., a
heat fusing process, to form steerable medical device 645.
[0236] A distal end of reinforcing member 631 may coincide with a
distal end of outer tubular member 620. For example, the distal end
of reinforcing member 631 can have a same axial location or extent
as a distal end of outer tubular member 620. In an embodiment, the
distal end of reinforcing member 631 is within the bond region
formed by fusing the inner tubular member 550, the outer tubular
member 620, and the distal flexible tip 640.
[0237] FIGS. 56A-H illustrate an exemplary external controller 650
that is adapted to steer a steerable medical device, optionally any
of the steerable devices herein that include first and second
tubular members, such as steerable medical device 645 that includes
outer tubular member 620 and inner tubular member 550. The
steerable medical device can include any of the inner and outer
tubular members herein, including any combination thereof.
[0238] FIG. 56A is a perspective view showing the assembled
assembly, including external controller 650 secured to steerable
device 645. FIG. 56B shows an exploded view of external controller,
which includes an actuator grip 651 (e.g., rotatable knob),
actuator nut 652, drive screw 653 including two wings 660 extending
radially from the screw, valve body 654 (and optionally a stopcock
tethered to the valve body 654 and placed in fluid communication
with the valve body 654 by a tubular flush line), handle shells or
grips 655 each including a slot 661, valve 656, valve cap 657,
friction members 658, and bearing 659. Also shown are outer tubular
member 620 and inner tubular member 550.
[0239] FIG. 56C shows an assembled view of controller but with one
handle shell removed, and compared to FIG. 56B would be considered
a bottom view with bottom handle shell 655 removed. FIG. 56D shows
a sectional view 90 degrees relative to the view in 56C. FIG. 56E
is a sectional view of the view from 56C. FIGS. 56F-H show
highlighted views of portions of the controller from the sectional
view from FIG. 56E. FIG. 56F shows a central region, FIG. 56G shows
a proximal region, and FIG. 56H shows a distal region of external
controller.
[0240] In this embodiment the proximal end of inner tubular member
550 is secured directly to valve body inside a channel in valve
body 654. Outer tubular member 620 is secured within a distal
region of drive screw 653. Distal movement of drive screw 653
pushes on outer tubular member and puts it in compression, and
because the tubular members are axially fixed distal to the
steerable portion, inner tubular member is put under tension.
Proximal movement of drive screw 653 pulls on outer tubular member
620, putting it in tension, which puts the inner tubular member in
compression. Distal movement of drive screw 653 causes the
steerable device 645 to steer in a first direction, while proximal
movement of drive screw 653 causes the steerable device 645 to bend
in a second direction. In embodiments in which the tubular members
have spines that are 180 degrees apart (such as with tubular
members 550 and 620), the two bending directions are in the same
plane, 180 degrees apart. Inner tubular member 550 is disposed
within drive screw 653 and drive screw 653 can move axially
relative to inner tubular member 550.
[0241] In an embodiment, drive screw 653 extends proximally from
outer tubular member 620 and surrounds at least a portion of inner
tubular member 550 between a proximal end of outer tubular member
620 and valve body 654. As such, drive screw 653 provides column
support to inner tubular member 550 by limiting transverse
deflection of inner tubular member 550. More particularly, when
inner tubular member 550 is placed in compression, it may have a
tendency to buckle, however, drive screw 653 around inner tubular
member 550 may prevent such buckling. Thus, drive screw 653 may
serve dual functions as both a force transmission element to
convert rotational motion of the actuator nut 652 into axial motion
of outer tubular member 620, and an anti-buckling element to
prevent buckling of inner tubular member 550 during steering.
[0242] In this embodiment axial movement of drive screw 653 is
caused by actuation of actuator grip 651, and in this embodiment,
rotation of actuator grip 651. Actuator grip 651 is secured to nut
652, such that rotation of actuator grip 651 causes nut 652 to
rotate as well. Actuator grip 651 is a gripping element that
facilitates the rotation of nut 652. Nut 652 has an internal
interfacing element that interfaces with the outer thread of drive
screw 653. In an embodiment, the internal interfacing element of
nut 652 is a single thread, i.e., a thread having a single turn, to
engage the thread of drive screw 653. Thus, the length of threaded
contact between nut 652 and drive screw 653 is fewer than ten
turns, e.g., fewer than five turns, in an embodiment. In an
embodiment, the threaded interface occurs at a central region 670
of drive screw 653. Additionally, drive screw 653 includes two
wings 660 (or pins) that are 180 degrees part, each of which
extends radially from the body of the screw and rides in a separate
slot 661 of handle grips 655. The interface between the wings and
the slots prevents the drive screw 653 from rotating when actuator
grip 651 is rotated. When actuator grip 651 is rotated, the
internal interfacing element of nut 652 rotates relative to the
thread of drive screw 653, the interface between wings 660 and
slots 661 prevents the drive screw from rotating, and the drive
screw 653 will move axially, either proximally or distally,
depending on the direction of rotation of actuator grip 651. The
ability to bend the steerable device 645 in two directions is
referred to generally herein as bi-directional steerability, which
external controller 650 provides.
[0243] The interfacing location 670 between the nut 652 and drive
screw 653 is relevant to the bi-directional steerability. Because
the interface is in a central region of the thread (i.e., not at an
extreme end of the thread of the drive screw), rotation of actuator
grip 651 in both directions causes axial movement of drive screw
653 (either distally or axially depending on the direction or
rotation). This puts the outer tubular member in either compression
or tension (depending on the direction of rotation), which puts the
inner tubular member in the other of compression and tension, and
under either scenario the steerable device is steered, but not
necessarily in the same direction, e.g., in opposite
directions.
[0244] By allowing the drive screw to move in both directions (such
as by interfacing the thread at a central region),
bi-directionality can be achieved. Interfacing the thread at the
extreme distal or proximal end may allow the drive screw to travel
in only one direction, and would thus remove the bi-directionality
of the device. As long as the interface is at a location that
allows for some axial movement in both directions (even if just
very little axial movement in one direction), bi-directionality can
be achieved. By changing the location 670 of the interface between
drive screw 653 and nut 652 (away from exact center of thread of
the drive screw), a bias can be put in the steerable device, such
that it can be steered more in one direction than the other. For
example, if range of travel of drive screw 653 is greater in a
certain axial direction, i.e., either distally or proximally, a
range of steering may be greater in a corresponding direction,
e.g., steerable device 645 may curve more in one direction than
another. If there is a bias, however, bi-directionality would still
be achieved.
[0245] In an embodiment, a direction of steering may be aligned
with the flush line extending from the valve body 654. Steering may
be within a plane containing a central axis of the steerable device
645. That is, deflection of steerable device 645 may result in
steering within the plane to one side or another of the central
axis. Since such steering ordinarily occurs while the steerable
device 645 is located in a patient anatomy, however, it may
difficult for a physician to ascertain the orientation of the
steerable device 645 relative to the controller 650 outside of the
patient anatomy. To compensate for this, the flush line may extend
laterally from a side wall of the valve body 654 in a direction
within the plane of steering. Thus, the physician may determine a
relative orientation between the flush line outside of the anatomy
and the distal end of steerable device 645 inside the anatomy to
predict a direction of steering inside the anatomy.
[0246] In some embodiments the actuator grip 651 and nut 652 could
be integral, such that they can be considered the same part (e.g.,
together an "actuator"). For example, actuator grip 651 may be a
rubber component overmolded on the nut 652 to form an integrated,
two-part body.
[0247] Controller 650 also includes valve 656, which is held in
place when valve cap 657 is secured to valve body 654. More
particularly, valve 656 may be compressed between valve cap 657 and
valve body 654. Valve 656 may, for example, include a slit
diaphragm, and thus, such compression may maintain an integrity of
the slit diaphragm to prevent leaking. For example, the compressed
diaphragm may prevent blood from leaking through valve 656, and
thus, valve 656 may maintain hemostasis of the controller 650.
Nonetheless, the slit diaphragm of valve 656 may permit passage of
a working device, e.g., a guidewire, through valve 656, controller
650, and steerable device 645. Actuator grip 651 and nut 652 can be
secured together using any number of known techniques. Actuator
grip 651 can be a soft material such as rubber that slides over nut
652, with internal features on the inside of actuator grip 651 that
interface with external features of nut 652 (see FIG. 56H). When
actuator grip 651 and nut 652 are not integral (such as in this
embodiment), torque may be transmitted from actuator grip 651 to
nut 652. Distal end of nut 652 has a plurality of female components
(see FIG. 56B) that interface with male components on the inside of
actuator grip 651, and the interface transmits torque. For example,
the male components may include radial fins extending laterally
from an inner surface of actuator grip 651, and the fins may engage
corresponding slots formed through an outer wall of nut 652.
Accordingly, the keyed relationship between the fins and the slots
may allow for rotation of actuator grip 651 to transmit a
rotational force from the fins to the slots to cause a
corresponding rotation of nut 652.
[0248] Bearing 659 may include a flattened ring, such as a washer
profile, to prevent contact between nut 652 and shells 655.
Accordingly, bearing 659 may reduce friction between nut 652 and
handle shells 655. This provides for ease of rotation of actuator
grip 651 and smooth actuation of steerable device 645.
[0249] Friction members 658 may be o-rings that act as frictional
elements to provide smooth friction, and are disposed in slots in
the handle shells. More particularly, the friction members 658 may
include an outer surface to slide against handle shells 655 and an
inner surface to slide against nut 652 to provide an increased and
repeatable surface contact and frictional force between those
elements. Accordingly, friction members 658 can reduce or prevent
backlash.
[0250] In some embodiments the proximal end of outer tubular member
is disposed inside the drive screw less than 2 inches from the
distal end of the drive screw, and can be secured in place relative
to the drive screw with glue injected into a glue port or a glue
hole in the drive screw. In some embodiment the proximal end of the
inner tubular member 550 extends 1 mm to 200 mm further proximally
that the proximal end of the outer tubular member 620.
* * * * *