U.S. patent application number 15/418466 was filed with the patent office on 2017-05-18 for collapsible sheath and tapered dilator for tissue puncture access.
This patent application is currently assigned to St. Jude Medical Puerto Rico LLC. The applicant listed for this patent is St. Jude Medical Puerto Rico LLC. Invention is credited to Zachary J. Tegels.
Application Number | 20170135725 15/418466 |
Document ID | / |
Family ID | 47827467 |
Filed Date | 2017-05-18 |
United States Patent
Application |
20170135725 |
Kind Code |
A1 |
Tegels; Zachary J. |
May 18, 2017 |
COLLAPSIBLE SHEATH AND TAPERED DILATOR FOR TISSUE PUNCTURE
ACCESS
Abstract
A tissue puncture access assembly that includes a sheath and a
dilator. The sheath is operable between an expanded position with a
first maximum outer diameter, and a collapsed position with a
second maximum outer diameter that is less than the first maximum
outer diameter. The dilator is insertable through the sheath and
has a leading end positionable distal of a distal end of the
sheath. The sheath is operated into the collapsed position prior to
and during insertion with the dilator into a tissue puncture. The
sheath is operated into the expanded position once positioned in
the tissue puncture.
Inventors: |
Tegels; Zachary J.;
(Minneapolis, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
St. Jude Medical Puerto Rico LLC |
Caguas |
PR |
US |
|
|
Assignee: |
St. Jude Medical Puerto Rico
LLC
Caguas
PR
|
Family ID: |
47827467 |
Appl. No.: |
15/418466 |
Filed: |
January 27, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13772933 |
Feb 21, 2013 |
9586033 |
|
|
15418466 |
|
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61692980 |
Aug 24, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 17/3431 20130101;
A61M 29/00 20130101; A61B 17/3417 20130101; A61B 17/3439 20130101;
A61B 17/0057 20130101 |
International
Class: |
A61B 17/34 20060101
A61B017/34; A61M 29/00 20060101 A61M029/00; A61B 17/00 20060101
A61B017/00 |
Claims
1-20. (canceled)
21. A tissue puncture access assembly, comprising: a sheath having
an expanded position with a first minimum inner diameter, the
sheath having a collapsed position with a second minimum inner
diameter, the second minimum inner diameter being less than the
first minimum inner diameter; a dilator insertable through the
sheath and having a leading end positionable distal of a distal end
of the sheath, the leading end having an outer diameter, the
dilator having a proximal end, the proximal end having a hub;
wherein the second inner diameter of the sheath substantially
matches the outer diameter of the leading end of the dilator.
22. The tissue puncture access assembly of claim 21, wherein the
dilator includes a taper at the leading end.
23. The tissue puncture access assembly of claim 21, wherein the
sheath changes shape from the collapsed position to the expanded
position in first and second stages, the first stage including
shortening in an axial direction, and the second stage including
expansion in a radial direction.
24. The tissue puncture access assembly of claim 21, wherein the
sheath is operable between the expanded and collapsed positions
using a braided construction.
25. The tissue puncture access assembly of claim 24, wherein the
braided construction is actuated by one of twisting, pushing,
pulling or lever action.
26. The tissue puncture access assembly of claim 21, wherein the
sheath is operable between expanded and collapsed positions using a
coil member.
27. A tissue puncture access assembly, comprising: a collapsible
sheath having a variable outer diameter and a lumen having a
variable inner diameter; a dilator insertable through the lumen of
the collapsible sheath, the dilator having a proximal end
integrated with a hub; wherein the collapsible sheath and dilator
are insertable together through a tissue puncture with the
collapsible sheath is in a collapsed position with a reduced outer
diameter, and operable into an expanded position with an increased
outer diameter when positioned in the tissue puncture to enlarge
the tissue puncture.
28. The tissue puncture access assembly of claim 27, wherein an
outer diameter of the dilator substantially matches the variable
inner diameter of the collapsible sheath.
29. The tissue puncture access assembly of claim 27, wherein the
dilator includes a tapered distal end positionable distal of a
distal end of the collapsible sheath when the collapsible sheath is
in the collapsed position.
30. The tissue puncture access assembly of claim 27, wherein the
collapsible sheath is moved between expanded and collapsed
positions to change the variable outer diameter using a rotatable
collapsing mechanism.
31. The tissue puncture access assembly of claim 27, wherein the
collapsible sheath includes a coil member operable to change the
collapsible sheath between the collapsed position and the expanded
position.
32. The tissue puncture access assembly of claim 27, wherein the
outer diameter of the dilator substantially matches the outer
diameter of the collapsible sheath when the collapsible sheath is
in the collapsed position.
33. The tissue puncture access assembly of claim 27, wherein the
dilator includes a stepped construction that permits collapsing of
the sheath into the collapsed position.
34. The tissue puncture access assembly of claim 27, wherein the
dilator comprises a body portion, the body portion insertable
through the lumen of the collapsible sheath, the body portion
having a variable outer diameter.
35. A method of accessing a tissue puncture, comprising: providing
a collapsible sheath and a dilator, the dilator having a proximal
end, the proximal end comprising a hub, the hub being movable
relative to the collapsible sheath; advancing the dilator through
the collapsible sheath until a distal end of the dilator extends
distal of the collapsible sheath; orienting the collapsible sheath
into a collapsed position around the dilator; advancing the
collapsible sheath and dilator through the tissue puncture with the
collapsible sheath in the collapsed position; orienting the
collapsible sheath into an expanded position to dilate the tissue
puncture.
36. The method of claim 35, wherein operating the collapsible
sheath into the collapsed position includes at least one of
reducing an outer diameter of the collapsible sheath and increasing
a length of the collapsible sheath.
37. The method of claim 35, wherein operating the collapsible
sheath into the collapsed position includes changing a length of
the collapsible sheath and changing an outer diameter of the
collapsible sheath.
38. The method of claim 35, wherein operating the collapsible
sheath into an expanded position includes rotating one end of the
collapsible sheath relative to an opposite end of the collapsible
sheath.
39. The method of claim 35, further comprising orienting the
collapsible sheath into the collapsed position around the dilator
after dilating the tissue puncture, and withdrawing the collapsible
sheath and dilator from the tissue puncture.
40. The method of claim 35, wherein orienting the collapsible
sheath into a collapsed position around the dilator comprises
collapsing the collapsible sheath to a diameter substantially
matching an outer diameter of the distal end of the dilator.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 13/772,933, filed on 21 Feb. 2013, now
pending, which application claims the benefit of U.S. Provisional
Application No. 61/692,980, filed on 24 Aug. 2012, the disclosures
of which are incorporated, in their entireties, by this
reference.
TECHNICAL FIELD
[0002] The present disclosure relates generally to accessing tissue
punctures, and more particularly, to methods and systems for
controlling dimensions of a sheath that is insertable through the
tissue puncture.
BACKGROUND
[0003] Various surgical procedures are routinely carried out
intravascularly or intraluminally. For example, in the treatment of
vascular disease, such as arteriosclerosis, it is a common practice
to access the artery and insert an instrument (e.g., a balloon or
other type of catheter) to carry out a procedure within the artery.
Such procedures usually involve the percutaneous puncture of the
artery so that an insertion sheath may be placed in the artery and
thereafter instruments (e.g., catheters) may pass through the
sheath to an operative position within the artery. Intravascular
and intraluminal procedures unavoidably present the problem of
stopping the bleeding at the percutaneous puncture after the
procedure has been completed and after the instruments (and any
insertion sheaths used therewith) have been removed. Bleeding from
puncture sites, particularly in the case of femoral arterial
punctures, is typically stopped by utilizing vascular closure
devices.
[0004] While there are a variety of prior art devices and
techniques for closing such punctures, one aspect of interest in
the ability to access the puncture prior to closing the puncture.
An insertion sheath is commonly inserted into the puncture to
create an access port for the closure device used to close the
puncture. A dilator is often used with the sheath to dilate or
enlarge the puncture at the time of inserting the sheath. The
dilator typically extends distal of a distal end of the sheath. The
maximum size (e.g., diameter) of the sheath may be greater than the
size of the puncture, which presents a challenge to avoid damaging
the tissue surrounding the puncture when inserting the sheath.
SUMMARY
[0005] One aspect of the present disclosure relates to a tissue
puncture access assembly that includes a sheath and a dilator. The
sheath is operable between an expanded position with a first
maximum outer diameter, and a collapsed position with a second
maximum outer diameter that is less than the first maximum outer
diameter. The dilator is insertable through the sheath and has a
leading end that may be positioned distal of a distal end of the
sheath. The sheath may be operable in the collapsed position prior
to and during insertion with the dilator into a tissue puncture,
The sheath is operated into the expanded position once positioned
in the tissue puncture.
[0006] The dilator may be operable between an expanded position
having a first dilator diameter, and a collapsed position having a
second dilator diameter that is less than the first dilator
diameter. The sheath may have a first minimum inner diameter in the
expanded position, and a second minimum inner diameter the
collapsed position, and the dilator has an outer diameter that is
no greater than the first minimum inner diameter of the sheath. The
dilator may include a taper at the leading (e.g., distal) end. The
leading end of the dilator may taper to a diameter that
substantially matches the second maximum outer diameter of the
sheath.
[0007] The sheath may change shape from the collapsed position to
the expanded position in first and second stages, wherein the first
stage includes shortening in an axial direction, and the second
stage includes expansion in a radial direction. The dilator may
include a stepped construction that permits collapsing of the
sheath into the collapsed position. The sheath may be operable
between the expanded and collapsed positions using a braided
construction. The braided construction may be actuated by one of
twisting, pushing, pulling or lever action. The sheath may be
operable between expanded and collapsed positions using a coil
member.
[0008] Another aspect of the present disclosure relates to a tissue
puncture access assembly that includes a collapsible sheath having
a variable outer diameter and a lumen having a variable inner
diameter, and a dilator insertable through the lumen of the
collapsible sheath. The sheath and dilator are insertable together
through a tissue puncture when the sheath is in a collapsed
position with a reduced outer diameter. The sheath is also operable
into an expanded position with an increased outer diameter when
positioned in the tissue puncture to enlarge the tissue
puncture.
[0009] An outer diameter of the dilator may substantially match the
inner diameter of the sheath. The dilator may include a tapered
distal end positionable distal of a distal end of the sheath when
in the collapsed position. The sheath may be moved between expanded
and collapsed positions to change the variable outer diameter using
a rotatable collapsing mechanism. The sheath may include a coil
member operable to change the sheath between the collapsed position
and the expanded position.
[0010] A further aspect of the present disclosure relates to a
method of accessing a tissue puncture. The method includes
providing a collapsible sheath and a dilator, advancing the dilator
through the sheath until a distal end of the dilator extends distal
Of the sheath, operating the sheath into a collapsed position
around the dilator, advancing the sheath and dilator through the
tissue puncture with the sheath in the collapsed position, and
orienting the sheath into an expanded position to dilate the tissue
puncture.
[0011] Orienting the sheath into the collapsed position may include
at least one of reducing an outer diameter of the sheath and
increasing a length of the sheath. Orienting the sheath into the
collapsed position may include changing a length of the sheath and
changing an outer diameter of the sheath. Orienting the sheath into
an expanded position may include rotating one end of the sheath
relative to an opposite end of the sheath. The method may also
include orienting the sheath into the collapsed position around the
dilator latter dilating the tissue puncture, and withdrawing the
sheath and dilator from the tissue puncture.
[0012] The foregoing and other features, utilities, and advantages
of the invention will be apparent from the following detailed
description of the invention with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The accompanying drawings illustrate various embodiments of
the present disclosure and are a part of the specification. The
illustrated embodiments are merely examples of the present
disclosure and do not limit the scope of the invention.
[0014] FIG. 1 is a side view of an example sheath assembly in
accordance with the present disclosure.
[0015] FIG. 2 is a cross-sectional view of the sheath assembly of
FIG. 1 taken along cross-section indicators 2-2.
[0016] FIG. 3 is an exploded view of the sheath assembly of FIG.
1.
[0017] FIG. 4 is a side view showing the sheath assembly of FIG. 1
with the sheath in an expanded position.
[0018] FIG. 5 is a cross-sectional view of the sheath assembly of
FIG. 4 taken along cross-section indicators 5-5.
[0019] FIG. 6A is a close-up view of a portion of the sheath of
FIG. 1 having a braid construction.
[0020] FIG. 6B is a close-up view of a portion of the sheath of
FIG. 4 having a braid construction.
[0021] FIG. 7A is a close-up view of a portion of the sheath of
FIG. 1 having a coil construction.
[0022] FIG. 7B is a close-up view of a portion of the sheath of
FIG. 4 having a coil construction.
[0023] FIG. 8A is a close-up view of a portion of the sheath of
FIG. 1 having a collapsible slit construction.
[0024] FIG. 8B is a close-up view of a portion of the sheath of
FIG. 4 having a collapsible slit construction.
[0025] FIG. 8C is a cross-sectional view of the portion of the
sheath of FIG. 8A.
[0026] FIG. 8D is a cross-sectional view of the portion of the
sheath of FIG. 8B.
[0027] FIG. 9 shows another example sheath assembly in accordance
with the present disclosure.
[0028] FIG. 10 shows the dilator of the sheath assembly of FIG. 9
having a step construction.
[0029] FIG. 11 shows another example dilator in accordance with the
present disclosure.
[0030] FIG. 12 shows the dilator of FIG. 11 in an expanded
position.
[0031] FIGS. 13-17 show steps of expanding a tissue puncture using
the sheath assembly of FIG. 1.
Throughout the drawings, identical reference numbers designate
similar, but not necessarily identical, elements.
DETAILED DESCRIPTION
[0032] The apparatuses and methods disclosed herein may be used to
access percutaneous punctures made through a body layer of a
patient to gain access to a body cavity. Access through a
percutaneous puncture allows a physician to carry out various
procedures in or through the body cavity for examination, surgery,
treatment and the like. While not meant to be limiting, the systems
are illustrated being used to access percutaneous punctures in
blood vessels in patients for various procedures. It will be
appreciated that the apparatuses and methods are applicable to
other procedures requiring access to a puncture through body tissue
into a cavity including, for example, laparoscopic surgery and
other microscopic surgery techniques using a relatively small
incision. Applications of access apparatuses and methods including
those implementing principles described herein include access of a
percutaneous puncture or incision in tissue separating two internal
portions of a living body, such as punctures or incisions in blood
vessels, ducts or lumens, gall bladders, livers, hearts, etc.
[0033] As used in this specification and the appended claims, the
terms "engage" and "engagable" are used broadly to mean interlock,
mesh, or contact between two structures or devices. Likewise
"disengage" or "disengagable" means to remove or capable of being
removed from interlock, mesh, or contact. A "tube" is an elongated
device with a passageway. The passageway may be enclosed or open
(e.g., a trough). A "lumen" refers to any open space or cavity in a
bodily organ, especially in a blood vessel. The words "including"
and "having," as well as their derivatives, as used in the
specification, including the claims, have the same meaning as the
word "comprising."
[0034] One aspect of the present disclosure is directed to a sheath
assembly that includes a sheath and a dilator, At least one of the
sheath and dilator are configured to operate between expanded and
collapsed shapes or positions. In one example, the sheath may be
operated between a collapsed position having a reduced outer
profile (e.g., outer diameter) that facilitates easier insertion
into a tissue puncture, and an expanded position that assists in
dilating or expanding the tissue puncture after positioning the
sheath within the tissue puncture. The sheath assembly may be
particularly useful when attempting to increase the tissue puncture
size from, for example, about 3 to 6 French to an expanded size of
about 10 to 20 French. Attempting to insert or remove a relatively
large diameter sheath (e.g., in the size of about 10 to 20 French)
relative to a smaller sized tissue puncture may create undesired
damage to the tissue.
[0035] The sheath assembly of the present disclosure may provide
for a reduced profile sheath asserting the sheath assembly through
the tissue puncture, and provide later expanding of the sheath to
dilate the tissue puncture after the sheath assembly is properly
positioned within the tissue puncture. The sheath assembly may also
be collapsible after conducting a treatment procedure via access
provided by the sheath. Collapsing the sheath prior to removing the
sheath assembly may also help limit damage to the tissue that
defines the tissue puncture.
[0036] An example dilator of the sheath assembly may have a tapered
distal end portion to help transition from a smaller diameter
distal tip of the dilator to a larger diameter distal end of the
sheath. The dilator may include a step feature that provides a
reduced diameter outer surface along a portion of a length of the
dilator proximal of the distal end of the dilator. The step feature
may accommodate a portion of the sheath, which when collapsed may
have an outer diameter that is similar in size to a maximum
diameter of the distal end portion of the dilator. The step feature
in the dilator may provide an improved shape transition from the
distal tip of the dilator to the sheath.
[0037] Various mechanical constructions and devices may be
implemented to operate the sheath between expanded and collapsed
positions. One example mechanism includes a tubular braided
structure. Applying an axially directed three to the braided
structure may change an outer diameter of the sheath. In another
example, the sheath includes a coil structure along at least a
portion of its length. Rotating the coil structure may change an
outer diameter of the sheath. Operating the braid and coil
structures may also change a length of the sheath. In a still
further example, the sheath includes a longitudinal slit, wherein
the longitudinal slit defines opposing side edges that are moveable
circumferentially and/or radially relative to each other. In a
collapsed position, the slit side edges overlap each other to
provide a reduced outer dimension for the sheath. In an expanded
position, the slit side edges are arranged adjacent to each other
to provide an increased outer diameter for the sheath. The relative
movement between the slit side edges may be implemented by
applying, for example, a rotation force to one end of the
sheath.
[0038] In a still further example, the dilator may also be operated
between expanded and collapsed positions. The outer diameter of the
dilator may change to more closely match an inner diameter of the
sheath as the sheath is operated between expanded and collapsed
positions. In at least one example, operating the dilator between
expanded and collapsed positions assists in changing the sheath
between expanded and collapsed positions. The dilator may be used
to advance the sheath assembly through a tissue puncture and then
be removed from the sheath prior to conducting treatment of the
patient with instruments that extend through the sheath 12.
Typically, the sheath is collapsed prior to removing the sheath
from the tissue puncture.
[0039] Referring now to FIGS. 1-5, an example sheath assembly 10 is
shown and described. The sheath assembly 10 includes a sheath 12
and a dilator 14. The dilator 14 extends through the sheath 12 such
that a distal end of the dilator extends distally of a distal end
of the sheath. A proximal end of the dilator is positioned proximal
to the proximal end of the sheath so that the operator can operate
and move the dilator 14 relative to tie sheath 12. In some
arrangements, the sheath is operated into an at least partially
expanded position prior to inserting the dilator 14 through the
sheath 12. In other arrangements, the dilator 14 may be advanced
through the sheath 12 when the sheath is in a substantially
collapsed position.
[0040] The sheath 12 includes a sheath body 30 and a hub 32. The
sheath body 30 includes distal and proximal ends 34, 36, a lumen 38
(see FIGS. 2 and 5), a collapsed outer diameter D.sub.1 (see FIG.
1), and an expanded outer diameter D.sub.2 (see FIG. 4). The sheath
body 30 may also include a collapsed length L.sub.1 (see FIG. 3)
and an expanded length (not shown).
[0041] The hub 32 is connected to the proximal end 36 of the sheath
body 30. The hub 32 may include an actuator 50, which when operated
changes the sheath body from the collapsed position shown in FIG. 1
to the expanded position shown in FIG. 4. Operating (e.g.,
orienting) the actuator 50 may also change the sheath body 30 from
the expanded position shown in FIG. 4 to the collapsed position
shown in FIG. 1.
[0042] The actuator 50 is shown schematically in the figures and
may represent any desired actuation device. In one example, the
actuator 50 may be rotatable about a longitudinal axis of the
sheath 12 to change the sheath body 30 between collapsed and
expanded positions. In other arrangements, the actuator 50 may move
axially to operate the sheath body 30 between collapsed and
expanded positions. In still further arrangements, the actuator 50
may include, for example, fasteners, clips, gauges, indicia,
threads, pull wires, or other features that may be used to operate
the sheath body between collapsed and expanded positions and help
maintain the sheath body in collapsed and expanded positions. The
actuator 50 may be directly connected to the sheath body 30. In
other arrangements, the actuator 50 may include an intervening
member that couples the actuator 50 to the sheath body 30 or a
portion of the sheath body used to operate the sheath body 30
between collapsed and expanded positions.
[0043] In at least some arrangements, operating or orienting the
sheath body 30 between expanded and collapsed positions changes
both the outer diameter as well as the length of the sheath body
30. For example, the sheath body 30 may have an outer diameter
D.sub.1 and a length L.sub.1 when in a collapsed position.
Operating the sheath body 30 into an expanded position changes the
outer diameter to an enlarged outer diameter D.sub.2 and changes
the length to a shortened, expanded length L.sub.2 (see FIG. 4). In
some arrangements, increasing the outer diameter automatically
shortens the length of the sheath body 30, and decreasing the outer
diameter automatically increases the length of the sheath body 30.
In other arrangements, increasing the length of the sheath body 30
automatically decreases the outer diameter, and decreasing the
length of the sheath body 30 automatically increases the outer
diameter.
[0044] Referring to FIGS. 6A and 6B, an example construction for
the sheath body 30 includes a braid 40. In the collapsed position
of FIG. 6A, at least some of structures 41, 43 of braid 40 may be
arranged at an angle .theta. in the range of about 20.degree. to
about 45.degree.. In the expanded position of FIG. 6B, the
structures 41, 43 of braid 40 may be arranged at an angle .theta.
of about 45.degree. to about 90.degree.. The structures 41, 43 may
extend in generally opposite directions. The braid 40 may be
operated by, for example, applying a rotation force to one end of
the sheath body 30 while maintaining an opposite end of the sheath
body in a generally fixed rotated position. In another arrangement,
the braid structure is operated by rotating the opposing ends in
opposite directions. Alternately, the braid structure may be
operated by applying a longitudinal force to the sheath body
30.
[0045] Referring now to FIGS. 7A and 7B, the sheath body 30 is
shown including a coil structure 42. The coil structure 42 may be
operated to move the sheath body between collapsed and expanded
positions by either rotating or applying a longitudinal force to
one end of the coil structure 42. The sheath body 30 may include
multiple coil members. The coil members may be arranged
co-extensive, or may be arranged radially inward from each other.
Many arrangements are possible for coil structures in a sheath body
30.
[0046] Referring to FIGS. 8A-D, the sheath body 30 is shown
including a longitudinal slit 44 having first and second
longitudinal slit edges 46, 48. In the collapsed position, the
first and second longitudinal edges 46, 48 are positioned
overlapping each other (see FIG. 8C). In the expanded position, the
first and second longitudinal edges 46, 48 may be positioned
adjacent to each other and possibly arranged facing each other as
shown in FIG. 8D. The longitudinal slit 44 may be arranged linearly
along a length of the sheath body 30. Alternatively, longitudinal
slit 44 may be arranged in a helical path along the length of the
sheath body 30. The sheath body 30 including the longitudinal slit
44 may be operated between collapsed and expanded positions, for
example, by applying longitudinal or rotational forces to one end
of the sheath body 30.
[0047] In another example (not shown), the sheath 12 may include a
pull wire or other device that extends along at least a portion of
the length of the sheath body 30. Operating the pull wire may apply
an axially directed force to the sheath body 30 that changes the
outer diameter between the collapsed outer diameter D.sub.1 and the
expanded outer diameter D.sub.2.
[0048] Referring now to FIGS. 1 and 3, the dilator 14 includes a
body portion 60 and a hub 62. The body portion 60 includes distal
and proximal end portions 64, 66, a lumen 69 (see FIG. 2), and an
outer diameter D.sub.3. The distal end portion 64 of the body
portion 60 may include a taper having a taper angle .alpha. (see
FIG. 3). The tapered construction of the distal end portion 64 may
improve insertability of the sheath assembly 10 through a
relatively small tissue puncture. The tapered construction of the
distal end portion 64 may transition to a larger outer diameter
D.sub.3 of the body portion 60 and the collapsed outer diameter
D.sub.1 of the sheath body 30.
[0049] In operation, the dilator 14 is inserted through the hub 32
of the sheath 12 and into the sheath body 30 until the distal end
portion 64 extends distal of the distal end 34 of the sheath body
30. In at least some arrangements, the diameter D.sub.3 is less
than diameter D.sub.1 of the sheath body 30. A more smooth
transition from the distal end portion 64 of the body portion 60 to
the sheath body 30 may be possible by providing a step feature
along a portion of the length of the dilator 14 that overlaps with
the sheath body 30. FIGS. 9 and 10 show an alternative dilator 114
construction that includes a step feature. The dilator 114 includes
a body portion 160 and a hub 162 that includes an actuator portion
170 used to move the dilator 114 relative to the sheath 12.
[0050] The body portion 160 includes distal and proximal ends 164,
166 and a step 168 having a reduced diameter D.sub.4. The step 168
has a step length L.sub.3 that is at least as long as the collapsed
and expanded lengths L.sub.1, L.sub.2 of the sheath body 30. The
reduced diameter D.sub.4 of the step 168 provides a space along the
dilator 114 for the sheath body 30 to collapse into. The sheath
body 30 may have a smaller collapsed outer diameter D.sub.1 as
compared to the collapsed outer diameter D.sub.1 possible with the
sheath assembly 10 shown in FIGS. 1-5. The diameter D.sub.3 at the
distal end 164 of the body portion 160 may be substantially the
same as the collapsed outer diameter D.sub.1 of the sheath body 30
as shown in FIG. 9.
[0051] Referring now to FIGS. 11 and 12. another example dilator
214 is shown and described. The dilator 214 may include a body
portion 260 and a hub 262. The body portion 260 may include distal
and proximal ends 264, 266. The hub 262 may include an actuator
270. The body portion 260 may be operable between collapsed and
expanded positions. The body portion 260 may have a constant
diameter along its entire length rather than including a tapered
structure at a distal end (e.g., see body portions 60, 160). The
body portion may have a collapsed outer diameter D.sub.5 when in a
collapsed position (see FIG. 11), and an expanded outer diameter
D.sub.6 when in an expanded position (see FIG. 12).
[0052] The dilator 214 may be used to help expand and collapse the
sheath 12. In some arrangements, the dilator 214 is expanded and
collapsed concurrently with expanding and collapsing the sheath 12.
In some arrangements, the dilator 214 may be expanded only after
completion of expansion of the sheath 12 and must be collapsed
prior to collapsing the sheath 12. In the expanded position of FIG.
12, the dilator 214 may have an expanded outer diameter D.sub.6
that substantially matches an inner diameter of the sheath 12 in
the expanded position of FIG. 4.
[0053] The actuator 270 may be used to operate the dilator 214
between the collapsed and expanded positions shown in FIGS. 11 and
12. The actuator 270 may, for example, apply a rotational force or
an axial force to the body portion 260 that provides expanding and
collapsing. The body portion 260 may have any one of the
constructions described above for the sheath 12 with reference to
FIGS. 6A-8D. The actuator features and construction for the body
portion 260 of the dilator 214 may be similar to what is included
in the sheath 12 (e.g., a braid, coil, or longitudinal slit).
[0054] Those features of the sheath assemblies disclosed herein
that provide collapsing and expansion of at least one of the sheath
and dilator may include a shape memory material such as Nitinol.
Other materials or objects that may be useful include, for example,
coil springs.
[0055] Referring now to FIGS. 13-17, an example method of operating
the sheath assembly 10 is shown and described. Typically, a first
step in operating the sheath assembly 10 to expand a tissue
puncture and provide access to a body cavity (e.g., a vessel lumen)
includes positioning a guidewire 16 extending through the tissue
puncture. In the example of FIGS. 13-17, the tissue puncture
includes a percutaneous incision 26 and vessel puncture 22 that
provide access to a vessel lumen 24 of a vessel 20. With the
guidewire 16 properly positioned as shown in FIG. 13, the sheath
assembly 10 is advanced along the guidewire 16 and into the vessel
lumen 24. Prior to advancing the sheath assembly 10 along the
guidewire 16, the sheath 12 is operated into a collapsed position
having a collapsed outer diameter D.sub.1. The dilator 14 may
include a tapered distal end portion 64 that assists in advancing
the sheath assembly 10 through the percutaneous incision 26 and
vessel puncture 22, which have a reduced original size. This
initial advancing of the sheath assembly 10 along the guidewire 16
into the vessel lumen 24 may provide some preliminary dilation or
expansion of the percutaneous incision 26 and vessel puncture
22.
[0056] Referring to FIG. 15, the sheath 12 is operated into an
expanded position having an expanded outer diameter D.sub.2. The
sheath 12 may be operated into the expanded position by operating
the actuator 50. The expanded outer diameter D.sub.2 enlarges the
percutaneous incision 26 and vessel puncture 22. Thereafter, the
dilator 14 and guidewire 16 are removed from the sheath 12. A
treatment device 18 may be advanced through the sheath 12 and into
the vessel 24 as shown in FIG. 16. The treatment device 18 may be
operated to treat the patient. After the treatment is completed,
the treatment device 18 is removed from the sheath 12.
[0057] The sheath 12 may be operated horn the expanded position
shown in FIG. 16 to the collapsed position shown in FIG. 17. The
collapsed position after treatment is completed may include a shape
for the sheath 12 that is similar to the collapsed position
provided at the time of advancing the sheath assembly 10 over the
guidewire 16 described with reference to FIG. 14. Prior to removing
the sheath 12 from the percutaneous incision 26 and vessel puncture
22, the guidewire 16 may be reinserted into the vessel lumen 24 to
maintain access into the vessel lumen 24. Collapsing the sheath 12
to the collapsed outer diameter D.sub.1 prior to removal may help
limit tissue damage in and around the percutaneous incision 26 and
vessel puncture 22.
[0058] In some arrangements, the sheath 12 may be used as part of a
vessel closure procedure to seal closed the percutaneous incision
26 and vessel puncture 22. Many example closure devices may be used
with the sheath 12 including, for example, the devices disclosed in
U.S. Pat. Nos. 7,931,670, 7,618,438 and 7,618,436, which are
incorporated herein in their entireties by this reference.
[0059] In some arrangements, the sheaths of the sheath assemblies
disclosed herein are operable independent of the dilator. The
sheath may include a tapered distal end that provides at least some
of the benefits of using a dilator. The sheath may be inserted
through a tissue puncture while in a collapsed position, operated
into an expanded position to expand the tissue puncture and provide
a path for treatment instruments into the patient, and then
operated into a collapsed position prior to being removed from the
tissue puncture. The dilators disclosed herein may also be used
independent of a collapsible sheath or may be used with various
sheaths having different features and functionality as compared to
a collapsible sheath.
[0060] The preceding description has been presented only to
illustrate and describe exemplary embodiments of the invention. It
is not intended to be exhaustive or to limit the invention to any
precise form disclosed. Many modifications and variations are
possible in light of the above teaching. It is intended that the
scope of the invention be defined by the following claims.
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