U.S. patent application number 15/608967 was filed with the patent office on 2017-09-14 for hand unit to release a self-expanding implant.
This patent application is currently assigned to C.R. Bard, Inc.. The applicant listed for this patent is C.R. Bard, Inc.. Invention is credited to Jurgen Dorn, Martina Hoffman.
Application Number | 20170258616 15/608967 |
Document ID | / |
Family ID | 47603974 |
Filed Date | 2017-09-14 |
United States Patent
Application |
20170258616 |
Kind Code |
A1 |
Dorn; Jurgen ; et
al. |
September 14, 2017 |
Hand Unit to Release a Self-Expanding Implant
Abstract
An elongate hand unit for deploying an elongate implant from the
distal end of a delivery catheter. The hand unit has a distal end
and a proximal end separated by a hand unit length. The hand unit
may include a pull component and a push component. The pull
component may include a pull grip sliding on the push component to
deploy the implant. The push component may be operatively connected
to the push element and include at its proximal end a push surface
to receive during deployment of the implant a force that pushes on
the push element shaft to resist proximal movement of the implant
during deployment. The push component may provide a guide rail that
defines a guide path for the pull grip, whereby proximal movement
of the pull grip along the guide path deploys the implant.
Inventors: |
Dorn; Jurgen; (Neulussheim,
DE) ; Hoffman; Martina; (Stutensee, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
C.R. Bard, Inc. |
Murray Hill |
NJ |
US |
|
|
Assignee: |
C.R. Bard, Inc.
Murray Hill
NJ
|
Family ID: |
47603974 |
Appl. No.: |
15/608967 |
Filed: |
May 30, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14056843 |
Oct 17, 2013 |
9687372 |
|
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15608967 |
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61715178 |
Oct 17, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2/9517 20200501;
A61F 2/966 20130101; A61F 2/97 20130101; A61F 2/013 20130101; F04C
2270/0421 20130101 |
International
Class: |
A61F 2/966 20060101
A61F002/966; A61F 2/97 20060101 A61F002/97 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 17, 2012 |
NL |
N2009648 |
Claims
1. A medical device comprising: an implant; a catheter including:
an inner shaft configured as a push element; and an outer shaft
configured as a pull element; and a hand unit comprising: an inner
tube; an outer tube; and a latch engaging the inner tube and the
outer tube, wherein an inner tube distal end is disposed within an
inner shaft proximal end; and a push component comprising a push
surface is disposed on an outer tube proximal end.
2. The medical device of claim 1 wherein the inner tube and the
outer tube form a telescopic arrangement yielding a pull grip guide
path extender.
3. The medical device of claim 2 wherein the latch permits the
telescopic arrangement to lengthen but not shorten.
4. The medical device of claim 3 wherein the inner and outer tube
form a composite guide path length greater than an inner or outer
tube guide path length.
5. The medical device of claim 4 wherein the outer tube comprises a
tang in the tube wall disposed to engage the inner tube.
6. The medical device of claim 5 comprising multiple tangs in the
tube wall.
7. The medical device of claim 6 wherein the hand unit further
comprises: an outer shaft pull component; and an outer shaft pull
grip, wherein an outer shaft proximal end is captured between the
pull component and the pull grip;
8. The medical device of claim 7, wherein the push component is
disposed proximal of the pull grip and pull component.
9. The medical device of claim 7 wherein the push surface is on a
push hub.
10. The medical device of claim 9 wherein the push hub is adapted
to receive a guidewire.
11. The medical device of claim 10 wherein the push hub includes a
coupling adapted to receive a flushing liquid.
12. The medical device of claim 11 wherein the pull grip is a pull
hub.
13. The medical device of claim 12 further comprising a spacer that
sets a minimum distance between the push surface and the pull
grip.
14. The medical device of claim 3 wherein the catheter further
comprises a rolling membrane that connects the inner and outer
shafts.
15. The medical device of claim 14 further comprising a tether
disposed between the push component and the pull grip.
16. The medical device of claim 1 further comprising a spacer that
sets a minimum distance between the push surface and the pull
grip.
17. The medical device of claim 1 wherein the catheter further
comprises a rolling membrane that connects the inner and outer
shafts.
18. The medical device of claim 1 wherein the latch permits the
telescopic arrangement to lengthen but not shorten.
19. The medical device of claim 1 wherein the inner and outer tube
form an composite guide path length greater than an inner or outer
tube guide path length.
20. A medical device comprising: an implant; a catheter including:
an inner shaft configured as a push element; an outer shaft
configured as a pull element; and a rolling membrane that connects
the inner and outer shafts; a hand unit comprising: a pull
component disposed on the outer shaft; an inner tube and an outer
tube, wherein an inner tube distal end is disposed within an inner
tube proximal end forming a telescopic arrangement yielding a guide
path extender with a composite guide path length greater than inner
or outer tube guide path lengths; a latch engaging the inner tube
and outer tube that permits the telescopic arrangement to lengthen
but not shorten wherein the latch comprises multiple tangs in the
tube wall adapted to engage the inner tube; an outer shaft pull
tab, wherein an outer shaft proximal end is captured between the
pull component and the pull grip, a push component comprising a
push hub with a push surface and a coupling adapted to receive a
flushing liquid wherein the push hub is disposed on an outer tube
proximal end; a tether disposed between the push component and the
pull grip; and a spacer that sets a minimum distance between the
push surface and the pull grip; wherein the push hub is adapted to
receive a guidewire, and the push component is disposed proximal of
the pull grip and pull component.
Description
PRIORITY
[0001] This application is a continuation of U.S. application Ser.
No. 14/056,843, filed Oct. 17, 2013, which claims the benefit of
U.S. Provisional Application No. 61/715,178, filed Oct. 17, 2012,
and of NL Application No. N2009648, filed Oct. 17, 2012, each of
which is incorporated by reference in its entirety into this
application.
TECHNICAL FIELD
[0002] This invention relates to a hand unit for a catheter device
for the delivery of an elongate implant mounted on the distal end
of the device.
[0003] More particularly, this invention relates to an elongate
hand unit for deploying an elongate implant from the distal end of
a delivery catheter, which catheter has a shaft between the distal
end carrying the implant and a proximal end to which the hand unit
may be coupled, the shaft comprising a push element to maintain the
position of the implant during deployment and a pull element to be
pulled proximally relative to the push element, by a release
distance sufficient to deploy the implant, the hand unit having a
distal end and a proximal end separated by a hand unit length, and
comprising a pull component and a push component, the pull
component having a pull grip, to be gripped and pulled proximally
by the release distance, sliding on the push component, thereby to
pull the pull element proximally, thereby to deploy the implant,
the push component to be operatively connected to the push element
of the catheter shaft and having at its proximal end a push surface
to receive during deployment of the implant a force that pushes on
the push element shaft to resist proximal movement of the implant
during deployment, the push component providing a guide rail that
defines a guide path for the pull grip, with a guide path length
along which the pull grip can slide proximally, from a distal to a
proximal end of the guide rail whereby the proximal movement of the
pull grip along the guide path deploys the implant.
BACKGROUND
[0004] Catheter delivery systems for trans-luminal delivery of
implants, particularly self-expanding stents, have a rich history
in the patent literature. Early proposals were for a simple sheath
radially surrounding the radially-compressed stent at the distal
end of the catheter system, the sheath being pulled back
proximally, to release the stent from its bed, progressively,
starting at its distal end of the bed, within the stenting site or
stenosis of the bodily lumen in which the catheter delivery system
had been advanced. Readers will appreciate that, because the stent
is self-expanding, it is pressing on the luminal surface of the
surrounding sheath, up to the moment of its release from the
sheath. Thus, friction forces between the stent and the surrounding
sheath must be taken into account when devising a delivery system
that will allow the sheath to slide proximally over the full length
of the outwardly-pushing, self-expanding stent.
[0005] The problems of friction will increase with the length of
the stent, and the pressure on delivery system designers is to
deliver ever-longer stents. Furthermore, there is steady pressure
on stent delivery system designers to come up with systems that
have ever-smaller passing diameters at the distal end of the
catheter. The conventional unit of dimensions for diameters of
systems to advance along a bodily lumen is the "French" which is
one third of a millimeter. Thus, one millimeter is "3 French". To
be able to reduce the passing diameter of a delivery system, for
example from 7 French to 6 French, is a notable achievement.
[0006] One way to respond to the challenge of friction forces
between a proximally withdrawing sheath and a self-expanding stent
confined within it is to adopt a "rolling membrane" sheath system,
in which the sheath is at least double the length of the stent that
it surrounds, being doubled back on itself at a point distally
beyond the distal end of the stent. Then, proximal withdrawal of
the radially outer doubled back portion of the sheath length will
cause the "rolling edge" between the outer and inner sheath
portions to retreat proximally, rolling proximally down the length
of the stent, to release the stent progressively, as with a single
layer surrounding sheath.
[0007] Regardless of whether a conventional or rolling membrane
sheath system is employed at the distal end of a stent delivery
system, the delivery system requires some form of deployment
mechanism provided at the proximal end of the stent delivery system
to enable an operator to control at the proximal end the deployment
of the distally located stent inside a patient. Typically, the
stent is provided on the distal end of a push rod that extends from
the proximal end to the distal end of the system. With this push
rod held stationary, the user operates such a mechanism at the
proximal end, resulting in the sheath system being pulled back,
thereby deploying the stent, as described above.
[0008] One stent deployment mechanism is disclosed in US
2007/0244540 A1 (here "D1"), which is incorporated by reference in
its entirety into this application. This mechanism involves the use
of a thumb slider that is repeatedly translated distally and
proximally, with each progressive proximal movement effecting
progressive retraction of the sheath. A disadvantage of this
deployment mechanism is the inability to deploy the stent in only
one, or at least only a few, translations of the deployment
mechanism. For lengthy stents, deploying the stent using this
mechanism would prove a laborious task, requiring many
translations. However, once the distal end of the implant is in
place on the wall of the lumen in the body that is receiving the
implant, a swift retraction of the sheath, to deploy the remaining
length of the implant in one smooth stroke, is not available from
this device.
[0009] D1 teaches the attractiveness of a hand unit that is
physically small. The sheath of D1 is not a roll back membrane.
Were it to be a roll back membrane, the distance it would have to
be pulled back proximally would be doubled. The present invention
aims to provide a simple and easy to manufacture hand unit that is
small in size but yet is capable of deploying a lengthy implant
covered by a roll back membrane.
SUMMARY
[0010] According to the present invention, a hand unit of the
general form identified above is characterized by a guide path
extender that is movable from a compact disposition in which the
push surface is a first distance from the distal end of the hand
unit to an extended disposition in which the push surface is a
second distance, greater than the first distance, from the distal
end of the hand unit, the guide path extender making available to
the pull grip an increased guide path length.
[0011] With the invention, the guide path extender provides a guide
path length that is long enough to pull back proximally the pull
element of the catheter shaft, far enough to deploy a lengthy
implant at the distal end of the catheter, even if the implant is
constrained by a roll back membrane that needs to be pulled back
proximally by a distance double the length of the implant
itself.
[0012] Furthermore, the invention makes available a system to
deploy an implant in which the pull grip travels over a linear path
that is co-linear with the longitudinal axis of the implant.
Providing such a path can maximise the tactile feedback that the
operator obtains from the distal end of the implant delivery stem
via the pull grip. Not only that; the transmission of deployment
force from the pull grip to the membrane that radially restrains
the implant till it is deployed is achieved most efficiently
through a line of action that is as straight as possible and a
minimum of end-to-end joints in the line of force transmission.
[0013] The state of the art includes proposals to release a
self-expanding stent from a delivery catheter with a hand unit that
includes a reel on which a pull wire can be wound, the winding of
the pull wire on the reel serving to pull back proximally a sheath
surrounding the implant at the distal end of the catheter.
Conveniently, successive squeezes of a trigger can be used to
achieve successive stepwise rotatory movement of the reel, each
squeeze of the trigger pulling back proximally the sheet
surrounding the implant, by a step along the length of the implant.
However, complexity is added by the need to convert the sheath
surrounding the implant into a pull wire for winding up on the
reel. Furthermore, some doctors prefer to deploy an implant in one
smooth single proximal movement of a pull grip, and so are less
comfortable with deployment using a large number of successive
squeezes of a trigger. In principle, a single long stroke of the
pull grip, to deploy the implant, is preferable whenever a more
rigorously step-wise deployment procedure runs a risk of imposing
on the bodily tissue of the lumen while receiving the implant any
sort of axial stress along the length of the bodily lumen. The
chances of such stresses being imposed on the tissue during a
single full stroke release of the implant are likely to be
significantly less. Minimising tissue trauma during implant
deployment is of course a general aim in all implant deployment
procedures and the present invention can help to minimise such
trauma.
[0014] Thus, a technical effect of the present invention is to
minimise tissue trauma when deploying self-expanding implants of
more than average length.
[0015] One way to provide the extra guide rail length is to resort
to a push component in the hand unit that is of the form of a
telescopic tube arrangement. Effectively, the guide path extender
extends distally of the guide path. Such an arrangement is likely
to exhibit first and second telescopically arranged tubes, one
radially inside the other and with a latch between them that
permits the tubes to extend their length telescopically but which
resists the reverse movement, to a smaller length. This is because
the push surface is on the proximal end of the push element, and
any tendency for the length of the telescopic tube arrangement to
collapse could frustrate delivery of a pushing force to the distal
end of the catheter where it is required to keep the implant in
position during deployment. Such a latch can be very simply and
economically provided by a series of detents, tangs or tabs on one
of the tubes, that will abut an end surface on the other of the
tubes to resist any telescopic collapsing relative movement between
the two tubes. With a telescopic arrangement, the guide rail can be
provided exclusively on the radially outer of the telescoping
tubes, with no requirement for any guide rail surface on the
radially inner of the two tubes. One example of such an arrangement
can be seen in the accompanying drawings, described below. It may
be convenient to arrange that the passage of each detent past the
end of the other of the telescopic tubes results in an audible
clicking sound, to inform the operator that the latch has
engaged.
[0016] Other than a telescopic arrangement, the push component can
be provided as first and second guide rail portions (and optionally
more guide rail portions), e.g. in the form of rods or tubes, that
can couple together, co-linearly and, in the case of tubes,
co-axially, to deliver together a guide rail and aggregate guide
path length that is greater than that present on any of the guide
rail portions individually. One can regard this as providing the
guide path extender proximal of the guide path as such. Just as a
chimney sweep can screw together endwise tube sections to advance a
sweeping brush up a chimney, or a person unblocking drains can
screw together endwise a series of rods that will be advanced along
the length of a drain, so the implant deployer can take at least
first and second push component rods or tubes and join them
together endwise to provide a run of guide rail that is long enough
to accommodate the full length of pull element of the implant
delivery catheter that needs to be accommodated within the hand
unit to release the implant from the distal end of the catheter. Of
course, endwise assembly of second and further push component rods
or tubes increases the length of the hand unit. However, the need
for a short and compact hand unit is felt during assembly,
packaging and transport of the delivery system. During deployment
of the implant, a much greater length of the hand unit can be
tolerated, temporarily.
[0017] In another variant, reminiscent of a collapsible walking
stick, the guide rail can be provided in portions linked end-to-end
by elastic bands that allow the portions to be stowed side by side
but which, on release, bring the portions into an end-to-end
connected relationship to provide one long guide rail that is
cylindrical with no irregularities on the continuous guide path
surface.
[0018] As to the push component of the hand unit, it will generally
be convenient to provide the push surface on a push hub at the
proximal end of the hand unit. That hub would conveniently receive
a guidewire, in the case that the delivery catheter is an "over the
wire" device. Otherwise, the push hub will conveniently include a
coupling for a flushing line to deliver flushing liquid to flush
the interior of the delivery catheter of gas prior to advancing the
catheter into the bodily lumen that is to receive the catheter.
[0019] Likewise, the pull grip can be provided in the form of a
pull hub that slides on the guide rail and that pull hub can
conveniently include a coupling for flushing liquid.
[0020] In general, devices that are to be actuated often include
one or other safety device that prevents premature actuation, and
might require a "cocking" or "priming" action as a first step in
the actuation process. So it can be with the hand units of the
present invention. In particular, it can be useful to include a
spacer that sets a minimum distance between the push surface and
the pull grip, which spacer is removed prior to actuating the
device. In particular embodiments, there may be advantage in having
a device such as a tether that will set a maximum distance that
separates the push surface and the pull grip. Such a device is
illustrated in the accompanying drawings.
[0021] The hand unit of the present invention will serve as part of
an implant delivery catheter system. In one simple arrangement, the
push element of the catheter has a proximal end portion that
extends proximally into the hand unit and provides the said push
component. In a delivery system that utilises a rolling membrane to
deploy a self-expanding implant at the distal end of the system,
the membrane can be extended back proximally, all the way to the
pull component of the hand unit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] For a better understanding of the present invention, and to
show more clearly how the same may be carried into effect,
reference will now be made, by way of example, to the accompanying
drawings, in which
[0023] FIG. 1 is a section through the long axis of a hand unit in
accordance with the present invention;
[0024] FIG. 2 is a section through the long axis of the distal end
of a stent delivery catheter that has at its proximal end the hand
unit of FIG. 1;
[0025] FIG. 3A shows the hand unit of FIG. 1, in the same axial
section, in a transport disposition, prior to actuation;
[0026] FIG. 3B is the same section as FIG. 3A, but after a first
step in the stent deployment process; and
[0027] FIG. 3C is the same section as FIGS. 3A and 3B, but showing
the hand unit after a further step in the deployment process.
DETAILED DESCRIPTION
[0028] FIG. 1 shows a hand unit 10, coupled to the shaft 12 of a
catheter delivery system for the stent 14 shown in FIG. 2. The
catheter shaft 12 has an inner shaft 16 which is the push element
of the catheter shaft. As can be seen from FIG. 2, the stent 14 is
carried on the distal end of the inner shaft 16 and is radially
confined by a roll back membrane 18 with a distal end 20 secured to
the inner shaft 16 at a location just proximal of the proximal end
of the stent 14. The membrane extends distally to the tip 22 of the
catheter, at which point it reverses direction at a roll back
annulus 24 and then advances proximally in a proximal overlapping
run 25 down the length of the stent. A little way proximal of the
stent, the membrane 18 is bonded to a catheter outer shaft
component 26, in an overlap zone 28 at the distal end of the outer
shaft 26.
[0029] Following the outer shaft 26 back to its proximal end, we
find it gripped between a pull hub 30 and a collar 32 threadably
engaged with the pull hub. The pull hub has a bore 34 and a
proximal end 36 which accommodates an O-ring 38 and retainer
annulus 40. In the cylindrical outer surface 42 of the pull hub 30
there is provided a female Luer lock connection 44 to receive
flushing liquid to flush the bore 34 defined by the pull hub
30.
[0030] Turning to the inner shaft 16 of the catheter, it terminates
at its proximal end in a telescopic tube arrangement of the push
component of the hand unit 10. The telescopic arrangement features
an inner tube 50 with a distal end 52 that is received within the
proximal end of the catheter inner shaft tube 16. Sleeving the
inner tube 50 within its bore is the radially outer tube 54 of the
telescopic arrangement. The outer telescope tube 54 runs back
proximally as far as a female Luer connector 56 to receive flushing
liquid to flush the bore of the catheter inner shaft tube 16.
Around the Luer 56 is a push hub 58 so that one can push on the
push hub 58 to push on the catheter shaft inner tube 16 and thereby
hold the stent in position during its deployment. Collapsing of the
telescopic arrangement is prevented by a series of tangs 60 that
are each formed with a simple U-shaped cut through the wall
thickness of the outer tube 54, each tang being predisposed to be
inclined very slightly radially inwardly, thereby to bear on the
proximal end of the inner tube 50 should any attempt be made to
collapse the telescopic arrangement longitudinally. Pulling each
tang 60 proximally past the proximal end of the inner tube 50
results in the issuance of an audible "click".
[0031] To illustrate how the hand unit of FIG. 1 is capable of
deploying the stent 14, attention is now invited to FIGS. 3A, 3B
and 3C of the drawings.
[0032] First, looking at FIG. 3A, we see an axial gap between the
pull hub 30 and the push hub 58. The gap is preserved by a spacer
70 and a tether 72. The spacer 70 can be removed when the time
comes to deploy the stent. It simply clips around the outer
telescopic tube 54 and physically prevents the two hubs 30 and 58
from moving any closer together.
[0033] The two hubs cannot move further apart because the tether 72
that connects the two of them is taut. Unlike the spacer 70, the
tether remains, connecting the two hubs, throughout the deployment
process. The cylindrical radially outer surface of the outer
telescopic tube 54 is smooth and provides a smooth, circular cross
section guide rail along which the pull hub 30 can slide
proximally, without impediment once the spacer 70 has been taken
away.
[0034] Indeed, FIG. 3B shows that first step of the deployment
process. Note that the push hub 58 has not moved but that the
spacer 70 has been taken away and the pull hub 30 has been pulled
back, by the distance of the spacer 70, until it lightly abuts the
distal end of the push hub 58. This movement collapses the tether
72 and also pulls back proximally the outer catheter shaft 26
sufficient to pull back proximally the roll back annulus 24 to a
point some distance proximal of the distal end of the stent 14, in
the illustrated case about half way along the length of the stent
14.
[0035] The position shown in FIG. 3B is only transient. The next
step is to pull proximally (rather than push distally) the push hub
58, thereby to extend telescopically the telescopic arrangement of
the push component 50/54. During this movement, the pull hub 30
does not move axially relative to the push element, the inner shaft
16 of the catheter, so there is no further deployment of the
implant during the proximal withdrawal of guide rail 54.
[0036] With the movement of the push hub completed, proximal
movement of the pull hub is once again possible until the tether 72
once again goes taut. Reverse movement of the guide rail is
prevented by that one of the series of tangs 60 which is
immediately proximal of the proximal end of the inner tube 50 but
which is first to engage with the proximal end as soon as any push
force is imposed on the push hub 58. After this proximal extension
of the telescope guide rail arrangement, the pull hub 30 is once
again free to embark on a run along the length of the guide rail
surface of the outer telescope tube 54, in the proximal direction,
thereby to carry the rolling annulus 24 along the length of the
proximal half of the length of the stent 14, thereby to complete
its release and deployment into the bodily lumen that has received
the catheter delivery system.
[0037] It will apparent that there are many other ways in which to
realise the present invention than the one shown in the drawings.
One could, for example, provide a hand unit with the push hub on a
separate tube component that is, prior to deployment, simply
offered up to the proximal end of the push component of the hand
unit, thereby to provide an increased length of the guide rail,
considerably longer than the length of the hand unit without the
extension tube.
[0038] In another embodiment, there could be more than one such
extension tube (in the manner of walking sticks, chimney rods or
drain rods). While the illustrated telescope arrangement has only
two tubes, it is envisaged that longer telescopes, of three or more
tubes, would also be feasible. While the tangs shown in the
drawings are a reliable and economical latch, skilled readers will
be readily able to envisage other sorts of latch to endow a
telescopic arrangement with the capability to resist telescopic
collapse in length.
[0039] The invention is not limited to the embodiments described
above. Many modifications are possible. The elongate hand unit may
be provided without the catheter, but may alternatively comprise
the catheter.
[0040] Notably, the present invention lends itself to modular
construction of delivery systems for implants, tailored to the
particular length of the specific implant to be delivered. With
increasing maturity of technology in the world of stenting, it
becomes ever more important to provide systems that lend themselves
to straightforward manufacturing, in which sterility issues can be
well managed. Keeping system design simple is not only a way to
keep manufacturing simple, but is also a way to minimise
variability and uncertainty in the operating theatre. Generally,
the simpler a delivery system is, mechanically, the more reliable
it will be in performance and therefore the safer for patients and
the more favoured by their medical practitioners.
* * * * *