U.S. patent application number 12/942217 was filed with the patent office on 2011-08-18 for braid ball embolic device features.
Invention is credited to Frank P. Becking, Nicholas C. deBeer, Siddharth Loganathan.
Application Number | 20110202085 12/942217 |
Document ID | / |
Family ID | 43558291 |
Filed Date | 2011-08-18 |
United States Patent
Application |
20110202085 |
Kind Code |
A1 |
Loganathan; Siddharth ; et
al. |
August 18, 2011 |
Braid Ball Embolic Device Features
Abstract
Embolic implants and methods of manufacture are disclosed. The
implants may be used for occluding blood flow at endovascular
sites. One use is in intracranial aneurysm emolization/occlusion
and another in parent vessel occlusion (PVO) or sacrifice. Various
features provide for improved use (e.g., regarding delivery,
recapture, visualization and/or occlusion) and
manufacturability.
Inventors: |
Loganathan; Siddharth;
(Mountain View, CA) ; Becking; Frank P.; (Palo
Alto, CA) ; deBeer; Nicholas C.; (Montara,
CA) |
Family ID: |
43558291 |
Appl. No.: |
12/942217 |
Filed: |
November 9, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61259585 |
Nov 9, 2009 |
|
|
|
Current U.S.
Class: |
606/200 |
Current CPC
Class: |
A61B 17/0057 20130101;
A61B 17/12022 20130101; A61B 17/12113 20130101; A61B 17/12109
20130101; A61B 90/39 20160201; A61B 2017/12054 20130101; A61B
17/12172 20130101 |
Class at
Publication: |
606/200 |
International
Class: |
A61M 31/00 20060101
A61M031/00 |
Claims
1. An detachable implant pusher system comprising an implant
including a proximal port section, an elongate pusher sleeve, a
plurality of elongate members received within a lumen of the
sleeve, wherein the sleeve is locked to the implant through
interference with a distal surface of the port section until the at
least one of the plurality of elongate members is drawn into the
sleeve, the improvement comprising: not all of the plurality of
elongate members exiting at proximal and distal ends of the pusher
sleeve and received through the implant port.
2. An detachable implant pusher system comprising: an implant
including a proximal port section; an elongate pusher sleeve; an
elongate member received within a lumen of the sleeve, exiting at
proximal and distal ends of the sleeve; the elongate member and the
distal end of the sleeve received through the implant port section,
wherein the sleeve is adapted to lock to the implant, through
interference with a distal surface of the port section, until the
elongate member is displaced.
3. An detachable implant pusher system comprising an implant
including a proximal port section, an elongate pusher sleeve, at
least one elongate member received within a lumen of the sleeve,
exiting at proximal and distal ends and received through the
implant port, wherein the sleeve is adapted to lock to the implant,
through interference with a distal surface of the port section,
until the at least one elongate member is drawn into the sleeve,
the improvement comprising: the proximal port configured as a
socket.
Description
CROSS-RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional
Application Ser. No. 61/259,585, filed Nov. 9, 2009, which is
incorporated herein by reference in its entirety.
BACKGROUND
[0002] Commonly-assigned U.S. patent application Ser. No.
12/465,475 to Becking, et al. (also PCT/US2009/041313) describes a
new class of braid-based embolization devices and delivery system
interfaces. The implants may be used for occluding blood flow at
endovascular sites. One use is in intracranial aneurysm
embolization or occlusion and another in parent vessel occlusion
(PVO) or sacrifice. Improvements to those devices are disclosed
herein.
SUMMARY
[0003] Braid-ball devices formed with folded-over and folded-flat
distal end are among the architectures described in Becking, et al.
These architectures are the ones best suited for treating brain
aneurysms. Distal marker approaches are described that are
especially suited for such devices. In addition, proximal end
finishing approaches are described that are suitable for these and
the rest of the devices described in Becking et al. All of the
features and technologies presented in Becking, et al. (U.S. patent
application Ser. No. 12/465,475 and PCT/US2009/041313) are
incorporated herein by reference.
[0004] Regarding the distal marker approaches, one improvement
comprises a tether to/for the distal marker included in the
implant. Specifically, with the marker affixed adjacent the distal
end of the implant (as in the folded-flat embodiments in the
incorporated application), the length of the tether/tie extends to
the proximal hub of the implant. It has a length set so that when
the implant is compressed, the marker is pulled into alignment with
the implant and/or catheter.
[0005] When a suture is employed for the tether, it can tie around
the interior of the distal fold with minimal interference. However,
it may be advantageous to use a wire ribbon (e.g., Pt or Nitinol)
for other reasons.
[0006] Namely, a tether ribbon (especially when pre-formed into a
"V" shape) can be threaded through the gap/hole and around as few
as one wire from the braid. So-disposed, there is no interference
with the compression of the distal end of the implant. What is
more, spring action in the ribbon tether (whether comprising two
filaments or trimmed to one after crimping, gluing, welding or
otherwise affixing at least one marker) can help position the
marker against/across the top of the implant when deployed. Such a
ribbon can also contribute to marker radiopacity, thereby allowing
a smaller marker size.
[0007] Another option is to include fibers and/or other thrombus
promoting material in connection with the tether. Whatever material
option is selected and/or additional features are provided, the
proximal end of the tether is advantageously captured between the
layers of braid or between the braid and either one of optional
inner or outer bands. It may be glued-in, affixed by welding or
otherwise.
[0008] Yet another set of improvements concerns the manner in which
the implant is finished. By "finished", what is meant is the manner
in which the proximal side of the implant is managed to define a
hub and/or delivery system detachment interface.
[0009] In one advantageous approach, in which use of an inner band
is desired for interface with detachment system components (such as
those described in the referenced application), processing is done
with an elongate hypotube set within the braid. The hypotube (e.g.,
about 2-5 cm long) serves as a means to hold and manipulate an
implant preform construct. In addition, when the tube is trimmed
off (or when the final or near-final implant is trimmed off
relative to the tube being held) the remaining portion of the
hypotube within the implant (now the "inner band") defines the
detachment interface lumen. Likewise--especially when a more
radiopaque material such as Pt/Ir or CoCr is used for the tube, the
same structure will improve and/or offer the requisite radiopacity
at the proximal end of the implant.
[0010] In all, the approach (optionally characterized as a
"sacrificial hypotube length" approach) is useful for gluing but
may also be applied in a welding technique. In fact, it may be
especially useful in the latter context by providing shielding from
weld slag and deformation for the proximal aperture/port to be
exposed by trimming the tube to define the inner band in the
implant. Namely, after welding, a clean cut can be made (e.g., with
a diamond saw, laser cutting, EDM, etc.--as above) and then any
deburring (by mechanical action, etching, EP or otherwise) can be
performed on the newly-exposed face as desired.
[0011] In conjunction with a sacrificial hypotube length approach
for gluing, or the original gluing approach described in the
referenced application, another advantageous option is offered by a
different post-processing step. Namely, after an outer band is used
at the proximal end of the implant to define an outer casting
boundary for adhesive/glue (e.g., Loctite 4014), it then may be
removed leaving the underlying glue casting in place. Outer band
removal offers potential to reduce all of the height, diameter and
appearance of the size of the proximal feature of the implant.
Accordingly, it may assist in developing a system with 0.021''
catheter crossing profile.
[0012] To facilitate removal, the band may advantageously comprise
NiTi alloy (that naturally forms a passivation layer) or it may be
coated or otherwise plated. A Titanium Nitride coating may be
desirable. Spray mold release (e.g., 3M) or dip-coating in mold
release may alternatively be employed to assist in slipping-off the
band after adhesive application and curing. Otherwise, the band can
be cut off the glue casting.
[0013] Another approach for achieving minimal implant hub
diameter--while maintaining necessary radiopacity--involves
affixing a platinum band on top of an inner NiTi band (i.e., in a
linear arrangement). The proximal/lower NiTi section can be easily
welded to the NiTi braid in the ball (when so-constructed) and the
Pt (including Pt/Ir and other alloys) provides an in-line
radiopaque marker. The detachment system control and anchor wires
are received through both bands. The bands may be attached (e.g.,
by welding, gluing or soldering) or merely associated with each
other until detachment system wire removal. In either case, they
may include interference fit, puzzle-piece or other groove or
tongue-and-groove features to make or assist in making a connection
between the bodies.
[0014] Another set of improvements concerns shaping the distal end
of a "folded-flat" type implant. It may be provided with a
flattened top. The flattened top derives from a flat formed in the
round tooling over which the braid is shaped. The flat can be
produced by milling about 0.010'' off the form. This depth cut
allows sufficient "table" for desired shaping and can be
consistently applied across a range of implants sized from about 5
mm to 12 mm in diameter with little effect on the perceived shape.
The resulting crease in the implant wire shaped by such a form
offers an immediate advantage to implant deployment. With the flat
placed so close to the distal end of the device, shape recovery of
the bend/crease around the flattened top drives early opening of
the implant when unsheathed (as compared to a situation where a
crease formed around the flat is set further away--or none is
provided).
[0015] Yet another set of implant improvements described herein
augments the density of the ball. Stated otherwise, provision is
made for an additional layer of braid material to further decrease
the braid matrix porosity, and possibly do so without any increase
in device crossing profile/delivery (micro)catheter
compatibility.
[0016] These improvements involve a third layer of braid that is
added to the two layers preferably already present in the
folded-flat base implant architecture. In one variation, a third
layer of braid is captured between the two layers and captured
within the hub region, but trimmed proximal to the distal
folded-over/flat section. In another variation, an inner layer is
set within the envelope of the aforementioned two layers. It is
advantageously attached to a distal end of the inner marker band
(above/distal) to any outer marker band provided. As such, the
braid's attachment will not increase the hub profile. To avoid any
profile increase at the distal end of the implant, the inner layer
will typically be trimmed so its compressed length is located
proximal to the folded-over braid at the distal end of the implant
when compressed. In its unconstrained form, the inner layer may
simply define a cup. Alternatively, it may define a secondary ball
shape. Such a ball shape may be substantially spherical or ovoid.
One advantageous configuration further includes unterminated distal
ends to the braid. The ends of the braid defining the inner ball
may be secured in a band or welded together. So-configured they can
offer another radiopaque marker feature within the ball. However,
it may be preferred that the braid ends of the inner layer (in cup,
ball form, or otherwise) are unterminated. As such, they may
improve thrombus formation within the body of the implant.
[0017] Finally, delivery system improvements are described. The
features described are "improvements"--as are the features noted
above--in a contextual sense. For example, certain of the delivery
system architectures may not be as space-efficient as others. Yet,
such larger system(s) may be desirable for reason of reduced
manufacturing complexity and/or cost.
[0018] The subject implant and delivery devices, kits in which they
are included, methods of use and manufacture are all included
within the scope of the present description. A number of aspects of
such manufacture are discussed above. More detailed discussion is
presented in connection with the figures below.
BRIEF DESCRIPTION OF THE FIGURES
[0019] The figures provided herein are not necessarily drawn to
scale, with some components and features exaggerated for clarity.
Variations from the embodiments pictured are contemplated.
Accordingly, depiction of aspects and elements of embodiments in
the figures are not intended to limit the scope of the
description.
[0020] In the figures, FIGS. 1A and 1B show an implant with a
marker tether as expanded and being compressed, respectively;
[0021] FIGS. 2A and 2B show the distal end and a side view of
another tethered-marker embodiment, respectively;
[0022] FIG. 3 is a detail view of a marker/tether subassembly;
[0023] FIG. 4 diagrammatically illustrates the assembly in FIG. 3
set within an implant;
[0024] FIG. 5 shows an implant preform prepared for proximal end
finishing;
[0025] FIG. 6 shows the proximal end welded;
[0026] FIG. 7 shows an implant preform prepared for proximal end
finishing according to another approach;
[0027] FIG. 8 shows the proximal end cut and welded;
[0028] FIGS. 9A and 9B show implants employing alternative proximal
end finishing approaches, with a detail view in FIG. 9B of a
low-profile embodiment;
[0029] FIGS. 10A and 10B show additional proximal end radiopaque
features as may be employed with various end-finishing
approaches;
[0030] FIG. 11 shows in implant formed with a distal flattened
top;
[0031] FIG. 12 shows implant forms for imparting an implant shape
as shown in FIG. 11 across a number of different implants of a
given size range;
[0032] FIGS. 13A and 13B, respectively, illustrate the operation of
an implant shaped according to FIG. 11/12 as compared to one that
is not;
[0033] FIGS. 14-17 diagrammatically illustrate improved density
implants as compared to the architecture presented in FIG. 4;
[0034] FIG. 18 shows an overview of an implant/detachment system
interface as may be employed in connection with the present
invention;
[0035] FIGS. 19A-19E and 20A-20E illustrate the stages of operation
(handle-side and implant-side, respectively) of the system shown in
FIG. 18;
[0036] FIG. 21 shows an optional improvement to the architecture of
the same system;
[0037] FIGS. 22A and 22B show an alternative delivery system
interface engaged and disengaged, respectively;
[0038] FIG. 23 is an end-on view of the delivery system interface
as pictured in FIG. 22B.
[0039] FIGS. 24A and 24B illustrate alternative end-on views of the
configuration of a pusher shaft in the same system;
[0040] FIGS. 25A and 25B show alternative delivery system interface
options (engaged and disengaged, respectively) based on the pusher
shaft configuration in FIG. 24B;
[0041] FIG. 26 shows an alternative implant-side interface with a
delivery system as presented in FIGS. 25A and 25B;
[0042] FIG. 27 shows an implant-side interface like that presented
in FIG. 26 with an alternative pusher-side architecture;
[0043] FIGS. 28A and 28B show an alternative
engagement/disengagement interface for a system like that shown in
FIGS. 22A and 22B;
[0044] FIGS. 29 and 30 show yet another engagement/disengagement
architecture for each of a braid-type implant and embolic coil,
respectively.
DETAILED DESCRIPTION
[0045] Various exemplary embodiments are described below. Reference
is made to these examples in a non-limiting sense, as it should be
noted, that they are provided to illustrate more broadly applicable
aspects of the devices, systems and methods. Various changes may be
made to these embodiments and equivalents may be substituted
without departing from the true spirit and scope of the invention.
In addition, many modifications may be made to adapt a particular
situation, material, composition of matter, process, process act(s)
or step(s) to the objective(s), spirit or scope of the present
invention. All such modifications are intended to be within the
scope of the claims made herein.
[0046] To the extent any dimensions are stated in the summary or
detailed description, such are intended to be merely examples and
are not to limit the inventive subject matter unless explicitly
recited in the claims.
[0047] Furthermore, the various features of the embodiments
described herein are intended to be complement each other and are
not intended to be purely alternatives unless stated so. In other
words, features from one embodiment may be freely combined with
features of another embodiment, as one of ordinary skill in the art
will readily recognize, unless it is stated that those features are
only to be used in the alternative. Applicants therefore intend
this paragraph to provide written support for any present or future
claim that recites features taken from different embodiments,
should such not already be clear from the summary, detailed
description, and claims.
[0048] Turning to the figures, FIGS. 1A and 1B show an implant 10.
In FIG. 1A, only the hub (not visible) of implant 10 is received
within a sheath or catheter 2. Roughly 40% of implant 10 is
received within sheath 2 in FIG. 1B. A radiopaque marker 20 (e.g.,
a Pt band) is visible in both views. As in Becking, et al., and
with further reference to FIG. 4, implant 10 includes a tie 22
positioned between braid layers 12 and 14 adjacent a distal fold 16
in the braid, which defines aperture 18 (also referred to herein as
the hole or gap in the braid). Marker 20 is held by tie 22. Tie 22
may also assist in closing or limiting the size to which aperture
18 may open.
[0049] While tie 22 terminates adjacent marker 20 in Becking et
al., it extends to proximal hub 30 of implant 10 in the present
description. The extension "tether" portions, or members, 24
so-provided operate to ensure axial alignment of marker 20 when
implant 10 is captured (especially when re-capturing) in a
catheter/sheath.
[0050] The length of tether member(s) 24 is therefore set such that
slack is present when the implant is expanded (as shown in FIG. 1A)
and the slack is removed when the implant is fully compressed or
tending thereto (as shown in FIG. 1B).
[0051] Whereas the tie and/or tether member shown in FIGS. 1A and
1B is typically made of suture material, it may be made of any
other biocompatible material including stainless steel, titanium,
Nitinol (possibly wire that is martinistic at body
temperature--commonly referred to as "muscle wire"), and the like.
When suture material is employed it can tie around the interior of
distal fold 16 with minimal interference and be knotted at point 26
(see FIG. 1A) to easily secure the position of marker 20. The same
approach may be accomplished with fine wire (e.g., 0.001 inch round
wire.)
[0052] It may instead be advantageous to use a wire ribbon (e.g.,
Pt or Nitinol) for other reasons. A construction as detailed in the
next figures was made using a superelastic NiTi ribbon with
dimensions set at about 0.001 inches by about 0.003 inches.
[0053] A tether ribbon 22 heatset into a tight loop or "V" shape
was threaded through gap 20 and around as few as one wire from the
braid at a distal end of implant 10 as shown in FIG. 4.
So-disposed, tether ribbon 22 does not substantially interfere with
compression of the distal end of the implant. What is more, spring
action in the tether ribbon (whether comprising two filaments or
trimmed to just one filament (as indicated by the broken line)
after crimping, gluing, welding or otherwise affixing marker 20 as
shown in FIG. 3) can help position marker 20 against (or across)
the top of implant 10 when deployed, as shown in FIGS. 2A and 2B.
As for affixing the marker, it is notable that the paired ribbon
sections, stacked upon each other, provide a good interface upon
which to crimp marker 20 without drastically altering the marker's
shape.
[0054] Also, the length of the tether may optionally be set in a
general "question-mark" shape to match (or more closely match) the
curvature of the implant when unconstrained (e.g., as the tether
appears in FIG. 4). Pre-shaping the tether to "match" (or
approximately match) one or more implant sizes can help ensure
predictable and similar performance of implants across a range of
different implant sizes and compressions.
[0055] As stated above, another improvement to the subject implants
concerns the manner of proximal end finishing. FIG. 5 shows an
implant preform 60 prepared for proximal end finishing. Here,
implant preform 60 such as prepared in Becking, et al. is prepared,
leaving an additional overhang section 50 extending past a proximal
marker band 32. In many respects, the setup resembles that shown in
FIG. 13A of Becking et al. with the implant preform 60 including an
inner NiTi tube 34 and the assembly set upon a mandrel 52. To
maintain the position of the components as shown, glue (e.g.,
Loctite 4014) is applied. Even so, and referring also to FIG. 6,
the hub region 30 can be welded effectively with a weld bead 54
incorporating the overhanging braid 50, inner tube 34 and at least
tack-welding an outer Pt band 32. It is noteworthy that achieving
such a near-optimal welding result through (or into) the glue
stabilized braid was a surprising result. In other words, it was
neither predictable nor expected by those of skill in the art of
welding (laser or otherwise). In any case, the length of the braid
overhang incorporated into weld 54 may vary depending on a number
of factors including implant diameter, wire diameter, braid
density, etc. As shown, the overhang is about 0.005 to about 0.010
inches in length.
[0056] Another proximal end finishing approach is described in
connection with FIG. 7. Specifically, preform 62 is not trimmed and
stabilized for welding as shown in FIG. 5. Rather, preform 62 is
prepared upon an elongate hypotube 54. The hypotube body provides a
means to hold the construct and stabilize its elongate "tail"
section 56 of braid layer 12 and/or layer 14 (e.g., by a wrap 58)
thereon.
[0057] With a narrow window defined (e.g., with about 0.010 to
about 0.025 inches of--preferably--exposed braid) laser energy is
applied as indicated by the larger area. The energy is sufficient
to weld the braid to the hypotube. The welding process does not,
however, weld the hypotube to the optional underlying mandrel
52.
[0058] After such welding, the majority of the length of hypotube
54 is "sacrificed". It is trimmed-off to define the inner band 34
of the implant as shown in FIG. 8. This inner band may provide some
or all of the radiopacity required in the hub region 30. However an
outer band (especially if it comprises Pt) can be tack welded to
the braid as indicated by the arrow Z in FIG. 7.
[0059] Irrespective of whether an outer marker band is included,
FIG. 8 illustrates an advantage of the finishing approach, namely,
the avoidance of weld bead flow artifacts associated with surface
tension at the end of a body (as seen in FIG. 6). Rather, the weld
64 is neatly faced and the inner lumen of the remaining band 34
de-burred and/or reamed. Both actual and apparent hub size can be
minimized accordingly.
[0060] FIGS. 9A and 9B illustrate another advantageous proximal end
finishing approach for minimizing proximal hub size. FIG. 9A shows
an implant with an outer marker band 32 as it will generally appear
as affixed by glue or welding. In instances where such a band is
affixed by glue, once a glue cast is formed therein the band can be
removed. An implant 10' will then include a proximal hub 30' that
is reduced in diameter (by as much as about 0.004 inches depending
on band thickness) and is also less noticeable by offering less
contrast. Outside the body (e.g., in packaging) a physician will
see a glaze or sheen of adhesive/glue 70 as a cast 72 in which the
braid is embedded instead of a high contrast marker 32.
[0061] While seemingly unimportant to function, this visual aspect
can indeed be relevant. The impression of physicians regarding the
bulk of the proximal feature can affect whether the physician
adopts the product. Conventional implants have been designed with
the proximal hub completely inset within the inner volume of the
implant. This is done to make the implant's appearance more
attractive to physicians. However, the implant suffers in
performance as a result (e.g., the implant is more difficult to
recapture; the requirements on the implant's wire size and strength
are heightened to force the implant to recover the inset shape,
leading to an undesirable increase in implant dimension; and other
performance deficiencies). In the present aspect of the invention,
the perceived hub size is reduced, which increases the visual
appeal without compromising performance.
[0062] FIGS. 10A and 10B illustrate additional embodiments that
eliminate the outer band while providing relatively increased
radiopacity. Specifically, minimal implant hub size can be achieved
by relocating a radiopaque band feature to an in-line arrangement
with the inner band 34. A simple Pt band 74 can be set atop the
inner band 34 as shown in FIG. 10A. These members may be joined
using conventional techniques (i.e., gluing, soldering, welding,
etc.) or be held in relation to one another on a temporary basis by
utilizing delivery system interface members as shown in FIG. 18,
etc. to the embodiment of FIG. 10B interlocks members 34 and 74
through the use of lock 76 and key 78 features.
[0063] Another implant feature is illustrated in connection with
FIGS. 11 and 12. The implant optionally includes a flattened top 80
adjacent distal aperture 18. The flattened top is generated by
providing a table surface 82 in the molding element 88 used to
define the bulk shape of the implant. Molding elements, or "forms,"
in different sizes 88, 88' and 88'' are shown in FIG. 12. They are
milled down from a spherical form to define flat 82 surrounded by
edge 84. The edge produces a crease 86 in the braid wire. Note that
flat 80 and crease 86 are shown in alternate views in FIGS. 2A and
2B.
[0064] During implant preform heatsetting, it has been found that
the flat section improves the quality of the distal fold 16 in the
implant, helping to maximize uniformity and minimize the bend
radius in the wires. As such, device trackability through tortuous
anatomy within a catheter is also improved. The crease at the edge
of the flattened area set in the implant also helps with delivery
performance upon deployment. Specifically, as illustrated in FIG.
13A, the crease 86 represents multiple bends in the wires forming
the implant braid matrix. Upon exit from the microcatheter, the
bends recover and cause the implant distal end to open more than an
implant without such a crease as shown in FIG. 13B (see also, the
implant in FIG. 1B). As a more open body, the implant is softer,
with more relaxed braid angle should it contact any fragile
tissue--such as the dome of an aneurysm.
[0065] Other architectural changes or augmentations that may be
applied to implants are shown in FIGS. 14-17. Each approach offers
the potential for diagrammatically improved density relative to the
parent architecture illustrated in FIG. 4.
[0066] Specifically, implant 90 includes an intermediate braid
layer 92 set between outer layer 12 and inner layer 14. Layer 92 is
captured in hub 30 as are the other layers at a proximal attachment
94. The distal extent 96 can be set at a number of positions.
Advantageously, it extends to around the half-way point or equator
of the device. This way, the layer will contribute to implant
density (or--stated otherwise--reduce porosity) even for wide-neck
aneurysms.
[0067] As shown in FIG. 14, the distal extent 96 of the braid is
adjacent to the folded-over section 16 of the implant. Here, the
density is highest so the inner layer wires will tend to stay best
trapped between layers 12 and 14. Yet, since the ends 96 do not
interfere with the fold 16 (which can be the highest profile aspect
of the implant) little or no increase in crossing profile need
result.
[0068] In production, the inner layer 92 of the implant can be
produced simply by cutting a preform (like preform 62) in half at
the distal fold. This produces a set of two inner layer sections
that can be used in two different devices from a single formation
procedure. However produced, because the inner layer may rely on
the other layers for structural definition, it may be made of finer
wire and/or with lower braid count than the other layers. For
instance, the inner layer may comprise 72-end 0.0008 inch wire
braid, whereas the outer layers comprise 96-end 0.0008 inch wire
braid. However, the reverse may be true, in which the inner layer
is more robust. In any case, it may be advantageous to mismatch the
number of wire ends included in the braid (such as in the example
directly above) to help avoid wire match-up, thereby minimizing
porosity.
[0069] Implant 100 shown in FIG. 15 illustrates another
advantageous approach to improving flow disruption effect, without
increasing device crossing profile. As in device 90, an
intermediate braid layer 90 is employed. However its proximal end
is not secured within the hub, thereby easing space constraints in
that region.
[0070] Instead, braid matrix integrity is maintained by coating the
braid layer with a polymer (e.g., TICOPHILIC coating by Lubrizol,
Inc.) or other coatings or processing. Hydrogel coating also offers
an appealing option, such as a hydrogel-based polymer network
capable of entrapping therapeutic agents as described in U.S. Pat.
No. 6,905,700 to Won et al. Likewise, while the implant elements
advantageously comprise Nitinol braid (typically superelastic
NiTi), the braid used for any of the layers may instead comprise
polymer--especially high strength biodegradable polymer such as
MX-2 (MAX-Prene), synthetic absorbable monofilament (90/10
Glycolide/L-Lactide) and/or G-2 (Glycoprene), synthetic absorbable
monofilament (Glycolide (PGA), .epsilon.-Caprolactone (PCL),
Trimethylene Carbonate (TMC) Copolymer) that is heat set into shape
(e.g., at 110 degrees centigrade for an hour) and/or coated with
the same to stabilize the braid matrix as described.
[0071] Implant 110 shown in FIG. 16 offers another yet another
approach for improved embolizing (or flow disrupting) effect with
little or no effect on crossing profile. Such effect is
accomplished by affixing an innermost/third braid layer 112 to
inner band 34 at its proximal end 114. It may be welded, glued,
soldered or otherwise affixed thereto. The distal end of the braid
116 may be trimmed and formed as shown or otherwise. For example,
the cup so-formed may closely follow the inner periphery of the
device up to or past its equator.
[0072] As with variations in the previous figures, the third layer
incorporated in the implant simply deploys and recaptures in unison
with the rest of the implant. Unique, however, to the architecture
of FIG. 16 is that the proximal end 114 of the braid is stably
secured, but secured such that it does not require space in the hub
(e.g., within the outer marker band 32) without dimensional
stackup.
[0073] A related implant configuration is shown in FIG. 17. Here,
in implant 120, the same proximal end 114 attachment approach is
employed. Yet, instead of forming (e.g., by heatsetting) the inner
layer of braid into a cup shape, an inner ball 118 is formed. The
proximal side of the ball improves overall proximal-side implant
density, and also defines separated flow stagnation zones A and B
within the implant to further assist in thrombus formation within
the implant.
[0074] Inner ball body 118 may be shape set over a form.
Alternatively, and more advantageously, the shape can be formed
without either an external or internal form by bunching the braid
up and tying it onto a mandrel for heatsetting. Such a
"free-forming" approach is functionally advantageous because it
maximizes braid angle (hence, density) in the final body. Yet, any
resulting inconsistency in shape is manageable given that the only
outer body of the implant defined by braid layers 12 and 14 is in
contact with an aneurysm.
[0075] Irrespective of how it is formed (and the particular braid
configuration selection) the inner ball 118 within the architecture
will be configured so that it will not interfere with the distal
end of the implant body/shell and/or marker and tether when the
device is compressed for delivery or recapture.
[0076] More generally, FIG. 18 provides an overview of implant-side
of a treatment system 200. The system includes an implant 10 (90,
100, 110, 120) and a pusher/catheter shaft 210 ultimately attached
to a handle 220 (e.g., as shown in FIGS. 19A-19-E). Any of these
may be constructed according to the teachings herein and/or
incorporated by reference.
[0077] One handle construction includes a single plunger. The
plunger pulls a collar that progressively engages and pulls sockets
connected to the wires; first each control wire 212 is pulled (one
at a time), then the anchor wire 214. Such action is illustrated in
FIGS. 19A-19E and 20A-20E. FIGS. 19A and 20A show the device
components as removed from packaging. FIG. 19B illustrates
unlocking the handle plunger 222 with a 120 degree rotation
relative to handle body 224. Such action has no effect on the
detachment interface 216 shown in FIG. 20B. However, progressive
pull of the plunger in FIGS. 19C-19E effect the release of the
system as shown in FIGS. 20C-20E.
[0078] FIG. 21 shows an optional improvement to the architecture of
system 200. Here, system 200' has only one "true" control wire 212
is received within the hub or inner band 30/34 of the implant 10.
Even so, the implant remains securely/stably attached to the
catheter shaft by virtue of the control wire interaction with
anchor ball 216 (e.g., as formed by laser or as otherwise
configured).
[0079] Release of the implant is effected as if progressing from
the steps in FIGS. 19C and 20C to 19E and 20E. However, a third
(floating or actuated) "dummy" wire 218 is still loaded within the
lumen of pusher shaft 210. Use of this wire maintains a
close-packed arrangement of the wires inside shaft 210, which can
be important in determining wire position within a tortuous
setting. Yet, release angle may be increased and plunger pull force
reduced because the wires within the implant have more space
between them allowing for spatial accommodation.
[0080] Note that the length "L" by which wire 218 is inset within
the pusher shaft may vary depending on purpose. It may have no
inset (i.e., essentially abut the implant proximal end). It may be
inset by about 1 mm so that any forward motion in a tortuous
setting does not result in contact with the implant. Or it may be
inset to a greater degree (e.g., between about 1 cm and 5 cm) to
improve distal tip flexibility of delivery pusher shaft 210.
[0081] FIGS. 22A and 22B show an alternative delivery system
interface in engaged and disengaged states, respectively. Here,
system 230 comprises a catheter/pusher shaft 232 actuated with the
assistance of a typical torque 234. Torquer 234 locks a position of
a central wire 236 including an anchor ball for implant 10
delivery. A bumper or shoulder 240 may be affixed to the catheter
(optionally a Pt band also serving as a marker) to abut a hub 30 of
the implant for pushing.
[0082] Engagement is achieved between the implant and pusher shaft
by virtue of extension 242 that is offset into an interfering
relationship with an inner band 34 of the implant when the anchor
ball 238 is in a retracted position as shown in FIG. 22A. When wire
236 (and its terminal ball feature 238) is advanced as shown in
FIG. 22B, extension section 242 is free to move (e.g., to return to
its original position by elastic action or upon catheter shaft
withdrawal) and slide out of the implant.
[0083] FIG. 23 is an end-on view of the delivery system interface
as pictured in FIG. 22B. As shown, no interference between the ball
238 and/or extension persists once wire 236 is advanced. FIG. 24A
portrays a similar view without the wire in place. It shows
extension 242 and catheter body 232. And while they are illustrated
as formed in one manner (i.e., with a 90 degree cut-down), it is to
be appreciated that the extension may instead be formed by an
angular cut or otherwise. Indeed, FIG. 24B shows an approach in
which the extension section is formed by pushing over the catheter
wall on one side to meet the other and optionally heat setting,
fusing or gluing the component parts 242 and 242' together.
[0084] FIGS. 25A and 25B show an alternative delivery system
interface 250 option (engaged and disengaged, respectively) based
on the pusher shaft extension configuration in FIG. 24B. Due to the
increased wall thickness offered by the double wall layer, the
system can work much as that shown in FIGS. 22A and 22B, except
without need for a distal interference feature (i.e., anchor
ball/band). As such, withdrawal of wire 236 will relieve the
interference and unlock the pusher shaft 232 (specifically, the
associated extension) for withdrawal from the implant 10.
[0085] FIG. 26 shows an alternative implant-side interface with a
delivery system as presented in FIGS. 25A and 25B. Here an implant
socket 260 is provided. Socket 260 may be defined by a cup 262
attached to one or more implant braid layers (12/14), by welding or
otherwise, and a reducer tube 264 threaded, pressed or otherwise
affixed in the proximal end of the cup. Note that with such an
arrangement that implant pushing can be accomplished without a
shoulder or other proximal interface. Instead, both push and pull
(for withdrawal) force application can occur within the socket
chamber. While such a socket will typically be larger than the
previous interfaces shown, it is easily retrofit or used as and
alternative to the screw-type release approaches employed in many
vessel sacrifice and closure devices as sold by AGA Medical, Inc.
and others.
[0086] The delivery system configuration in FIG. 27 shows the same
implant-side interface 260, with an alternative pusher-side
engagement/disengagement (or latch) architecture 270. This
architecture is a simplified version of that shown in FIG. 18 of
Becking et al. Specifically, a pusher shaft 272 (e.g., metal
hypotube) is provided with a single window cutout 274. The window
(configured as a square cutout, rounded, or a simple kerf) allowing
a core member 276 (e.g., NiTi ribbon) to pass therethrough and
provide interference against pusher shaft distal face 276 to
prevent delivery system detachment until core member
withdrawal.
[0087] FIGS. 28A and 28B show an alternative latch interface 280
for a system like that shown in FIGS. 22A and 22B. In this system,
a bent back wire hook 282 serves the function of the ball in the
former system. Such a system offers the advantage of very low cost
production, as well as a secure anchoring feature. FIG. 29 shows a
system 290 most closely related to that in FIG. 21, except that
multiple control and/or dummy wires are replaced with a single
ribbon 292.
[0088] Finally, FIG. 30 shows a detachment system 300. As in system
290 a ribbon 292 may be used in conjunction with a round anchor
wire 214 with a ball-shaped anchor 216. An alternative approach
that may be used in either system is to employ a ribbon as the
"anchor wire" and form the interference feature at its end by tying
a knot therein (as a substitute for a laser-formed ball). Such a
knot can be shape set, glued or welded to stabilize its shape. It
can be reliably be produced at low cost at a very small size, on a
ribbon. A socket-type interface can be formed within the coil by
fitting a collar feature 302 within its proximal end. The collar
may be threaded-in (i.e., into the coils like a thread pitch). An
alternative approach involves flowing solder between the coils and
defining a lumen therein using a removable mandrel. The mandrel may
be prepared in any manner to facilitate its removal, including
those described for the removable hub in connection with the
improvement described in connection with FIG. 9B.
[0089] In the various delivery system architectures, the
catheter/pusher shaft comprise a simple extrusion (e.g., PTFE, FEP,
PEEK, etc.) or may be constructed using conventional catheter
construction techniques and include a liner, braid support and
outer jacket (not shown). An exemplary construction is available
through MicroLumen, Inc. as Braid Reinforced Polyimide. A distal
section of the Polyimide may be ablated and replaced with fused
Pebax to provide a softer or progressively-flexible end to the
catheter. A loading sheath is typically provided over the pusher
shaft. Advantageously, the loading sheath is splittable.
[0090] If not preloaded, after removal from sterile packaging (not
shown), the implant is pulled into the loading sheath. The loading
sheath is received within the hub of the catheter to be used for
implant delivery and the implant is advanced into the catheter.
Then, the implant may be advanced to and deployed at a treatment
site. Or it may be retrieved in exchange for another size
implant--else repositioned, if desired, prior to ultimate
detachment as illustrated in the incorporated patent application
subject matter.
[0091] In the present invention, the subject methods may include
each of the physician activities associated with implant
positioning and release. As such, methodology implicit to the
positioning and deployment of an implant device forms part of the
invention. Such methodology may include placing an implant within a
brain aneurysm, or at parent vessel targeted for occlusion, or
other applications. In some methods, the various acts of implant
introduction to an aneurysm or parent vessel are considered.
[0092] More particularly, a number of methods according to the
present invention involve the manner in which the delivery system
operates in reaching a treatment site, for example. Other methods
concern the manner in which the system is prepared for delivering
an implant, for example attaching the braid ball to the delivery
system. Any method herein may be carried out in any order of the
recited events which is logically possible, as well as in the
recited order of events, or slight modifications of those events or
the event order.
[0093] It is contemplated that any optional feature of the
inventive variations described may be set forth and claimed
independently, or in combination with any one or more of the
features described herein. Reference to a singular item, includes
the possibility that there is a plurality of the same items
present. More specifically, as used herein and in the appended
claims, the singular forms "a," "an," "said," and "the" include
plural referents unless specifically stated otherwise. In other
words, use of the articles allow for "at least one" of the subject
item in the description above as well as the claims below. It is
further noted that the claims may be drafted to exclude any
optional element As such, this statement is intended to serve as
antecedent basis for use of such exclusive terminology as "solely,"
"only" and the like in connection with the recitation of claim
elements, or use of a "negative" limitation.
[0094] Without the use of such exclusive terminology, the term
"comprising" in the claims shall allow for the inclusion of any
additional element irrespective of whether a given number of
elements are enumerated in the claim, or the addition of a feature
could be regarded as transforming the nature of an element set
forth in the claims. Except as specifically defined herein, all
technical and scientific terms used herein are to be given as broad
a commonly understood meaning as possible while maintaining claim
validity.
[0095] The breadth of the present invention is not to be limited to
the examples provided and/or the subject specification, but rather
only by the scope of the claim language. Use of the term
"invention" herein is not intended to limit the scope of the claims
in any manner. Rather it should be recognized that the "invention"
includes the many variations explicitly or implicitly described
herein, including those variations that would be obvious to one of
ordinary skill in the art upon reading the present specification.
Further, it is not intended that any section of this specification
(e.g., the Summary, Detailed Description, Abstract, Field of the
Invention, etc.) be accorded special significance in describing the
invention relative to another or the claims. All references cited
are incorporated by reference in their entirety. Although the
foregoing invention has been described in detail for purposes of
clarity of understanding, it is contemplated that certain
modifications may be practiced within the scope of the appended
claims.
* * * * *