Abstract:
Embolic implants, methods of manufacture and delivery are disclosed. The subject implants are especially suitable for use is stent-caged aneurysm treatment.

Description:
RELATED APPLICATIONS 
       [0001]    The present filing claims the benefit of each of U.S. Patent Application Ser. No. 61/046,594 filed Apr. 21, 2008, Ser. No. 61/083,961 filed Jul. 28, 2008, Ser. No. 61/145,097 filed Jan. 15, 2009, and Ser. No. 12/465,475 filed May 13, 2009, each of which is incorporated herein by reference in its entirety, along with all references cited therein. 
     
    
     BACKGROUND 
       [0002]    Numerous companies have pursued ball type embolization devices for aneurysm treatment. Many of these, including embodiments in the above-referenced parent applications of the present application, are designed to be sized to substantially fill the sac of a given aneurysm. US Patent Application No. 2009/0025820 (Adams) discloses the use of a “string of pearls” type approach to filling aneurysms. The implant comprises a braid structure formed into multiple expandable ball segments separated by articulation segments. Each of Pub. No. 2007/0265656 (Amplatz, et al.), see, e.g., FIG. 15, and Pub. No. 2009/0112251 (Quain, et al.) disclose a similar approach. An approach described in U.S. Pat. Nos. 5,749,891 and 6,033,423 (Ken, et al.) is distinguished in the &#39;820 Adams patent publication. These Ken et al. patents teach producing ball-shaped devices (e.g., generally oval or spherical) from a coil wound upon itself into a secondary shape (i.e., forming a “coil of a coil”) for filling aneurysms. 
         [0003]    None of these references focus on use of a stent across the neck of the aneurysm to maintain embolization device position during treatment. However, the use of stents to “cage” an aneurysm for implant retention is well known. The commercially marketed NEUROFORM and ENTERPRISE stents are used in stent-assisted coiling. See also: U.S. Pat. No. 6,190,402 (Horton, et al.); U.S. Pat. Nos. 6,096,034; 6,168,592 and 6,344,041 (Kupiecki, et al.); U.S. Pat. No. 7,303,571 (Makower, et al.); U.S. Pat. No. 7,211,109 (Thompson) and U.S. Patent Publication No. 2008/0045996 (Makower, et al.). 
         [0004]    Now-abandoned US Publication No. 2005/0060017 (Fischell, et al.) teaches a method of filling a stent-caged aneurysm with a plurality of expandable spherical or cylindrical filler bodies. 
         [0005]    The present inventions are directed at a new type of implant and methods for using that implant with the advantages described and implied herein in embolizing stent-caged aneurysms. 
       SUMMARY 
       [0006]    Generally, braid-balls for stent-caged aneurysm embolization are described. More specifically, variations of the “folded-flat” implant architecture in the above-referenced parent application(s) are described and elaborated upon. In this regard, the implant variation presented in FIG. 9 of U.S. patent application Ser. No. 12/465,475 and PCT/US2009/041313 (Becking, et al.), reproduced herein at  FIG. 2A , is of particular use. This implant employs the folded-flat architecture without hub securing ends of the implant braid opposite the folded-flat section. Among other reasons, such an implant is clearly distinguishable from the implants disclosed in US Pub. No. 2009/0082803 (Adams, et al). These implants all have free ends of braid at both ends of the device. The “folded-flat” architecture described herein specifically does not. 
         [0007]    The folded-over and flattened braid of the subject implant imparts stability to the shaped body and provides a consistent closed end. The closure can be supplemented with a tie, or can rely only on the heatset determining its at-rest configuration. In either case, the closed end of the implant (positioned either proximally or distally in use) is one feature that enables the implant to reliably open after exiting a delivery catheter/microcatheter. 
         [0008]    The shape of the implant may be substantially spherical. Otherwise, it may include a flat section adjacent the closed end with associated benefits as taught in U.S. patent application Ser. No. 12/942,209 (Becking, et al.), also incorporated herein by reference. 
         [0009]    Alternatively (or additionally), the implant may be heatset over an ovaloid form. For a given size implant, such an approach decreases the radius around the waist of the implant. When compressed for delivery, the result is more stored energy to drive full shape recovery. This measure may be useful in overcoming any entangled/disordered free ends of the braid wire otherwise apt to interfere with full recovery of the implant shape from compression. 
         [0010]    In the implant configurations described (i.e., folded-flat designs without an opposite-side hub) the wires are not subject to high stresses generated in compressing the braid for delivery. As such, even at larger wire diameters (i.e., in this context being upwards of 0.001″ and possibly at 0.002″ or more—depending on implant configuration) no superelasticity is required of the material. Nitinol may still be used to construct the implant given its convenience for heat setting and biocompatibility. However, other materials such as beta-Titanium are feasibly employed without loss of performance. Indeed, improved radiopacity may result in using a beta-Titanium alloy such as Ti-15Mo, Ti 11.5Mo-6Zr-4.5Sn or Ti-3Al-8V-6Cr-4Zr-4Mo. 
         [0011]    The subject implants may include or omit radiopaque markers. Advantageous marker approaches are disclosed. Otherwise, the density of the braid from which the implant is constructed may be relied upon for radiopacity. 
         [0012]    To achieve commercial success, low cost is preferred feature of the device. Simply put, with the number of implants to be used in the subject “multi-ball” treatment approach, per-piece production should be economical. By producing an implant without a hub and/or marker(s), cost is controlled. Additional savings can be realized by using the implant without a detachment system. Basic deployment with a low-cost pusher is a feasible when filling a stent (or neck-bridge) caged aneurysm. 
         [0013]    Notably, the implant may be delivered with the folded section oriented proximally or distally. Generally, a proximal-facing fold will be preferred to help ensure that portions of the implant interacting with the caging stent remain patent. So-orienting the implant can avoid disruption of the open-end braid matrix from contact with stent struts. However, the implant can be inverted for use and such disruption avoided by selectively applying a polymer coating to maintain a consolidated relationship of the wire ends in the braid. 
         [0014]    Coordinated use of the subject implant(s) is covered. Specifically, more than one may be packaged in a delivery sheath (or tube), a loading sheath, or a transfer sheath for use. The implants may be advantageously packaged in multiples of 2, 3, or more. Thus, a physician can select from a desired panel or pallet of options in determining how many implants are to be delivered in one “shot” or “go” at deployment. 
         [0015]    Irrespective of such considerations, the subject implants offer profound performance benefit potential as compared to the current standard of care (comparable, in this case, to stent-assisted coiling). Various studies by the applicant have demonstrated that the braid matrix of the device is particularly effective in disrupting blood flow to embolize a site. Moreover, as compared to coils, the braid matrix provides for superior tissue colonization and growth to seal-off aneurysms. 
         [0016]    The braid matrix is particularly effective as its density increases. For a given catheter crossing profile, a certain maximum braid configuration is possible. For example, folded-flat implants, intended to track to the neurovasculature through commercially available 3Fr/0.027 inch catheters (such as the commercially available REBAR or MARKSMAN), may be constructed from a 72×0.001″ braid configuration (as originally provided or etched thereto) or 96×0.0009″ braid configuration. 
         [0017]    At these braid densities, implants produced with binary NiTi are sufficiently visible in the 4-6 mm diameter size range for individual viewing during intracranial use. They appear as dark cylindrical objects during catheter tracking and as a lighter circular or oval “halo” upon deployment. Still, other braid configurations may be employed in constructing the subject implants. 
         [0018]    Regardless, implants in this size range may be preferred for intracranial aneurysm treatment as described. However, larger implant sizes may be employed as well. Even if not individually viewable without marker features, they can be visualized in aggregate. When delivered caged behind a stent (having cells sized to retain the expanded implants), escape is not a concern. 
         [0019]    Naturally, implant sizing may vary. However, the sizing need not vary so significantly as with implants intended to fill a range of aneurysms alone. Rather in a multi-ball application, small, medium and large sizes will suffice for intracranial aneurysm treatment. The small size may have a volume equivalent to about a 4 mm sphere, a medium size of about that of a 5.5 mm sphere, and the large of about a 7 mm sphere—whether the devices are spherical, ovaloid or have other shapes. 
         [0020]    Larger sizes in the given braid configurations are not as desirable for intracranial use. Not only is radiopacity decreased (i.e., at least in connection with 0.027 inch catheter-compatible braid configurations), but stability of the unconnected ends of braid degrades. For other indications/approaches, however, larger sized implants delivered through larger catheters may be desired. Indeed, for back-filling an aortic aneurysm around a stent, stent-grafts or flow disruptor to prevent endoleaks, balls as large as 1 cm or more may be beneficially used. Use of a larger catheters than suitable for neuro applications makes employing 144-end and 192-end braid configurations feasible in constructing the subject implants. 
         [0021]    Aspects of the present invention include the subject implants and devices, kits in which they are included, methods of use and methods of manufacture. A number of aspects of such manufacture are discussed above. More detailed discussion is presented in connection with the figures below. 
         [0022]    Other systems, methods, features and advantages will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the inventive subject matter, and be protected by the accompanying claims. It is also intended that the inventive subject matter not be limited to the details of the example embodiments nor any representations made in this summary section. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0023]    The figures provided herein are not necessarily drawn to scale, with some components and features exaggerated for clarity. Variations of the inventive subject matter from the embodiments pictured are contemplated. Accordingly, the figures are not intended to limit the scope of the claims. 
           [0024]      FIG. 1  shows an overview of the subject implant; 
           [0025]      FIGS. 2A and 2B  are side-sectional views of different implants (with and without a detachment system, respectively) suitable for stent-caged aneurysm treatment; 
           [0026]      FIGS. 3A-3C  show the implants in use to define a treatment system; 
           [0027]      FIGS. 4A-4C  are side-sectional views of different implant configurations; 
           [0028]      FIGS. 5A-5D  show different implant loading strategies; 
           [0029]      FIGS. 6A and 6B  illustrate a technique for presetting the shape of the implant fold; 
           [0030]      FIGS. 7A and 7B  illustrate another technique for the same; and 
           [0031]      FIGS. 8A-8H  are views illustrating stages of overall implant manufacture and an optional packaging approach. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    Various exemplary embodiments of the inventive subject matter are described below. Reference is made to these examples in a non-limiting sense. They are provided to illustrate more broadly applicable aspects of the inventive subject matter. Various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the inventive subject matter. 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 inventive subject matter. All such modifications are intended to be within the scope of the claims made herein. 
       Implant System and Treatment Options 
       [0033]      FIG. 1  shows an overview of the subject implant  100 . It is formed from tubular braid stock  102  comprising a resilient material such as Nitinol that defines an open volume (generally round, spherical, ovular/ovoid, and the like) in an uncompressed/unconstrained state. 
         [0034]    The implant is generally dome-shaped adjacent a fold  104  in the braid resulting in a two-layer  106 ,  108  (inner and outer layer, respectively) construction The fold  104  in the braid is set at a tight radius, defining an aperture  110  closing the end of the implant. 
         [0035]    Such features are more easily visualized in  FIG. 2A  showing one variation of the subject implant in cross section. In addition, one can see that the folded end of the implant  100  may be oriented proximally for use. As such, aperture  110  formed by the folded section (especially when held by a ring, band or tie  112 ) can be utilized as the interface for a detachable delivery system  150 . 
         [0036]    The opposite end of the implant may incorporate an inset hub or terminate with trimmed ends  114  (with or without incorporated polymer) or be otherwise configured as shown in  FIG. 2B . The trimmed ends of braid may be coated with a polymer (e.g., TICOPHYLIC urethane by Lubrizol Advanced Materials, Inc.) to maintain a consolidated relationship of the wire ends. 
         [0037]    Such coating is not a necessary provision. Instead, the implant is advantageously trimmed and subsequently handled to maintain braid integrity. Before describing these aspects, however, further reference is made to  FIG. 2B . 
         [0038]    Here, the implant  100 ′ is shown in association with a simple (i.e., non-detachable) pusher  150 ′. The pusher may be any elongate body ranging from a typical guidewire to a custom-made device. In any case, the pusher is used to track the device (possibly multiple devices as elaborated upon below) through a catheter/microcatheter (not shown) to the treatment site. 
         [0039]    Features of interest incorporated in implant  100 ′ include a table or flat  114  across the side of the implant in which the doubled-up braid fold  104  is formed. Such an approach may assist in shaping the braid fold and also in driving implant shape recovery upon exit of the delivery catheter. 
         [0040]    Another feature of interest is presented at the opposite side of the implant adjacent to where the free ends of the braid are trimmed. Namely, the braid is shaped with a conical inset  116 . A simple conical shape (the triangular projection seen in cross-section) is advantageous. The free ends of the braid are urged inwardly relative to the implant body upon deployment by virtue of the crease/bend  118  formed in the braid. The depth, diameter and angle (α) of the inset, radius of the crease, and gap (G) between opposing ends of filaments in the braid of the conical inset can be varied. A tighter crease, higher cone angle and larger gap will help insure deployment of the feature. 
         [0041]    In comparing  FIGS. 2A and 2B , it is apparent that the folded-over (aperture  110 ) side of the implant can be oriented proximally or distally in relation to the delivery system for use. Even without taking advantage of the aperture for a detachment interface, it may still be desirable to orient the aperture proximally. This is the case because the bends forming aperture  104  may present a more stable face to the caging stent upon deployment. Even without a tie, the heatset of the braid maintains the aperture closure when the braid implant is deployed. 
         [0042]    However, catheter tracking of the device may be improved if the rounded bend sections are oriented distally. Thus, depending on the circumstances, either orientation may be preferred. 
         [0043]    Also, it is contemplated that more than one implant may be tracked through a delivery catheter/microcatheter at one time. The implants may be oriented in the same direction, or face opposite one another. In one advantageous configuration, two implants are loaded simultaneously, with the trimmed ends of each in contact. Such options are discussed further below in connection with  FIGS. 5A-5D . 
         [0044]    Irrespective of the delivery mechanics,  FIGS. 3A-3D  illustrate an intended result. In each figure, a complete treatment system  200  comprises multiple braid-ball implants  100  and a caging device. More specifically with respect to  FIG. 3A , a “flow-disruptor” type stent  202  such as the PIPELINE (commercially available through Covidien, Inc.) is set across the neck of a side wall aneurysm  204 . The ball-shaped implants  100  are delivered using a catheter “jailed” between the stent and the vessel wall  206  as per a technique common to aneurysm coiling. The result is multiple of the subject implants  100  sequestered within an otherwise challenging aneurysm shape. 
         [0045]    Of course, a tube-cut stent such as the NEUROFORM or ENTERPRISE may be substituted for the PIPELINE stent—the former being employed in the model(s) pictured in  FIG. 3C . An appreciation of the variety of aneurysms which the subject implants can be employed to treat is typically more important that selection of the stent itself. Because of their small size, in which a plurality of devices are used to at least partially fill an aneurysm, and the ability to retain them using any number of commercially available devices, the subject implants  100  are especially useful in treating irregularly shaped aneurysms (such as multi-lobular and fusiform types) not easily addressed with the other devices, either alone or in combination with coils, which often prolapse or otherwise protrude into the parent vessel in which a stent is placed. 
         [0046]    The aneurysms appearing in  FIGS. 3A and 3C  are challenging because of irregular shape and large neck-to-dome length ratios. In addition, the placement of aneurysm  204 ′ in  FIG. 3B  at a vascular bifurcation  208  make is prone to recanalization (at least when coiling) due to the flow dynamics. 
         [0047]    In treating a terminal aneurysm (such as the bifurcation aneurysm  208 ), a device like the now-defunct TRISPAN (commercially available through Target Therapeutics, Inc.) or neck bridge  210  (commercially available through Pulsar Medical Inc.) is placed across the neck of the aneurysm. Then, this device is “crossed” by a catheter to deliver the subject implants  100 , which fill the available space, efficiently packing the aneurysm. Under fluoroscopy, the physician determines the number of implants to deliver in order to loosely or more densely pack the aneurysm. In either case, the braid matrix of each implant offers appreciable obstruction to flow and can quickly occlude the aneurysm as thrombus forms where flow is disrupted. 
         [0048]      FIGS. 4A-4C  illustrate the subject implant as provided in various relative (not actual) sizes A, B, C. The same or different-sized implants may be used in a given procedure or different sizes may be used for different treatment indications. For a selected braid configuration, it is notable that in larger sizes, the softness of the implant may call for maintaining the medial curvature of the device in order to drive full shape recovery upon deployment. Accordingly, although the implants increase is size/volume in examples A, B and C, they maintain approximately the same equatorial radius. 
         [0049]    The subject implants may be loaded for use in a variety of ways.  FIGS. 5A-5D  illustrate implants in loading sheaths  300  (full-length or partial view) as typically employed with a variety of self-expanding interventional devices. The loading sheath may be constructed in a tear-away format such as produced by Galt, Inc. and may include handle features, perforations or other features not shown. 
         [0050]    As referenced above, the implants  100  may be loaded into the sheaths according to different strategies. In  FIG. 5A , the free ends  114  of the braid are oriented distally (and folded side  104  oriented proximally) for use. In  FIG. 5B , the free ends  114  are set proximally. In  FIG. 5C , two implants are loaded in the sheath together, with their free ends  114  in contact. In  FIG. 5D  three implants are provided, all facing in the same direction with their free ends  114  directed distally. 
         [0051]    As noted above, for caging device interaction, it may advantageous to orient the free ends distally, leaving the more stable aperture section of the device to face proximally. As such, proximal-side contact between the subject implants  100  and the caging device is achieved minimizing the potential for free ends of the braid extending into blood flow past the caging device. 
       Implant Manufacture 
       [0052]    Prior to forming the gross/overall shape of the implant, the folded-over section may be heat treated into shape. Braid so-treated forms the stable, closed end of the device.  FIGS. 6A and 7A  show suitable tooling for forming braid into a minimally crimped bend into which it is heatset. In such a configuration, as illustrated in each of  FIGS. 6B and 7B , the braid is essentially bottomed-out (or in the so-called “jam” condition) to that it is closed-off to the maximum extent possible (i.e., without buckling the braid matrix). 
         [0053]    In the final implant construction, the braid may be tied closed in this position to define a fully immobile aperture for a delivery system interface (as shown in  FIG. 2A ) or simply retain stability in a closed position by virtue of the heatset imparted to the braid (as shown in the implant of  FIG. 2B ). 
         [0054]    With specific reference to  FIGS. 6A and 6B , these figures illustrate a crimper technique for presetting the shape of the implant fold. In  FIG. 6A , wedges  400  of a crimper device (e.g., as available through Machine Solutions, Inc. and others) receive braid  102  that is folded over to define a plurality of individual filament bends  118 . A mandrel  402  is advantageously set inside the braid. The mandrel limits compression of the braid tube, requiring the bends radius tighten when the cavity  404  formed by the wedges is closed as indicated in  FIG. 6B . The shape of the fold is set by heat and/or a combination of strain and heat. The heat may be applied by a torch, within a furnace, by induction or—advantageously—by running current though the mandrel. In another approach, a multi-element chuck or collet type device is employed in a similar fashion to the crimper wedges illustrated above. 
         [0055]      FIGS. 7A and 7B  illustrate another pre-treatment approach for the fold. Specifically, the braid is pulled through a band or hypotube  406 . Again, a mandrel  402  is set inside the braid to limit the inward bowing of the braid. Outward bowing is limited either by setting the braid fully within the band/hypotube or limiting its extension beyond the band. The braid  102  is then heat treated (e.g., as per above) either along its length or locally at the bend to set the tightly folded-over shape. 
         [0056]    Note also, the fold/bend ultimately shown in  FIG. 7B  may be imparted in stages. For example, first a smaller mandrel may be used for a more relaxed fold with a first heat treat. Then, a tighter mandrel fit inside the braid to minimize the fold bend diameter. In another approach, the fold may first be heat treated some distance from the end of the band, then the band moved directly adjacent the bend to minimize it as shown in  FIG. 7A  for a secondary heat treatment. 
         [0057]    In any case, the repeated heat treatment for the fold is not problematic given that oxides can be removed by etch and any changes to material properties has minimal effect because the closed end of the implant defined at the fold basically only pivots during delivery. In other words, the wire bends defining the closed end remain essentially stable during delivery and deployment, changing shape very little. 
         [0058]    When pre-treating the braid, the fold may be formed by everting or inverting the braid. The result is that either layer  106 / 108  may be turned inside out in the final implant construction. 
         [0059]    Regardless, with the braid so-shaped, the overall implant may be formed largely as described in connection with  FIGS. 8C  onward. This may occur with or without the use of the suture tie as described further below—instead relying on clamping pressure. Whatever approach employed, pre-treatment of the folded-over section can improve the consistency of the procedure described by handling the challenging aspect (i.e., bend/fold formation) of implant production in advance under highly constrained and controlled conditions. 
         [0060]    Without reliance on pre-treating the bend, an optional manufacturing process begins with  FIG. 8A . Here, a section of braid  500  is tied with suture  502  or a higher-strength filament/line alternative such as DYNEMA or SPECTRA—also referred to as “GSP” line (Gelspun Polyethylene)—upon a mandrel  504 . The tie may be offset from where the braid is cut so when the braid is inverted as shown in  FIG. 8B , that the outer layer  506  extends past the inner layer  508 . A loose fold  510  is developed and the braid surrounds the implant shaping form  512 . 
         [0061]    In  FIG. 8C , the braid is stretched and secured by wrap  514  (typically Pt, Nichrome or Stainless Steel wire) around the ball form  512 . Compression forms  516 ,  518  are also shown (held by fixturing as indicated by arrows). Fold-side form  518  compresses the fold to a minimum profile during heat setting (e.g., for Nitinol braid at 500-550° C. for about 5 minutes). 
         [0062]    At this stage, the braid is “folded-flat” within the meaning of the present invention. It may indeed be shaped across a flattened section of a ball as referenced above, or be substantially flat as formed at the apex of a sphere or ovaloid body. Even though it necessarily includes an aperture that may vary somewhat in size, is also “closed” as described above with respect to the pre-folded braid approaches discussed. 
         [0063]    As per the approach in  FIG. 8C , when heated, suture tie  502  burns away removing any impediment for achieving a zero or near-zero radius bend at the fold. Opposite form  516  optimally defines a sharp junction (to help define a clean indication or line for cutting when that end of the ball is to be trimmed, as described below) or an inset corresponding to a recess within form  516  to define a conical shape as pictured in  FIG. 2B . Note that this junction (J) is indicated in  FIG. 8E . 
         [0064]    After shape-setting, a device perform  520  is ready once the internal tool piece is finally removed as illustrated in  FIG. 8D . During this process, the ends of the braid are forced open and typically lose braid integrity/engagement. So that such action does not adversely affect the implant integrity, a “tail”  522  incorporated in the perform  520  should be sufficiently long (i.e., often about 2 cm or more) so as to avoid any damage from unraveled braid ends impacting the intended body  524  of the implant. 
         [0065]    If the implant is formed from braid that includes an oxide layer, the perform is next etched, then passivated. However, if pre-etched wire is employed in braiding and any heatsetting performed in a salt pot, vacuum furnace, or using other equipment to minimize oxide formation, the perform may simply be subject to Nitric acid passivation. During any such etching, the length of the tail may likewise be useful for maintaining implant integrity through any implant manipulation that includes such as opening the end of the ball opposite the fold to ensure consistency. 
         [0066]    After tying the outer layer  506  with a wrap  524  as shown in  FIG. 8E , the tail of the implant is easily inserted (“back loaded”) into a working tube  526  for trimming as shown in  FIG. 8F . Without the inner layer underneath, the tied section  528  offers an effective lead-in to the tube. Alternatively, the wrap (and any intentional difference in length between the inner and outer layers in the tail) may be omitted and the implant “front loaded” into a working tube  526 ′ including an introducer section  530  as shown in  FIG. 8G . 
         [0067]    Preferably set upon a mandrel (i.e., tied thereon as in  FIG. 8E  or inserted therein at  FIG. 8G ), the implant preform is trimmed to length (as indicated by the paired arrows) defining the final implant. The mandrel may be cut through with the implant or instead left intact to serve as a backing to help maintain braid integrity (e.g., if using a diamond wheel saw around the device instead of cutters). 
         [0068]    Trimming at precisely the correct location is facilitated by the angular junction J that appears as a v-grove or notch when then the implant (body, tail or both) are constrained is a reduced diameter adjacent thereto. Form  516  optimally has no significant radius around the edge used to define the junction (other than a typical “break” to the edge as in common in machining practice). In any case, how “sharp” the angle that defines the junction (i.e., how small the radius at the junction) need be is driven by the associated functional utility in providing a clean cut line. Optionally, as an indication of where to cut, and also allowing for as small an associated aperture as desirable with the braid ends substantially tangent to the curvature of the implant body. 
         [0069]    While generally to be avoided, a large aperture defined by the trimmed braid ends (ranging from about 1 to about 2 mm in diameter) or a “tail” remnant (ranging from about 0.5 to about 1 mm in length) may sometimes be acceptable. Yet, the former is non-optimal due to loss of implant size, matrix for flow disruption and tissue colonization and braid integrity. The latter is non-optimal given (at least the perception) of a potentially-traumatic nubbin. In any case, such a feature may be coated or potted in polymer (such as TICOPHYLIC) to either stabilize the braid and/or provide a “soft-tip” tissue interface. 
         [0070]    Optional marker features as shown in  FIG. 8E  may also be incorporated in the device before trimming. A shaped tether  532  (e.g., made of NiTi ribbon) with proximal and distal markers (e.g., Pt bands)  534 ,  536  is set within the implant preform  520 . Alternatively, it may be set between the braid layers. In either case, it may be secured by threading a loop  538  through one or more filaments of the braid located at the fold  510 , or otherwise. The markers can be affixed by crimping, adhesive, etc. When the implant is constrained for delivery the preset shape on the tether straightens. The shape is resumed upon implant expansion in deployment. 
         [0071]    Yet another “active” tether option is shown to the left of the implant preform. Here, tether  540  is set in a zig-zag or shallow helical configuration. When the implant is compressed, the tether is straightened and marker  536  located outside the interior of the braid-ball body. Upon deployment, the tether resumes its preset shape, pulling the marker into contact with the face of expanded implant (or potentially into the conical inset, if provided). Alternatively, the tether may pull marker  536  slightly into the interior of the expanded implant. 
         [0072]    Instead of using a shaped tether, cost can be reduced by employing either one of alternate approaches shown to the left of the implant preform. In one approach, linear strand(s)  542  carry markers  534 ,  536  comprising more radiopaque material. The subassembly is sized to span the implant when in an expanded state. Using a more radiopaque material (such as platinum) for the strand(s) allows for an approach in which a polymer sleeve  544  is substituted for discrete marker bands. By wicking adhesive (e.g., LOCTITE 4014) into the sleeve or heating a heat-shrink sleeve to contract its diameter, the components are secured in a very cost-effective package. 
         [0073]    Regardless of whether marker features are included, once trimmed the implant is ready for use. In which case, the working tube members  526 / 526 ′ may serve as the loading sheath  300  discussed above. However, as shown in  FIG. 8H  the implant may instead be transferred (e.g., using a push rod  550 ) into a typical loading sheath  300 ′. 
         [0074]    The braid ends may undergo ultrasonic cleaning, passivation or other processing prior to loading for use and packaging. In any case, the bulk of the implant is intended to remain the working tube—ideally to maintain the relation of the free braid ends without disorganization—up to the point of implant transfer into the loading sheath or (using the working sheath as a loading sheath in a medical procedure) into a catheter hub for use. 
         [0075]    Once the final implant  100  is loaded into the sheath  300 ′, the system is either then complete or one or more additional implants may be loaded into the sheath as described above. Moreover, the sheath may be sterile-packaged alone, or in combination with a pusher. Pairing the loaded sheath with a generic guidewire may offer consumers a particularly economically-advantageous bundle. 
       Variations 
       [0076]    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. 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. 
         [0077]    Also, 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. 
         [0078]    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. 
         [0079]    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. 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.