US20140005698A1 - Endovascular Closure System - Google Patents

Abstract

An aneurysm closure device having a pair of retention clips joined together. Each of the clips has an aneurysm anchor joined to a root-vessel anchor, and is made of material having a resilient installed state, in which the aneurysm anchor and the root-vessel anchor are urged together, thereby squeezing and being retained by interposed tissue. Also, an aneurysm seal, to seal an aneurysm, bridges the clips, causing the aneurysm to atrophy.

Description

RELATED APPLICATIONS
• This application is a continuation of application serial number PCT/US12/27259, filed on Mar. 1, 2012 which claims priority from provisional application Ser. No. 61/448,459, filed on Mar. 2, 2011 which are incorporated by reference as if fully set forth herein.
BACKGROUND
• The present disclosure is directed to repairing blood vessel defects, such as aneurysms, and other physiological defects or cavities formed in lumens, tissue, and the like, and, more particularly, to an endovascular implantable device and related endoluminal delivery procedure and deployment techniques.
• Cranial aneurysms occur when a weakened cerebral blood vessel (root vessel) locally expands to form a bulge or balloon-like enlargement in the vessel wall. These aneurysms can occur along a vessel wall or at locations of vessel branches, such as a T-intersection or V-intersection.
• Currently, options for the treatment of brain aneurysms are limited. In one technique, the cranium is opened and a clip is placed at the aneurysm neck to cut off blood flow from the root vessel, thereby reducing swelling and stopping expansion. In another technique, the interior of the aneurysm is accessed by way of a cranial artery, which in turn is reached with a device inserted into the femoral artery. In this technique, coiling material is inserted into the aneurysm, thereby causing clotting which closes off the aneurysm. Both techniques have drawbacks. Opening the cranium always entails some risk. Some locations in the cranium are difficult or impossible to access from the outside. On the other hand, causing clotting in the aneurysm can increase the mass and size of the aneurysm, causing it to press against delicate and critical tissue, and causing further damage.
• Devices and techniques have been developed to facilitate treatment of aneurysms. The application herein is a joint inventor on the following U.S. Patent Publication Nos. 2006/0264905 (“Improved Catheters”), 2006/0264907 (“Catheters Having Stiffening Mechanisms”), 2007/0088387 (“Implantable Aneurysm Closure Systems and Methods”), and 2007/0191884 (“Methods and Systems for Endovascularly Clipping and Repairing Lumen and Tissue Defects”). All of these published applications are incorporated by reference herein in their entirety, to the extent legally possible.
• For example, referring toFIGS. 1A and 1B, which are reproduced from U.S. Patent Publication No. 2007/0191884, shown therein is adevice130 having a patch orclosure structure131 mounted to or associated with twoanchoring structures132,133. Theclosure structure131 is supported by aframework structure134 that is provided at least in a perimeter portion and is attached to theclosure structure131 by means of bonding, suturing, or the like. Theframework structure134 is mounted to or associated with the wing-like anchoring structures132,133. Theseanchoring structures132,133 in a deployed condition are designed so that at least a portion thereof contacts an inner wall of an aneurysm or an internal wall of an associated blood vessel following deployment.
• As can be seen inFIG. 1A, theanchoring structures132,133 are generally formed to curve outwardly from anattachment joint135 to theframework structure134 and then back inwardly toward one another at the end remote from theattachment point135. Theanchoring loops132,133 are generally of the same configuration and same dimension and are located opposite one another as shown inFIG. 1A.
• FIG. 1B illustrates a similar device having aclosure structure136 withanchoring structures137,138 that attach to or project from aframework structure139 along opposed, lateral edges of the framework structure. Theanchoring structures137,138 as illustrated inFIG. 1B are gently curved and, at their terminal sections, extend beyond corresponding terminal sections of the framework structure and the closure structure. The closure and framework structures in this embodiment are generally provided having a surface area that exceeds the surface area of the aneurysm neck, and the anchoring structures generally reside inside the aneurysm following placement of the device. In this configuration, the anchoring structures exert lateral and downward force on the closure structure so that it generally conforms to the profile of the vessel wall at the site of the aneurysm, thereby sealing the neck of the aneurysm from flow in the vessel and providing reconstruction of the vessel wall at the site of the aneurysm. Unfortunately,framework structure139 andstructures137 and138 are mismatched in length and are too stiff to apply the mutually opposing forces on interposed tissue, necessary to form an effective clip. In addition this structure is too stiff and expanded to be able to collapse into a configuration that can be fit into the space available in a placement device, small enough to be introduced into the smaller cranial blood vessels. Moreover, its boxy shape makes it difficult to maneuver as is necessary to effect placement into an aneurysm.
• FIGS. 1C-1F schematically illustrate the devices ofFIGS. 1A and 1B deployed at the site of an aneurysm. A bulge in the blood vessel B forms an aneurysm A. As shown inFIGS. 1C and 1D, when thedevice130 is deployed across the neck of and within the aneurysm A, theclosure structure131 is positioned to cover the opening of the aneurysm and theanchoring structures132 and133 are retained inside and contact an inner aneurysm wall along at least a portion of their surface area. In this fashion, theclosure structure131 and theframework portion134 are supported across the aneurysm opening and are biased against the neck of the aneurysm from outside the aneurysm.
• In the embodiment illustrated inFIGS. 1C and 1D, theclosure structure131 and theframework portion134 are deployed outside the internal space of the aneurysm. In an alternative embodiment illustrated inFIG. 1E, theclosure structure131 and theframework portion134 are supported across the aneurysm opening and biased against the neck of the aneurysm from inside the aneurysm.
• FIG. 1F illustrates an alternative deployment system and methodology, wherein a device having at least two anchoring structures is deployed such that theclosure structure131 is positioned to cover the opening of the aneurysm, and theanchoring structures132,133 are positioned outside the aneurysm and contact an inner blood vessel wall B in proximity to the aneurysm. In this embodiment, theanchoring structures132,133 may be generally sized and configured to match the inner diameter of the vessel in proximity to the neck of the aneurysm so that following deployment the anchoring structures contact the vessel wall in a substantially continuous manner without straining or enlarging the vessel wall in the area of the aneurysm. In all of these embodiments, following placement of the device, the closure structure substantially covers the aneurysm neck to effectively repair the vessel defect. The anchoring structures do not substantially interfere with flow of blood in the vessel.
• As can be seen in the foregoing, the structures may be difficult to place, particularly in the circuitous blood vessel network of the brain. For the typical aneurysm, extending in a perpendicular manner from its root blood vessel, it may be a challenge to insert the structure into the aneurysm. Moreover, for the device to seal or close the aneurysm, the anchoring structures must mutually press against the aneurysm sides. If one side wall of an aneurysm is not well suited for supporting an anchoring structure, the anchor for the opposite side will not be well supported to provide sufficient pressure on this opposite side wall. This problem drives the design ofanchor structures132 and133 to be larger, to facilitate receiving sufficient support from the aneurysm interior surface. This, in turn, has the potential to create a mass effect problem, in which the mass of thestructures132 and133, plus any clotting that occurs around them, causes the aneurysm to become more massive, potentially pressing against delicate nervous system tissue as a result.
• Moreover, the situation is even more difficult for aneurysms formed at the intersection of vessels, such as a T-intersection or V-intersection.FIG. 1G illustrates asaccular bifurcation aneurysm150 appearing at the intersection of twovessels152,154, branching from astem vessel156. Cerebral bifurcation aneurysms are commonly found at the middle cerebral artery, internal carotid artery, anterior communicating artery, basilar artery, posterior communicating artery, and other locations.
• Typically, to placedevice130 into a blood vessel of the brain requires a number of steps. First, an incision is made into the femoral artery and a sheath is introduced, extending approximately to the aorta. A first guide catheter is inserted through the sheath and extended up into the carotid artery. A second guide catheter is coaxially introduced through the first guide catheter and extended up into the target aneurysm. Both guide catheters are introduced using a guide wire having a steerable tip of either stainless steel or nitinol. Then, microcatheter introducer is inserted through the guide catheter, to the aneurysm, anddevice130 is placed at the aneurysm site. Heretofore, however, once reaching the aneurysm there has been no effective method for positioning a device that requires precise positioning. A device that would require a definite orientation, at least partially inside the aneurysm, presents particular challenges in positioning during implantation
• Another difficulty in delivering a complex implant into an aneurysm is the lack of space to pack such an implant in a lumen at the end of a microcatheter. Any such device must fold into a cylinder having an internal diameter on the order of 1 mm and a length of about 10 mm. Upon delivery it must expand to anchor itself in place and to seal an area that could be as large as 10 mm². The seal over the neck of the aneurysm although thinner than 1 mm, must be strong enough to affirmatively occlude the aneurysm, with a very high degree of certainty.
SUMMARY
• The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements.
• In a first separate aspect, the present invention may take the form of an aneurysm closure device having a pair of retention clips joined together. Each of the clips has an aneurysm anchor joined to a root-vessel anchor, and is made of material having a resilient installed state, in which the aneurysm anchor and the root-vessel anchor are urged together, thereby squeezing and being retained by interposed tissue. Also, an aneurysm seal, to seal an aneurysm, bridges the clips, causing the aneurysm to atrophy.
• In a second separate aspect, the present invention is a method of treating an aneurysm in a patient's brain, extending from a root blood vessel. The method uses an aneurysm closure device that includes a pair of retention clips, joined together. Each clip has an aneurysm anchor coupled to a root-vessel anchor, and is made of material having a resilient installed state, in which the aneurysm anchor and the root-vessel anchor are urged together, thereby squeezing and being retained by any interposed material. An aneurysm seal, bridges the clips. The aneurysm closure device is implanted so that it seals the aneurysm by positioning the aneurysm anchors in opposed positions inside the aneurysm and the root vessel anchors inside the root blood vessel so that each the aneurysm anchor is urged toward its coupled root-vessel anchor, thereby retaining the aneurysm closure device by pressure placed by the clips on the interposed aneurysm and root vessel tissue, and thereby placing the seal over the aneurysm, reducing blood flow to the aneurysm and causing eventual atrophy of the aneurysm.
• In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed descriptions.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
• Exemplary embodiments are illustrated in referenced drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive.
• FIG. 1A illustrates an enlarged schematic front isometric view of a known implantable device in a deployed condition;
• FIG. 1B illustrates an enlarged schematic front isometric view of another known implantable device in a deployed condition;
• FIGS. 1C,1D,1E, and1F schematically illustrate the devices ofFIGS. 1A and 1B deployed at the site of an aneurysm;
• FIG. 1G illustrates a saccular bifurcation aneurysm;
• FIG. 2A is a sectional side view of an aneurysm closure device, according to the present invention, installed in the neck of an aneurysm that has developed at the side of a blood vessel.
• FIG. 2B is a sectional side view of the aneurysm closure device ofFIG. 2A, according to the present invention, installed in the neck of an aneurysm that has developed at a Y-intersection of blood vessels.
• FIG. 3 is an isometric view of the aneurysm closure device ofFIG. 2A.
• FIG. 4 is an isometric view of an implantation catheter, according to the present invention, with the closure device ofFIG. 2A retracted.
• FIG. 5 is an isometric view of the catheter ofFIG. 4, with the closure device ofFIG. 2A exposed.
• FIG. 6 is an isometric exploded view of the user control portion of the catheter ofFIG. 4.
• FIG. 7 is a sectional side view of the distal end of the catheter ofFIG. 4, with the closure device ofFIG. 2A retracted.
• FIG. 8 is an isometric view of the distal portion of the positioning assembly ofFIG. 4, with the closure device ofFIG. 2A extended.
• FIG. 9 is a cross-sectional view of the distal portion ofFIG. 8, taken at view line9-9.
• FIG. 10 is a cross-sectional view of the distal portion ofFIG. 8, taken at view line10-10.
• FIG. 11 is a cross-sectional view of the distal portion ofFIG. 8, taken at view line11-11.
• FIG. 12A is a side view of the user control ofFIG. 6, set in a neutral position.
• FIG. 12B is a side view of the user control of the distal end ofFIG. 7, corresponding to the user control setting ofFIG. 12A.
• FIG. 13A is a side view of the user control ofFIG. 6, set in a skewed position.
• FIG. 13B is a side view of the user control of the distal end ofFIG. 7, corresponding to the user control setting ofFIG. 13A.
• FIG. 14A is a side view of the user control ofFIG. 6, set in a position skewed opposite to that ofFIG. 13A.
• FIG. 14B is a side view of the user control of the distal end ofFIG. 7, corresponding to the user control setting ofFIG. 12A.
• FIG. 15A is an isometric view of a work piece shown connected to the distal end ofFIG. 7 for ease of presentation and representing a stage in the manufacturing of the closure device ofFIG. 3.
• FIG. 15B is a detail view of a portion ofFIG. 15A, as indicated bycircle15B, inFIG. 15A.
• FIG. 15C is an isometric view of a work piece shown connected to the distal end ofFIG. 7 for ease of presentation and representing a further stage in the manufacturing of the closure device ofFIG. 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• In the following description, certain specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. However, one skilled in the relevant art will recognize that embodiments may be practiced without one or more of these specific details, or with other methods, components, materials, etc. In other instances, well-known structures or components or both associated with endovascular coils, including but not limited to deployment mechanisms, have not been shown or described in order to avoid unnecessarily obscuring descriptions of the embodiments.
• Unless the context requires otherwise, throughout the specification and claims that follow, the word “comprise” and variations thereof, such as “comprises” and “comprising” are to be construed in an open inclusive sense, that is, as “including, but not limited to.” The foregoing applies equally to the words “including” and “having.”
• Reference throughout this description to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification are not necessarily all referring to the same embodiment.
• Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
• The present disclosure is directed to closing a bulge or aneurysm formed in blood vessel, such as an artery or vein (referred to more generally herein as “vessel”), in a manner that does not suffer from some of the drawbacks of prior art methods. For example, in the prior art method involving the insertion of a wire coil into the aneurysm, the resultant blood clot can create problems through its mass and the possibility of pressing against nearby nerves. In addition, the wire coil can have the effect of keeping the neck open, possibly causing another aneurysm to form.
• The embodiments of the present disclosure combine the closure structure and the anchoring structure into a single unit to improve compactness, allow delivery into the tortuous intracranial circulation system via a microcatheter, and to improve the aneurysm neck closure. In addition, the embodiments of the present disclosure provide enhanced rotation control and placement of the device within the aneurysm via two attachment points for a microcatheter. Moreover, markers can be used at the junctions of the device structure to aid in tracking the movement of the closure device during insertion and placement.
• Referring toFIG. 2A, a preferred embodiment of ananeurysm closure device10 is shown in its implanted environment of ananeurysm12 attached to aroot vessel14.FIG. 2B shows thedevice10, implanted environment, on an aneurysm that has developed at a Y-intersection of blood vessels.FIG. 3 shows a more detailed perspective view ofclosure device10. InFIG. 2A,aneurysm closure device10 is held in place by four anchors: Afirst aneurysm anchor16A and a firstroot vessel anchor18A mutuallyanchor closure device10 to a distal side of theaneurysm12, while asecond aneurysm anchor16B and a secondroot vessel anchor18B, mutuallyanchor closure device10 on a proximal side of theaneurysm12. Referring toFIG. 3, it is seen that in the installed state ofFIG. 2A, aseal20 is placed over the neck ofaneurysm12, thereby preventing further blood flow intoaneurysm12 and causing it to atrophy over time.
• First anchors16A and18A act as a first clip, mutually applying gentle pressure toward each other, thereby clipping about the interposed tissue. In similar manner,second anchors16B and18B act as a second clip. Working together, anchors16A,18A,16B and18B hold theseal20 in place, thereby blocking the flow of blood intoaneurysm12.
• Closure device10 includes awire frame22, which is made of nitinol, or some other shape-memory material. Prior to use,closure device10 is maintained at a temperature below human body temperature, thereby causing wire frame to assume the shape shown inFIG. 3, when first pushed out ofterminal lumen56. In one preferred embodiment, after warming to37C, however, anchors16A and18A, are urged together, as areanchors16B and18B, thereby more securely clipping to the interposed tissue. In another preferred embodiment, however, the natural spring force of the nitinol causesdevice10 to expand when it is pushed out offossa56, and it retains this shape during positioning and use. A set ofeyeholes24 are defined byframe22 and expanded poly tetrafluoroethylene (ePTFE) thread orfiber26 is threaded into theseeyeholes24 to form a lattice. Theeyeholes24 are filled with gold solder (FIG. 15B), thereby anchoringthread26 and closingeyeholes24. Accordingly, although materials may be useable asthread26 whatever material is used must be capable of withstanding the temperature of molten gold solder, which is typically 716° C. TheePTFE lattice work26 is then coated withsilicone28, which in one preferred embodiment is cured in situ to form theseal20. In another preferred embodiment, sheets of silicone are cut to the correct dimensions and adhered together about theePTFE lattice26. In the embodiment shown,silicone28 is placed on the aneurysm anchors16A and16B, but in an alternative embodiment, the ePTFE portion onanchors16A and16B are there to complete the threading arrangement, but are not coated with silicone. In another alternative preferred embodiment more, and smaller,eyeholes24 are defined. In a preferred embodiment, two spots ofradiopaque material30 are placed at the tip of eachaneurysm anchor16A and16B and one spot ofradiopaque material30 is placed at the tip of eachroot vessel anchor18A and18B. Accordingly, a surgeon placingclosure device10 can determine the position ofclosure device10, through a sequence of X-ray images, relative to the contours of theaneurysm12, which is shown by the use of a radiopaque dye, placed into the bloodstream.
• In an alternative preferred embodiment at least some of the anchors, serving the function ofanchors16A-18B, are made of a thin sheet of nitinol, or a thin sheet of nitinol covered with a biocompatible silicone, or polymeric material, for forming a good grip on the tissue it contacts. In yet another embodiment, at least some of the anchors are made entirely of polymeric material. In an additional preferred embodiment,ePTFE thread26 lattice, is replaced with metal filigree, made of a metal such as gold, having a high melting point. In addition, there is a broad range of engineered materials that can be created for this type of purpose. In yet another preferred embodiment, anchors, serving the function ofanchors16A-18B, are made of wire loops or arcs, some of which support an ePTFE reinforced silicone barrier, thereby providing a closure mechanism for an aneurysm.
• Referring toFIGS. 4-14B, prior to installation,closure device10 forms a part of a micro-catheter closuredevice installation assembly40, which although specifically adapted to installclosure device10 at an aneurysm also embodies mechanisms that could be used for other tasks, particularly in accessing tissue through a blood vessel.Assembly40 comprises amicro-catheter subassembly42, and a user-control subassembly44. A first wire-head handle46A and a second wire-head handle46B, are attached to afirst wire48A and asecond wire48B, respectively.
• Referring toFIGS. 7-14B, inmicro-catheter subassembly42,wires48A and48B pass through aflexible tube50, which has an exterior diameter of about 1.5 mm, and which has a hydrophilic exterior surface, to aid in progressing toward a blood vessel destination.Tube50 is divided into a proximalsingle lumen extent52, near-distaldual lumen extent54, and a distal fossa or wide-lumen extent56. This construction permits for the control of the shape and orientation of distal portion oftube50, and for the positioning ofclosure device10, after it has been pushed out offossa56. As shown inFIG. 13A and 13B, if the first wire-head handle46A is retracted relative to second wire-head handle46B, thendistal fossa56 bends towardshandle46A. Likewise, as shown inFIGS. 14A and 14B, if the second wire-head handle46B is retracted relative to first wire-head handle46A, thendistal fossa56 bends towardshandle46B. The orientation offossa56, and the direction it turns to when handle46A or46B is retracted, can be changed by rotating the wire-head handles46A and46B, together. Afterclosure device10 is pushed out offossa56, it responds in like manner, bending toward wire-head handle46A, whenhandle46A is retracted, and towardhandle46B, whenhandle46B is retracted. It can be rotated, and the direction that it bends whenwire46A or46B is pulled can be determined, by rotating thehandles46A and46B, together. This freedom in positioning is important during the implantation process, when as shown inFIGS. 2A and 2B anchors16A and16B must be maneuvered through the neck of theaneurysm12, and positioned so that they extend along the same dimension asroot vessel14. The radiopaque markings30 (FIG. 3) are invaluable during this process.
• Referring now toFIG. 6,subassembly42 is threaded through anend cap60, and passes into atransparent chamber62, wherewires48A and48B, emerge fromtube50, pass through a slider64 and are separately anchored inhandles46A and46B, respectively. The travel extent of slider64 is limited by astop pin66 and aslot68.
• Wires48A and48B each include a region70 (FIGS. 7 and 8) that is susceptible to electrolytic disintegration. To detachclosure device10, after placement, an electric current is passed throughwires48A and48B, causingregions70 to electrolytically disintegrate, freeingclosure device10 fromwires48A and48B, so that it can be left in place in its target location, sealinganeurysm12. In a preferred embodiment, handles46A and46B each includes an electrical contact connected to wire48A and48B, respectively, for attaching to a source of electricity for performing the above-described step.
• Subassembly42 is introduced into the femoral artery and guided through the carotid artery into the brain's arterial system, and further guided to theaneurysm12. At thispoint closure device10 is pushed out offossa56, anchors16A and16B are guided intoaneurysm12, and anchors18A and18B are positioned inroot artery14. Then a pulse of electricity seversclosure device10 fromwires48A and48B andclosure device10 is installed in place.
• Wires48A and48B are made of stainless steel alloy304, which may also be referred to as alloy 18-8. This material is coated with poly tetrafluoroethylene, except for at detachment points70 and the points where they are connected to a source of electricity. The nitinol alloy that frame22 (FIG. 3) is made of is 54.5% to 57% nickel, with the remainder titanium, which forms a super-elastic alloy. Theintroducer tube50 is made of high density polyethylene, coated at the distal tip with a hydrophilic coating. Finally, thesilicone28 of theclosure device10 is silicone MED 4820 or MED-6640, which is a high tear strength liquid silicone elastomer, having a Shore A durometer reading of 20-40. A MED6-161 Silicone Primer is used to attachsilicone28 toNitinol frame22.
• While a number of exemplary aspects and embodiments have been discussed above, those possessed of skill in the art will recognize certain modifications, permutations, additions and sub-combinations, thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope.

Claims (24)

1. An aneurysm closure device, comprising:

a. a pair of retention clips, joined together;

b. each said clip having an aneurysm anchor joined to a root-vessel anchor, and being made of material having a resilient installed state, in which said aneurysm anchor and said root-vessel anchor are urged together, thereby squeezing and being retained by interposed tissue;

c. an aneurysm seal, bridging said clips, to seal an aneurysm, causing it to decay.

2. The closure device ofclaim 1, wherein a portion of said root vessel anchors forms a portion of said seal.

3. The closure device ofclaim 1, wherein said aneurysm anchors include wire frames.

4. The closure device ofclaim 3, wherein said wire frames are made of shape memory material.

5. The closure device ofclaim 4, wherein said shape memory material is nitinol.

6. The closure device ofclaim 1, wherein said root-vessel anchors include wire frames, supporting sealing material that forms said seal.

7. The closure device ofclaim 6, wherein said seal comprises an expanse of silicone supported and reinforced by a lattice of fibers that are, in turn, supported and anchored by said wire frames.

8. The closure device ofclaim 7, wherein said silicone was applied in raw form and cured in situ.

9. The closure device ofclaim 7, wherein said silicone was applied by adhering cured sheets of silicone to both sides of said lattice.

10. The closure device ofclaim 7, wherein said fibers are anchored by solder.

11. The closure device ofclaim 10, wherein said solder is gold solder.

12. The closure device ofclaim 10, wherein said fibers are heat resistant, to at least 716° C.

13. The closure device ofclaim 7, wherein said fibers are made of poly-tetrafluoroethylene.

14. The closure device ofclaim 13, wherein said poly tetrafluoroethylene is expanded poly tetrafluoroethylene.

15. The closure device ofclaim 7, wherein said wire frames define eyeholes through which said fibers are threaded.

16. The closure device ofclaim 15, wherein said eyeholes are filled with gold solder, thereby retaining said thread closing said eyehole.

17. The aneurysm closure device ofclaim 1, further wherein said device is collapsible into a collapsed storage state and wherein in said collapsed storage state said aneurysm anchors from said pair of retention clips are placed in abutting proximity with each other and said root-vessel anchors from said pair of retention clips are placed into proximity with each other, said aneurysm anchors in a more distal position than said root-vessel anchors.

18. The aneurysm closure device ofclaim 17, further including a fossa, which holds said pair of retention clips and seal in said collapsed storage state.

19. The aneurysm closure device ofclaim 18, further including a partially deployed state, in which said aneurysm anchors are out of said fossa and have spread apart from each other, but said root-vessel anchors remain in said fossa.

20. The aneurysm closure device ofclaim 1, further being collapsible into a volume of no greater than about 1 mm diameter and 10 mm length.

21. A method of treating an aneurysm in a patient's brain, extending from a root blood vessel, comprising:

a. providing an aneurysm closure device, that includes:

i. a pair of retention clips, joined together;

ii. each said clip having an aneurysm anchor coupled to a root-vessel anchor, and being made of material having a resilient installed state, in which said aneurysm anchor and said root-vessel anchor are urged together, thereby squeezing and being retained by any interposed material; and

iii. an aneurysm seal, bridging said clips;

b. implanting said aneurysm closure device so that it seals said aneurysm by positioning said aneurysm anchors in opposed positions inside said aneurysm and said root vessel anchors inside said root blood vessel so that each said aneurysm anchor is urged toward its coupled root-vessel anchor, thereby retaining said aneurysm closure device by pressure placed by said clips on said interposed aneurysm and root vessel tissue, and thereby placing said seal over said aneurysm, reducing blood flow to said aneurysm and causing eventual atrophy of said aneurysm.

22. The method ofclaim 21, wherein said step of implanting said aneurysm closure device includes inserting a guide catheter from an incision in the femoral artery to said aneurysm, providing a positioning assembly retaining said closure device in a distal portion thereof, extending said positioning assembly through said guide catheter and using said positioning assembly to position said closure device into place at said aneurysm location.

23. The method ofclaim 22, wherein said positioning assembly comprises:

a. a flexible tube that defines:

i. a pair of parallel lumens; and

ii. a distal lumen, expanded in diameter, relative to said proximal lumen, containing said closure device in a folded state;

b. two separately controlled wires attached to separate locations on said closure device.

24. The method ofclaim 21 wherein said flexible tube defines a single lumen portion, proximal to said pair of parallel lumens.

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