Patent Publication Number: US-2009228029-A1

Title: Aneurysm shield anchoring device

Description:
TECHNICAL FIELD 
     Inventive subject matter described herein relates to aneurysm shield embodiments, aneurysm shield anchoring mechanism embodiments and method embodiments for making and using aneurysm shields and aneurysm shield anchoring mechanisms, referred to as an aneurysm treatment system. 
     COPYRIGHT 
     A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. This notice applies to the products, processes and data as described below and in the tables that form a part of this document: Copyright 2008, Neurovasx, Inc. All Rights Reserved. 
     BACKGROUND 
     An aneurysm is a balloon-like swelling in a wall of a blood vessel. An aneurysm results in weakness of the vessel wall in which it occurs. This weakness predisposes the vessel to tear or rupture with potentially catastrophic consequences for any individual having the aneurysm. Vascular aneurysms are a result of an abnormal dilation of a blood vessel, usually resulting from disease and/or genetic predisposition, which can weaken the arterial wall and allow it to expand. Aneurysm sites tend to be areas of mechanical stress concentration so that fluid flow seems to be the most likely initiating cause for the formation of these aneurysms. 
     Aneurysms in cerebral circulation tend to occur in an anterior communicating artery, a posterior communicating artery, or a middle cerebral artery. The majority of these aneurysms arise either from curvature in the vessels or at bifurcations of these vessels. Cerebral aneurysms are most often diagnosed by the rupture and subarachnoid bleeding of the aneurysm. 
     Cerebral aneurysms are most commonly treated in open surgical procedures where the diseased vessel segment is clipped across the base of the aneurysm. While considered to be an effective surgical technique, particularly considering an alternative which may be a ruptured or re-bleed of a cerebral aneurysm, conventional neurosurgery suffers from a number of disadvantages. The surgical procedure is complex and requires experienced surgeons and well-equipped surgical facilities. Current treatment options for cerebral aneurysm fall into two categories, surgical and interventional. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to depict the manner in which the embodiments are obtained, a more particular description of embodiments briefly described above will be rendered by reference to exemplary embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments that are not necessarily drawn to scale and are not, therefore, to be considered to be limiting of its scope, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
         FIG. 1  is a top plan of an aneurysm treatment system according to an embodiment; 
         FIG. 2  is a cross-section elevation of the aneurysm treatment system depicted in  FIG. 1  according to an embodiment; 
         FIG. 3  is an elevational perspective of the aneurysm treatment system depicted in  FIG. 1  according to an embodiment; 
         FIGS. 4   a  and  4   b  are front elevations of the aneurysm treatment system depicted in  FIG. 1  according to an embodiment; 
         FIG. 5  is an elevational perspective of the aneurysm treatment system according to an embodiment; 
         FIG. 6  is a side elevation of the aneurysm treatment system depicted in  FIG. 5  according to an embodiment; 
         FIG. 7  is a cut-away elevation of an aneurysm treatment system when it is deployed within a bio lumen according to an embodiment; 
         FIG. 8  is a top plan of an aneurysm treatment system according to an embodiment; 
         FIG. 9  is a front elevation of an aneurysm treatment system according to an embodiment; 
         FIG. 10  is a perspective elevation of an aneurysm treatment system according to an embodiment; and 
         FIG. 11  is a cut-away elevation of an aneurysm treatment system when it is deployed within a bio lumen according to an embodiment; and 
         FIG. 12  is a method flow diagram deploying an aneurysm treatment system according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Although detailed embodiments are disclosed herein, it is to be understood that the disclosed embodiments are merely exemplary of the embodiments that may be configured in various and alternative forms. Specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for teaching one skilled in the art to variously employ the aneurysm treatment system embodiments. Throughout the drawings, like elements may be given with like numerals. 
     Referred to herein are trade names for materials including, but not limited to, polymers and optional components. Reference to such trade names is not intended to limit such materials described and referenced by a certain trade name. Equivalent materials (e.g., those obtained from a different source under a different name or catalog (reference) number to those referenced by trade name may be substituted and utilized in the methods described and claimed herein. All percentages and ratios are calculated by weight unless otherwise indicated. All percentages are calculated based on the total composition unless otherwise indicated. All component or composition levels are in reference to the active level of that component or composition, and are exclusive of impurities, for example, residual solvents or by-products, which may be present in commercially available sources. 
       FIG. 1  is a top plan of an aneurysm treatment system  100  according to an embodiment. The aneurysm treatment system  100  may be referred to as a device  100  for occluding an aneurysm. The aneurysm treatment system  100  may be referred to as an aneurysm shield anchoring device  100 . 
     The aneurysm treatment system  100  includes a curved surface  110  to shield an aneurysm. The curved surface  110  may also be referred to as an aneurysm shield  110 . The curved surface  110  includes a major (or longitudinal) axis  112  with first and second major-axis edges  114  and  116  respectively. The aneurysm treatment system  100  also includes a minor axis  118  that is orthogonal to the major axis  112 . The aneurysm treatment system  100  also includes first and second minor-axis edges  120  and  122 , respectively. In an embodiment, the aneurysm treatment system  100  exhibits an eccentric form factor that is disposed symmetrically along the axes  112  and  118 . 
       FIG. 2  is an elevational cross section  200  of the aneurysm treatment system  100  depicted in  FIG. 1 . In the cross-section elevation, the curved surface  110  exhibits a semi-circular form factor that is orthogonal to the major axis  112 . In  FIG. 2 , the major axis  112  is depicted as orthogonal to the plane of the FIG. An aneurysm-occlusion structure  124  is disposed along the curved surface  110 . The aneurysm-occlusion structure  124  is depicted in arbitrary shape and frequency. In an embodiment, the aneurysm-occlusion structure  124  is a plurality of seats for cell-growth materials. In an embodiment, the aneurysm-occlusion structure  124  is a plurality of seats to anchor expandable materials. A spring  126  completes a circular structure that includes the curved surface  110 . The spring  126  and the curved surface  110  comprise an aneurysm shield anchoring device. 
       FIG. 3  is an elevational perspective  300  of the aneurysm treatment system  100  depicted in  FIG. 1  according to an embodiment. In an embodiment, the curved surface  110  carries the aneurysm-occlusion structure  124 , and the curved surface  110  is configured such that insertion of the aneurysm treatment system  300  into a bio lumen will allow the aneurysm-occlusion structure  124  to be urged against an aneurysm when it is deployed. 
     In an embodiment, the aneurysm treatment system  300  includes the spring  126  that is coupled to the curved surface  110 . As illustrated, the spring  126  is connected by an affixture  128  at the minor-axis edges  120  and  122 . The affixture  128  is depicted in  FIG. 3  as a local point structure, such as a staple or rivet. In an embodiment, the affixture  128  is a heat weld between the curved surface  110  and the spring  126 . In an embodiment, the affixture  128  is an adhesive material between the curved surface  110  and the spring  126 . Other structures for the affixture  128  may be used according to conventional technique. When viewed in elevational cross section as in  FIG. 2 , the spring  126  completes the formation of a circular structure with the curved surface  110  as the remainder of the circular structure. 
     In an embodiment, the spring  126  is made of one or more of wires. Usable wire materials include super elastic Nitinol, NIP35N, Beta 3 titanium, stainless steel, and shape memory Nitinol. It is believed that any plastically deformable, biocompatible material such as a metal, alloy or polymer is suitable for use as at least a component of the spring  126 . 
     In an embodiment, the spring  126  is constructed of “shape memory” metal alloy (e.g., Nitinol) capable of self-expansion at internal temperatures of the target vessel host. In an embodiment, the spring  126  is configured after tomographical data of the aneurysm site has been ascertained, such that upon deployment into the target bio lumen, the spring  126  may expand to urge the curved surface  110  against the ascertained topology of the aneurysm site. Consequently, a programmed self-expansion temperature of the spring  126  may be installed into the aneurysm treatment system  100   
     The manner by which the spring  126  is manufactured is not particularly restricted. In an embodiment, the spring  126  is produced by laser cutting techniques applied to a starting material. Thus, the starting material could be a thin tube or sheet of a metal, alloy or polymer as described above. In an embodiment, the spring  126  is cut from a shape memory metal and is contoured to reach a final shape under temperature conditions of the target vessel for which the aneurysm treatment system  100  is to be deployed. 
     In an embodiment, the aneurysm-occlusion structure  124  includes a mesh material that facilitates occlusion of an aneurysm. Such aneurysm-occlusion mesh material may have a pore size that facilitates in vivo fibrotic cell growth in the aneurysm-occlusion structure  124 . In an example embodiment, the aneurysm-occlusion structure  124  includes a polymeric material such as polyethylene. 
     In an embodiment, the aneurysm-occlusion structure  124  includes a hydrogel foam portion that can be entrained in a polyethylene matrix. In an embodiment, the hydrogel is swellable and has a swell ratio of 10:1-2:1. The foam provides a desirable surface for rapid cell ingrowth. The hydrogel foam or other filler material is shapeable at the aneurysm neck to form a smooth, closed surface at the aneurysm neck. 
     Swellable materials for use as the aneurysm-occlusion structure  124  include acrylic-based materials according to an embodiment. For example, the aneurysm-occlusion structure  124  is deployed upon the curved surface  110 , where the curved surface  110  is a core material that is stiffer than the outer material of the aneurysm-occlusion structure  124 . In an embodiment, at least some active portions of the aneurysm-occlusion structure  124  have a time-dependent rate of dissolution such that swellable materials are encapsulated, but after deployment in a target vessel, the swellable materials may be contacted with in vivo fluids that dissolve encapsulation layer(s). 
     The hydrogel deployed within the aneurysm-occlusion structure  124  may be stiffened as a consequence of an increased degree of crosslinkage as compared to the an outer layer of the aneurysm-occlusion structure  124 . While a hydrogel is described, it is understood that other biocompatible, swellable materials are suitable for use in selected embodiments. Other materials include acetates, such as cellulose acetate or polyvinylacetate, for the aneurysm-occlusion structure  124 . Other materials include alcohols, such as ethylene vinyl alcohol copolymers, for the aneurysm-occlusion structure  124 . Other materials include nitrites, such as polyacrylonitriles, for the aneurysm-occlusion structure  124 . Other materials include cellulose acetate butyrate, nitrocellulose, copolymers of urethane/carbonate, copolymers of styrene/maleic acid, or mixtures thereof for the aneurysm-occlusion structure  124 . In particular, a hydrogel/polyurethane foam is usable in for the aneurysm-occlusion structure  124 . 
     In an embodiment, the aneurysm-occlusion structure  124  includes a polymer-based, coil-like structure that is fabricated with soft biocompatible polymers such as PTFE, urethanes, polyolefins, nylons and the like. In an embodiment, the aneurysm-occlusion structure  124  includes at least one of solid strings and hollow strings. The aneurysm-occlusion structure  124  may also be fabricated from biodegradable materials such as PLA, PGA, PLGA, polyanhydrides and other similar biodegradable materials. Use of biodegradable materials provokes a wound healing response and concomitantly eliminates a mass effect of the aneurysm shield anchor over time. 
     The material of the aneurysm-occlusion structure  124  described herein may be one or more of polymeric and polymeric hybrids such as PEBAX, Grilamids, polyester, and silica. Aneurysm-occlusion structure materials may also include reabsorbables such as PGLA, PEG, PGLA and base polymer. Other aneurysm-occlusion structure materials may include textiles such as rayon, nylon, silk, Kyeon, Kevlar, and cotton. Other aneurysm-occlusion structure materials may include biopolymers such as collagen, filaments, and coated polymeric material. Other aneurysm-occlusion structure materials may include elastomers such as urethanes, silicones, nitrites, TecoFlex® of Thermedics, Inc. of Woburn, Mass., Carbothane® of Noveon IP Holding Corp. of Cleveland Ohio, and silicone hybrids. 
     In an embodiment, the aneurysm treatment system  100  may include a coating material thereon. The coating material may be disposed continuously or discontinuously on the surface of the aneurysm treatment system  100 , including both the curved surface  110  and the spring  126 . The coating may be disposed on the interior and/or the exterior surface(s) of the aneurysm treatment system  100 . The coating material can be one or more of a biologically inert material (e.g., to reduce the thrombogenicity of the prosthesis), a medicinal composition which leaches into the wall of the body passageway after implantation (e.g., to provide anticoagulant action, to deliver a pharmaceutical to the body passageway) and the like. 
     For some embodiments, the aneurysm treatment system  100  is provided with a biocompatible coating in order to minimize adverse interaction with the walls of the body vessel and/or with the liquid, usually blood, flowing through the vessel. For some embodiments, the coating is a polymeric material, which is provided by applying to the prosthesis a solution or dispersion of preformed polymer in a solvent and removing the solvent. Non-polymeric coating material may alternatively be used. Suitable coating materials, for instance polymers, may be polytetraflouroethylene or silicone rubbers, or polyurethanes that are known to be biocompatible. In an embodiment the polymer has zwitterionic pendant groups, generally ammonium phosphate ester groups, such as phosphoryl choline groups or analogues thereof. 
       FIG. 4   a  is a front cross-section elevation of an aneurysm treatment system  400  according to an embodiment. Minor-axis edges  420  and  422  respectively, are depicted similar to the minor-axis edges  120  and  122  depicted in  FIG. 1 . In an embodiment, deployment of the aneurysm treatment system  400  includes first folding the spring  426  to decrease the X-Z dimensional footprint. By folding the spring  426 , the aneurysm treatment system  400  may be inserted into a bio lumen, followed by releasing the spring from the folded configuration. In an embodiment, the spring  426  is a shape-memory material such as a shape-memory alloy. In an embodiment, the spring  426  is a shape-memory material such as a biased plastic. 
       FIG. 4   b  is a front elevation of the aneurysm treatment system depicted in  FIG. 4   a  after further deployment. The spring  426  ( FIG. 4   a ) in the aneurysm treatment system  401  has been released from the folded configuration, such that the aneurysm treatment system  401  has been allowed to alter the shape of the curved surface  410 , such that the curved surface  410  may be urged against the wall of a bio lumen to occlude an aneurysm. 
     In this manner of deployment, the spring  426  is disposed to urge more force upon the curved surface  410  at the minor-axis edges  420  and  422 , respectively, than at the major-axis edges. Accordingly, the method allows for a customized configuration of at least a portion of the spring  426  to achieve an altered shape of the curved surface  410 . This altered shape may conform to a unique concave surface within a bio lumen. 
     It can now be seen that method embodiments of allowing the curved surface, e.g., curved surface  410 , to alter shape to be urged against and occlude an aneurysm, may be carried out by methods other than folding the spring  426 . Other methods of folding the aneurysm treatment system  401 , or a part thereof, may be employed such that the aneurysm treatment system  401  may be allowed to alter the shape of the curved surface within a bio lumen. 
       FIG. 5  is an elevational perspective of an aneurysm treatment system  500  according to an embodiment. A curved surface  510  carries the aneurysm-occlusion structure  524  such that insertion of the aneurysm treatment system  500  into a bio lumen will allow the aneurysm-occlusion structure  524  to alter shape and for the curved surface  510  to be urged against an aneurysm when it is deployed. 
     In an embodiment, the aneurysm treatment system  500  includes a spring  526  that is coupled to the curved surface  510 . The spring  526  exhibits a racetrack form factor. As illustrated, the spring  526  is connected by an affixture  528  at the minor-axis edges  520  and  522 . The affixture  528  may be any embodiment as set forth in this disclosure. 
       FIG. 6  is a side elevation of the aneurysm treatment system depicted in  FIG. 5 . An aneurysm treatment system  600  is illustrated with a longitudinal (Y-axis) dimension running across the plane of the figure. and the minor axis (X) running into and out of the plane of the figure. The spring  526  is illustrated as providing foot regions at the ends thereof that are below first and second major-axis edges  514  and  516  respectively. This embodiment illustrates a smaller material-volume presence that the aneurysm treatment system depicted in  FIGS. 1-4   b . When the aneurysm treatment system  600  is deployed within a bio lumen, it may have less fluid-flow hindrance below the curved surface  510  than below the curved surface  110  depicted in the previous FIGs. 
       FIG. 7  is a cut-away elevation of an aneurysm treatment system  700  when it is deployed within a bio lumen according to an embodiment. A bio lumen  740  is depicted with an aneurysm neck  742  and an aneurysm  744  that is distended outside the normal confines of the bio lumen  740 . An aneurysm treatment system, such as the aneurysm treatment system depicted in  FIGS. 1 ,  2 , and  3  is deployed. A curved surface  710  is urged against the bio lumen  740  by use of a spring  726  and an affixture  728  that couples the curved surface  710  to the spring  726 . The curved surface  710  exhibits major-axis edges  714  and  716  and a minor-axis edge  720 . The spring  726  is disposed to urge more force upon the curved surface  710  at the minor-axis edges ( 720  depicted) than at the major-axis edges  714  and  716 . Consequently, the curved surface  710  is urged against the location of the aneurysm  742  neck in the longitudinal configuration of the bio lumen  740 . 
     An aneurysm-occlusion structure  724  is disposed along the curved surface  710 . The aneurysm-occlusion structure  724  is depicted in arbitrary shape and frequency. In an embodiment, the aneurysm-occlusion structure  724  may be any aneurysm-occlusion structure set forth in this disclosure. 
       FIG. 8  is top plan of an aneurysm treatment system  800  according to an embodiment. The aneurysm treatment system  800  may be referred to as a device  100  for occluding an aneurysm. The aneurysm treatment system  800  may be referred to as an aneurysm shield anchoring device  800 . 
     The aneurysm treatment system  800  includes a curved surface  810  to shield an aneurysm. The curved surface  810  may also be referred to as an aneurysm shield  110 . The curved surface  810  has a major (or longitudinal) axis  812  with first and second major-axis edges  814  and  816  respectively. The aneurysm treatment system  800  also includes a minor axis  818  that is orthogonal to the major axis  812 . The aneurysm treatment system  800  also includes first and second minor-axis edges  820  and  822 , respectively. The aneurysm treatment system  800  exhibits an eccentric form factor that is disposed symmetrically along the major axis  812 . 
       FIG. 9  is an elevational cross section  900  of the aneurysm treatment system  800  depicted in  FIG. 8 . In the cross-section elevation, the curved surface  810  exhibits a semi-circular form factor that is orthogonal to the major axis  812 . In  FIG. 9 , the major axis  812  is depicted as orthogonal to the plane of the figure. An aneurysm-occlusion structure  824  is disposed along the curved surface  810 . The aneurysm-occlusion structure  824  is depicted in arbitrary shape and frequency. According to an embodiment, any aneurysm-occlusion structure and/or materials that are set forth in this disclosure may be used to construct the aneurysm-occlusion structure  824 . 
     A spring  826  is located integral with and below the curved surface  810 , such that it mimics the semi-circular form factor of the curved surface  810 . According to an embodiment, any spring structure and/or materials that are set forth in this disclosure may be used to construct the spring  826 . 
     The spring  826  and the curved surface  810  comprise an aneurysm shield anchoring device. In an embodiment, the spring  826  is a shape memory material such as a metal, plastic, or metalloplastic composite that can achieve a selected topology when it has been deployed into a bio lumen under the life conditions thereof. 
     In an embodiment, the spring  826  is not present as a separate structure. Rather, the spring is integral with the curved surface  810 , in that the curved surface has been biased during formation. Consequently, the curved surface  810  has a characteristic topology that is expandable more at the minor-axis edges  816  and  818 , respectively, than at the major-axis edges. In this configuration, the curved surface  810  is urgeable against an aneurysm when it is deployed. 
       FIG. 10  is an elevational perspective  1000  of the aneurysm treatment system  800  and  900  depicted in  FIGS. 8 and 9  according to an embodiment. The curved surface  810  carries the aneurysm-occlusion structure  824 , and the curved surface  810  is configured such that insertion of the aneurysm treatment system  800  into a bio lumen will allow the aneurysm-occlusion structure  824  to be urged against an aneurysm when it is deployed. 
     In an embodiment, the aneurysm treatment system  800  includes the spring  826  that is coupled to the curved surface  810  as depicted in  FIG. 9 . The spring  826  is configured such that upon deployment in a bio lumen, the minor-axis edges  820  and  822  may urged against the bio lumen wall under more force than the major-axis edges  820  and  822 . 
       FIG. 11  is a cut-away elevation of an aneurysm treatment system  1100  when it is deployed within a bio lumen according to an embodiment. A bio lumen  1140  is depicted with an aneurysm neck  1142  and an aneurysm  1144  that is distended outside the normal confines of the bio lumen  1140 . An aneurysm treatment system, such as the aneurysm treatment system depicted in  FIGS. 8 ,  9 , and  10 , is deployed. A curved surface  1110  is urged against the bio lumen  1140  by use of a spring that is integral to the curved surface  1110 . The curved surface  1110  exhibits major-axis edges  1114  and  1116  and a minor-axis edge  1120 . A spring (obscured in  FIG. 11 ) is disposed to urge more force upon the curved surface  1110  at the minor-axis edges ( 1120  depicted) than at the major-axis edges  1114  and  1116 . Consequently, the curved surface  1110  is urged against the location of the aneurysm  1142  in the longitudinal configuration of the bio lumen  1140 . 
     An aneurysm-occlusion structure  1124  is disposed along the curved surface  1110 . The aneurysm-occlusion structure  1124  is depicted in arbitrary shape and frequency. In an embodiment, the aneurysm-occlusion structure  1124  may be any aneurysm-occlusion structure set forth in this disclosure. 
       FIG. 12  is a method flow diagram  1200  for deploying an aneurysm treatment system according to an embodiment. 
     At  1210 , the method includes inserting an aneurysm shield anchor into a bio lumen. 
     At  1220 , the method includes allowing the aneurysm shield anchor to assist a curved surface of the aneurysm shield anchor to alter shape to occlude an aneurysm. 
     The Abstract is provided to comply with 37 C.F.R. §1.72(b) requiring an abstract that will allow the reader to quickly ascertain the nature and gist of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 
     In the foregoing Detailed Description, various features are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments of the invention require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate preferred embodiment. 
     It will be readily understood to those skilled in the art that various other changes in the details, material, and arrangements of the parts and method stages, which have been described and illustrated in order to explain the nature of this invention, may be made without departing from the principles and scope of the invention as expressed in the subjoined claims.