Patent Application
20080319527
The inventive subject matter described herein relates to a shaped multi-durometer aneurysm filler and to a method for repairing an aneurysm. The inventive subject matter also relates to a method for making, a method for using the shaped multi-durometer aneurysm filler.
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. The following notice applies to the products, processes and data as described below and in the tables that form a part of this document: Copyright 2007, Neurovasx, Inc. All Rights Reserved.
An aneurysm is a balloon-like swelling in a wall of a blood vessel. Aneurysms result 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, posterior communicating artery, and a middle cerebral artery. The majority of these aneurysms arise from either curvature in the vessels or at bifurcations of these vessels. The majority of cerebral aneurysms occur in women. 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. Surgical cerebral aneurysm repair has a relatively high mortality and morbidity rate of about 2% to 10%.
Current treatment options for cerebral aneurysm fall into two categories, surgical and interventional. The surgical option has been the long held standard of care for the treatment of aneurysms. Surgical treatment involves a long, delicate operative procedure that has a significant risk and a long period of postoperative rehabilitation and critical care. Successful surgery allows for an endothelial cell to endothelial cell closure of the aneurysm and therefore a cure for the disease. If an aneurysm is present within an artery in the brain and bursts, this creates a subarachnoid hemorrhage, and a possibility that death may occur. Additionally, even with successful surgery, recovery takes several weeks and often requires a lengthy hospital stay.
In order to overcome some of these drawbacks, interventional methods and prostheses have been developed to provide an artificial structural support to the vessel region impacted by the aneurysm. The structural support must have an ability to maintain its integrity under blood pressure conditions and impact pressure within an aneurysmal sac and thus prevent or minimize a chance of rupture. U.S. Pat. No. 5,405,379 to Lane, discloses a self-expanding cylindrical tube which is intended to span an aneurysm and result in isolating the aneurysm from blood flow. While this type of stent-like device may reduce the risk of aneurysm rupture, the device does not promote healing within the aneurysm. Furthermore, the stent may increase a risk of thrombosis and embolism. Additionally, the wall thickness of the stent may undesirably reduce the fluid flow rate in a blood vessel. Stents typically are not used to treat aneurysms in a bend in an artery or in tortuous vessels such as in the brain because stents tend to straighten the vessel.
U.S. Pat. No. 5,354,295 to Guglielmi et al., describes a type of vasoclusion coil. Disadvantages of use of this type of coil are that the coil may compact, may migrate over time, and the coil does not optimize the patient's natural healing processes.
Although detailed embodiments of the invention are disclosed herein, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied 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 filler embodiments. Throughout the drawings, like elements are given like numerals.
Referred to herein are trade names for materials including, but not limited to, polymers and optional components. The inventors herein do not intend to be limited by 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.
As used herein, the term “multi-durometer” refers to a polymeric material having different degrees of hardness along its area or volume.
Embodiments of the invention described herein include a multi-durometer, preshaped polymeric aneurysm filler. The pre-shaping produces a three-dimensional filler which, when deployed from a catheter, takes on a predetermined shape. In one embodiment, the polymeric material used to make the filler includes varying durimeter features of one type of polymer or, for other embodiments, includes a variety of durometers of multiple materials reformed in aggregate to form a filler shaft. A benefit of using multiple materials is that a greater number of materials' properties is available for use.
For some embodiments, the polymeric filler is formed into a three-dimensional shape. The method includes a use of a scaffold that includes but is not limited to a sphere, rod, square, triangle, rectangle, or any other geometric shape that can be fabricated. The scaffold is, for some embodiments, made of a metal or suitable polymer. For some embodiments, pins 16, shown in
The sphere 14 is placed in or near a heat source in order to raise the temperature of the filler material to its glass transition temperature point, Tg. The glass transition temperature was held for a time effective to produce a heat set. When the heating time expired, the sphere and scaffold were allowed to cool. Once cooled, the filler material was removed from the scaffold and a mandrel was carefully inserted into the filler while being straightened. A reason for artificially straightening is that the filler has taken the heat set.
Once a mandril is in place, the filler can be processed as shown in
The aneurysm filler embodiments may be formed by one or more processes such as reflow, thermal welding, adhesive welding, extrusion processing or other mechanisms for attaching two or more materials together.
Another embodiment includes a filler that includes two or more materials of varying durometers forming the length of the filler. The materials may be the same with differing durometers or may be different but compatible materials that posses certain desirable features such as compliance (filling, packing, geometry); lubricity; radiopacity; improved tracking; improved strength and improved healing response.
One method of fabrication includes multi-head and multi-durometer extrusion and reflow of material durometers using a heat mandril and appropriate heat shrink materials. One example of this filler embodiment is shown at 40 in
Other components of this embodiment include a non fill pusher shaft, a filler midshaft and a distal filler shaft.
An embodiment of an extruded, tapered, multidurometer core made of a material such as PEEK or Teflon is illustrated at 500 in
One other embodiment of an extruded, tapered, multidurometer core is shown at 600 in
The embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and formulation and method of using changes may be made without departing from the scope of the invention. The detailed description is not to be taken in a limiting sense, and the scope of the invention is defined only by the appended claims, along with the full scope of equivalents to which such claims are entitled.
