Oriented polymeric spinal implants
A polymeric spinal implant is disclosed wherein the polymer material is substantially uniformly oriented. The spinal implant is advantageous because the substantially uniformly oriented polymer material creates anisotropic properties, especially increased strength perpendicular to the orientation of the polymer material.
1 . A method for producing a spinal implant comprising a substantially uniformly oriented polymer material, comprising:
providing a polymer material suitable for molding into a spinal implant;
supplying the polymer material to the mold;
orienting the polymer material to form a substantially uniformly oriented polymer material;
molding the polymer material into a spinal implant; and
allowing the polymer to solidify.
2 . The method of claim 1 , wherein molding the polymer material takes place prior to orienting the polymer material.
3 . The method of claim 1 , wherein molding the polymer material takes place after orienting the polymer material.
4 . The method of claim 1 , wherein the polymer material comprises a polymer and a reinforcing additive.
5 . The method of claim 4 , wherein the reinforcing additive is selected from the group consisting of metallic fibers, ceramic fibers, polymeric fibers, carbon fibers, KEVLAR® fibers, SPECTRA® fibers, polyester fibers, hydroxyapatite particles, short fibers, long fibers, continuous fibers, woven or spun bonded fibers, filaments, and mixtures thereof.
6 . The method of claim 4 , wherein the reinforcing additive is capable of orientation by application of external energy.
7 . The method of claim 6 , further comprising supplying external energy to the polymeric material to substantially uniformly orient the reinforcing additive.
8 . The method of claim 7 , wherein the external energy is selected from the group consisting of heat, light, magnetism, electrical, mechanical and irradiation.
9 . The method of claim 1 , wherein supplying the polymer material to the mold comprises supplying the polymer material through a communicating gate.
10 . The method of claim 9 , wherein the communicating gate is positioned so as to cause the polymer material to substantially uniformly orient perpendicular to the compressive load to which the spinal implant will be subjected.
11 . The method of claim 10 , wherein the communicating gate is positioned in the center of the mold.
12 . The method of claim 10 , wherein the communicating gate is positioned at one end of an elongated mold having a length greater than its effective diameter, thereby providing a polymer material substantially uniformally oriented along the length of the mold.
13 . The method of claim 1 , wherein orienting the polymer material comprises supplying the polymer material to the mold in a manner that the polymer material is substantially oriented in a direction substantially parallel to the supplying direction.
14 . The method of claim 1 , wherein orienting the polymer material comprises further processing the polymer material after it has been molded.
15 . The method of claim 14 , wherein further processing comprises stretching.
16 . A polymeric spinal implant comprising a substantially uniformly oriented polymer material.
17 . A polymeric spinal implant comprising a substantially uniformly oriented polymer material, prepared by the method of claim 1 .
18 . The implant of claim 17 , wherein the polymer material is substantially uniformly oriented perpendicular to the compressive load to which the implant will be subjected.
19 . The implant of claim 17 , wherein the polymer material comprises a polymer selected from the group consisting of elastomeric materials, hydrogels, thermoplastic polymers, liquid monomers, polymer dispersions, gel based polymers, liquid crystal polymers, macromolecular composites, crystalline polymers, semi-crystalline polymers, amorphous polymers, hydrophilic polymers, and composites or mixtures thereof.
20 . The implant of claim 19 , wherein the polymer is selected from the group consisting of silicone, polyurethanes, copolymers of silicone and polyurethane, polyisobutylene, polyisoprene, neoprene, nitrile, vulcanized rubber, natural hydrogels, hydrogels formed from polyvinyl alcohol, polyacrylic acid, poly(acrylonitrile-acrylic acid), polyethylene glycol, poly(N-vinyl-2-pyrrolidone), poly(2-hydroxy ethyl methacrylate), copolymers of acrylates with N-vinyl pyrrolidone, N-vinyl lactams, acrylamide, polyacrylonitrile, thermoplastic polyurethanes, aliphatic polyurethanes, segmented polyurethanes, hydrophilic polyurethanes, polyether-urethane, polycarbonate-urethane, silicone polyetherurethane, glucomannan gel, hyaluronic acid, cross-linked carboxyl-containing polysaccharides, polyesters, polyamides, polyethylene terephtalate, high-density polyethylene, polypropylene, polysulfones, polyphenylene oxides, polymethylmethacrylate, polyetheretherketone, polylactide, polyglycolide, poly(lactide-co-glycolide), poly(dioxanone), poly([epsilon]-caprolactone), poly(hydroxylbutyrate), poly(hydroxylvalerate), tyrosine-based polycarbonate, polypropylene fumarate, and mixtures and combinations thereof.
21 . The implant of claim 17 , wherein the polymer material comprises a reinforcing additive.
22 . The implant of claim 21 , wherein the reinforcing additive is selected from the group consisting of metallic fibers, ceramic fibers, polymeric fibers, carbon fibers, KEVLAR® fibers, SPECTRA® fibers, polyester fibers, hydroxyapatite particles, short fibers, long fibers, continuous fibers, woven or spun bonded fibers, filaments, and mixtures thereof.
23 . The implant of claim 17 , wherein the polymer material further comprises an additive selected from the group consisting of antibiotics, anti-retroviral drugs, nutrients, preservatives, binders, osteoconductive agents, osteoinductive agents, and mixtures thereof.
24 . The implant of claim 17 , wherein the implant has a tensile strength within the range of about 10 Mpa to about 250 Mpa.
25 . The implant of claim 24 , wherein the implant has a tensile strength within the range of from about 20 Mpa to about 150 Mpa.