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Articulating diamond-surfaced spinal implants

  • US 7,494,507 B2
  • Filed: 08/28/2002
  • Issued: 02/24/2009
  • Est. Priority Date: 01/30/2000
  • Status: Expired due to Fees
First Claim
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1. An articulating two part sintered polycrystalline diamond-surfaced prosthetic spinal implant for implantation between vertebrae in a human body, the implant comprising:

  • a first spinal implant component,said first spinal implant component having a convex protruding dome member,said dome member including a first component load bearing and articulation surface for providing articulation when implanted in a human spine,said first component load bearing and articulation surface being formed at least in part by a polycrystalline diamond table sintered on a substrate,said sintered polycrystalline diamond table in said first component serving to provide a durable, biocompatible and low-friction surface for articulation of the implant first component against sintered diamond of the second component when implanted in a human spine,said first component load bearing and articulation surface being non-planar,a crystalline diamond structure located in said sintered polycrystalline diamond table,interstitial spaces in said crystalline diamond structure of said sintered polycrystalline diamond table,a solvent-catalyst metal present in at least some of said interstitial spaces of said sintered polycrystalline diamond table,substrate surface topographical features on said substrate,diamond in said sintered polycrystalline diamond table having a coefficient of thermal expansion CTEcd,said substrate having a coefficient of thermal expansion, CTEsub,CTEcd not being equal to CTEsub,said diamond in said sintered polycrystalline diamond table having a modulus Mcd,said substrate to which said diamond table is sintered having a modulus Msub,Mcd not being equal to Msub,a residual stress field in said sintered polycrystalline diamond table formed as a result of the difference of said CTEcd and said CTEsub and the difference of said Mcd and said Msub,said residual stress field tending to enhance the strength of said sintered polycrystalline diamond table,a mechanical grip between said diamond table and said substrate, said mechanical grip tending to secure said diamond table to said substrate as a result of a combination of said residual stress field and said substrate surface topographical features,a second spinal implant component,said second component having a concave trough,said trough having a shape and size that permits said protruding dome member to protrude therein,said trough having a shape and size that permits contact of said protruding dome member therewith at a plurality of contact points,said trough including a second component load bearing and articulation surface against which said first spinal implant component can articulate when implanted in a human spine,said second component load bearing and articulation surface being formed at least in part by a sintered polycrystalline diamond table,said sintered polycrystalline diamond table in said second component serving to provide a durable, biocompatible and low-friction surface for articulation of the implant,said first component being movable with respect to said second component in at a point that has diamond to diamond contact between said first and second components,a gradient transition zone in said at least one sintered polycrystalline diamond table,said gradient transition zone having a first side and a second side, said gradient transition zone having both solvent-catalyst metal and diamond therein, and said gradient transition zone exhibiting a transition of ratios of percentage content of solvent-catalyst metal to diamond from said first side to said second side such that at a first point in said gradient transition zone, the ratio of percentage content of solvent-catalyst metal to diamond is greater than it is at a second point in said gradient transition zone,chemical bonds in said zone, said chemical bonds including diamond-to-diamond bonds in said diamond table, diamond to metal bonds in said gradient transition zone, and metal to metal bonds in said solvent-catalyst metal.

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