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

• Current Assignee: Diamicron, Inc.
• Original Assignee: Diamicron, Inc.
• Inventors: Taylor, Jeffery Karl, Gardinier, Clayton Frank, Pope, Bill J., Medford, Troy J., Dixon, Richard H., Blackburn, Dean C.
• Primary Examiner(s): Pellegrino; Brian E.
• Application Number:
  US10/229,907
• Publication Number:
  US 20030191533A1
• Time in Patent Office: 2,372 Days
• Field of Search: 623/17.14, 623/17.15, 623/19.12, 623/21.13, 623/21.16, 623/23.4, 623/23.53, 427/2.26, 427/2.27
• US Class Current: 623/17.14
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61F 2/30749 Fixation appliances for connecting prostheses to the body
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/4425 made of articulated components
• CPC Class Codes: A61F 2002/30004 the prosthesis being made from materials having different values of a given property at different locations within the same prosthesis
• CPC Class Codes: A61F 2002/30084 Materials having a crystalline structure
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2002/30331 made by longitudinally pushing a protrusion into a complementarily-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2002/30392 Rotation
• CPC Class Codes: A61F 2002/30398 Sliding
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30451 soldered or brazed or welded
• CPC Class Codes: A61F 2002/30578 having apertures, e.g. for receiving fixation screws
• CPC Class Codes: A61F 2002/30649 Ball-and-socket joints
• CPC Class Codes: A61F 2002/30685 Means for reducing or preventing the generation of wear particulates
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30884 Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/30892 parallel
• CPC Class Codes: A61F 2002/30904 : serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/30934 : Special articulating surfaces
• CPC Class Codes: A61F 2002/30968 : Sintering
• CPC Class Codes: A61F 2002/3097 : using laser
• CPC Class Codes: A61F 2002/30971 : Laminates, i.e. layered products
• CPC Class Codes: A61F 2002/443 : having two transversal endplates and at least one intermediate component
• CPC Class Codes: A61F 2210/0014 : using shape memory or superelastic materials, e.g. nitinol
• CPC Class Codes: A61F 2220/0008 : Fixation appliances for connecting prostheses to the body
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2220/0058 : soldered or brazed or welded
• CPC Class Codes: A61F 2250/0014 : having different values of a given property or geometrical feature, e.g. mechanical property or material property, at different locations within the same prosthesis
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00095 : Niobium or Nb-based alloys
• CPC Class Codes: A61F 2310/00131 : Tantalum or Ta-based alloys
• CPC Class Codes: A61F 2310/00149 : Platinum or Pt-based alloys
• CPC Class Codes: A61F 2310/00167 : Diamond or diamond-like carbon
• CPC Class Codes: A61F 2310/00269 : based on metal carbides
• CPC Class Codes: A61F 2310/00281 : containing silicon carbide
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/0058 : Coating made of diamond or of diamond-like carbon DLC
• CPC Class Codes: A61L 27/04 : Metals or alloys
• CPC Class Codes: A61L 27/045 : Cobalt or cobalt alloys
• CPC Class Codes: A61L 27/08 : Carbon ; Graphite
• CPC Class Codes: A61L 27/303 : Carbon
• CPC Class Codes: B29C 2043/043 : rotating on their own axis without linear displacement
• CPC Class Codes: B29C 2043/3618 : plurality of counteracting elements
• CPC Class Codes: B29C 43/006 : Pressing and sintering powders, granules or fibres
• CPC Class Codes: B29C 43/361 : with pressing members independently movable of the parts for opening or closing the mould, e.g. movable pistons transfer moulding B29C45/02; injection-compression moulding B29C45/561
• CPC Class Codes: B29L 2031/7532 : Artificial members, protheses

Abstract

Articulating diamond-surfaced spinal implants are disclosed. Materials which may be used to make the spinal implants and manufacturing and finishing techniques for making the implants are also disclosed.

Claims

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 CTE_cd,

said substrate having a coefficient of thermal expansion, CTE_sub,

CTE_cd not being equal to CTE_sub,

said diamond in said sintered polycrystalline diamond table having a modulus M_cd,

said substrate to which said diamond table is sintered having a modulus M_sub,

M_cd not being equal to M_sub,

a residual stress field in said sintered polycrystalline diamond table formed as a result of the difference of said CTE_cd and said CTE_sub and the difference of said M_cd and said M_sub,

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.

2. An implant as recited in claim 1 wherein said first component and said second component are able to articulate with respect to each other to provide rotation about the axial, coronal and/or sagittal axes of the human spine.

3. An implant as recited in claim 1 wherein said first component and said second component are able to articulate with respect to each other to provide translation in the axial plane of a human spine.

4. An implant as recited in claim 1 wherein said first component and said second component are able to articulate with respect to each other to provide rotation about the axial, coronal and/or sagittal axes of the human spine;

and wherein said first component and said second component are able to articulate with respect to each other to provide translation in the axial plane of a human spine;

and wherein said rotation and translation accommodate anterior bending, posterior bending, lateral bending, twisting of a spine about its longitudinal axis, anterior translation, posterior translation and lateral translation.

5. An implant as recited in claim 1 wherein said dome member has a shape that is at least partially spherical convex.

6. An implant as recited in claim 1 wherein said first and second components include congruent bearing surfaces.

7. An implant as recited in claim 1 wherein said first and second components include non-congruent bearing surfaces.

8. An implant as recited in claim 1 wherein said solvent-catalyst metal was used to facilitate sintering of said polycrystalline diamond compact at high temperature and high pressure.

9. An implant as recited in claim 8 wherein said solvent-catalyst metal includes a material selected from the group consisting of Co, Cr and Mo in order to enhance biocompatibility of the implant.

10. An implant recited in claim 8 wherein said solvent-catalyst metal includes CoCr in order to enhance biocompatibility of the implant.

11. An implant as recited in claim 8 wherein said solvent-catalyst metal includes CoCrMo in order to enhance biocompatibility of the implant.

12. An articulating prosthetic spinal implant for implantation between vertebrae in a human body, the implant comprising:

a first body of solid, unitary, free-standing sintered polycrystalline diamond,

said first body being configurated for implanation in a human spine,

a sintered polycrystalline diamond protrusion on said first body,

a protrusion load bearing and articulation surface located on said protrusion,

said protrusion load bearing and articulation surface being formed by a sintered polycrystalline diamond compact being solid diamond that derives its structural integrity solely from its diamond structure rather than from a substrate,

said protrusion having a curvature defined by at least one radius R1,

a second body of solid, unitary, free-standing sintered polycrystalline diamond,

said second body being configurated for implanation in a human spine,

a sintered polycrystalline diamond receptacle on said second body,

a receptacle load bearing and articulation surface located on said receptacle,

said receptacle load bearing and articulation surface being formed by a sintered polycrystalline diamond compact being solid diamond that derives its structural integrity solely from its diamond structure rather than from a substrate,

said receptacle having a curvature defined by at least one radius R2,

a solvent-catalyst metal located in said sintered polycrystalline diamond,

diamond to solvent-catalyst metal bonds between said diamond and said solvent-catalyst metal in said sintered polycrystalline diamond,

a gradient transition zone in said sintered polycrystalline diamond,

said protrusion and said receptacle being sized and curved to accommodate said protrusion protruding into said receptacle, and to accommodate said protrusion load bearing and articulation surface contacting said receptacle load bearing and articulation surface,

said contact of said protrusion with said receptacle being accomplished by diamond to diamond contact of said protrusion and receptacle load bearing and articulation surfaces,

said contact of said protrusion with said receptacle occurring at a diamond to diamond contact point where diamond of said protrusion contacts diamond of said receptacle,

said diamond to diamond contact resulting in diamond on diamond articulation between said protrusion and said receptacle,

said protrusion being translationally movable with respect to said receptacle in the axial plan of a human spine, said translational movement being accomplished by a sliding or rolling movement of diamond against diamond;

wherein R1 and R2 are chosen to accommodate said translational movement; and

wherein at least some of said translational movement occurs in the axial plane of a human spine about an arc of a circle having a radius R3 whose center is located at the base of the spinal process of a human spine, and wherein R3 is not equal to R1 or R2.