Spinal facet implant with spherical implant apposition surface and bone bed and methods of use

• US 7,588,590 B2
• Filed: 06/02/2004
• Issued: 09/15/2009
• Est. Priority Date: 12/10/2003
• Status: Active Grant

• Current Assignee: Globus Medical, Inc.
• Original Assignee: Facet Solutions, Inc. (Globus Medical, Inc.)
• Inventors: Justin, Daniel F., Hoy, Robert W., Triplett, Daniel J., Fallin, T. Wade, Chervitz, Alan
• Primary Examiner(s): Robert; Eduardo C
• Assistant Examiner(s): HAMMOND, ELLEN CHRISTINA
• Application Number:
  US10/860,778
• Publication Number:
  US 20050131545A1
• Time in Patent Office: 1,931 Days
• Field of Search: 606/61, 606/247, 623 1711- 1716
• US Class Current: 606/247
• CPC Class Codes: A61B 17/7049 Connectors, not bearing on the vertebrae, for linking longitudinal elements together A61B17/7055, A61B17/7053, A61B17/7019 take precedence
• CPC Class Codes: A61B 17/7064 Devices acting on, attached to, or simulating the effect of, vertebral facets; Tools therefor
• CPC Class Codes: A61B 17/7067 Devices bearing against one or more spinous processes and also attached to another part of the spine; Tools therefor
• CPC Class Codes: A61B 17/8625 Shanks, i.e. parts contacting bone tissue
• CPC Class Codes: A61B 17/8695 Washers surrounding screw head in plate hole A61B17/8047, between bone plate and bone A61B17/8028
• CPC Class Codes: A61B 2017/8655 with special features for locking in the bone
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2/4405 for apophyseal or facet joints, i.e. between adjacent spinous or transverse processes devices implanted between spinous or transverse processes A61B17/7062
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/30125 elliptical or oval
• CPC Class Codes: A61F 2002/30154 square
• CPC Class Codes: A61F 2002/30156 triangular
• CPC Class Codes: A61F 2002/30171 rosette- or star-shaped
• CPC Class Codes: A61F 2002/30179 X-shaped
• CPC Class Codes: A61F 2002/30426 Bayonet coupling
• CPC Class Codes: A61F 2002/30433 using additional screws, bolts, dowels, rivets or washers e.g. connecting screws
• CPC Class Codes: A61F 2002/30448 using adhesives
• CPC Class Codes: A61F 2002/30514 using a locking washer
• CPC Class Codes: A61F 2002/30574 with an integral complete or partial collar or flange
• CPC Class Codes: A61F 2002/30576 with extending fixation tabs
• CPC Class Codes: A61F 2002/30578 : having apertures, e.g. for receiving fixation screws
• CPC Class Codes: A61F 2002/30579 : with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30616 : Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30663 : multiaxial, e.g. biaxial; multipolar, e.g. bipolar or having an intermediate shell articulating between the ball and the socket
• CPC Class Codes: A61F 2002/3082 : Grooves
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/3085 : with a threaded, e.g. self-tapping, bone-engaging surface, e.g. external surface
• CPC Class Codes: A61F 2002/30934 : Special articulating surfaces
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0041 : using additional screws, bolts, dowels or rivets, e.g. connecting screws
• CPC Class Codes: A61F 2220/005 : using adhesives
• CPC Class Codes: A61F 2230/0008 : elliptical or oval
• CPC Class Codes: A61F 2230/0021 : square
• CPC Class Codes: A61F 2230/0023 : triangular
• CPC Class Codes: A61F 2230/005 : Rosette-shaped, e.g. star-shaped
• 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 2310/00131 : Tantalum or Ta-based alloys
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00203 : containing alumina or aluminium oxide
• CPC Class Codes: A61F 2310/00239 : containing zirconia or zirconium oxide ZrO2
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite
• CPC Class Codes: A61F 2310/00928 : Coating or prosthesis-covering structure made of glass or of glass-containing compounds, e.g. of bioglass

Abstract

Superior and/or inferior facets of one or more facet joints may be replaced by superior and/or inferior facet joint prostheses. In one embodiment, a kit of superior or inferior prostheses is provided, in which the prostheses have at least two dimensions that vary among members of the kit independently of each other. Each prosthesis may have a bone engaging surface having a surface that is polyaxially rotatable against a corresponding resection of a vertebra. Each prosthesis may also have an articulating surface shaped such that, after attachment to the spine, the replaced or partially replaced facet joints provide a larger medial-lateral range of motion when the spine is flexed than when the spine is extended. Crosslinks may be used to connect left and right prosthesis together in such a manner that they are stabilized in a position in which they are seated directly against the vertebra.

Claims

1. An implant for replacing at least a portion of a facet of a mammalian vertebra, the implant comprising:

a fixation element implantable into the vertebra;

a coupling portion shaped to be coupled to the vertebra, the coupling portion having a curved bone engaging surface shaped to engage a resection in the vertebra in such a way as to selectively allow polyaxial rotation of the coupling portion against the resection prior to fixation of the coupling portion with respect to the resection, the curved bone engaging surface having a curvature which intersects an aperture shaped to receive the fixation element;

a fastener for coupling the coupling portion to the resection, the fastener having a connection feature to connect the fastener directly to the fixation element, the fastener further having an implant engaging end to thrust against the coupling portion, the implant engaging end having a shape generally conforming to a fastener engaging surface of the coupling portion proximate thereto; and

an articulating surface attached to the coupling portion, wherein the articulating surface is shaped and positioned to articulate against a second facet surface.

2. The implant of claim 1, wherein the fixation element comprises a porous coating that facilitates bone ingrowth.

3. The implant of claim 2, wherein the porous coating comprises a substance selected from the group consisting of osteoconductive, osteoinductive and osteogenic substances.

4. The implant of claim 1, wherein the bone engaging surface of the coupling portion comprises a porous coating that facilitates bone ingrowth.

5. The implant of claim 4, wherein the porous coating comprises a substance selected from the group consisting of osteoconductive, osteoinductive and osteogenic substances.

6. The implant of claim 1, wherein the bone engaging surface is shaped to engage the resection in such a way as to selectively allow tri-axial rotation of the coupling portion against the vertebra.

7. The implant of claim 6, wherein the bone engaging surface of the coupling portion is shaped to protrude into the vertebra to engage an inversely-shaped portion of the resection.

8. The implant of claim 7, wherein the bone engaging surface of the coupling portion has a generally semispherical shape and the inversely-shaped portion of the resection comprises a generally semispherical shape.

9. The implant of claim 6, wherein the coupling portion is selectively polyaxially movable with respect to the fixation element.

10. The implant of claim 9, wherein the fixation element extends through the aperture of the coupling portion, the aperture having a diameter larger than an outer diameter of the fixation element adjacent to the aperture, wherein the outer diameter is taken in a direction perpendicular to a longitudinal axis of the fixation element.

11. The implant of claim 1, wherein the implant engaging end is deformable under pressure to conform to the fastener engaging surface of the coupling portion proximate thereto.

12. The implant of claim 1, wherein the articulating surface is constructed of a material selected from the group consisting of a polymeric bearing material attached to a metal substrate, a ceramic bearing material, a metal bearing material, and combinations thereof.

13. The implant of claim 12, wherein the articulating surface comprises a proximal end positioned relatively nearer the vertebra, a distal end positioned relatively further from the vertebra, wherein the articulating surface curves such that the proximal and distal ends both extend away from the coupling portion.

14. The implant of claim 1, wherein the articulating surface comprises a convex shape.

15. The implant of claim 1, wherein a component selected from the group consisting of the fixation element and a nut coupled to the fixation element is actuatable to fix a position and orientation of the bone contacting surface with respect to the resection.

16. The implant of claim 1, wherein the coupling portion is separate from the fixation element and is shaped to be gripped against the vertebra by the fixation element.

17. The implant of claim 1, wherein the connection feature comprises threads.

18. An implant for replacing at least a portion of a facet of a mammalian vertebra, the implant comprising:

a fixation element implantable into the vertebra;

a coupling portion shaped to be coupled to the vertebra, the coupling portion having a bone engaging surface having a semispherical convex shape for engaging a semispherical concave resection of the vertebra in such a way as to selectively allow polyaxial pivotal movement of the coupling portion against the resection prior to coupling the coupling portion to the resection, the bone engaging surface intersecting an aperture shaped to receive the fixation element;

a fastener for coupling the coupling portion to the resection, the fastener connecting directly to the fixation element, the fastener further having an implant engaging end to thrust against the coupling portion, the implant engaging end having a shape generally conforming to a fastener engaging surface of the coupling portion proximate thereto; and

an articulating surface attached to the coupling portion, wherein the articulating surface is shaped and positioned to articulate against a second facet surface.

19. The implant of claim 18, wherein the coupling portion is selectively polyaxially moveable with respect to the fixation element.

20. The implant of claim 19, wherein the aperture has a diameter larger than an outer diameter of the fixation element adjacent to the aperture, wherein the outer diameter is taken in a direction perpendicular to a longitudinal axis of the fixation element.

21. The implant of claim 18, wherein connecting directly to the fixation element comprises threading directly to the fixation element.