Spinal facet joint implant

• US 8,906,063 B2
• Filed: 09/29/2008
• Issued: 12/09/2014
• Est. Priority Date: 02/17/2004
• Status: Active Grant

• Current Assignee: Globus Medical, Inc.
• Original Assignee: Gmedelaware 2 LLC (Globus Medical, Inc.)
• Inventors: Hoy, Robert W., Triplett, Daniel J., Fallin, T. Wade, Chervitz, Alan, Justin, Daniel F.
• Primary Examiner(s): Philogene, Pedro
• Assistant Examiner(s): SUMMITT, LYNNSY M
• Application Number:
  US12/240,320
• Publication Number:
  US 20090030461A1
• Time in Patent Office: 2,262 Days
• Field of Search: 606/60, 606/246, 606/247, 606254-260, 606/279
• 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. A spinal implant kit for replacement of a superior facet and an inferior facet of one or more vertebrae, the spinal implant kit comprising:

a plurality of superior facet prostheses, each of which is selectable to replace the superior facet, wherein each of the superior facet prostheses has an articulating component having an articulating surface with a generally concave shape, a coupling portion having a bone engaging surface with a generally convex shape, an angled flat extending between the articulating component and the coupling portion, and a first dimension, wherein the first dimension varies in magnitude among the superior facet prostheses; and

a plurality of inferior facet prostheses, each of which is selectable to replace the inferior facet, wherein each of the inferior facet prostheses has an articulating surface shaped to articulate against the articulating surface of any of the superior facet prostheses, and a second dimension,

wherein the second dimension varies in magnitude among the inferior facet prostheses, wherein each of the plurality of superior facet prostheses are anteriorly inclined from a longitudinal axis of the spine, when attached thereto, to provide greater clearance between the articulating surfaces when the spine is under flexion, wherein each of the plurality of superior facet prostheses includes a hole defining an axis for receiving a fastener therethrough, wherein the axis does not intersect the articulating surface, and

wherein the each articulating surface of the superior facet prosthesis comprises a uniform radius of curvature and the radius of curvature of each of the articulating surface of the inferior facet prosthesis is non-uniform.

2. The spinal implant kit of claim 1, wherein the superior facet prostheses comprise a first superior facet prosthesis and a second superior facet prosthesis, wherein the first dimension varies in magnitude between the first and second superior facet prostheses, wherein the inferior facet prostheses comprise a first inferior facet prosthesis and a second inferior facet prosthesis, wherein the second dimension varies in magnitude between the first and second inferior facet prostheses.

3. The spinal implant kit of claim 2, wherein the superior facet prostheses further comprise a third superior facet prosthesis and a fourth superior facet prosthesis, wherein the first dimension varies in magnitude between the first, second, third, and fourth superior facet prostheses, wherein the inferior facet prostheses further comprise a third inferior facet prosthesis and a fourth inferior facet prosthesis, wherein the second dimension varies in magnitude between the first, second, third, and fourth inferior facet prostheses.

4. The spinal implant kit of claim 3, wherein the superior facet prostheses further comprise fifth, sixth, seventh, eighth, and ninth superior facet prostheses, wherein the inferior facet prostheses further comprise fifth, sixth, seventh, eighth, ninth, and tenth inferior facet prostheses.

5. The spinal implant kit of claim 1, wherein each of the superior facet prostheses has a third dimension that varies in magnitude among the superior facet prostheses independently of the first dimension, wherein each of the inferior facet prostheses has a fourth dimension that varies in magnitude among the inferior facet prostheses independently of the second dimension.

6. The spinal implant kit of claim 1, wherein the first dimension is selected from the group consisting of a resection angle (α

) defining an orientation of a flat surface positioned to lie against a resection surface of the vertebra, and a facet angle (β

) defining an orientation of the articulating surface.

7. The spinal implant kit of claim 6, wherein α

and β

vary in magnitude among the superior facet prostheses independently of each other.

8. The spinal implant kit of claim 7, wherein α

ranges in magnitude from about 30°

to about 70° and

β

ranges from about 60°

to about 100°

.

9. The spinal implant kit of claim 1, wherein the articulating surface of each of the inferior facet prostheses comprises a center of an articulation radius, wherein each of the inferior facet prostheses further comprises an implant pedicle saddle point positioned to substantially overlie a pedicle saddle point (S1) of the vertebra when the inferior facet prosthesis is attached to the vertebra, wherein the second dimension is selected from the group consisting of a resection angle (Iα

) defining an orientation of a flat surface positioned to lie against a resection surface of the resected vertebra, and a z offset (Z) between S1 and the center of the articulation radius.

10. The spinal implant kit of claim 9, wherein Iα

and Z vary in magnitude among the superior facet prostheses independently of each other.

11. The spinal implant kit of claim 10, wherein Iα

ranges in magnitude from about 30°

to about 70° and

Z ranges from about 20 mm to about 40 mm.

12. The spinal implant kit of claim 1, wherein at least one of the superior facet prostheses comprises a bearing surface mounted to a substrate of the articulating surface, and the bearing surface is of a different material from the substrate.

13. The spinal implant kit of claim 12, wherein the bearing surface comprises a ceramic and the substrate comprises a metal alloy.

14. The spinal implant kit of claim 1, wherein a second axis extends perpendicularly to the axis of the hole, and the articulating component is in a fixed position relative to the coupling portion along the second axis.

15. The spinal implant kit of claim 1, wherein the articulating surface is angled relative to the axis of the hole.