Multiple axis intervertebral prosthesis

• US 6,146,421 A
• Filed: 01/19/1999
• Issued: 11/14/2000
• Est. Priority Date: 08/04/1997
• Status: Expired due to Fees

• Current Assignee: Gordon, Maya, Roberts And Thomas, Number 1, LLC
• Original Assignee: Gordon, Maya, Roberts And Thomas, Number 1, LLC
• Inventors: Roberts, Rick D., Maya, William E., Thomas, James C. Jr., Gordon, Dennis P.
• Primary Examiner(s): Milano, Michael J.
• Application Number:
  US09/233,566
• Time in Patent Office: 665 Days
• Field of Search: 623/17.11, 623/17.16, 606/61
• US Class Current: 623/17.15
• CPC Class Codes: A61B 17/68 Internal fixation devices , including fasteners and spinal fixators, even if a part thereof projects from the skin bone staples A61B17/0642
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence
• CPC Class Codes: A61B 17/86 Pins or screws or threaded wires; nuts therefor A61B17/72 take precedence
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2/4425 made of articulated components
• CPC Class Codes: A61F 2002/3013 figure-"8"- or hourglass-shaped
• CPC Class Codes: A61F 2002/302 toroidal, e.g. rings
• CPC Class Codes: A61F 2002/30225 Flat cylinders, i.e. discs
• CPC Class Codes: A61F 2002/3023 wedge-shaped cylinders
• CPC Class Codes: A61F 2002/30578 having apertures, e.g. for receiving fixation screws
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30662 with rotation-limiting means
• CPC Class Codes: A61F 2002/30777 Oblong apertures
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/3079 Stepped or enlarged apertures, e.g. having discrete diameter changes
• CPC Class Codes: A61F 2002/30934 Special articulating surfaces
• CPC Class Codes: A61F 2002/443 having two transversal endplates and at least one intermediate component
• CPC Class Codes: A61F 2002/4631 the prosthesis being specially adapted for being cemented
• CPC Class Codes: A61F 2230/001 Figure-8-shaped, e.g. hourglass-shaped
• CPC Class Codes: A61F 2230/0065 : toroidal, e.g. ring-shaped, doughnut-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2310/00011 : Metals or alloys
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00592 : Coating or prosthesis-covering structure made of ceramics or of ceramic-like compounds

Abstract

The present invention relates to an intervertebral prosthetic disk. The prosthesis includes a male component with a support plate, an attachment element allowing fixation to a vertebra, and an articulating projection defining a concave lower surface. The prosthesis also includes a female component with a support plate, an attachment element allowing fixation to a vertebra, and a circular pocket with a flat bottom and angled walls suitable for receiving the articulating projection. A generally hemispheric bearing is provided between the male and female components. The hemispheric bearing includes an upper convex surface for cooperating with the concave lower surface of the articulating projection of the male component and a flat lower surface for cooperating with the flat bottom surface of the circular pocket of the female component. The male component is placed inside the female component with the hemispheric bearing between the two components and the male and female components are attached to adjacent vertebrae and act as a replacement for a disk. The prosthesis allows for a natural range of motion for the patient.

Claims

1. An intervertebral prosthetic disk comprising:

a male component comprising a first support plate, a first attachment element allowing fixation to a vertebra, and an articulating projection, the articulating projection defining a concave lower bearing surface;

a female component comprising a second support plate, a second attachment element allowing fixation to a vertebra, and a circular pocket with a flat bottom bearing surface having a first diameter and angled walls suitable for receiving the articulating projection; and

a bearing comprising a convex upper bearing surface adapted to engage the concave bearing surface of the male component and a flat lower bearing surface with a second diameter smaller than the first diameter of the flat bottom bearing surface of the female component adapted to engage the flat bottom bearing surface of the female component.

2. The prosthetic disk of claim 1, wherein the first and second attachment elements each comprise at least one vertical flange extending from the support plate and contain at least one opening through which a mechanical attachment element can pass.

3. The prosthetic disk of claim 2, wherein the mechanical attachment element is selected from the group consisting of screws, pegs and rods.

4. The prosthetic disk of claim 3 wherein for both the male and female components, the number of openings and mechanical attachment elements is at least two.

5. The prosthetic disk of claim 1, wherein each of the first and second attachment elements comprises a porous coating for permanent bony fixation on a bone-facing surface of the respective support plate.

6. The prosthetic disk of claim 1, wherein the first and second attachment elements each comprise at least one flange, at least one mechanical attachment element, and a porous coating on a bone-facing surface of the respective support plate.

7. The prosthetic disk in claim 1, wherein the first support plate is wedge shaped to facilitate building lordosis.

8. The prosthetic disk of claim 1, wherein at least one of the components is made of a material selected from the group consisting of ceramics and metal alloys.

9. The prosthetic disk of claim 1, wherein the articulating projection is doughnut shaped to facilitate range of motion.

10. The prosthetic disk of claim 7 wherein the wedge shaped plate defines a recessed, angled hole through which an attachment element can pass.

11. The prosthetic disk of claim 10 wherein the attachment element is a screw.

12. The prosthetic disk of claim 1 wherein the second support plate comprises a recessed, angled hole through which an attachment element can pass.

13. The prosthetic disk of claim 12 wherein the attachment element is a screw.

14. An intervertebral prosthetic disk comprising:

a male component comprising an articulating projection with a double radius and a concave bearing surface;

a bearing comprising a convex upper surface for engagement with the concave bearing surface of the male component and a lower surface opposite the upper surface; and

a female component comprising a pocket adapted to receive the articulating projection of the male component and the lower surface of the bearing so that the bearing is laterally moveable within the pocket.

15. An intervertebral prosthetic disk recited in claim 14 wherein a coating or insert is provided on the inside surface of the pocket.

16. The intervertebral prosthetic disk recited in claim 14 wherein the bearing is of a generally hemispheric shape.

17. An prosthetic disk for insertion between first and second adjacent vertebrae comprising:

a first component comprising a first plate for fixation to the first vertebra and a rounded projection extending from the first plate away from the first vertebra, the projection defining a concave bearing surface distal the first plate;

a bearing comprising a convex surface for engagement with the concave bearing surface of the first component and a generally flat surface having a first diameter opposite the convex surface; and

a second component comprising a second plate for fixation to the second vertebra and a cup extending from the second plate away from the second vertebra, the cup defining an angled circular side wall for engagement with the rounded projection and a generally flat lower surface having a second diameter greater than the first diameter of the bearing for engaging the generally flat surface of the bearing so that the bearing is laterally moveable on the flat lower surface of the cup.

18. The prosthetic disk recited in claim 17 wherein the bearing is of a generally hemispheric shape.

19. The prosthetic disk recited in claim 17 wherein one of the first and second plates is wedge shaped.

20. The prosthetic disk recited in claim 17 wherein each of the first and second plates further includes a flange to assist in fixing the plate to the respective vertebra.

21. An intervertebral prosthetic disk comprising:

a male component comprising a first support plate, a first attachment element allowing fixation to a vertebra, and an articulating projection, the articulating projection defining a concave lower bearing surface;

a female component comprising a second support plate, a second attachment element allowing fixation to a vertebra, and a circular pocket with a flat bottom bearing surface and angled walls suitable for receiving the articulating projection; and

a bearing comprising a convex upper bearing surface adapted to engage the concave bearing surface of the male component and a flat lower bearing surface adapted to engage the flat bottom bearing surface of the female component;

wherein the articulating projection of the male component is supported both on the walls of the circular pocket of the female component and on the convex upper bearing surface of the bearing; and

wherein movement occurs between the articulating projection of the male component and the circular pocket of the female component, between the convex upper surface of the bearing and the concave lower bearing surface of the articulating projection, and through movement of the bearing within the pocket.

22. An intervertebral prosthetic disk comprising:

a male component comprising an articulating projection with a double radius and a concave bearing surface;

a bearing comprising a convex upper surface for engagement with the concave bearing surface of the male component and a lower surface opposite the upper surface; and

a female component comprising a pocket adapted to receive the articulating projection of the male component and the lower surface of the bearing;

wherein the articulating projection of the male component is supported both on the walls of the pocket of the female component and on the convex upper surface of the bearing and movement occurs between the articulating projection of the male component and the pocket of the female component, between the convex upper surface of the bearing and the concave lower bearing surface of the articulating projection, and through movement of the bearing within the pocket.