Low wear artificial spinal disc

• US 5,676,701 A
• Filed: 06/07/1995
• Issued: 10/14/1997
• Est. Priority Date: 01/14/1993
• Status: Expired due to Term

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: Smith & Nephew Incorporated (Smith & Nephew PLC)
• Inventors: Small, Laura C., Carls, Thomas A., Davidson, James A., Lin, Chih-I, Yuan, Hansen A.
• Primary Examiner(s): BRITTINGHAM, DEBRA
• Application Number:
  US08/480,762
• Time in Patent Office: 860 Days
• Field of Search: 623/16, 623/17, 606/60, 606/61
• US Class Current: 623/17.15
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/4425 made of articulated components
• CPC Class Codes: A61F 2002/30016 differing in hardness, e.g. Vickers, Shore, Brinell
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30398 Sliding
• CPC Class Codes: A61F 2002/30649 Ball-and-socket joints
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30892 parallel
• CPC Class Codes: A61F 2002/30922 Hardened surfaces
• CPC Class Codes: A61F 2002/443 having two transversal endplates and at least one intermediate component
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0015 Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2250/0019 differing in hardness, e.g. Vickers, Shore, Brinell
• 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 2310/00089 Zirconium or Zr-based alloys
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00449 Coating made of chromium or Cr-based alloys
• CPC Class Codes: A61L 27/045 Cobalt or cobalt alloys
• CPC Class Codes: Y10S 606/907 : Composed of particular material or coated

Abstract

An artificial spinal disc for surgical placement between adjacent vertebrae including a first component for attaching to a first vertebrae, the first component having a concave recess, with the concave contoured surface having a circumference of 360°. A second component for attaching to a second vertebrae, the second component including a projection with a convex surface, the convex contoured surface having a circumference of 360°. The corresponding contoured surfaces shaped to allow an unrestricted rotational and a flexion/extension bending motion between the first and second components relative to a patient'"'"'s normal spinal axis when in a standing position with the spine in a straightened position.

Claims

1. An artificial spinal disc for surgical placement between first and second adjacent vertebrae of a patient'"'"'s spine, comprising:

(a) a first component for attaching to the first vertebrae, said first component including a concave recess, the concave recess having a contoured surface with a circumference of 360°

;

(b) a second component for attaching to the second vertebrae, said second component including a projection that fits the concave recess of the first component, said projection having a convex contoured surface with a circumference of 360°

;

(c) the corresponding contoured surfaces being configured so as to allow an unrestricted rotational and a flexion/extension bending motion between the first and second components relative to a patient'"'"'s normal spinal axis when in a standing position with the spine in a straightened position, said corresponding contoured surfaces allowing for a flexion/extension angle of about between 20°

to 30°

.

2. The artificial spinal disc of claim 1, wherein the contoured surface of at least one component is formed from a chromium-containing metal having a chromium content in excess of about 15 weight percent.

3. The artificial spinal disc of claim 1, wherein at least one contoured surface is formed from a cobalt-chromium-molybdenum alloy.

4. The artificial spinal disc of claim 1, wherein both contoured surfaces are formed from a cobalt-chromium-molybdenum alloy.

5. The artificial spinal disc of claim 1, wherein the first and second component include anchoring means for attachment to the respective first and second vertebrae.

6. The artificial spinal disc of claim 5, wherein the anchoring means is selected from the group consisting of pegs, posts and screws.

7. The artificial spinal disc of claim 5, wherein the anchoring means includes a surface selected from the group consisting of a porous-coated and a macro-textured surface to facilitate bone ingrowth.

8. An artificial spinal disc of claim 1, wherein the components are generally oval in shape with the contoured surfaces being positioned approximately in the center of the component.

9. An artificial spinal disc of claim 1, wherein the first and second components are configured so as to allow the artificial spinal disc to be implanted as one unit in which over distraction is eliminated.

10. An artificial spinal disc for surgical placement between first and second adjacent vertebrae of a patient'"'"'s spine, comprising:

(a) a first component for attaching to the first vertebrae, said first component including a concave recess, the concave recess having a contoured surface with a circumference of 360°

;

(b) a second component for attaching to the second vertebrae, said second component including a projection that fits the concave recess of the first component, said projection having a convex contoured surface with a circumference of 360°

;

(c) the corresponding contoured surfaces being configured so as to allow an unrestricted rotational and a flexion/extension bending motion between the first and second components relative to a patient'"'"'s normal spinal axis when in a standing position with the spine in a straightened position, said corresponding contoured surfaces allowing for a flexion/extension angle of about between 20°

to 30°

;

(d) wherein the first and second components are configured so as to allow the artificial spinal disc to be implanted as one unit in which openings in bone of the adjacent vertebrae are created in order to allow the artificial spinal disc to be slid into place so as to prevent over distraction.