Intervertebral motion disc having articulation and shock absorption

• US 7,156,876 B2
• Filed: 10/08/2003
• Issued: 01/02/2007
• Est. Priority Date: 10/09/2002
• Status: Active Grant

• Current Assignee: Depuy Spine Incorporated (Johnson & Johnson)
• Original Assignee: Depuy Acromed Incorporated (Johnson & Johnson)
• Inventors: Hawkins, John Riley, Moumene, Missoum
• Primary Examiner(s): Robert; Eduardo C.
• Assistant Examiner(s): Reimers; Annette R.
• Application Number:
  US10/681,473
• Publication Number:
  US 20040073310A1
• Time in Patent Office: 1,182 Days
• Field of Search: 623/17.11, 623/17.12, 623/17.13, 623/17.14, 623/17.15, 623/17.16, 606/61
• US Class Current: 623/17.13
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• 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 2002/30563 having elastic means or damping means, different from springs, e.g. including an elastomeric core or shock absorbers
• CPC Class Codes: A61F 2002/30682 Means for preventing migration of particles released by the joint, e.g. wear debris or cement particles
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30904 serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/30917 for avoiding direct contact between bone and implant, e.g. extensible membrane for preventing contamination or for easy removal
• 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 2310/00203 containing alumina or aluminium oxide
• CPC Class Codes: A61F 2310/00239 containing zirconia or zirconium oxide ZrO2

Abstract

A motion disc having an intermediate portion including a central articulating core component adapted to maintain the proper intervertebral spacing and a peripheral shock-absorbing component.

Claims

1. A motion disc comprising:

a) a first prosthetic vertebral endplate comprising;

i) an first outer surface having a porous coating thereon and adapted to mate with a first vertebral body,

ii) an first inner surface comprising an first peripheral surface and a first articulation surface,

iii) a body portion connecting the first inner and outer surfaces,

b) a second prosthetic vertebral endplate comprising;

i) an second outer surface having a porous coating thereon and adapted to mate with a second vertebral body, and

ii) an second inner surface comprising a second peripheral surface and a second articulation surface,

iii) a body portion connecting the second inner and outer surfaces,

c) an articulating core member adapted to maintain intervertebral spacing and comprising;

i) a first articulation surface adapted for articulation with the first articulation surface of the first endplate, and

ii) a second articulation surface adapted for articulation with the first articulation surface of the second endplate,

wherein the articulating core member is disposed between the prosthetic endplates and oriented to produce a first articulation interface between the first articulation surface of the first endplate and the first articulation surface of the core member, and a second articulation interface between the first articulation surface of the second endplate and the second articulation surface of the core member, and

d) a peripheral shock-absorbing component comprising;

i) a first surface contacting the first peripheral surface of the first endplate, and

ii) a second surface contacting the second peripheral surface of the second endplate,

wherein the core component is selected from the group consisting of polyethylene, PEEK, ceramic and metals, and

wherein the shock-absorbing component comprises an elastomer, and

wherein each peripheral surface of the shock-absorbing component is tenaciously attached to the respective inner surface of each endplate.

2. The disc of claim 1 wherein each of the first and second articulation surfaces of the core component is convex.

3. The disc of claim 1 wherein each endplate is made of a non-metallic material.

4. The disc of claim 1 wherein each endplate is made of a polymer composite material.

5. The disc of claim 1 wherein each endplate is made of a PEEK-carbon fiber composite material.

6. The disc of claim 1 wherein the body portion of each endplate comprises a posterior portion and an anterior portion, wherein the anterior portion is thicker than the posterior portion, thereby providing lordosis.

7. The disc of claim 6 wherein the lordosis produces an angle of between 5 and 20 degrees.

8. The disc of claim 1 wherein the body portion of each endplate comprises a posterior portion and an anterior portion, wherein the anterior portion is equal in thickness to the posterior portion.

9. The disc of claim 1 wherein the interior surface of each opposed endplate comprises a channel adapted to closely receive the peripheral shock-absorber.

10. The disc of claim 1 wherein the peripheral shock absorbing component comprises a posterior portion and an anterior portion, wherein the anterior portion is thicker than the posterior portion, thereby providing lordosis.

11. The disc of claim 1 further comprising a sheath adapted to at least partially enclose the articulation surfaces.

12. The disc of claim 1 further comprising:

e) a second articulating core member comprising;

i) a first articulation surface adapted for articulation with the first articulation surface of the first endplate, and

ii) a second articulation surface adapted for articulation with the first articulation surface of the second endplate,

wherein the second articulating core member is disposed between the prosthetic endplates and oriented to produce a third articulation interface between the first articulation surface of the first endplate and the first articulation surface of the second articulating core member, and a fourth articulation interface between the first articulation surface of the second endplate and the second articulation surface of the second articulating core member.

13. The disc of claim 1 further comprising:

e) a second peripheral shock-absorbing component comprising;

i) a first surface contacting the first peripheral surface of the first endplate, and

ii) a second surface contacting the second peripheral surface of the second endplate.

14. The disc of claim 1 further comprising:

e) a lubricant disposed upon the first articulation interface.