Artificial intervertebral disc

• US 6,626,943 B2
• Filed: 08/23/2002
• Issued: 09/30/2003
• Est. Priority Date: 08/24/2001
• Status: Expired due to Term

• Current Assignee: Zimmer GmbH (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Sulzer Orthopedics Inc. (Centerpulse Orthopedics Incorporated)
• Inventors: Fröhlich, Markus, Casutt, Simon, Eberlein, Robert
• Primary Examiner(s): SNOW, BRUCE EDWARD
• Application Number:
  US10/226,517
• Publication Number:
  US 20030045940A1
• Time in Patent Office: 403 Days
• Field of Search: 623/17.11, 623/17.12, 623/17.13, 623/17.14, 623/17.15, 606/61
• US Class Current: 623/17.15
• 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 2002/30014 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30383 made by laterally inserting a protrusion, e.g. a rib into a complementarily-shaped groove
• 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 2002/30451 soldered or brazed or welded
• CPC Class Codes: A61F 2002/30495 using a locking ring
• CPC Class Codes: A61F 2002/30517 using a locking plate
• 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 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30879 Ribs
• CPC Class Codes: A61F 2002/30884 Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/30909 Nets
• CPC Class Codes: A61F 2002/30975 made of two halves
• 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 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 2220/0058 soldered or brazed or welded
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0018 : differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys

Abstract

The invention relates to an artificial intervertebral disc for implantation between two vertebral bodies (W) comprising two end plates (1, 2) and an elastically deformable disc (3) pre-stressed between the end plates (1, 2) in the axial direction, with the disc (3) lying within a tubular, elastically deformable, fibre ring (4) and the end plates (1, 2) being in tensile communication with the fibre ring (4). The disc (3) has a contact surface (5, 6) which enlarges with a compression of the artificial intervertebral disc and which adjoins one of the end plates (1, 2) so that the elastic properties of the artificial intervertebral disc show a non-linear behaviour with increasing deformation at least with respect to a compression force (F).

Claims

1. An artificial intervertebral disc for implantation between two vertebral bodies (W) comprising two end plates (1, 2) and an elastically deformable disc (3) pre-stressed between the end plates (1, 2) in the axial direction, with the disc (3) lying within a tubular, elastically deformable, fibre ring (4) and the end plates (1, 2) being in tensile connection with the fibre ring (4), wherein the disc (3) has a contact surface (5, 6) with one of the adjoining end plates (1, 2) which enlarges with a compression of the artificial intervertebral disc, and the elastic properties of the artificial intervertebral disc shown a non-linear behavior with increasing deformation at least with respect to a compression force (F).

2. An artificial intervertebral disc in accordance with claim 1, wherein the value for the stiffness of the artificial intervertebral disc under a compression force (F) of 2,500 N lies in a range between 1,700 N/mm and 4,500 N/mm.

3. An artificial intervertebral disc in accordance with claim 1, wherein the shear modulus of the disc (3) increases in the radial direction such that the stiffness of the artificial intervertebral disc likewise increases with an increasing compression force (F).

4. An artificial intervertebral disc in accordance with claim 1, wherein the fibre ring (4) consists of a fabric, a knitted fabric or a braid and comprises one or more layers.

5. An artificial intervertebral disc in accordance with claim 1, wherein the materials building up the fibre ring (4) comprise one or more plastics such as polyamide, polyimide, carbon fibres or polyether etherketone (PEEK), preferably polyethylene terephthalate (PET).

6. An artificial intervertebral disc in accordance with claim 1, wherein the disc (3) comprises two concentrically arranged ring parts (7, 8) mutually effectively fixedly connected.

7. An artificial intervertebral disc in accordance with claim 1, wherein the materials building up the disc (3) comprise silicon elastomers or rubber materials.

8. An artificial intervertebral disc in accordance with claim 1, wherein the end plates (1, 2) consist of a metal, preferably of titanium, of a titanium alloy or of plastic.

9. An artificial intervertebral disc in accordance with claim 1, wherein the end plates (1, 2) are formed as anchoring platforms in order to achieve a growing together of the adjoining vertebral bodies (W) with the outwardly directed areas (9, 10) of the end plates (1, 2).

10. An artificial intervertebral disc in accordance with claim 1, at which one of the end plates (1, 2) has a groove (11, 12) extending in the peripheral direction in order to receive the fibre ring (4).

11. An artificial intervertebral disc in accordance with claim 10, at which the fibre ring (4) is pressed in one of the grooves (11, 12) by cold forming (V) for the connection to one of the end plates (1, 2).

12. An artificial intervertebral disc in accordance with claim 10, at which the fibre ring (4) is fixed by an annular clamping element (13) in one of the grooves (11, 12) for the connection to one of the end plates (1, 2).

13. An artificial intervertebral disc in accordance with claim 1, at which the fibre ring (4) is fixed by a holding element (14), preferably by means of a screw connection (15), for the connection to one of the end plates (1, 2).

14. An artificial intervertebral disc in accordance with claim 10, at which the fibre ring (4) is adhesively bonded or welded in one of the grooves (11, 12) for the connection to one of the end plates (1, 2).

15. An artificial intervertebral disc in accordance with claim 10, at which the fibre ring (4) is injection moulded with plastic in an annular manner in one of the grooves (11, 12) of the end plates (1, 2) for the connection to one of the end plates (1, 2).

16. An artificial intervertebral disc in accordance with claim 1, at which the fibre ring (4) is injection moulded with plastic for the connection to one of the end plates (1, 2) at one of the surfaces (9, 10) thereof.

17. An artificial intervertebral disc in accordance with claim 1, wherein the end plates (1, 2) have a projecting central rib (16), which extends.

18. An artificial intervertebral disc in accordance with claim 1, wherein the end plates (1, 2) have a toothed arrangement (17) directed to the vertebra (W) at its outer rim such that a form-locked connection is achieved by the ingrowth of bone material for the transmission of torsional, bending and shear forces.

19. An artificial intervertebral disc in accordance with claim 1, wherein the pre-stress under which the disc (3) is put by the fibre ring (4) in the unloaded state is so high that with a maximum pressure stress, the fibre ring (4) still always has a positive residual stress in the tension direction.