Intervertebral implant

• US 20060265075A1
• Filed: 04/14/2003
• Published: 11/23/2006
• Est. Priority Date: 04/14/2003
• Status: Active Grant

• Current Assignee: Synthes USA LLC (Johnson & Johnson)
• Original Assignee: Synthes USA LLC (Johnson & Johnson)
• Inventors: Burri, Adrian, Wymann, Martin, Gago Ho, Mario, Baumgartner, Daniel
• Granted Patent: US 7,429,270 B2
• Time in Patent Office: Days
• US Class Current: 623/17.160
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/441 made of inflatable pockets or chambers filled with fluid, e.g. with hydrogel
• 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 2002/30009 differing in fibre orientations
• CPC Class Codes: A61F 2002/30448 using adhesives
• CPC Class Codes: A61F 2002/30462 retained or tied with a rope, string, thread, wire or cable
• 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 2002/30581 having a pocket filled with fluid, e.g. liquid
• CPC Class Codes: A61F 2002/30827 Plurality of grooves
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/4495 having a fabric structure, e.g. made from wires or fibres
• CPC Class Codes: A61F 2220/005 using adhesives
• CPC Class Codes: A61F 2220/0075 sutured, ligatured or stitched, retained or tied with a rope, string, thread, wire or cable
• CPC Class Codes: A61F 2250/0028 differing in fibre orientations
• CPC Class Codes: A61F 2310/00023 Titanium or titanium-based alloys, e.g. Ti-Ni alloys

Abstract

Disclosed is an intervertebral implant (1) comprising a central axis (2), a bottom cover plate (3) and a top cover plate (4), which are respectively provided with an exterior surface (7; 8) that extends transversal to the central axis (2), and a central part (10). Said central part (10) is located between the cover plates (3; 4) and is provided with a sleeve (12) encompassing a fiber system (5) that is connected to the cover plates (3; 4) and is embedded in an enveloping body (25) made of a homogeneous material. In analogy with the anatomic structure of the natural disk, the inventive intervertebral implant (1) can transfer occurring compressive forces onto the cover plates (3, 4) thereof as tensile forces that are applied to the individual fibers of the fiber system (5) thereof.

Claims

1. An intervertebral implant (1) with a central axis (2), comprising

A) a bottom cover plate (3) and a top cover plate (4), each with an external surface (7, 8) extending transversely to the central axis (2),

B) a central part (10) with a sheathing (12) that surrounds a fibre system (5) provided between the cover plates (3, 4), wherein

C) the fibre system (5) is joined with the cover plates (3, 4) at least partially, characterised in that

D) the fibre system (5) is guided over the external surfaces (7, 8) of both cover plates (3, 4) and surrounds at least partially the central part as well as both cover plates (3, 4), and

E) the sheathing (12) comprises an elastic sheathing body (25) that surrounds the central part (10) on the periphery and is made from a homogeneous material and is passed through by the fibre system (5).

2. An intervertebral implant (1) according to claim 1, characterised in that the entire fibre system is embedded in the elastic sheathing body (25).

3. An intervertebral implant (1) according to claim 1, characterised in that the fibre system is only partially embedded in the elastic sheathing body (25).

4. An intervertebral implant (1) according to claim 3, characterised in that the fibre system (5) has a radial thickness δ

relative to the central axis (2) and the sheathing body (25) has a radial thickness d, and the δ

d×

100% ratio is in a range between 80% and 350%.

5. An intervertebral implant (1) according to any one of claims 1 to 4, characterised in that the fibre system (5) can move relative to the sheathing body (25).

6. An intervertebral implant (1) according to any one of claims 1 to 4, characterised in that the fibre system (5) is so mounted that it cannot move relative to the sheathing body (25).

7. An intervertebral implant (1) according to any one of claims 1 to 6, characterised in that the entire fibre system (5) is joined with the cover plates (3, 4).

8. An intervertebral implant (1) according to any one of claims 1 to 7, characterised in that the sheathing body is made from an elastic, biocompatible material, preferably an elastomer, in particular based on polyurethane or silicone rubber, polyethylene, polycarbonate urethane or polyethylene terephthalate.

9. An intervertebral implant (1) according to any one of claims 1 to 8, characterised in that the central part (10) is filled at least partially with an incompressible medium.

10. An intervertebral implant (1) according to claim 9, characterised in that the incompressible medium is a liquid.

11. An intervertebral implant (1) according to claim 10, characterised in that the central part (10) comprises an incompressible liquid core (13) and an elastic formed body (9) provided around it.

12. An intervertebral implant (1) according to any one of claims 1 to 11, characterised in that the central part (10) has a cavity (11).

13. An intervertebral implant (1) according to any one of claims 1 to 12, characterised in that the fibre system (5) is mechanically anchored on or in the cover plates (3, 4).

14. An intervertebral implant (1) according to any one of claims 1 to 12, characterised in that the fibre system (5) is adhered to the cover plates (3, 4).

15. An intervertebral implant (1) according to any one of claims 1 to 12, characterised in that the central part (10) with the integrated fibre system (5) is joined with the cover plates (3, 4) in a form-locking manner.

16. An intervertebral implant (1) according to any one of claims 1 to 15, characterised in that the fibre system (5) is formed by an endless fibre, preferably in the form of a fabric or is knitted.

17. An intervertebral implant (1) according to any one of claims 1 to 16, characterised in that each cover plate comprises on its periphery a lateral surface (21, 22) and grooves (18) distributed on the circumference and radially penetrating into the lateral surfaces (21, 22) and that the fibre system (5) can be anchored in these grooves (18).

18. An intervertebral implant (1) according to any one of claims 1 to 17, characterised in that channels (19) are mortised in the external surfaces (7, 8) of the cover plates (3, 4) to accommodate the fibre system (5).

19. An intervertebral implant (1) according to any one of claims 1 to 18, characterised in that the fibre system (5) is formed by a woven material.

20. An intervertebral implant (1) according to any one of claims 1 to 19, characterised in that the central part (10) is essentially hollow-cylindrical, hollow-prismatic or is in the form of a body of rotation, an ellipsoid, a partial sphere or barrel-shaped with an axis of rotation that is coaxial with the central axis (2).

21. An intervertebral implant (1) according to claim 19 or 20, characterised in that the woven material is formed from first and second fibres (6a, 6b), and the first fibres (6a) include an angle α

with the central axis (2) and the second fibres (6b) include an angle β

with the central axis (2).

22. An intervertebral implant (1) according to claim 21, characterised in that the first and second fibres (6a, 6b) are interwoven with one another.

23. An intervertebral implant (1) according to any one of claims 11 to 22, characterised in that the elastic formed body (9) has at right angles to the central axis (2) a cross-sectional surface F_F, the central part has at right angles to the central axis (2) a cross-sectional surface F_M and the F_F/F_M ratio of these two cross-sectional surfaces is between 30% and 65%.

24. An intervertebral implant (1) according to any one of claims 22 to 23, characterised in that the angle α

is between 15° and

60°

.

25. An intervertebral implant (1) according to any one of claims 22 to 24, characterised in that the angle β

is between 15° and

60°

.

26. An intervertebral implant (1) according to-any one of claims 11 to 25, characterised in that the elastic formed body (9) is surrounded by a semi-permeable membrane and in the interior of the elastic formed body (9) preferably physiological table salt solution is present.

27. An intervertebral implant (1) according to any one of claims 1 to 26, characterised in that with regard to the central axis (2) the fibre system (5) is single-layered.

28. An intervertebral implant (1) according to any one of claims 1 to 26, characterised in that with regard to the central axis (2) the fibre system (5) is multi-layered, preferably 2-6 layered.

29. An intervertebral implant (1) according to any one of claims 11 to 28, characterised in that the fibre system (5) is wound on the elastic formed body (9).

30. An intervertebral implant (1) according to claim 29, characterised in that the fibre system (5) is wound on the elastic formed body (9) in two different directions, preferably rotationally symmetrically.

31. An intervertebral implant (1) according to any one of claims 1 to 30, characterised in that the fibre system (5) is made from UHMWPE (ultra high molecular weight polyethylene).

32. An intervertebral implant (1) according to any one of claims 1 to 31, characterised in that a closing plate (14, 15) can be fastened on each cover plate (3, 4), the closing plate having at right angles to the central axis (2) an external surface (16, 17) with a macroscopic structure, preferably in the form of teeth.

33. An intervertebral implant (1) according to any one of claims 1 to 32, characterised in that the diameter of the fibres is in a range of 0.005 mm and 0.025 mm.