Intervertebral spacer device having a wave washer force restoring element

1. An intervertebral spacer device comprising:

first and second plates disposed in a spaced apart relationship, said first and second plates having inner surfaces that confront one another and outer surfaces that face away from one another; and

at least one ring-shaped wave washer disposed between the inner surfaces of the first and second plates for counteracting compressive loads applied to the outer surfaces of said plates, wherein said at least one ring-shaped wave washer has a longitudinally undulating circumferential extent forming an uninterrupted circular hoop.

2. The device as claimed in claim 1 , further comprising a flexible circumferential skirt disposed about and between lateral perimeters of said first and second plates for defining an interior volume of said device in which said at least one ring-shaped wave washer is disposed.

3. The device as claimed in claim 1 , wherein the flexible circumferential skirt comprises a resilient material.

4. An intervertebral spacer device comprising:

a first plate having an inner surface and an outer surface;

a second plate having an inner surface and an outer surface, wherein the inner surfaces of said first and second plates oppose one another;

a wave washer including a band having an undulated surface of arches and valleys, wherein said wave washer is disposed between the inner surfaces of said first and second plates for counteracting compressive loads applied to the outer surfaces of said plates;

a securing element attached to one of said plates and engaging said wave washer for securing said wave washer between the inner surfaces of said plates.

5. The device as claimed in claim 4 , wherein said wave washer comprises a ring-shaped wave washer forming an uninterrupted circular hoop.

6. The device as claimed in claim 4 , wherein said wave washer comprises a ring-shaped wave washer forming a circular hoop interrupted by a radial slot.

7. The device as claimed in claim 4 , wherein said wave washer comprises a spiral-shaped wave washer wound in a spiral pattern around a center of said wave washer.

8. The device as claimed in claim 7 , wherein said spiral-shaped wave washer includes a series of the arches and the valleys.

9. The device as claimed in claim 7 , wherein the band of said spiral-shaped wave washer sweeps through an angle greater than 360 degrees so that the band spirals inwardly from relatively larger-diameter outer ring portions to increasingly relatively smaller-diameter inner ring portions, the outer and inner ring portions undulating in the same laterally extending plane.

10. The device as claimed in claim 8 , wherein at least some of the arches are aligned with one another and at least some of the valleys are aligned with one another.

11. The device as claimed in claim 8 , wherein at least some of the arches are not aligned with one another and at least some of the valleys are not aligned with one another.

12. The device as claimed in claim 4 , wherein the band of said wave washer includes an opening and said securing element includes a fastener for securing said wave washer to one of said plates.

13. The device as claimed in claim 12 , wherein said fastener comprises a threaded fastener.

14. The device as claimed in claim 13 , wherein the one of said plates has a threaded opening and said threaded fastener is threadable into the threaded opening.

15. The device as claimed in claim 4 , wherein said securing element comprises a plurality of radially extending shafts that are aligned with at least some of the arches and the valleys of said wave washer for securing said wave washer to one of said plates.

16. The device as claimed in claim 15 , wherein said securing element includes a threaded opening and a screw is insertable into the threaded opening of said securing element for securing said securing element to the one of said plates.

17. The device as claimed in claim 4 , further comprising a flexible circumferential skirt disposed about and between said first and second plates for defining an interior volume of said device in which said wave washer is disposed.

18. The device as claimed in claim 17 , wherein said flexible circumferential skirt comprises a resilient material.

19. The device as claimed in claim 18 , wherein said flexible circumferential skirt is porous.

20. An intervertebral spacer device comprising:

first and second plates disposed in a spaced apart relationship so that inner surfaces of said plates confront one another outer surfaces of said plates face away from one another;

at least one spiral-shaped wave washer disposed between the inner surfaces of said plates for counteracting compressive loads applies to said plates, the at least one spiral shaped wave washer having a longitudinally undulating extent that sweeps through an angle greater than 360 degrees, wherein the extent spirals inwardly from relatively larger-diameter outer ring portions to increasingly relatively smaller-diameter inner ring portions, the outer and inner ring portions undulating in the same laterally extending plane; and

wherein at least one of the first and second plates includes a wave washer securing mechanism mounted to the inner surface thereof for securing the at least one spiral-shaped wave washer to the one of said first and second plates.

21. The device as claimed in claim 20 , further comprising a flexible circumferential skirt disposed about and between lateral perimeters of said first and second plates for defining an interior volume of said device in which the at least one spiral-shaped wave washer is disposed.

22. The device as claimed in claim 21 , wherein said flexible circumferential skirt comprises a resilient material.

23. The device as claimed in claim 21 , wherein said flexible circumferential skirt is porous.

24. The device as claimed in claim 20 , wherein said wave washer securing mechanism is mounted to the inner surface of one of said first and second plates.