Composite interbody spacer

1. A composite interbody spacer comprising:

a first portion being formed of a first material, the first portion shaped and sized for placement in an intervertebral disc space between an upper vertebral body and a lower vertebral body to separate the upper and lower vertebral bodies at a distance that provides proper spinal column function, the first portion being configured as a load bearing portion, the first portion having an upper surface shaped and sized to bear loads applied from the upper vertebral body and having a lower surface shaped and sized to bear loads applied from the lower vertebral body, the first portion having an outwardly facing front surface and having a rear surface opposing the front surface, the front surface having a first bore formed therein, the first bore having a surface shape and wherein the first bore extends at an oblique angle relative to the front surface; and

a second portion being formed of a second material, at least a portion of the second portion having an outer surface shape closely matching the surface shape of the first bore and being at least partially disposed within the first bore in a manner that reinforces the first bore and in a manner to interface with a bone anchor extending through the first bore, the second portion including a second bore formed therein that is at least partially disposed within the first bore in a manner that a bone anchor can extend through the first and second bores, the second bore having an outer surface,

wherein the outer surface of the second bore forms a continuous perimeter adjacent to the surface of the first bore such that the second portion substantially resists elastic yielding.

2. The spacer of claim 1 , wherein the second portion includes an unthreaded second bore formed therein that is at least partially disposed within the first bore in a manner that a bone anchor can extend through the first and second bores.

3. The spacer of claim 1 , wherein the first portion is a polymer and the second portion is a metal.

4. The spacer of claim 3 , wherein the first portion is formed of a member of the polyaryletherketone family.

5. The spacer of claim 1 , wherein the first portion includes a hollow region.

6. The spacer of claim 1 , wherein the second portion is a tubular sleeve.

7. The spacer of claim 6 , wherein the tubular sleeve includes an inner shoulder.

8. The spacer of claim 1 , wherein the second portion is embedded entirely within the first bore.

9. The spacer of claim 1 , wherein the second portion includes a second bore and a third bore formed therein and being partially disposed within the first bore in a manner that a first bone anchor can extend through the first and second bores and a second bone anchor can extend through the first and third bores.

10. The spacer of claim 9 , wherein the second and third bores extend at different angles through the second portion.

11. An implantable device including:

the composite interbody spacer of claim 1 ; and

a bone anchor extending through the first bore and interfacing with the second portion, wherein the front surface of the first portion has a first height measured between the first upper and lower load bearing surfaces, the first height being greater than the diameter of the bone anchor.

12. The device of claim 11 , including a screw locking mechanism configured to inhibit back-out of the bone anchor from the second portion.

13. The device of claim 12 , wherein the screw locking mechanism includes a protruding portion and a spring.

14. A composite interbody spacer comprising:

a first portion shaped and sized for placement in an intervertebral disc space between an upper vertebral body and a lower vertebral body to separate the upper and lower vertebral bodies at a distance that provides proper spinal column function, the first portion being formed of a first material, the first portion being configured as a load bearing portion and having a first bore formed therein, the first bore having a surface shape; and

a second portion being formed of a second material, the second portion having an outer surface shape closely matching the surface shape of the first bore, the second portion being at least partially disposed within the first bore in a manner that reinforces the first bore and in a manner to interface with a bone anchor extending through the first bore,

wherein the outer surface of the second portion forms a continuous perimeter adjacent to the surface of the first bore such that the second portion substantially resists elastic yielding, and

wherein the first portion includes an upper bearing surface shaped and sized to bear loads applied from the upper vertebral body and having a lower bearing surface shaped and sized to bear loads applied from the lower vertebral body, and an outwardly facing front surface between the upper and bottom bearing surfaces, the first bore being formed in the front surface and one of the upper and bottom bearing surfaces.

15. The spacer of claim 14 , wherein the second portion comprises edges shaped to correspond to the front surface said one of the upper and bottom surfaces.

16. The spacer of claim 14 , wherein the first portion is a polymer and the second portion is a metal.

17. The spacer of claim 14 , wherein the first portion includes a hollow region.

18. The spacer of claim 14 , wherein the second portion is a tubular sleeve including an inner shoulder configured to engage and limit passage of a portion of a bone screw.

19. The spacer of claim 14 , wherein the second portion is embedded entirely within the first bore.

20. The spacer of claim 14 , wherein the second portion includes a second bore and a third bore formed therein and being partially disposed within the first bore in a manner that a first bone anchor can extend through the first and second bores and a second bone anchor can extend through the first and third bores.

21. The spacer of claim 20 , wherein the second and third bores extend at different angles through the second portion.

22. A composite interbody spacer comprising:

a first portion formed of a first material, the first portion being shaped and sized for placement in an intervertebral disc space between an upper vertebral body and a lower vertebral body to separate the upper and lower vertebral bodies at a distance that provides proper spinal column function, and being configured for placement between the upper and the lower vertebra as a load bearing portion, the first portion having an upper surface shaped and sized to bear loads applied from the upper vertebral body and having a lower surface shaped and sized to bear loads applied from the lower vertebral body, the first portion also having a first bore formed therein; and

a second portion formed of a second material and disposed at least partially within the first bore of the first portion, the second portion having a second bore formed therein for receiving an anchor, the second portion being configured so that the second bore is formed at an oblique angle relative to the upper and lower surfaces of the first portion, such that an axis through the second bore intersects at least one of the first and second surfaces,

wherein the second bore is at least partially disposed within the first bore in a manner that a bone anchor can extend through the first and second bores, the second bore having an outer surface,

wherein the outer surface of the second bore forms a continuous perimeter adjacent to the surface of the first bore such that the second portion substantially resists elastic yielding.

23. The spacer of claim 22 , wherein the first material is a non-metal material and the second material is a metal material.

24. The spacer of claim 22 , wherein the first bore has a cylindrical shape.

25. The spacer of claim 22 , wherein the first portion has a U-shape having a first end and a second end, and wherein the second portion extends from the first end to the second end, the first bore being formed in one of the first and second ends.

26. The spacer of claim 22 , wherein the second bore is unthreaded.

27. The spacer of claim 22 , wherein the first portion includes a hollow region.

28. The spacer of claim 22 , wherein the second portion is a tubular sleeve including an inner shoulder configured to engage and limit passage of a portion of a bone screw.

29. The spacer of claim 22 , wherein the first portion includes an upper surface, a bottom surface, and a front surface connecting the upper and bottom surfaces, the first bore being formed in the front surface and one of the upper and bottom surface.

30. The spacer of claim 22 , wherein the second portion is embedded entirely within the first bore.

31. The spacer of claim 22 , wherein the second portion includes a third bore formed therein and being partially disposed within the first bore in a manner that a first bone anchor can extend through the first and second bores and a second bone anchor can extend through the first and third bores.

32. The spacer of claim 31 , wherein the second and third bores extend at different angles through the second portion.