Intervertebral body fusion cage with keels and implantation methods

1. An intervertebral spinal fusion implant comprising:

a D-shaped body which defines an inner cavity;

said body having a peripheral wall that encloses said inner cavity, said peripheral wall defining a D-shaped cross-section and comprising a curved anterior end and an opposite posterior end with an anterior-posterior axis drawn from the curved anterior end to the posterior end, the peripheral wall further comprising a leading end and an opposite trailing end extending between the curved anterior end and the posterior end;

said body having superior and inferior sides with the superior side adapted to mate with an upper vertebral body and the inferior side adapted to mate with a lower vertebral body, the superior and inferior sides being generally planar and tapering relative to one another along the anterior-posterior axis from the anterior end to the posterior end to provide the body with a wedge shape;

said superior side having an opening which is substantially defined inside of said peripheral wall;

said inferior side having an opening which is substantially defined inside of said peripheral wall;

a rib that extends across the inner cavity and is joined at one end to the peripheral wall and is joined at another end to the peripheral wall; and

a first keel extending from the superior side, a second keel extending from the inferior side, and wherein each of the keels extends from said rib and along a longitudinal axis, each of the keels extends from the leading end of the peripheral wall to the trailing end of the peripheral wall, and wherein each of the keels is T-shaped and is formed integral with the rib, the longitudinal axis of the keels being substantially perpendicular to the anterior-posterior axis drawn from the curved anterior end to the posterior end.

2. The implant of claim 1 wherein extending from the peripheral wall are a plurality of teeth.

3. The implant of claim 1 wherein said peripheral wall includes a plurality of apertures.

4. The implant of claim 1 wherein said first and second keels are adapted to be substantially perpendicular to a sagittal plane of a patient.

5. The implant of claim 1 wherein said first keel and said second keel are each substantially perpendicular to said anterior-posterior axis.

6. The implant of claim 1 wherein the peripheral wall is in the shape of an intervertebral disk space.

7. The implant of claim 1 wherein the first and second keels each extend along an entire length of the rib from the leading end to the trailing end of the body.

8. The implant of claim 1 further comprising a plurality of apertures extending through the peripheral wall to place the inner cavity in communication with an exterior of the body, one of the apertures positioned on each side of the first and second keels.

9. The implant of claim 1 wherein the leading end of the body is tapered to facilitate insertion of the body into an intervertebral space.

10. The implant of claim 1 wherein each of the first and second keels extends from an exterior of the peripheral wall at the leading end to an exterior of the peripheral wall at the trailing end.

11. The implant of claim 1 wherein each of the first and second keels extends along an entire outer dimension of the D-shaped body along the longitudinal axis.

12. The implant of claim 1 wherein the first and second keels and the rib constitute a single, unitary piece of the D-shaped body.

13. The implant of claim 1 wherein the wedge shape of the body tapers from a narrower end at one of the anterior and posterior ends to a broader end at the other of the anterior and posterior ends.

14. The implant of claim 13 wherein the wedge shape of the body is narrower at the anterior end and broader at the posterior end.

15. The implant of claim 1 wherein the leading end comprises a planar leading end wall extending between the curved anterior end and the posterior end;

wherein the trailing end comprise a planar trailing end wall extending between the curved anterior end and the posterior end.

16. The implant of claim 15 wherein the planar leading end wall and the planar trailing end wall are arranged parallel to one another.

17. An intervertebral spinal fusion implant comprising:

a D-shaped body which has a peripheral wall that defines an inner cavity, the peripheral wall comprising a curved anterior end and an opposite posterior end with an anterior-posterior axis drawn from the curved anterior end to the posterior end, the peripheral wall further comprising a leading end and an opposite trailing end extending between the curved anterior end and the posterior end;

said body having superior and inferior sides with the superior side adapted to mate with an upper vertebral body and the inferior side adapted to mate with a lower vertebral body, the superior and inferior sides being generally planar and tapering relative to one another along the anterior-posterior axis from the anterior end to the posterior end to provide the body with a wedge shape;

said superior side having an opening which is substantially defined inside of said peripheral wall; and

said inferior side having an opening which is substantially defined inside of said peripheral wall;

a rib that spans said inner cavity and is joined at one end to the peripheral wall and is joined at another end to the peripheral wall; and

a first keel extending from the superior side, a second keel extending from the inferior side, and wherein each of the keels extends from said rib and along a longitudinal axis, each of the keels extends from the leading end of the peripheral wall to the trailing end of the peripheral wall, and wherein each of the keels is T-shaped and is formed integral with the rib, the longitudinal axis of the keels being substantially perpendicular to the anterior-posterior axis drawn from the curved anterior end to the posterior end.

18. The implant of claim 17 including teeth extending from said peripheral wall.

19. The implant of claim 17 wherein the first and second keels each extend along an entire length of the rib from the leading end to the trailing end of the body.

20. The implant of claim 17 further comprising a plurality of apertures extending through the peripheral wall to place the inner cavity in communication with an exterior of the body, one of the apertures positioned on each side of the first and second keels.

21. The implant of claim 17 wherein the leading end of the body is tapered to facilitate insertion of the body into an intervertebral space.

22. The implant of claim 17 wherein each of the first and second keels extends from an exterior of the peripheral wall at the leading end to an exterior of the peripheral wall at the trailing end.

23. The implant of claim 17 wherein each of the first and second keels extends along an entire outer dimension of the D-shaped body along the longitudinal axis.

24. The implant of claim 17 wherein the first and second keels and the rib constitute a single, unitary piece of the D-shaped body.

25. The implant of claim 17 wherein the wedge shape of the body tapers from a narrower end at one of the anterior and posterior ends to a broader end at the other of the anterior and posterior ends.

26. The implant of claim 25 wherein the wedge shape of the body is narrower at the anterior end and broader at the posterior end.

27. The implant of claim 17 wherein the leading end comprises a planar leading end wall extending between the curved anterior end and the posterior end;

wherein the trailing end comprise a planar trailing end wall extending between the curved anterior end and the posterior end.

28. The implant of claim 27 wherein the planar leading end wall and the planar trailing end wall are arranged parallel to one another.

29. An intervertebral fusion implant to be surgically implanted from a lateral approach, the implant comprising:

a D-shaped cage, said cage including a peripheral wall comprising:

a curved anterior end;

a posterior end located opposite the curved anterior end;

an anterior-posterior axis drawn from the curved anterior end to the posterior end;

a leading end and an opposite trailing end extending between the curved anterior end and the posterior end to define a hollow interior;

superior and inferior sides with the superior side adapted to mate with an upper vertebral body and the inferior side adapted to mate with a lower vertebral body, the superior and inferior sides being generally planar and tapering relative to one another along the anterior-posterior axis from the anterior end to the posterior end to provide the cage with a wedge shape;

a rib that spans the hollow interior and is joined at one end to the peripheral wall and is joined at another end to the peripheral wall;

a first keel and a second keel, each of the keels adapted to anchor the implant in a vertebral body, each of the keels extending from the rib and along a longitudinal axis, each of the keels extends from the leading end of the peripheral wall to the trailing end of the peripheral wall, and wherein each of the keels is T-shaped and is formed integral with the rib, the longitudinal axis of the keels being substantially perpendicular to the anterior-posterior axis drawn from the curved anterior end to the posterior; and

a plurality of apertures extending through the peripheral wall to place the hollow interior in communication with an exterior of the cage with one of the apertures is positioned on each side of the first keel.

30. The implant of claim 29 including bone growth-promoting material selected from the group of materials consisting of naturally occurring bone, processed bone, synthetic bone, hydroxyapatite, calcium phosphate compounds, naturally occurring bone morphogenic proteins, recombinant bone morphogenic proteins, synthetic bone morphogenic proteins, growth factors, and cytokines.

31. The implant of claim 29 wherein the cage is made of a material selected from the group consisting of bioceramics, calcium phosphate ceramics, chrome cobalt, titanium, stainless steel, biocompatible carbon fiber reinforced polymer, biocompatible polymers, copolymers, and blends and composites of polymers.

32. The implant of claim 29 wherein the implant is comprised of a biocompatible polymer including polyaryl ester ketone.

33. The implant of claim 29 wherein the implant is comprised of a biocompatible polymer including polyalkyl biocompatible polymers selected from the group consisting of polyethylenes, polypropylenes, and the like.

34. The implant of claim 29 wherein the first and second keels each extend along an entire length of the rib from the leading end to the trailing end of the cage.

35. The implant of claim 29 wherein the leading end of the cage is tapered to facilitate insertion of the body into an intervertebral space.

36. The implant of claim 29 wherein each of the first and second keels extends from an exterior of the peripheral wall at the leading end to an exterior of the peripheral wall at the trailing end.

37. The implant of claim 29 wherein each of the first and second keels extends along an entire outer dimension of the D-shaped cage along the longitudinal axis.

38. The implant of claim 29 wherein the first and second keels and the rib constitute a single, unitary piece of the D-shaped cage.

39. The implant of claim 29 wherein the wedge shape of the cage tapers from a narrower end at one of the anterior and posterior ends to a broader end at the other of the anterior and posterior ends.

40. The implant of claim 39 wherein the wedge shape of the cage is narrower at the anterior end and broader at the posterior end.

41. The implant of claim 29 wherein the leading end comprises a planar leading end wall extending between the curved anterior end and the posterior end;

wherein the trailing end comprise a planar trailing end wall extending between the curved anterior end and the posterior end.

42. The implant of claim 41 wherein the planar leading end wall and the planar trailing end wall are arranged parallel to one another.