Intervertebral Implant for transforaminal posterior lumbar interbody fusion procedure

• US 20040172133A1
• Filed: 02/26/2004
• Published: 09/02/2004
• Est. Priority Date: 05/03/2001
• Status: Abandoned Application

• Current Assignee: DePuy Synthes Products LLC (Johnson & Johnson)
• Original Assignee: Synthes, Inc. (Johnson & Johnson)
• Inventors: Messerli, Dominique, Gerber, David, Paul, David
• Application Number:
  US10/787,984
• Publication Number:
  US 20040172133A1
• Time in Patent Office: Days
• US Class Current: 623/17.11
• CPC Class Codes: A61B 17/1604 Chisels; Rongeurs; Punches; Stamps
• CPC Class Codes: A61B 17/1659 Surgical rasps, files, planes, or scrapers
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/3008 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• 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 2002/30492 using a locking pin
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30538 for adjusting angular orientation
• CPC Class Codes: A61F 2002/30594 slotted, e.g. radial or meridian slot ending in a polar aperture, non-polar slots, horizontal or arcuate slots
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30787 inclined obliquely with respect to each other
• CPC Class Codes: A61F 2002/30797 internally-threaded
• CPC Class Codes: A61F 2002/30843 Pyramidally-shaped
• CPC Class Codes: A61F 2002/30904 serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/30975 : made of two halves
• CPC Class Codes: A61F 2002/4628 : with linear motion along or rotating motion about an axis transverse to the instrument axis or to the implantation direction, e.g. clamping
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2230/0015 : Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2250/0006 : for adjusting angular orientation
• CPC Class Codes: A61F 2250/0098 : radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00359 : Bone or bony tissue

Abstract

An intervertebral implant for fusing vertebrae is disclosed. The implant has a body with curved, substantially parallel posterior and anterior faces separated by two narrow implant ends, superior and inferior faces having a plurality of undulating surfaces for contacting upper and lower vertebral endplates, and at least one depression at a first end for engagement by an insertion tool. The arcuate implant configuration facilitates insertion of the implant from a transforaminal approach into a symmetric position about the midline of the spine so that a single implant provides balanced support to the spinal column. The implant may be formed of a plurality of interconnecting bodies assembled to form a single unit. An implantation kit and method are also disclosed.

Claims

1. An intervertebral implant comprising:

a body having

a substantially curved anterior face, a substantially curved posterior face,

a pair of narrow ends separating the posterior and anterior faces;

a superior surface and an inferior surface for contacting upper and lower vertebral endplates, the superior and inferior surfaces defining a thickness of the implant; and

first and second non-threaded, horizontal channels configured and adapted for engagement by an implant insertion tool, the first channel disposed along at least a portion of the curved posterior face and the second channel disposed along at least a portion of the curved anterior face;

wherein the first and second channels are curved with the anterior and posterior faces.

2. The implant of claim 1, wherein the anterior face is convex and the posterior face is concave.

3. The implant of claim 2, wherein the anterior face and the posterior face are substantially parallel.

4. The implant of claim 3, wherein the anterior face has a radii of curvature R1, the posterior face has a radii of curvature R2, wherein R1 is approximately 28 millimeters and R2 is approximately 19 millimeters.

5. The implant of claim 1, wherein the thickness of the implant is greatest approximately at a mid-section of the implant between the ends of the implant.

6. The implant of claim 5, wherein the thickness of the implant tapers from the mid-section of the implant to the ends of the implant.

7. The implant of claim 5, wherein the superior and inferior surfaces have a convex-arcuate shape with a radii of curvature of approximately 100 mm.

8. The implant of claim 7, wherein the thickness of the implant does not taper along a transverse axis of the implant so that the distance between the superior and inferior surfaces remain substantially constant for any given cross section taken perpendicular to the longitudinal axis of the implant.

9. The implant of claim 5, wherein the thickness of the implant at the mid-section is approximately 7.0 millimeters to approximately 17.0 millimeters and the thickness at the ends of the implant is approximately 1.5 millimeters to approximately 2.0 millimeters less than the thickness at the mid-section.

10. The implant of claim 1, wherein the implant has a longitudinal length measured along a longitudinal axis of the implant from approximately 26 millimeters to approximately 32 millimeters and a transverse width from approximately 9 millimeters to approximately 11 millimeters.

11. The implant of claim 1, wherein the implant is formed of a plurality of interconnecting bodies assembled to form a single unit.

12. The implant of claim 11, wherein the plurality of interconnecting bodies have interlocking grooves and pallets to press-fit the bodies together.

13. The implant of claim 12, further comprising at least one pin extending through an opening in the plurality of bodies to hold the bodies together as a single unit.

14. The implant of claim 12, further comprising at least one screw extending through an opening in the plurality of bodies to hold the bodies together as a single unit.

15. The implant of claim 11, wherein the implant is formed from exactly two pieces, the first piece has an inferior surface for engaging an adjacent vertebral and a top surface, the second piece has a superior surface for engaging an adjacent vertebral and a bottom surface for interlocking with the top surface of the first piece so that the pieces are stacked one on top of the other.

16. The implant of claim 15, wherein the first and second pieces are formed allograft bone.

17. The implant of claim 1, wherein the implant is formed from the group consisting of metal, allograft, a metal allograft composite, a carbon-fiber polymer, a polymer, or plastic.

18. The implant of claim 1, further comprising a plurality of projections on the superior and inferior faces for engaging the adjacent vertebrae.

19. The implant of claim 18, wherein the projections are teeth for providing a mechanical interlock between the superior and inferior surfaces of the implant and the end plates of the adjacent vertebral.

20. The implant of claim 1, wherein at least one of the narrow ends is rounded.

21. The implant of claim 1, wherein at least one of the narrow ends is substantially straight.

22. An intervertebral implant comprising:

a body having

a curved posterior face and a curved anterior face, both curved posterior and anterior faces extending in the direction of a longitudinal axis of the implant body;

a pair of narrow end faces separating the posterior and anterior faces;

superior and inferior faces for contacting upper and lower vertebral endplates, the superior and inferior surfaces defining a thickness of the implant; and

first and second non-threaded, horizontal channels configured and adapted for engagement by an implant insertion tool, the first channel disposed along at least a portion of the curved posterior face and the second channel disposed along at least a portion of the curved anterior face;

wherein the posterior face and the anterior face are both curved substantially from one of the end faces to the other end face.

23. The implant of claim 22, wherein the first and second channels are curved with the anterior and posterior faces.

24. The implant of claim 23, wherein the anterior face is convex and the posterior face is concave.

25. The implant of claim 24, wherein the anterior face and the posterior face are substantially parallel.

26. The implant of claim 24, wherein the anterior face has a radii of curvature R1, the posterior face has a radii of curvature R2, wherein R1 is approximately 28 millimeters and R2 is approximately 19 millimeters.

27. The implant of claim 22, wherein the thickness of the implant is greatest approximately at a mid-section of the implant between the end faces of the implant.

28. The implant of claim 27, wherein the thickness of the implant tapers from the mid-section of the implant to the end faces of the implant.

29. The implant of claim 27, wherein the superior and inferior surfaces have a convex-arcuate shape with a radii of curvature of approximately 100 mm.

30. The implant of claim 29, wherein the thickness of the implant does not taper along a transverse axis of the implant so that the distance between the superior and inferior surfaces remain substantially constant for any given cross section taken perpendicular to the longitudinal axis of the implant.

31. The implant of claim 27, wherein the thickness of the implant at the mid-section is approximately 7.0 millimeters to approximately 17.0 millimeters and the thickness at the end faces of the implant is approximately 1.5 millimeters to approximately 2.0 millimeters less than the thickness at the mid-section.

32. The implant of claim 22, wherein the implant has a longitudinal length measured along a longitudinal axis of the implant from approximately 26 millimeters to approximately 32 millimeters and a transverse width from approximately 9 millimeters to approximately 11 millimeters.

33. The implant of claim 22, wherein the implant is formed of a plurality of interconnecting bodies assembled to form a single unit.

34. The implant of claim 33, wherein the plurality of interconnecting bodies have interlocking grooves and pallets to press-fit the bodies together.

35. The implant of claim 34, further comprising at least one pin extending through an opening in the plurality of bodies to hold the bodies together as a single unit.

36. The implant of claim 34, further comprising at least one screw extending through an opening in the plurality of bodies to hold the bodies together as a single unit.

37. The implant of claim 33, wherein the implant is formed from exactly two pieces, the first piece has an inferior surface for engaging an adjacent vertebral and a top surface, the second piece has a superior surface for engaging an adjacent vertebral and a bottom surface for interlocking with the top surface of the first piece so that the pieces are stacked one on top of the other.

38. The implant of claim 37, wherein the first and second pieces are formed allograft bone.

39. The implant of claim 22, wherein the implant is formed from the group consisting of metal, allograft, a metal allograft composite, a carbon-fiber polymer, a polymer, or plastic.

40. The implant of claim 22, further comprising a plurality of projections on the superior and inferior faces for engaging the adjacent vertebrae.

41. The implant of claim 40, wherein the projections are teeth for providing a mechanical interlock between the superior and inferior surfaces of the implant and the end plates of the adjacent vertebral.

42. The implant of claim 22, wherein at least one of the end faces is convex.

43. The implant of claim 22, wherein at least one of the end faces is substantially straight.

44. An intervertebral implant comprising:

a body having

a substantially convex anterior face, a substantially concave posterior face, wherein the convex anterior face has a radii of curvature of approximately 28 millimeters, the concave posterior face has a radii of curvature of approximately 19 millimeters;

a pair of narrow ends separating the posterior and anterior faces;

a superior convex surface and an inferior convex surface for contacting upper and lower vertebral endplates, the superior and inferior surfaces defining a thickness of the implant, wherein the thickness of the implant is greatest approximately at a mid-section of the implant between the ends of the implant, and the superior and inferior surfaces have a radii of curvature of approximately 100 mm;

so that the thickness of the implant at the mid-section is approximately 7.0 millimeters to approximately 17.0 millimeters and the thickness at the ends of the implant is approximately 1.5 millimeters to approximately 2.0 millimeters less than the thickness at the mid-section; and

first and second non-threaded, horizontal channels configured and adapted for engagement by an implant insertion tool, the first channel disposed along at least a portion of the curved posterior face and the second channel disposed along at least a portion of the curved anterior face;

wherein the first and second channels are curved with the anterior and posterior faces.

45. An intravertebral implant for maintaining a desired space between vertebral bodies comprising:

a solid body having

a convex anterior face, the anterior face shaped to match the shape of the anterior perimeter of the vertebrae;

a concave posterior face;

arcuate convex end faces connected between the posterior and anterior faces, the posterior and anterior faces being at least double the length of the end faces and the posterior and anterior faces each having at least one curved channel extending from one of the end faces toward the other end face configured and adapted to be engageable with an insertion tool; and

superior and inferior faces for contacting upper and lower vertebral end plates, the superior and inferior faces having teeth,

wherein the implant is configured and adapted to be inserted into the disc space through a transforaminal window formed in the posterior of the spinal column and positioned behind the dura between vertebral end plates to maintain balanced support about the midline of the spine.