Anterior cervical plate system
View Patent ↗Anatomically contoured anterior cervical plates with bone ingrowth surfaces, providing for intersegmental compressive preloading, and a rigid and locked interface to all of the bone screws, with those engaging the vertebrae deployed in highly convergent pairs. The bone screws have a tapered self-tapping leading end, an increasing root diameter with a generally constant outer diameter with a thread that is narrow and sharp throughout and an enlarged head portion capable of an interference fit to the receiving holes of the plate. Instrumentation consists of plate holders, a compression apparatus and a pilot hole forming device that interlocks with the plate. Methods for spinal compression and bone hole preparation are provided.
1. A plate adapted to be applied to the anterior human cervical spine for contacting the anterior aspects of at least two cervical vertebral bodies to be fused together, said plate comprising:
a mid-longitudinal axis, a lower surface being concave along a substantial portion of the mid-longitudinal axis of said plate and adapted to contact the cervical vertebral bodies, and an upper surface opposite said lower surface;
at least two bone screw receiving holes extending through said plate from said upper surface through said lower surface, each of said bone screw receiving holes having a central longitudinal axis and a radius, each of said bone screw receiving holes being adapted to receive a bone screw for engaging said plate to the cervical spine; and
opposite first and second ends along the mid-longitudinal axis of said plate, at least said first end having one of said bone screw receiving holes on each side of the mid-longitudinal axis of said plate, at least said first end having an end wall extending from said upper surface to said lower surface, said end wall being proximate to a straight line connecting the central longitudinal axes of each bone screw receiving hole at said first end, said end wall being located a distance from the line that is less than a distance of the radius of either of said bone screw receiving holes at said first end to form an indentation at said first end, said indentation having a maximum width transverse to the mid-longitudinal axis that is greater than the minimum distance separating said bone screw receiving holes at said upper surface and along the straight line.
2. The plate of claim 1 , wherein said lower surface has a radius of curvature between approximately 15 cm to 30 cm.
3. The plate of claim 1 , wherein said lower surface has a radius of curvature between approximately 20 cm to 25 cm.
4. The plate of claim 1 , wherein said lower surface has a second concave curvature transverse to the mid-longitudinal axis of said plate, said second concave curvature having a radius of curvature between approximately 15 mm to 25 mm.
5. The plate of claim 4 , wherein said second concave curvature has a radius of curvature between approximately 19 mm to 21 mm.
6. The plate of claim 1 , wherein said plate has a thickness between said upper surface and said lower surface of between approximately 2 mm to 3 mm.
7. The plate of claim 6 , wherein the thickness of said plate is between approximately 2.25 mm to 2.5 mm.
8. The plate of claim 1 , wherein said plate has a generally rectangular configuration with lobes extending from at least the corners of said plate and has at least one of said bone screw receiving holes located within one of said lobes.
9. The plate of claim 1 , wherein said plate has a minimum length longer than a maximum width.
10. The plate of claim 9 , wherein said plate has a length sufficient to span at least three consecutive vertebral bodies.
11. The plate of claim 1 , wherein the central longitudinal axis of each bone screw receiving hole is generally perpendicular to said lower surface of said plate.
12. The plate of claim 1 , wherein at least a portion of said lower surface comprises a bone ingrowth material.
13. The plate of claim 1 , wherein at least a portion of said lower surface comprises a bone growth material.
14. The plate of claim 1 , wherein at least a portion of said plate is coated with a material to induce the formation of bone.
15. The plate of claim 1 , wherein said plate comprises bone morphogenetic protein.
16. The plate of claim 1 , wherein at least a portion of said plate is made of a material which is resorbable.
17. The plate of claim 16 , wherein said resorbable material is polyglyconate.
18. The plate of claim 16 , wherein said resorbable material is impregnated with a fusion promoting substance.
19. The plate of claim 1 , wherein at least a portion of said lower surface is textured so as to promote bone ingrowth.
20. The plate of claim 19 , wherein said textured portion is impregnated with a fusion promoting substance.
21. The plate of claim 1 , wherein said lower surface is porous so as to promote bone growth.
22. The plate of claim 21 , wherein said lower surface has a porosity of approximately between 50 microns to 500 microns.
23. The plate of claim 22 , wherein said lower surface has a porosity of approximately between 100 microns to 300 microns.
24. The plate of claim 1 , in combination with an interbody implant.
25. The plate of claim 1 , in combination with a bone graft.
26. The plate of claim 1 , in combination with a bone growth promoting material.
27. The plate of claim 26 , wherein said bone growth promoting material is at least in part other than bone.
28. The plate of claim 26 , wherein said bone growth promoting material is at least in part bone.
29. The plate of claim 26 , wherein said bone growth promoting material includes at least one of bone morphogenetic protein, hydroxyapatite, and hydroxyapatite tricalcium phosphate.
30. The plate of claim 1 , in combination with a bioresorbable material.
31. The plate of claim 1 , wherein said end wall includes a generally flat portion where said end wall is closest to the straight line.
32. The plate of claim 1 , wherein said plate has a fixed length.
33. The plate of claim 1 , wherein said plate includes at least one locking element recess.
34. The plate of claim 1 , wherein said plate includes an opening having a central longitudinal axis along the mid-longitudinal axis of said plate, said opening being separated from one of said bone screw receiving holes at said first end by a distance that is less than the radius of either of said bone screw receiving holes at said first end.
35. The plate of claim 1 , wherein said end wall includes a portion that forms an arc of a circle having a central longitudinal axis coaxial with the central longitudinal axis of one of said bone screw receiving holes at said first end.
36. A plate adapted to be applied to the anterior human cervical spine for contacting the anterior aspects of at least two cervical vertebral bodies to be fused together, said plate comprising:
a longitudinal axis, a transverse axis and a height perpendicular to the longitudinal and transverse axes of said plate;
a lower surface being concave along a substantial portion of the longitudinal axis of said plate and adapted to contact the cervical vertebral bodies, and an upper surface opposite said lower surface;
at least two bone screw receiving holes extending through said plate from said upper surface through said lower surface, each of said bone screw receiving holes being adapted to receive a bone screw for engaging said plate to the cervical spine; and
opposite ends along the longitudinal axis of said plate, each of said opposite ends having an end wall extending from said upper surface to said lower surface, at least one of said ends having a recess located at the juncture of said end wall and said lower surface, said recess being configured to cooperate with a compression tool for compressing at least two vertebral bodies toward each other, said recess having a height perpendicular to the longitudinal and transverse axes of said plate, the height of said recess being less than the height of said plate at said end wall.
37. The plate of claim 36 , wherein said lower surface has a radius of curvature between approximately 15 cm to 30 cm.
38. The plate of claim 36 , wherein said lower surface has a radius of curvature between approximately 20 cm to 25 cm.
39. The plate of claim 36 , wherein said lower surface has a second concave curvature transverse to the longitudinal axis of said plate, said second concave curvature having a radius of curvature between approximately 15 mm to 25 mm.
40. The plate of claim 39 , wherein said second concave curvature has a radius of curvature between approximately 19 mm to 21 mm.
41. The plate of claim 36 , wherein said plate has a thickness between said upper surface and said lower surface of between approximately 2 mm to 3 mm.
42. The plate of claim 41 , wherein the thickness of said plate is between approximately 2.25 mm to 2.5 mm.
43. The plate of claim 36 , wherein said plate has a generally rectangular configuration with lobes extending from at least the corners of said plate and has at least one of said bone screw receiving holes located within one of said lobes.
44. The plate of claim 36 , wherein said plate has a minimum length longer than a maximum width.
45. The plate of claim 44 , wherein said plate has a length sufficient to span at least three consecutive vertebral bodies.
46. The plate of claim 36 , wherein at least a portion of said lower surface comprises a bone ingrowth material.
47. The plate of claim 36 , wherein at least a portion of said lower surface comprises a bone growth material.
48. The plate of claim 36 , wherein at least a portion of said plate is coated with a material to induce the formation of bone.
49. The plate of claim 36 , wherein said plate comprises bone morphogenetic protein.
50. The plate of claim 36 , wherein at least a portion of said plate is made of a material which is resorbable.
51. The plate of claim 50 , wherein said resorbable material is polyglyconate.
52. The plate of claim 50 , wherein said resorbable material is impregnated with a fusion promoting substance.
53. The plate of claim 36 , wherein at least a portion of said lower surface is textured so as to promote bone ingrowth.
54. The plate of claim 53 , wherein said textured portion is impregnated with a fusion promoting substance.
55. The plate of claim 36 , wherein said lower surface is porous so as to promote bone growth.
56. The plate of claim 55 , wherein said lower surface has a porosity of approximately between 50 microns to 500 microns.
57. The plate of claim 56 , wherein said lower surface has a porosity of approximately between 100 microns to 300 microns.
58. The plate of claim 36 , in combination with an interbody implant.
59. The plate of claim 36 , in combination with a bone graft.
60. The plate of claim 36 , in combination with a bone growth promoting material.
61. The plate of claim 60 , wherein said bone growth promoting material is at least in part other than bone.
62. The plate of claim 60 , wherein said bone growth promoting material is at least in part bone.
63. The plate of claim 60 , wherein said bone growth promoting material includes at least one of bone morphogenetic protein, hydroxyapatite, and hydroxyapatite tricalcium phosphate.
64. The plate of claim 36 , in combination with a bioresorbable material.