Multilock anterior cervical plating system

• US 20030191471A1
• Filed: 04/09/2003
• Published: 10/09/2003
• Est. Priority Date: 02/11/1997
• Status: Active Grant

• Current Assignee: Zimmer Spine, Inc. (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Zimmer Spine, Inc. (Zimmer Biomet Holdings, Inc.)
• Inventors: Michelson, Gary K.
• Granted Patent: US 6,936,050 B2
• Time in Patent Office: Days
• US Class Current: 606/248
• CPC Class Codes: A61B 17/1604 Chisels; Rongeurs; Punches; Stamps
• CPC Class Codes: A61B 17/1671 for the spine
• CPC Class Codes: A61B 17/1728 for holes for bone plates or plate screws
• CPC Class Codes: A61B 17/1757 for the spine
• CPC Class Codes: A61B 17/7058 Plates mounted on top of bone anchor heads or shoulders
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence
• CPC Class Codes: A61B 17/80 Cortical plates , i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates
• CPC Class Codes: A61B 17/8019 where the means are a separate tool rather than being part of the plate
• CPC Class Codes: A61B 17/8033 having indirect contact with screw heads, or having contact with screw heads maintained with the aid of additional components, e.g. nuts, wedges or head covers
• CPC Class Codes: A61B 17/8042 the additional component being a cover over the screw head
• CPC Class Codes: A61B 17/8085 with pliable or malleable elements or having a mesh-like structure, e.g. small strips A61B17/8071, A61B17/8076 take precedence
• CPC Class Codes: A61B 17/861 specially shaped for gripping driver
• CPC Class Codes: A61B 17/8625 Shanks, i.e. parts contacting bone tissue
• CPC Class Codes: A61B 17/863 with thread interrupted or changing its form along shank, other than constant taper
• CPC Class Codes: A61B 17/8695 Washers surrounding screw head in plate hole A61B17/8047, between bone plate and bone A61B17/8028
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• CPC Class Codes: A61B 2017/0046 with a releasable handle; with handle and operating part separable for prosthetic joint-implanting tools A61F2/4603
• CPC Class Codes: A61B 2017/8655 with special features for locking in the bone
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• CPC Class Codes: Y10S 606/902 Cortical plate specifically adapted for a particular bone
• CPC Class Codes: Y10S 606/907 : Composed of particular material or coated
• CPC Class Codes: Y10S 606/908 : Bioabsorbable material
• CPC Class Codes: Y10S 606/91 : Polymer

Abstract

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.

Claims

1. A plate system adapted for application to the anterior human cervical spine and for contacting at least a portion of the anterior aspects of at least two cervical vertebral bodies, said plate system comprising:

a plate having a longitudinal axis and a length sufficient to span a disc space and overlap portions of at least two adjacent cervical vertebral bodies, said plate having a lower surface for placement against the vertebral bodies and an upper surface opposite said lower surface, said lower surface being concave along a substantial portion of the longitudinal axis of said plate;

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 being adapted to receive a bone screw to attach said plate to the cervical spine; and

a lock for preventing the inadvertent backing out of the screws from within said bone screw receiving holes, said lock having a threaded shaft member with a longitudinal axis and a cover portion adapted to cover at least a portion of at least two of said bone screw receiving holes, said cover portion of said lock having a non-circular perimeter lying generally in a plane transverse to the longitudinal axis of said threaded shaft member, said threaded shaft member being adapted to engage said plate to secure said cover portion of said lock over a portion of said plate and a portion of at least two bone screw receiving holes.

2. The plate system of claim 1, wherein said plate includes a recess configured to receive at least a portion of the perimeter of said cover portion.

3. The plate system of claim 1, wherein at least two of said bone screw receiving holes lie along a line transverse to the longitudinal axis of said plate to overlie one of the cervical vertebral bodies.

4. The plate system of claim 1, wherein at least a portion of said lower surface of said plate is other than smooth.

5. The plate system of claim 1, wherein said lock is removably coupled to said plate.

6. The plate system of claim 1, further comprising at least a third bone screw receiving hole, said cover portion of said lock being configured to cover at least three of said bone screw receiving holes.

7. The plate system of claim 6, further comprising at least a fourth bone screw receiving hole, said cover portion of said lock being configured to cover at least four of said bone screw receiving holes.

8. The plate system of claim 1, wherein said lock comprises of a screw.

9. The plate system of claim 1, in combination with at least two bone screws each having a central longitudinal axis and being adapted to engage each of the at least two vertebral bodies, respectively, each of said bone screws having a leading end for insertion into the vertebral bodies and a trailing end opposite said leading end.

10. The plate system of claim 9, comprising at least in part of a bioresorbable material.

11. The plate system of claim 1, wherein at least a first pair of said bone screw receiving holes is transversely oriented side-by-side in said plate to overlie the anterior aspect of a cervical vertebral body, said cover portion of said lock being adapted to cover at least in part a portion of each of said transversely oriented side-by-side bone screw receiving holes.

12. The plate system of claim 1, in combination with an interbody implant.

13. The plate system of claim 1, in combination with a bone graft.

14. The plate system of claim 1, in combination with a bone growth promoting material.

15. The plate system of claim 14, wherein said bone growth promoting material is at least in part other than bone.

16. The plate system of claim 14, wherein said bone growth promoting material is at least in part bone.

17. The plate system of claim 14, wherein said bone growth promoting material includes at least one of bone morphogenetic protein, hydroxyapatite, and hydroxyapatite tricalcium phosphate.

18. The plate system of claim 1, wherein at least a portion of said lower surface comprises a bone ingrowth material.

19. The plate system of claim 1, wherein at least a portion of said lower surface of said plate includes a bone ingrowth surface.

20. The plate system of claim 1, wherein at least a portion of one of said plate and said lock is a bioresorbable material.

21. A plate system adapted for application to the anterior human cervical spine and for contacting at least a portion of the anterior aspects of at least two cervical vertebral bodies, said plate system comprising:

a plate having a longitudinal axis and a length sufficient to span a disc space and overlap portions of at least two adjacent cervical vertebral bodies, said plate having a lower surface for placement against the vertebral bodies and an upper surface opposite said lower surface, said lower surface being concave along a substantial portion of the longitudinal axis of said plate;

at least two bone screws each having a central longitudinal axis and one each being adapted to engage one each of the at least two vertebral bodies, each of said bone screws having a leading end for insertion into the vertebral bodies and a trailing end opposite said leading end;

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 being adapted to receive a bone screw to attach for engaging said plate to the cervical spine; and

a lock comprising at least in part a threaded shaft member having a longitudinal axis to cooperatively engage said plate and a cover portion adapted to cover at least a portion of said trailing ends of at least two bone screws to prevent the inadvertent backing out of said at least two bone screws from said plate, said cover portion of said lock having a maximum dimension and a minimum dimension transverse to the longitudinal axis of said shaft, the minimum dimension being less than and generally perpendicular to the maximum dimension, the maximum dimension of said cover portion of said lock being generally transverse to the longitudinal axis of said plate to retain at least two bone screws to said plate.

22. The plate system of claim 21, wherein said plate includes a recess configured to receive at least a portion of the perimeter of said cover portion.

23. The plate system of claim 21, wherein at least two of said bone screw receiving holes lie along a line transverse to the longitudinal axis of said plate to overlie one of the cervical vertebral bodies.

24. The plate system of claim 21, wherein at least a portion of said lower surface of said plate is other than smooth.

25. The plate system of claim 21, wherein said lock is removably coupled to said plate.

26. The plate system of claim 21, further comprising at least a third bone screw receiving hole, said cover portion of said lock being configured to cover at least three of said bone screw receiving holes.

27. The plate system of claim 26, further comprising at least a fourth bone screw receiving hole, said cover portion of said lock being configured to cover at least four of said bone screw receiving holes.

28. The plate system of claim 21, wherein said lock comprises of a screw.

29. The plate system of claim 21, in combination with at least two bone screws each having a central longitudinal axis and being adapted to engage each of the at least two vertebral bodies, respectively, each of said bone screws having a leading end for insertion into the vertebral bodies and a trailing end opposite said leading end.

30. The plate system of claim 29, comprising at least in part of a bioresorbable material.

31. The plate system of claim 21, wherein at least a first pair of said bone screw receiving holes is transversely oriented side-by-side in said plate to overlie the anterior aspect of a cervical vertebral body, said cover portion of said lock being adapted to cover at least in part a portion of each of said transversely oriented side-by-side bone screw receiving holes.

32. The plate system of claim 21, in combination with an interbody implant.

33. The plate system of claim 21, in combination with a bone graft.

34. The plate system of claim 21, in combination with a bone growth promoting material.

35. The plate system of claim 34, wherein said bone growth promoting material is at least in part other than bone.

36. The plate system of claim 34, wherein said bone growth promoting material is at least in part bone.

37. The plate system of claim 34, wherein said bone growth promoting material includes at least one of bone morphogenetic protein, hydroxyapatite, and hydroxyapatite tricalcium phosphate.

38. The plate system of claim 21, wherein at least a portion of said lower surface comprises a bone ingrowth material.

39. The plate system of claim 21, wherein at least a portion of said lower surface of said plate includes a bone ingrowth surface.

40. The plate system of claim 21, wherein at least a portion of one of said plate and said lock is a bioresorbable material.