Posterior fixation system

• US 20030004512A1
• Filed: 08/28/2002
• Published: 01/02/2003
• Est. Priority Date: 09/15/2000
• Status: Active Grant

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Inventors: Foley, Kevin T., Farris, Robert A., Poyner, Jeffrey Wade, Sasso, Ricardo, Papadopoulos, Stephen M.
• Granted Patent: US 7,699,872 B2
• Time in Patent Office: Days
• US Class Current: 606/61
• CPC Class Codes: A61B 17/7002 Longitudinal elements, e.g. rods
• CPC Class Codes: A61B 17/7032 Screws or hooks with U-shaped head or back through which longitudinal rods pass
• CPC Class Codes: A61B 17/7035 Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other
• CPC Class Codes: A61B 17/7037 wherein pivoting is blocked when the rod is clamped
• CPC Class Codes: A61B 17/7041 with single longitudinal rod offset laterally from single row of screws or hooks A61B17/7044 takes precedence
• CPC Class Codes: A61B 17/7044 also having plates, staples or washers bearing on the vertebrae
• CPC Class Codes: A61B 17/7049 Connectors, not bearing on the vertebrae, for linking longitudinal elements together A61B17/7055, A61B17/7053, A61B17/7019 take precedence
• CPC Class Codes: A61B 17/705 for linking adjacent ends of longitudinal elements
• CPC Class Codes: A61B 17/7055 connected to sacrum, pelvis or skull
• CPC Class Codes: A61B 17/7059 Cortical plates A61B17/7007, A61B17/7058 take precedence

Abstract

A posterior fixation system includes a saddle member, an anchoring member, an occipital plate, an occipital rod, and a cross-link connector. The anchoring member anchors the saddle member to bone. The saddle member includes a pair of upright portions that define a channel. The channel is adapted to receive an orthopedic rod, and the saddle member can include a hole to receive the anchoring member. The saddle member and the anchoring member can be coupled so as to allow multi-axial movement of the members. The anchoring member in one embodiment is a screw coupled to the hole of the saddle, and in another embodiment, the anchoring member is a hook. The offset member may be coupled to the saddle member to allow for offset connection of rods. Connection of individual rods can be accomplished by connecting the rods with the cross-link connector. The cross-link connector has an integrally formed cylindrical member that couples a pair of coupling portions together. The cylindrical member can be bent along multiple axes. The occipital plate secures the rods to the occipital bone of the skull. The occipital plate has a cross-shaped plate with a plurality of apertures defined in the plate and at least one saddle member coupled to the plate. Alternatively, the occipital rod can be secured to the occipital bone.

Claims

1. A multi-axial bone attachment assembly, comprising:

a saddle member having a plurality of upright portions that define a channel through said saddle member, said saddle member further having a hole therethrough bounded by an inner wall, said hole forming a lower opening in said saddle member;

a bone anchoring member extending through said opening, said bone anchoring member including a head portion and an anchoring portion; and

a washer having a recessed portion for accommodating an orthopedic rod and a radially extending projection, said washer being fitted within said hole of said saddle member and atop said bone anchoring member.

2. The assembly of claim 1, wherein said inner wall includes a groove, and said assembly further comprises a snap-ring fitted in said groove and over said washer to hold said washer in said hole of said saddle member.

3. The assembly of claim 2, wherein said upright portions include threaded portions, and said assembly further comprises a threaded member for engagement with said threaded portions.

4. The assembly of claim 3, wherein said upright portions are internally threaded, and said threaded member is an externally threaded set screw.

5. The assembly of claim 4, wherein said set screw includes an upper surface that is convexly rounded.

6. The assembly of claim 3, wherein said threaded portions have reverse angle threads.

7. The assembly of claim 1, wherein said washer includes an upper portion and a lower portion, said recessed portion being a part of said upper portion and said projection being a part of said lower portion.

8. The assembly of claim 7, wherein said inner wall includes a groove, and said assembly further comprises a snap-ring fitted in said groove and over said lower portion of said washer to hold said washer in said hole of said saddle member.

9. The assembly of claim 7, wherein said upper portion of said washer includes a plurality of recessed portions.

10. The assembly of claim 7, wherein said lower portion of said washer includes a plurality of projections.

11. The assembly of claim 1, wherein said upright portions include threaded portions, and said assembly further comprises a threaded member for engagement with said threaded portions.

12. The assembly of claim 1, wherein said anchoring member is a bone screw.

13. The assembly of claim 12, wherein said bone screw includes a head portion having a convex underside.

14. The assembly of claim 13, wherein said convex underside is spherical.

15. The assembly of claim 14, wherein said bone screw includes a portion having a thread with a load flank and a root surface, and the angle between said load flank and said root surface is acute.

16. The assembly of claim 15, wherein said angle is about 86 degrees.

17. The assembly of claim 1, wherein said anchoring member is a hook member.

18. The assembly of claim 17, wherein said anchoring portion includes a curved portion connected to said head portion and a straight portion connected to said curved portion, said head portion including a plurality of spherical portions for coupling said anchoring member to said saddle member.

19. The assembly of claim 1, wherein said upright portions each have a trough defined therein, said washer including a plurality of projections with each provided in one of said troughs.

20. The assembly of claim 1, wherein said lower opening includes a concave wall portion and a conical wall portion for allowing angular movement of said bone anchoring member.

21. A spinal implant system, comprising:

a saddle member having a plurality of upright portions that define a channel through said saddle member, said saddle member further having a transverse hole defined through said upright portions that is transverse with respect to said channel;

a bone anchoring member coupled to said saddle member for anchoring said saddle member to bone; and

an offset member adapted to couple to an orthopedic rod, said offset member having a body adapted to couple to said rod and a coupling member extending from said body through said transverse hole in said upright portions.

22. The system of claim 21, wherein said upright portions include threaded portions, and said system further comprises a threaded member for engagement with said threaded portions.

23. The system of claim 22, wherein said upright portions are internally threaded, and said threaded member includes an externally threaded set screw.

24. The system of claim 22, wherein said threaded portions have reverse angle threads.

25. The system of claim 21, wherein said anchoring member includes a hook member.

26. The system of claim 21, wherein said offset member includes a rod receiving channel defined in said body for receiving said rod.

27. The system of claim 26, wherein said offset member includes a threaded bore intersecting said rod receiving channel and a threaded set screw provided in said threaded bore.

28. The system of claim 26, further comprising a slot defined in said rod receiving channel.

29. The system of claim 21, wherein said body includes a pair of body members that define a channel in said body for receiving said rod.

30. The system of claim 29, wherein said offset member has a longitudinal axis extending along said coupling member, and said body members extend parallel to said longitudinal axis.

31. The system of claim 29, wherein said offset member has a longitudinal axis extending along said coupling member, and said body members extend perpendicular to said longitudinal axis.

32. The system of claim 29, wherein one of said body members has a threaded bore defined therein and a threaded set screw provided in said threaded bore.

33. The system of claim 21, further comprising a washer having a recessed portion adapted to accommodate said orthopedic rod and a radially extending projection, said washer being fitted within said saddle member.

34. The system of claim 33, further comprising a snap ring provided in said saddle for securing said washer in said saddle member.

35. The system of claim 21, further comprising said orthopedic rod coupled to said offset member.

36. The system of claim 35, wherein said orthopedic rod includes an occipital rod.

37. The system of claim 35, further comprising an occipital plate coupled to said rod, said plate including:

a cross-shaped member having a longitudinal axis connecting first and second longitudinal ends and a transverse axis connecting first and second transverse ends, said cross-shaped member having a plurality of apertures therethrough; and

a plate saddle member coupled to said cross-shaped member, said plate saddle member having a plurality of upright portions that define a channel through said plate saddle member, wherein said rod is coupled in said channel.

38. The system of claim 37, further comprising a cross-link connector having a pair of coupling ends each adapted to couple to a rod and a cylindrical member provided between said coupling ends, one of said coupling ends being coupled to said rod.

40. The plate of claim 39, wherein said plate includes a plurality of saddle members attached to said cross-shaped member, each of said saddle members having a plurality of upright portions that define respective channels through said saddle members.

41. The plate of claim 39, wherein said saddle member is integral with said cross-member.

42. The plate of claim 39, wherein said saddle member is pivotally coupled to said cross-member.

43. The plate of claim 39, wherein said saddle member is located at one of said first and second longitudinal ends.

44. The plate of claim 39, wherein said channel of said saddle member has an axis, and said channel axis is substantially perpendicular to said longitudinal axis of said cross-shaped member.

45. The plate of claim 39, wherein said cross-member has at least one of said apertures at each of said first and second transverse ends of said cross-member.

46. The plate of claim 39, wherein said apertures are bounded by a surface having a conical portion.

47. The plate of claim 46, wherein said surface has an upper conical portion and a lower conical portion.

48. The plate of claim 39, wherein said cross-shaped member is curved.

49. The plate of claim 39, wherein said cross-shaped member is curved so that said longitudinal axis has a curved portion and said transverse axis is substantially straight.

39. An orthopedic fixation plate, comprising:

a cross-shaped member having a longitudinal axis connecting first and second longitudinal ends and a transverse axis connecting first and second transverse ends, said cross-shaped member having a plurality of apertures therethrough; and

a saddle member coupled to said cross-shaped member, said saddle member having a plurality of upright portions that define a channel through said saddle member.

50. A cross-link connector, comprising:

a plurality of coupling ends each adapted to couple to an orthopedic rod; and

a cylindrical member integrally connected to said coupling ends, said cylindrical member having a cylindrical shape for permitting multi-axial bending of said cylindrical member.

51. The cross-link connector of claim 50, wherein each of said coupling ends includes a curved member that defines a cavity adapted to receive said rod.

52. The cross-link connector of claim 51, wherein each of said coupling ends includes a threaded bore and a set screw received in said bore for securing said rod.

53. The cross-link connector of claim 50, wherein said cylindrical member is arched between said coupling ends.

54. A multi-axial bone attachment assembly, comprising:

a saddle member having a plurality of upright portions that define a channel through said saddle member, said saddle member further having a hole therethrough bounded by an inner wall, said hole forming a lower opening in said saddle member;

a bone anchoring member extending through said opening, said bone anchoring member including a coupling portion provided in said hole for permitting multi-axial movement of said anchoring member and an anchoring portion; and

an expansion member coupled to said anchoring member for expanding said coupling portion to lock said anchoring member into position.

55. The assembly of claim 54, wherein said anchoring portion includes a hook member.

56. The assembly of claim 54, wherein said coupling portion has a substantially spherical shape.

57. The assembly of claim 54, wherein said coupling portion includes a plurality of part spherical members.

58. The assembly of claim 57, wherein said expansion member is coupled to said anchoring member between said part spherical members.

59. The assembly of claim 54, wherein said expansion member includes a set screw.

60. The assembly of claim 54, wherein said expansion member includes a tool engaging portion, a threaded portion engaged with said coupling member, and a conically shaped expansion portion provided between said tool engaging portion and said threaded portion.

61. The assembly of claim 54, wherein said upright portions include threaded portions, and said assembly further comprises a threaded member for engagement with said threaded portions.

62. The assembly of claim 61, wherein said threaded portions have reverse angle threads.