Multi-variable-height fusion device

• US 6,641,614 B1
• Filed: 03/24/1998
• Issued: 11/04/2003
• Est. Priority Date: 05/01/1997
• Status: Expired due to Term

• Current Assignee: Zimmer Spine, Inc. (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Spinal Concepts Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Wagner, Erik J., Dinsdale, Michael C.
• Primary Examiner(s): Snow, Bruce
• Application Number:
  US09/046,759
• Time in Patent Office: 2,051 Days
• Field of Search: 623/17.15, 623/17.16, 623/17.11, 606/61
• US Class Current: 623/17.15
• CPC Class Codes: A61B 17/8875 Screwdrivers, spanners or wrenches
• CPC Class Codes: A61F 2/30724 Spacers for centering an implant in a bone cavity, e.g. in a cement-receiving cavity
• CPC Class Codes: A61F 2/30744 End caps, e.g. for closing an endoprosthetic cavity
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/442 Intervertebral or spinal discs, e.g. resilient non-disc-shaped intervertebral inflatable pockets A61F2/441; non-disc-shaped intervertebral fusion implants A61F2/4455
• CPC Class Codes: A61F 2/4455 for the fusion of spinal bodies, e.g. intervertebral fusion of adjacent spinal bodies, e.g. fusion cages intervertebral discs A61F2/442
• CPC Class Codes: A61F 2/4611 of spinal 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 2002/30131 horseshoe- or crescent- or C-shaped or U-shaped
• CPC Class Codes: A61F 2002/30143 hexagonal
• CPC Class Codes: A61F 2002/30158 trapezoidal
• CPC Class Codes: A61F 2002/30166 H-shaped or I-shaped
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/30324 differing in thickness
• CPC Class Codes: A61F 2002/30326 differing in height or in length
• CPC Class Codes: A61F 2002/30354 Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/3037 Translation along the common longitudinal axis, e.g. piston
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/30405 made by screwing complementary threads machined on the parts themselves
• CPC Class Codes: A61F 2002/30411 : having two threaded end parts connected by a threaded central part with opposite threads at its opposite ends, i.e. for adjusting the distance between both end parts by rotating the central part
• CPC Class Codes: A61F 2002/30495 : using a locking ring
• CPC Class Codes: A61F 2002/30507 : using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30515 : using a locking wedge or block
• CPC Class Codes: A61F 2002/30538 : for adjusting angular orientation
• CPC Class Codes: A61F 2002/3055 : for adjusting length
• CPC Class Codes: A61F 2002/30556 : for adjusting thickness
• CPC Class Codes: A61F 2002/30579 : with mechanically expandable devices, e.g. fixation devices
• CPC Class Codes: A61F 2002/30593 : hollow
• 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 2002/30616 : Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30624 : Hinged joint, e.g. with transverse axle restricting the movement
• CPC Class Codes: A61F 2002/30774 : internally-threaded
• CPC Class Codes: A61F 2002/30777 : Oblong apertures
• CPC Class Codes: A61F 2002/30785 : parallel
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/448 : comprising multiple adjacent spinal implants within the same intervertebral space or within the same vertebra, e.g. comprising two adjacent spinal implants
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2230/0013 : Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2230/0017 : Angular shapes
• CPC Class Codes: A61F 2230/0026 : trapezoidal
• CPC Class Codes: A61F 2230/0028 : Shapes in the form of latin or greek characters
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2250/0006 : for adjusting angular orientation
• CPC Class Codes: A61F 2250/0009 : for adjusting thickness
• CPC Class Codes: A61F 2250/0036 : differing in thickness
• CPC Class Codes: A61F 2250/0037 : differing in height or in length
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures

Abstract

Method and apparatus for promoting a spinal fusion between neighboring vertebrae are disclosed. Apparatus may be located within the intervertebral disc space and preferably includes a pair of engaging plates for contacting the vertebrae. An alignment device may be used to alter the vertical height between the engaging plates to customize the apparatus to fit a given patient. In one embodiment, the alignment device includes two turnbuckles and two pairs of cam blocks for adjusting the height between the engaging plates.

Claims

1. A spinal implant for facilitating fusion between neighboring vertebrae of a spine, comprising:

a bracket assembly having a first side edge located opposite a second side edge;

a pair of engaging plates configured to fit between and engage the vertebrae to maintain a disc space between the vertebrae during use, each engaging plate of the pair of engaging plates comprising a width substantially between the first side edge and the second side edge, and wherein an engaging plate of the pair of engaging plates is configured to move relative to the bracket assembly;

a first alignment device positionable between engaging plates of the pair of engaging plates and coupled to the bracket assembly, wherein activation of the first alignment device moves an engaging plate of the pair of engaging plates relative to the bracket assembly such that a first posterior height of the pair of engaging plates adjacent the first side edge increases and such that a first anterior height of the pair of engaging plates adjacent the first side edge increases;

a second alignment device positionable between the engaging plates of the pair of engaging plates and coupled to the bracket assembly, wherein activation of the second alignment device moves an engaging plate of the pair of engaging plates relative to the bracket assembly such that a second posterior height of the pair of engaging plates adjacent the second side edge increases and such that a second anterior height of the pair of engaging plates adjacent the second side edge increases; and

wherein the first alignment device and the second alignment device are independently operable during use to establish a desired separation between the vertebrae.

2. The spinal implant of claim 1, wherein an anterior height of the pair of engaging plates varies between a first location proximate the first side edge and a second location proximate the second side edge, and wherein a posterior height of the pair of engaging plates varies between a third location proximate the first side edge and a fourth location proximate the second side edge.

3. The spinal implant of claim 1, wherein an engaging plate of the pair of engaging plates comprises a protrusion, the protrusion configured to extend into a vertebra of the neighboring vertebrae during use.

4. The spinal implant of claim 1, further comprising a track in a first engaging plate of the pair of engaging plates, wherein a portion of the first alignment device couples to the track.

5. The spinal implant of claim 1, wherein the track comprises a sloped surface, and wherein the first alignment device comprises a sloped surface that fits within the track.

6. The spinal implant of claim 5, wherein movement of the sloped surface of the first alignment device on the sloped track changes a height of the pair of engaging plates.

7. The spinal implant of claim 1, wherein an engaging plate of the pair of engaging plates comprises biocompatible metal.

8. The spinal implant of claim 1, wherein an engaging plate of the pair of engaging plates comprises biocompatible ceramic.

9. The spinal implant of claim 1, wherein an engaging plate of the pair of engaging plates comprises biocompatible polymer.

10. The spinal implant of claim 1, further comprising bone graft material.

11. The spinal implant of claim 10, wherein the bone graft material is positioned between the engaging plates of the pair of engaging plates.

12. The spinal implant of claim 11, further comprising a retaining plate positioned between the engaging plates of the pair of engaging plates to keep the bone graft material within the spinal implant.

13. The spinal implant of claim 1, further comprising openings in an engaging plate of the pair of engaging plates.

14. The spinal implant of claim 13, further comprising bone graft material positioned between engaging plates of the pair of engaging plates.

15. The spinal implant of claim 1, further comprising openings through an engaging plate of the pair of engaging plates, and wherein an area of the openings is greater than about fifty percent of the total surface area of an outer surface of the engaging plate.

16. The spinal implant of claim 1, wherein the bracket assembly supports the first alignment device.

17. The spinal implant of claim 16, wherein the bracket assembly comprises grooves configured to conform to a curvature of the first alignment device.

18. The spinal implant of claim 1, wherein an engaging plate of the pair of engaging plates comprises a groove configured to conform to a curvature of the first alignment device.

19. A spinal implant for facilitating a fusion between neighboring vertebrae of a spine, comprising:

a bracket assembly having a first side edge located opposite a second side edge;

a pair of engaging plates adapted to fit between and engage the vertebrae to maintain a disc space between the vertebrae during use, each engaging plate of the pair of engaging plates comprising an inner surface, wherein an engaging plate of the pair of engaging plates is configured to move relative to the bracket assembly;

a first pair of cam blocks configured to be coupled to inner surfaces of engaging plates of the pair of engaging plates during use;

a second pair of cam blocks configured to be coupled to the inner surfaces of the engaging plates of the pair of engaging plates during use;

a first member coupled to the first pair of cam blocks and to the bracket assembly adjacent the first side edge, wherein the first member is configured such that rotation of the first member in a first direction moves the first pair of cam blocks such that a first posterior height of the pair of engaging plates adjacent the first side edge is increased and such that a first anterior height of the pair of engaging plates adjacent the first side edge is increased; and

a second member coupled to the second pair of cam blocks and to the bracket assembly adjacent the second side edge, wherein the second member is configured such that rotation of the second member in a second direction moves the second pair of cam blocks such that a second posterior height of the pair of engaging plates adjacent the second side edge is increased and such that a second anterior height of the pair of engaging plates adjacent the second side edge is increased.

20. The spinal implant of claim 19, wherein a posterior height of the pair of engaging plates varies between a first location proximate the first side edge and a second location proximate the second side edge such that the posterior height ranges between about a height of the pair of engaging plates at the first location and about a height of the pair of engaging plates at the second location.

21. The spinal implant of claim 19, wherein an anterior height of the pair of engaging plates varies between a first location proximate the first side edge and a second location proximate the second side edge such that the anterior height ranges from between about a height of the pair of engaging plates at the first location and a height of the pair of engaging plates at the second location.

22. The spinal implant of claim 19, wherein a posterior height of the pair of engaging plates varies between a first location proximate the first side edge and a second location proximate the second side edge such that the posterior height ranges between about a height of the pair of engaging plates at the first location and about a height of the pair of engaging plates at the second location and wherein an anterior height varies between a third location proximate the first side edge and a fourth location proximate the second side edge such that the anterior height ranges between about a height of the pair of engaging plates at the third location and about a height of the pair of engaging plates at the fourth location.

23. The spinal implant of claim 19, wherein the first member is oriented substantially parallel to and substantially adjacent the first side edge of the bracket assembly, and wherein the second member is oriented substantially parallel to and substantially adjacent the second side edge of the bracket assembly.

24. The spinal implant of claim 19, wherein the bracket assembly supports the first member and the second member.

25. The spinal implant of claim 24, wherein the bracket assembly comprises ends including arcuate grooves configured to conform to a curvature of the first member.

26. The spinal implant of claim 19, wherein the inner surfaces of the engaging plates of the pair of engaging plates include arcuate grooves configured to conform to a curvature of the first member.

27. The spinal implant of claim 19, wherein the inner surface of each of the engaging plates of the pair of engaging plates comprises a sloped track, and wherein the first pair of cam blocks couple to the sloped tracks such that rotation of the first member moves the first pair of cam blocks to adjust the first anterior height of the pair of engaging plates and the first posterior height of the pair of engaging plates during use.

28. The spinal implant of claim 19, wherein the inner surface of each of the engaging plates of the pair of engaging plates comprises a sloped track, wherein the first pair of cam blocks couple to the sloped tracks, and wherein each cam block of the first pair of cam blocks includes a first surface sloped to substantially conform to the sloped tracks in the inner surfaces of the engaging plates of the pair of engaging plates.

29. The spinal implant of claim 28, wherein the first surface of each cam block of the first pair of cam blocks and the sloped tracks in the inner surfaces of the engaging plates of the pair of engaging plates are configured such that movement of the cam blocks of the first pair of cam blocks toward each other increases the first anterior height of the pair of engaging plates and the first posterior height of the pair of engaging plates during use.

30. The spinal implant of claim 25, wherein the first surface of each cam block of the first pair of cam blocks and the sloped tracks in the inner surfaces of the engaging plates of the pair of engaging plates are configured such that movement of the cam blocks of the first pair of cam blocks toward each other decreases the first anterior height of the pair of engaging plates and the first posterior height of the pair of engaging plates during use.

31. The spinal implant of claim 19, wherein the spinal implant comprises a biocompatible material.

32. The spinal implant of claim 19, wherein outer surfaces of the engaging plates of the pair of engaging plates are substantially planar so as to inhibit subsidence of the vertebrae during use.

33. The spinal implant of claim 19, wherein the engaging plates of the pair of engaging plates comprise a plurality of openings to allow bone growth to occur through the engaging plates during use.

34. The spinal implant of claim 19, further comprising bone graft material packed between the engaging plates of the pair of engaging plates, wherein the engaging plates comprise a plurality of openings to allow bone growth to occur through the engaging plates during use.

35. The spinal implant of claim 19, further comprising protrusions extending from at least one of the engaging plates of the pair of engaging plates for enhancing engagement between a vertebra of the neighboring vertebrae and the spinal implant during use.

36. The spinal implant of claim 19, further comprising protrusions extending from at least one of the engaging plates of the pair of engaging plates for enhancing engagement between the spine and the spinal implant during use, the protrusions being adapted to extend into the spine.

37. The spinal implant of claim 19, further comprising bone graft material and a retaining plate, the bone graft material being packed between the engaging plates of the pair of engaging plates, the retaining plate being configured to keep the bone graft material between the engaging plates during use.

38. The spinal implant of claim 19, wherein at least one engaging plate of the pair of engaging plates comprises a face and openings extending through the face to allow bone growth to occur through the at least one engaging plate during use, the openings having a total area that is greater than about fifty percent of a total surface area of the face.

39. The spinal implant of claim 19, wherein at least one engaging plate of the pair of engaging plates comprises a face and openings extending through the face to allow bone growth to occur through the engaging plate during use, the openings having a total area that is between about sixty percent and about eighty percent of a total surface area of the face.

40. The spinal implant of claim 19, wherein an end of the first member includes an indentation adapted to accept a tip of an adjusting tool that rotates the first member.

41. The spinal implant of claim 40, wherein the adjusting tool comprises a tool selected from the group consisting of screwdrivers and allen wrenches.