LATERALLY EXPANDABLE CAGE

• US 20040088054A1
• Filed: 11/01/2002
• Published: 05/06/2004
• Est. Priority Date: 11/01/2002
• Status: Active Grant

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Inventors: Berry, Bret
• Granted Patent: US 6,723,126 B1
• Time in Patent Office: Days
• US Class Current: 623/17.11
• 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 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/3039 with possibility of relative movement of the rib within the groove
• 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 2002/30523 by means of meshing gear teeth
• CPC Class Codes: A61F 2002/30525 Worm gears
• CPC Class Codes: A61F 2002/30556 for adjusting thickness
• CPC Class Codes: A61F 2002/30571 Leaf springs
• 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 2002/30845 with cutting edges
• CPC Class Codes: A61F 2002/30883 dovetail-shaped
• CPC Class Codes: A61F 2002/30904 serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/4627 with linear motion along or rotating motion about the instrument axis or the implantation direction, e.g. telescopic, along a guiding rod, screwing inside the instrument
• CPC Class Codes: A61F 2220/0025 Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2250/0009 for adjusting thickness

Abstract

A laterally expandable spinal implant includes a central body and two wings that are adapted to be received within an inner chamber formed within the central body. The wings have guide rails that fit into grooves defined in the central body. To ensure that the implant is properly secured, each guide rail has an outer end with a cutting surface that cuts into vertebral end plates when the wings are extended. The two wings are connected together through a central turnbuckle shaft that has geared teeth and threading on both ends that engage threaded cavities in the wings. Through the gear teeth, the turnbuckle shaft is able to be rotated so as to laterally extend the wings from the central member. A locking mechanism locks the turnbuckle shaft to prevent the wings from retracting.

Claims

1. A spinal implant, comprising:

a cage defining an interior cavity;

an expansion mechanism received in said cavity of said cage;

a pair of wings operatively coupled to said expansion mechanism, said wings each having opposing vertebrae engaging surfaces that are configured to engage opposing vertebrae; and

wherein said expansion mechanism is operable to laterally move said wings between the vertebrae from a compact configuration in which at least a majority of said wings are received in said cavity of said cage to an expanded configuration in which said wings extend from said cage with said vertebrae engaging surfaces on each of said wings engaging the vertebrae.

2. The implant of claim 1, wherein said expansion mechanism includes a shaft having threaded portions on opposite ends that threadedly engage said wings.

3. The implant of claim 2, wherein said shaft includes a gear positioned between said threaded portions for rotating the shaft.

4. The implant of claim 2, wherein said threaded portions are oppositely threaded and have equal thread pitch.

5. The implant of claim 2, further comprising a lock mechanism operable to lock said wings in said expanded configuration.

6. The implant of claim 5, wherein:

said lock mechanism includes lock cavities defined in said wings; and

said lock cavities are configured to prevent rotation of said shaft when said shaft is positioned within said lock cavities.

7. The implant of claim 6, wherein only a portion of each of said lock cavities is threaded.

8. The implant of claim 5, wherein said lock mechanism includes a leaf spring engaged to said cage, said leaf spring being operable to at least prevent rotation of said shaft in one direction.

9. The implant of claim 8, wherein said shaft includes a gear engageable with said leaf spring.

10. The implant of claim 1 further comprising a lock mechanism to lock said wings in an expanded configuration.

11. The implant of claim 10, wherein said lock mechanism included lock cavities constructed and arranged to lock said wings in said expanded configuration.

12. The implant of claim 10, wherein said lock mechanism includes a leaf spring coupled to said cage.

13. The implant of claim 1, wherein said cage has a generally rectangular cross-sectional shape.

14. The implant of claim 1, wherein said cage defines a tool opening for providing access to said cavity.

15. The implant of claim 1, wherein said cage defines wing openings on opposite sides of said cage in which said wings are slidably received.

16. The implants of claim 15, wherein:

at least one of said wing openings defines a guide channel; and

at least one of said wings has a guide member slidably received in said guide channel.

17. The implants of claim 16, wherein said guide member has a dovetail cross-sectional shape.

18. The implant of claim 17, wherein said guide member has a cutting edge operable to cut one of the vertebrae during extension of said wings.

19. The implant of claim 16, wherein said guide member has a cutting edge operable to cut one of the vertebrae during extension of said wings.

20. The implant of claim 1, wherein:

the vertebrae have apophyseal rings; and

said wings have a generally arcuate shape to coincide with the shape of the apophyseal rings of the vertebrae.

21. The implant of claim 1, wherein said cage has opposing surfaces configured to engage the vertebrae.

22. The implant of claim 21, wherein said opposing surfaces are textured surfaces to prevent expulsion of said implant.

23. The implant of claim 22, wherein said textured surfaces include ridges.

24. The implant of claim 1, wherein said vertebrae engaging surfaces of said wings are contoured to correspond in shape to the vertebrae.

25. The implant of claim 1, wherein at least one of said wings has a guide rail received in a guide rail channel defined in said cage.

26. The implant of claim 25, wherein said guide rail has a dovetail cross-sectional shape.

27. The implant of claim 25, wherein said guide rail has an outer cutting edge constructed and arranged to cut the vertebrae during extension of said wings.

28. The implant of claim 1, wherein said cage has oppositely facing vertebrae engagement surfaces and said interior cavity extends between said vertebrae engagement surfaces of said cage.

29. The implant of claim 1, wherein wings define an access opening for allowing access to said expansion mechanism when said wings are in said compact configuration.

30. A fusion device for implanting between opposing vertebrae that define a disc space, comprising:

a central member;

at least one pair of lateral members slidably coupled to said central member; and

means for extending said lateral members from said central member into the disc space between the vertebrae with each of said lateral members engaging both of the vertebrae.

31. The fusion device of claim 30, wherein said means for extending said lateral members includes a shaft with threaded portions coupled to said lateral members.

32. An apparatus, comprising:

a spinal implant including

a central member defining an interior cavity and a pair of openings defined on opposite sides of said central member that open into said interior cavity,

a pair of wings slidably received in said openings in said central member, and

a shaft coupled to said wings, said shaft having at least one threaded portion threadedly engaging at least one of said wings.

33. The apparatus of claim 32, wherein:

said openings have guide channels; and

said wings have guide rails slidably received in said guide channels.

34. The apparatus of claim 32, wherein said at least one threaded portion has a pair of oppositely threaded portions at opposite ends of said shaft.

35. The apparatus of claim 32, further comprising an inserter engaged with said implant to extend said wings.

36. The apparatus of claim 35, wherein said shaft on said spinal implant includes a gear.

37. The apparatus of claim 36, wherein said inserter includes:

an actuation knob;

a drive shaft coupled to said knob;

a drive gear coupled to said drive shaft; and

an intermediate gear engaging said drive gear and said gear on said shaft of said spinal implant.