Laterally expandable cage

• US 6,953,477 B2
• Filed: 03/03/2004
• Issued: 10/11/2005
• Est. Priority Date: 11/01/2002
• Status: Expired due to Fees

• Current Assignee: Warsaw Orthopedic Incorporated (Medtronic Plc)
• Original Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Inventors: Berry, Bret
• Primary Examiner(s): Robert, Eduardo C.
• Assistant Examiner(s): COMSTOCK, DAVID C
• Application Number:
  US10/792,331
• Publication Number:
  US 20040172134A1
• Time in Patent Office: 587 Days
• Field of Search: 606/61, 606/63, 606/76, 606/78, 623/17.11, 623/17.12, 623/17.13, 623/17.15, 623/17.16, 623/23.47, 623/23.5
• 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:

at least two lateral members, said lateral members each being shaped to engage apophyseal rings of opposing vertebrae when said lateral members are in an extended configuration, said lateral members each having a lateral side with a curved shape that coincides in shape to the apophyseal rings; and

a expansion mechanism coupled to said lateral members to extend said lateral members away from one another into said extended configuration at which said lateral members engage the apophyseal rings of the opposing vertebrae.

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

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

4. The implant of claim 1, further comprising a lock mechanism operable to lock said lateral members in said extended configuration.

5. The implant of claim 4, wherein said lock mechanism included lock cavities constructed and arranged to lock said lateral members in said extended configuration.

6. The implant of claim 4, wherein said lock mechanism includes a leaf spring.

7. The implant of claim 1, wherein at least one of said lateral members has a guide rail.

8. The implant of claim 7, wherein said guide rail has a dovetail cross-sectional shape.

9. The implant of claim 7, wherein said guide rail has an outer cutting edge constructed and arranged to cut the vertebrae during extension of said wings.

10. The implant of claim 1, further comprising a cage in which said lateral members are received.

11. A spinal implant, comprising:

at least two lateral members, said lateral members each being shaped to engage apophyseal seal rings of opposing vertebrae when said lateral member are in an extended configuration;

a expansion mechanism coupled to said lateral members to extend said lateral members away from one another into said extended configuration at which said lateral members engage the apophyseal rings of the opposing vertebrae;

wherein said expansion mechanism includes a shaft having threaded portions on opposite ends that threadedly enagaes said lateral members; and

wherein said shaft includes a gear positioned between said threaded portions for rotating said shaft.

12. A method, comprising:

inserting a spinal implant in a compact configuration between opposing vertebrae that have apophyseal rings, wherein the implant has an expansion mechanism coupled between at least two wings; and

expanding the wings from one another in a lateral direction between the opposing vertebrae with the expansion mechanism to an expanded configuration at which the wings each engage the apophyseal rings of both the vertebrae.

13. The method of claim 12, wherein:

the expansion member includes a threaded shaft; and

said expanding includes rotating the threaded shaft.

14. The method of claim 12, further comprising locking the wings in the expanded configuration.

15. The method of claim 14, wherein:

the expansion member includes a shaft with a gear;

the implant includes a leaf spring; and

said locking includes engaging the leaf spring with the gear.

16. The method of claim 14, wherein:

the expansion member includes a shaft;

the lateral members have lock cavities; and

said locking includes sliding the shaft into the lock cavities.

17. The method of claim 12, further comprising:

securing the spinal implant to a spinal inserter prior to said inserting.

18. The method of claim 17, wherein said expanding includes expanding the wings with the inserter.