Modular interbody fusion implant

• US 20030040799A1
• Filed: 10/16/2002
• Published: 02/27/2003
• Est. Priority Date: 01/22/2001
• Status: Active Grant

• Current Assignee: Eddie F. Ray III, Jeffrey Kozak, Lawrence M. Boyd
• Original Assignee: Eddie F. Ray III, Jeffrey Kozak, Lawrence M. Boyd
• Inventors: Boyd, Lawrence M., Ray, Eddie F. III, Kozak, Jeffrey
• Granted Patent: US 6,896,701 B2
• Time in Patent Office: Days
• US Class Current: 623/17.11
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• 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 2002/30004 the prosthesis being made from materials having different values of a given property at different locations within the same prosthesis
• CPC Class Codes: A61F 2002/30057 made from both cortical and cancellous adjacent parts
• CPC Class Codes: A61F 2002/30131 horseshoe- or crescent- or C-shaped or U-shaped
• CPC Class Codes: A61F 2002/30133 kidney-shaped or bean-shaped
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/30448 using adhesives
• CPC Class Codes: A61F 2002/30507 using a threaded locking member, e.g. a locking screw or a set screw
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30772 Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30828 parallel
• CPC Class Codes: A61F 2002/30831 perpendicular with respect to each other
• CPC Class Codes: A61F 2002/30904 serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/4485 comprising three or more 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 2220/005 using adhesives
• CPC Class Codes: A61F 2230/0013 : Horseshoe-shaped, e.g. crescent-shaped, C-shaped, U-shaped
• CPC Class Codes: A61F 2230/0015 : Kidney-shaped, e.g. bean-shaped
• CPC Class Codes: A61F 2250/0014 : having different values of a given property or geometrical feature, e.g. mechanical property or material property, at different locations within the same prosthesis

Abstract

An interbody fusion device for engagement between vertebrae includes a pair of lateral spacers for spacing the vertebrae, and a connecting member adapted to couple together the lateral spacers when inserted between the vertebrae. The connecting member, individual lateral spacers, or the entire spinal spacer can be made of bone in order to promote fusion of the vertebrae. The modular construction permits use of bone segments otherwise unsuitable due to size or strength in stable fusion devices.

Claims

1. A method of assembling a spinal implant, comprising:

providing a connecting member and a pair of lateral spacers, wherein the lateral spacers are each made of bone remnant and have medial sides defined at least in part by a medullary canal;

inserting the lateral spacers in a disc space between adjacent vertebrae with the medial sides facing one another, wherein the vertebrae have apophyseal rings;

spreading the lateral spacers apart from one other to positions along the apophyseal rings of the vertebrae; and

connecting together the lateral spacers with the connecting member by inserting the connecting member between the medial sides of the lateral spacers.

2. The method of claim 1, wherein:

the lateral spacers have slots on the medial sides;

the connecting member has a pair of rails; and

said connecting includes sliding the rails of the connecting member into the slots in the lateral spacers.

3. The method of claim 1, wherein:

the lateral spacers have rails on the medial sides;

the connecting member has a pair of channels; and

said connecting includes sliding the rails of the lateral spacers into the slots in the connecting member.

4. The method of claim 1, further comprising:

wherein the connecting member has a central opening defined by a second medullary canal portion; and

packing osteogenic material into the central opening.

5. The method of claim 1, wherein said connecting includes attaching a second connecting member between the lateral spacers to define a central opening between the lateral spacers.

6. The method of claim 5, further comprising packing osteogenic material into the central opening, wherein the second connecting member is made of bone.

7. A method of manufacturing a spinal spacer, comprising:

obtaining a first piece of bone remnant having a portion thereof defined by a first medullary canal portion;

defining a first coupling structure on the first medullary canal portion of the first piece; and

obtaining a second piece of bone remnant having a portion thereof defined by a second medullary canal portion;

defining a second coupling structure on the second medullary canal portion of the second piece;

defining at least a pair of third coupling structures on a third piece that are configured to engage the first and second coupling structures.

8. The method of claim 7, wherein:

said defining the first coupling structure includes forming a first channel in the first medullary canal portion of the first piece;

said defining the second coupling structure includes forming a second channel in the second medullary canal portion of the second piece; and

said defining at least the pair of third coupling structures includes forming a pair of rails on opposite sides of the third piece.

9. The method of claim 8, further comprising engaging the pair of rails on the third piece with the first channel and the second channel.

10. The method of claim 7, further comprising attaching the third piece between the first piece and the second piece.

11. The method of claim 7, wherein said defining at least the pair of third coupling structures includes shaping the pair of third coupling structures from bone.

12. The method of claim 7, comprising

shaping a first pair of grooved vertebrae engaging surfaces on the first piece;

shaping a second pair of grooved vertebrae engaging surfaces on the second piece; and

shaping a third pair of grooved vertebrae engaging surfaces on the third piece.

13. The method of claim 12, further comprising:

beveling a first lateral side of the first piece; and

beveling a second lateral side of the second piece.

14. The method of claim 7, wherein:

the first medullary canal portion defines a concave surface; and

said defining the first coupling structure includes forming a first channel in the first medullary canal portion of the first piece in which a portion of the first channel is interrupted by the concave surface.

15. A spinal implant for engagement between vertebrae, comprising:

at least two lateral spacers made of bone remnant, said lateral spacers each having opposite lateral and medial sides, wherein at least a portion of one of said medial sides is defined by at least a portion of a medullary canal wall; and

a separate connecting member connected to said lateral spacers at said medial sides.

16. The implant of claim 15, wherein said connecting member has a pair of rails, and wherein each of said medial sides of said lateral spacers has a channel defined therein to engage said rails.

17. The implant of claim 16, wherein:

said lateral spacers each has a posterior end and an anterior end;

said anterior end defines an anterior end wall;

said medullary canal wall defines a concave medial surface; and

said channel is interrupted by said concave medial surface and resumes at said posterior end.

18. The implant of claim 15, wherein said lateral sides each has a convex arcuate shape to coincide with an apophysis ring of the vertebrae.