Multipiece allograft implant

• US 7,226,482 B2
• Filed: 09/01/2004
• Issued: 06/05/2007
• Est. Priority Date: 09/02/2003
• Status: Active Grant

• Current Assignee: Synthes USA LLC (Johnson & Johnson)
• Original Assignee: Synthes USA LLC (Johnson & Johnson)
• Inventors: Boyer, Michael L. II, Messerli, Dominique, Myer, Jacqueline, Angelucci, Christopher H.
• Primary Examiner(s): Willse; David H.
• Assistant Examiner(s): Blanco; Javier G.
• Application Number:
  US10/931,788
• Publication Number:
  US 20050113918A1
• Time in Patent Office: 1,007 Days
• Field of Search: 623/17.11, 623/17.16, 623/17.12, 623/17.13, 623/17.14, 623/17.15, 623/16.11, 623/23.51
• US Class Current: 623/17.11
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• 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 2002/30014 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2002/30032 differing in absorbability or resorbability, i.e. in absorption or resorption time
• CPC Class Codes: A61F 2002/30057 made from both cortical and cancellous adjacent parts
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/30448 using adhesives
• CPC Class Codes: A61F 2002/30492 using a locking pin
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30843 Pyramidally-shaped
• CPC Class Codes: A61F 2002/30904 serrated profile, i.e. saw-toothed
• 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 2250/0018 differing in elasticity, stiffness or compressibility
• CPC Class Codes: A61F 2250/003 differing in adsorbability or resorbability, i.e. in adsorption or resorption time

Abstract

An allogenic implant for use in intervertebral fusion is formed from two parts. The first part, composed of cortical bone, provides mechanical strength to the implant, allowing the proper distance between the vertebrae being treated to be maintained. The second part, composed of cancellous bone, is ductile and promotes the growth of new bone between the vertebrae being treated and the implant, thus fusing the vertebrae to the implant and to each other. The implant is sized and shaped to conform to the space between the vertebrae. Teeth formed on the superior and inferior surfaces of the implant prevent short-term slippage of the implant.

Claims

1. An intervertebral implant having superior and inferior surfaces each for contacting a vertebral endplate comprising:

a first part composed of cortical bone; and

a second part composed of cancellous bone;

wherein

the first part and the second part are connected with a dovetail joint, and along a single, continuous surface, to form a substantially solid implant;

each of the superior and inferior surfaces are formed by the combination of the first and second part;

substantially the entire superior and inferior surfaces of the first part further comprise a plurality of teeth; and

the superior and inferior surfaces of the second part further comprise a toothed section and a smooth section, wherein the smooth section has a greater area than the toothed section.

2. The implant of claim 1, wherein the teeth are arranged in a two dimensional array, with the teeth being of a pyramid shape.

3. The implant of claim 1, wherein the superior and inferior surfaces are parallel and are spaced by a distance that approximates that of an intervertebral disc.

4. The implant of claim 1, further comprising an exterior surface formed by the combination of the first and second parts wherein the exterior surface has been processed to a predetermined shape.

5. The implant of claim 1, wherein the implant further comprises a pin, wherein the pin connects the first part and the second part.

6. The implant of claim 1, wherein the first part and the second part are connected by an adhesive.

7. A method of manufacturing an intervertebral implant having a superior surface, an inferior surface, and an exterior surface, comprising the steps of:

forming a first part from cortical bone;

forming a second part from cancellous bone;

wherein the second part is larger than the first part;

connecting the first part with the second part using a dovetail joint; and

forming a plurality of teeth on the superior and inferior surfaces to form a superior toothed portion and an inferior toothed portion;

wherein the first part comprises more of the superior and inferior toothed portions than the second part.

8. The method of claim 7, wherein the step of forming a first part further comprises forming a male portion of the dovetail joint, and wherein the step of forming a second part further comprises forming a female portion of the dovetail joint.

9. The method of claim 8, wherein the step of forming a first part further comprises forming a hole in the male portion, and wherein the step of forming a second part further comprises forming a hole in the second part, and wherein the method further comprises the steps of:

forming a pin; and

inserting the pin through the holes in the male portion and the female portion after the first part is connected to the second part.

10. An intervertebral implant comprising:

a cortical portion having a first surface configured to engage a first vertebrae, a second surface configured to engage a second vertebrae, a connecting side surface, and an exterior side surface;

a cancellous portion having a third surface configured to engage the first vertebrae, a fourth surface configured to engage the second vertebrae, a connecting side surface, and an exterior side surface;

wherein the connecting side surface of the cortical portion and the connecting side surface of the cancellous portion are connected by a dovetail joint having a male portion and a female portion;

wherein a plurality of teeth are disposed along substantially the entire first and second surfaces of the cortical portion; and

wherein a plurality of teeth are disposed along only a portion of the third and fourth surfaces of the cancellous portion.

11. The implant of claim 10, wherein the plurality of teeth on the cortical and cancellous portion form a substantially continuous area that contains teeth distributed thereon.

12. The implant of claim 10, wherein a portion of the third and fourth surfaces of the cancellous portion are substantially without teeth.

13. The implant of claim 10, wherein the cortical portion forms the male portion of the dovetail joint, and wherein the cancellous portion forms the female portion of the dovetail joint.

14. The implant of claim 10, wherein the implant has a single dovetail joint.

15. The implant of claim 10, further comprising a pin.

16. An intervertebral implant comprising:

a cortical portion having a first surface configured to engage a first vertebrae, a second surface configured to engage a second vertebrae, a side surface, and a first toothed section disposed along the first surface;

a cancellous portion having a third surface configured to engage the first vertebrae, a fourth surface configured to engage the second vertebrae, a side surface, a second toothed section disposed on at least a portion of the third surface, and a first smooth section disposed adjacent the second toothed section;

wherein the cortical portion and the cancellous portion are connected by a dovetail joint; and

wherein the cancellous portion further comprises a ledge disposed between the second toothed section and the first smooth section.

17. The implant of claim 16, wherein the first and second toothed sections form a substantially continuous area that contains teeth distributed thereon.

18. The implant of claim 17, wherein the dovetail joint is disposed on at least a portion of the substantially continuous area that contains teeth distributed thereon.

19. The implant of claim 16, wherein the implant has a first height at the first toothed section, and a second height at the second toothed section.

20. The implant of claim 19, wherein the first height is substantially equal to the second height.

21. The implant of claim 16, wherein the first and second toothed sections and first smooth section are substantially coplanar.

22. The implant of claim 16, wherein the first smooth section has a greater area than the second toothed section.