HYBRID INTERVERTEBRAL SPINAL IMPLANT

• US 20100094426A1
• Filed: 10/13/2009
• Published: 04/15/2010
• Est. Priority Date: 10/14/2008
• Status: Abandoned Application

• Current Assignee: Praxis Powder Technology, Inc.
• Original Assignee: Praxis Powder Technology, Inc.
• Inventors: MacNeal, Tracy M., Walter, Mark, Grohowski, Joseph A. Jr.
• Application Number:
  US12/578,446
• Publication Number:
  US 20100094426A1
• Time in Patent Office: Days
• US Class Current: 623/17.16
• CPC Class Codes: A61F 2/447 substantially parallelepipedal, e.g. having a rectangular or trapezoidal cross-section
• CPC Class Codes: A61F 2002/30056 differing in radiographic density
• CPC Class Codes: A61F 2002/3008 radio-opaque, e.g. radio-opaque markers
• CPC Class Codes: A61F 2002/30331 made by longitudinally pushing a protrusion into a complementarily-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/30448 using adhesives
• CPC Class Codes: A61F 2002/30451 soldered or brazed or welded
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30769 madreporic
• CPC Class Codes: A61F 2002/30904 serrated profile, i.e. saw-toothed
• CPC Class Codes: A61F 2002/3092 having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/3093 for promoting ingrowth of bone tissue
• CPC Class Codes: A61F 2002/3097 using laser
• 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 2220/005 using adhesives
• CPC Class Codes: A61F 2220/0058 soldered or brazed or welded
• CPC Class Codes: A61F 2250/0032 differing in radiographic density
• CPC Class Codes: A61F 2250/0098 : radio-opaque, e.g. radio-opaque markers
• 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 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00131 : Tantalum or Ta-based alloys
• CPC Class Codes: A61F 2310/00185 : based on metal oxides
• CPC Class Codes: A61F 2310/00269 : based on metal carbides
• CPC Class Codes: A61F 2310/00299 : based on metal nitrides
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite
• CPC Class Codes: Y10T 29/49876 : by snap fit

Abstract

A spinal implant of hybrid construction. The implant includes both porous and radiolucent elements. In this manner, the implant allows for substantial fusing of vertebrae while simultaneously allowing for useful follow-on evaluations through imaging. Furthermore, in spite of the potentially differing material character of the porous and radiolucent elements, they may nevertheless be coupled together in an interlocking configuration such that the implant exhibits the behavior of a single unitary device.

Claims

1. A spinal implant for positioning at an intervertebral space and comprising:

a porous portion having a first surface for interfacing a vertebra defining the intervertebral space; and

a radiolucent body coupled to said porous portion at a second surface thereof, substantially opposite the first surface.

2. The spinal implant of claim 1 wherein said radiolucent body is coupled to said porous portion through interlocking engagement.

3. The spinal implant of claim 1 wherein said porous portion is metal.

4. The spinal implant of claim 3 wherein the metal is one of titanium, titanium alloy, cobalt/chromium alloy, tantalum, and stainless steel.

5. The spinal implant of claim 3 wherein said porous portion is one of a nitride, a carbide, and an oxide of the metal.

6. The spinal implant of claim 1 wherein said porous portion is a metal coated radiolucent material.

7. The spinal implant of claim 6 wherein the metal comprises titanium.

8. The spinal implant of claim 1 wherein said porous portion is one of a superior porous portion for interfacing the vertebra at a superior position relative to the intervertebral space and an inferior porous portion for interfacing the vertebra at an inferior position relative to the intervertebral space.

9. The spinal implant of claim 1 wherein said porous portion comprises pores having a major pore diameter of between about 70 microns and about 500 microns.

10. The spinal implant of claim 1 wherein said porous portion comprises pores having a minor pore diameter of between about 40 microns and about 225 microns.

11. The spinal implant of claim 1 wherein said porous portion has a porosity of more than about 45%.

12. The spinal implant of claim 1 wherein said porous portion has a compressive strength of at least about 25 MPa.

13. The spinal implant of claim 1 wherein said radiolucent body is of a cage-like configuration to accommodate bone material at an internal space thereof.

14. The spinal implant of claim 1 wherein said radiolucent body is a biocompatible polymer.

15. The spinal implant of claim 14 wherein the biocompatible polymer is polyetheretherketone.

16. The spinal implant of claim 14 wherein the biocompatible polymer includes an imaging contrast incorporated therein.

17. An intervertebral implant for positioning at a spine and comprising:

a radiolucent body; and

a porous portion for interlocking engagement with said radiolucent body at one side thereof and configured for interfacing bone of the spine at a substantially opposite side thereof.

18. The intervertebral implant of claim 17 wherein said radiolucent body comprises tracks extending therefrom to slidably receive mating portions extending from said porous portion to allow for the engagement.

19. The intervertebral implant of claim 17 wherein said radiolucent body is of a biocompatible polymer and said porous portion is of metal.

20. The intervertebral implant of claim 19 wherein said porous portion is of a size to be used for radiolocation without obstructing the biocompatible polymer.

21. A spinal implant comprising:

a superior porous metal portion having a first surface for interfacing a superior vertebra defining a superior side of an intervertebral space;

a polymeric radiolucent body coupled to a second surface of said superior porous metal portion substantially opposite the first surface; and

an inferior porous metal portion having a first surface for interfacing an inferior vertebra defining an inferior side of the intervertebral space and a second opposite surface coupled to said polymeric radiolucent body.

22. The spinal implant of claim 21 having a height of between about 5 mm and about 15 mm.

23. The spinal implant of claim 21 having a length of up to about 30 mm.

24. The spinal implant of claim 21 wherein each of said porous metal portions is of a height between about 0.75 mm and about 1.75 mm.

25. The spinal implant of claim 21 having a shape that is substantially one of horseshoe, circular, banana, block, and vertebral.

26. The spinal implant of claim 21 wherein the first surfaces comprise teeth.

27. The spinal implant of claim 21 wherein the first surfaces are of a roughness extending between about 150 microns and about 250 microns thereinto.

28. The spinal implant of claim 21 further comprising a coating of a calcium phosphate based ceramic at the first surfaces to promote vertebral bone ingrowth thereinto.

29. A method of forming a spinal implant for intervertebral placement, the method comprising interlockingly coupling a porous metal portion to a polymeric radiolucent body.

30. The method of claim 29 wherein said coupling further comprises snap fitting the porous metal portion on the polymeric radiolucent body.

31. The method of claim 29 wherein said coupling further comprises:

cooling of the polymeric radiolucent body from an oversized state into fitting engagement with the porous metal portion at an interface thereof; and

returning the polymeric radiolucent body to the oversized state to impart substantial compressive force at the interface.

32. The method of claim 29 further comprising applying an adhesive at a surface of one of the porous metal portion and the polymeric radiolucent body prior to said coupling.

33. The method of claim 32 wherein the adhesive is a cement of one of bone, cyanoacrylate, and acrylic.

34. The method of claim 32 wherein the adhesive is of a tailored viscosity to avoid significant capillary uptake into the porous metal portion.

35. The method of claim 32 further comprising texturing of the surface by one of blasting, sanding, brushing, and cutting prior to said applying.

36. The method of claim 29 further comprising:

roughening a surface of the porous metal portion; and

providing an osteoinductive agent at the surface to promote vertebral growth thereinto.