Vertically expanding intervertebral body fusion device

• US 6,758,863 B2
• Filed: 12/12/2002
• Issued: 07/06/2004
• Est. Priority Date: 10/25/2000
• Status: Expired due to Term

• Current Assignee: Valve Holdings, LLC
• Original Assignee: SDGI Holdings Incorporated (Medtronic Plc)
• Inventors: Dickson, Andrew M., Estes, Bradley T.
• Primary Examiner(s): Isabella, David J.
• Assistant Examiner(s): Phan, Hieu
• Application Number:
  US10/317,660
• Publication Number:
  US 20030093154A1
• Time in Patent Office: 572 Days
• Field of Search: 623/13.11, 623/13.12, 623/13.18, 623/14.13, 623/16.11, 623/17-1-
• US Class Current: 623/17.16
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• 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 2/4465 having a circular or kidney shaped cross-section substantially perpendicular to the axis of the spine
• CPC Class Codes: A61F 2/4611 of spinal prostheses
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• 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 2002/286 Bone stimulation by mechanical vibrations for enhancing ossification
• 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 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30092 using shape memory or superelastic materials, e.g. nitinol
• 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 2002/30192 J-shaped
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/3055 for adjusting length
• CPC Class Codes: A61F 2002/30556 for adjusting thickness
• CPC Class Codes: A61F 2002/30593 hollow
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/30772 : Apertures or holes, e.g. of circular cross section
• CPC Class Codes: A61F 2002/30779 : arcuate
• CPC Class Codes: A61F 2002/30785 : parallel
• CPC Class Codes: A61F 2002/30789 : perpendicular with respect to each other
• CPC Class Codes: A61F 2002/30879 : Ribs
• CPC Class Codes: A61F 2002/30957 : using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30971 : Laminates, i.e. layered products
• CPC Class Codes: A61F 2002/444 : for replacing the nucleus pulposus
• CPC Class Codes: A61F 2002/448 : comprising multiple adjacent spinal implants within the same intervertebral space or within the same vertebra, e.g. comprising two adjacent spinal implants
• CPC Class Codes: A61F 2210/0004 : bioabsorbable
• CPC Class Codes: A61F 2210/0023 : operated at different temperatures whilst inside or touching the human body, heated or cooled by external energy source or cold supply
• CPC Class Codes: A61F 2210/0042 : using a fluid, e.g. circulating
• 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 2230/0041 : J-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0009 : for adjusting thickness
• 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

This invention relates to intervertebral spacers for use in orthopedic treatment of spinal defects. The intervertebral space is formed of a shaped memory polymer material. The spacer can be fabricated into a desired configuration and then deformed into an alternative or deformed configuration. Cooling the deformed spacer effectively freezes the spacer into its deformed conformation. The deformed configuration can be selected to facilitate implantation of the spacer into a prepared disc space between adjacent vertebrae. During operation, the surgeon can heat the spacer to allow it to revert to its original configuration. The spacer in its original conformation is sized to restore and/or maintain the adjacent vertebrae in a desired conformation and disc space height.

Claims

1. An intervertebral spacer for implantation between opposing endplates of adjacent vertebrae, said spacer comprising a body formed from a biodegradable shape memory polymeric material and having an upper first surface, an opposite second surface and a peripheral sidewall extending therebetween, said body provided in a first configuration and capable of deforming under selected stimuli to an expanded second configuration, wherein the upper surface is provided to bear against a first end plate of a first vertebra while the lower surface is provided to bear against a opposing endplate of an adjacent vertebra.

2. The spacer of claim 1 wherein the body is cylindrical.

3. The spacer of claim 1 wherein the body is kidney shaped.

4. The spacer of claim 1 wherein the body is C-shaped.

5. The spacer of claim 1 wherein the body is an elongate body having a longitudinal axis positioned to lie substantially parallel to the first surface.

6. The spacer of claim 1 wherein the body includes an interior cavity for receipt of an osteogenic material.

7. The spacer of claim 1 wherein at least one of the sidewall, first surface and the second surface has at least one opening extending therethrough.

8. The spacer of claim 1 wherein the stimuli includes thermal or photoradiation energy.

9. The spacer of claim 1 wherein the selected stimuli includes heating to a deformation temperature greater than about 37°

C.

10. The spacer of claim 9 wherein the body at a temperature below the deformation temperature exhibits a compression modulus comparable to that of cortical bone.

11. The spacer of claim 1 wherein the stimuli includes heating to a deformation temperature between about 40°

C. and about 100°

C.

12. The spacer of claim 11 wherein the deformation temperature is between about 40°

C. and about 65°

C.

13. The spacer of claim 1 wherein the polymeric material is a thermoplastic.

14. The spacer of claim 1 wherein the shaped memory polymeric material is selected from the group consisting of:

polylactide, polyglycolide, poly(lactide-co-glycolide), poly(ε

-caprolactone), poly(β

-hydroxybutyrate), poly(β

-hydroxybutyrate-co-hydroxyvalerate), and mixtures, copolymers and blends thereof.

15. The spacer of claim 1 wherein the body is adapted to withstand 500 Newtons compressive force without significant deformation when maintained below the deformation temperature.

16. The spacer of claim 1 wherein the peripheral sidewall comprises a first lateral wall portion, a second lateral wall portion and an end wall portion therebetween.

17. The spacer of claim 1 wherein said body deforms to said second configuration upon implantation in an intervertebral disc space.

18. The spacer of claim 7 wherein in the second configuration, said first bearing surface conforms to an opposing endplate of a first vertebra and said second bearing surface conforms to an opposing endplate of an second vertebra adjacent to said first vertebra.

19. An intervertebral spacer for implantation between adjacent vertebrae, said spacer comprising a body comprising a first bearing surface, an opposite second bearing surface, and a peripheral sidewall therebetween and composed of a biodegradable, shape memory polymeric material, said body capable of withstanding a compressive force of at least 500 Newtons without significant deformation when maintained at a temperature below a deformation temperature, yet capable of deforming above the deformation temperature.

20. The spacer of claim 19 wherein the body is cylindrical.

21. The spacer of claim 19 wherein the body is kidney shaped.

22. The spacer of claim 19 wherein the body is C-shaped.

23. The spacer of claim 19 wherein the body is an elongate body having a longitudinal axis positioned to lie substantially parallel to the first surface.

24. The spacer of claim 19 wherein the body includes an interior cavity for receipt of an osteogenic material.

25. The spacer of claim 19 wherein at least one of the sidewalls, the first surface and the second surface has at least one opening extending therethrough.

26. The spacer of claim 19 wherein the stimuli includes thermal or photoradiation energy.

27. The spacer of claim 19 wherein the stimuli includes heating to a deformation temperature between about 40°

C. and about 100°

C.

28. The spacer of claim 27 wherein the deformation temperature is between about 40°

C. and about 65°

C.

29. The spacer of claim 19 wherein the polymeric material is a thermoplastic.

30. The spacer of claim 19 wherein the shaped memory polymeric material is selected from the group consisting of:

polylactide, polyglycolide, poly(lactide-co-glycolide), poly(ε

-caprolactone), poly(β

-hydroxybutyrate), poly(β

-hydroxybutyrate-co-hydroxyvalerate), and mixtures, copolymers and blends thereof.

31. A method of orthopedic treatment, said method comprising:

preparing a disc space between adjacent vertebrae to receive a spacer to receive an intervertebral spacer,

implanting an intervertebral spacer in the prepared disc space, said spacer composed of a biodegradable, shape memory polymeric material and provided in a first configuration exhibiting a first external volume, and

subjecting said spacer to a selected stimuli wherein said spacer deforms to a second configuration exhibiting a second external volume greater than the first external volume.

32. The method of claim 31 wherein said subjecting comprises subjecting the spacer to a selected stimuli after the spacer has been implanted into the prepared disc space.

33. The method of claim 31 wherein the selected stimuli comprises heating the spacer to a temperature between about 40°

C. and about 60°

C.

34. The method of claim 31 wherein the body is cylindrical.

35. The method of claim 31 wherein the body is kidney shaped.

36. The method of claim 31 wherein the body is C-shaped.

37. The method of claim 31 wherein the body is an elongate body having a longitudinal axis positioned to lie substantially parallel to the first surface.

38. The method of claim 31 wherein the body includes an interior cavity for receipt of an osteogenic material.

39. The method of claim 31 comprising contacting the endplates with osteogenic material to promote spinal fusion.