Intervertebral disc nucleus implants and methods
Nucleus pulposus implants that are resistant to migration in and/or expulsion from an intervertebral disc space are provided. In one form of the invention, an implant includes a load bearing elastic body surrounded in the disc space by an anchoring, preferably resorbable, outer shell. In certain forms of the invention, the elastic body is surrounded by a supporting member, such as a band or jacket, and the supporting member is surrounded by the outer shell. Kits for forming such implants are also provided. In another form of the invention, an implant is provided that has locking features and optional shape memory characteristics. In yet another aspect of the invention, nucleus pulposus implants are provided that have shape memory characteristics and are configured to allow short-term manual, or other deformation without permanent deformation, cracks, tears, breakage or other damage. Methods of forming and implanting the implants are also described, as are delivery devices and components thereof for delivering the implants.
1. An intervertebral disc nucleus pulposus implant, comprising:
a load bearing elastic body having shape memory and sized for placement into an intervertebral disc space, said body having a first arm, a second arm, and a central portion located between the first and second arms,
wherein said shape memory biases the body to a first configuration in which said body is folded in a manner that forms a first aperture between the first arm and the central portion and forms a second aperture between the second arm and the central portion,
said elastic body configurable into a second, straightened configuration for insertion through an opening in an intervertebral disc annulus fibrosis, wherein said shape memory is effective for returning said body to said first configuration after said insertion.
2. The implant of claim 1 , wherein the first arm includes a first end, the second arm including a second end, the first end facing and being spaced from the second end when in the first configuration.
3. The implant of claim 1 , wherein said first end and said second end each have an inner edge and an outer edge, at least one of said inner and outer edges having a rounded configuration.
4. The implant of claim 1 , wherein the central portion has a partial dome shape when viewed from a top view.
5. The implant of claim 1 , wherein the first region includes first inner side surface, the second region includes a second inner side surface, and the central portion includes an inner side surface,
wherein, when in the first configuration, the inner side surface of the first region is configured to contact the inner side surface of the central portion such that the first aperture is a closed or completely bounded aperture, and the inner side surface of second region is configured to contact the inner side surface of the central portion such that the second aperture is a closed or completely bounded aperture.
6. The implant of claim 1 , further comprising an external side surface including a plurality of grooves that relieve compressive force on the external side when the implant is in the second configuration.
7. The implant of claim 1 , wherein the central portion includes an inner side surface and an outer side surface, the inner and outer side surfaces having a substantially concentric curvature.
8. The implant of claim 1 , wherein the central portion and the first and second arms each include an inner side surface and an outer side surface, the outer sides surfaces of the central portion, the first arm, and the second arm cooperatively forming a kidney shape fittable within the nucleus region of the intervertebral disc space.
9. The implant of claim 1 , wherein the first and second apertures are arcuate.
10. The implant of claim 1 , wherein said elastic body is comprised of one or more of an elastomer and a hydrogel material.
11. The implant of claim 1 , wherein said body further includes an inner surface with projections extending therefrom, said projections extending into said first aperture.
12. The implant of claim 1 , wherein said elastic body has an outer surface having projections extending therefrom, said projections configured for enhancing fixation of said body in said intervertebral disc space.
13. (Previously presented The implant of claim 1 , wherein said body further comprises a reinforcing material at said inner fold surface.
14. The implant of claim 1 , wherein said body has at least one surface depression in its second configuration, said first aperture formed from said surface depression.
15. The implant of claim 1 wherein one of the first and second arms of said implant has a length greater than the other of the first and second arms.
16. The implant of claim 15 , wherein said first aperture has a cross-sectional shape selected from the group consisting of annular-shaped, elliptical-shaped, and star-shaped.
17. The implant of claim 1 wherein said body comprises a top surface for contacting an upper vertebral endplate of an intervertebral disc and a bottom surface for contacting a lower vertebral endplate of an intervertebral disc; said top and bottom surfaces configured to be complementary to the endplate they are in contact with.
18. The implant of claim 1 , wherein said body comprises a top surface for contacting an upper vertebral endplate of an intervertebral disc; a bottom surface for contacting a lower vertebral endplate of an intervertebral disc, and an external side surface, said body having at least one groove on said side surface, said groove extending between said top surface and said bottom surface.
19. An intervertebral disc nucleus pulposus implant, comprising:
a load bearing elastic body having shape memory and sized for placement into an intervertebral disc space, said body having a first arm, a second arm, and a central portion located between the first and second arms, each of the first arm, the second arm, and the central portion having inner facing surfaces and outer facing surfaces,
wherein said shape memory biases the body to a first configuration in which said first arm is folded in a manner that forms a first aperture between the first arm and the central portion and said second arm is folded in a manner that forms a second aperture between the second arm and the central portion, the first and second arms having respective first and second ends, the ends facing each other and being spaced apart from each other by a gap;
said elastic body configurable into a second, straightened configuration for insertion through an opening in an intervertebral disc annulus fibrosis, wherein said shape memory is effective for returning said body to said first configuration after said insertion.
20. The implant of claim 19 , wherein the inner side surface of the first arm is spaced apart from the inner side surface of the central portion by a distance less than a width of the first aperture, and wherein the inner side surface of the second arm is spaced apart from the inner side surface of the central portion by a distance less than a width of the second aperture.