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.
