Ratcheting Nucleus Replacement

A method of replacing a nucleus of an intervertebral disc located between a pair of vertebral bodies, the method comprising:

• accessing an annulus surrounding the nucleus;
• forming an opening in the annulus;
• inserting an intervertebral nucleus replacement implant wherein the implant comprises:
• a core member having a first height dimension along an axis defined by the pair of vertebral bodies and a cavity running perpendicular to the axis;
• and
• a fist post and a second post each having a bottom portion with a plurality of teeth, the first and second posts are disposed substantially in the center of the core member along the axis with the bottom portions of the first and second post extending into the cavity at opposite sides of the cavity;
• providing a plug having a tapered end with engaging mechanism that are configured to mate with the plurality of teeth of the bottom portions of the first and second post;
• inserting the plug into the cavity with the tapered end in first;
• and
• advancing the plug between the bottom portions of the first and second post until the core member expands from the first height dimension to a second height dimension.

An implant for replacing at least a portion of a nucleus of an intervertebral disc between a pair of vertebral bodies, the implant comprising:

• a first post and a second post each having a bottom portion with a plurality of teeth, the first and second posts are positioned along an axis defined by the pair of vertebral bodies with the bottom portions facing each other;
• a core member surrounding the first and second posts and having a cavity running perpendicular to the axis, the bottom portions of the first and second post extending into the cavity of the core member;
• and
• an insert having a tapered portion with engaging mechanisms configured to allow for ratcheting with the bottom portions of the first and second post;
• wherein the insert is advanced in the cavity between the bottom portions of the first and second post, thereby expanding the implant to a desired height.