Spinal implants and methods to repair annular defects in intervertebral discs and provide dynamic stability to the spine in the vicinity of a repaired disc are described. Some implants include head and tail portions. In some embodiments, the head portion of an implant is enlarged relative to the tail portion. Some head portions and tail portions are adapted to support adjacent vertebrae and resist collapse of the intervertebral disc. Head portions provide a spacer function to maintain separation between adjacent vertebrae. A tapered portion of some implants engages end plates of adjacent vertebrae to resist forces tending to push the implant out of the intervertebral space. The tail portion of some implants includes a tail flange (which in some embodiments is of similar diameter to the head portion) that abuts extradiscal lips of the adjacent vertebrae and resists forces tending to push the implant deeper into the intervertebral space.