Spinal motion preservation assemblies

A spinal implant assembly for placement in a spine, the spinal implant assembly adapted to distribute load applied to the spinal implant assembly between:

• a membrane partially filled with elastically deformable material and
• a pivoting support member that can pivot relative to at least one of two support anchors implanted in adjacent vertebrae;
• the spinal implant assembly adapted for selective adjustment of an anchored spinal implant assembly to allow a change in the allocation of the load applied to the membrane partially filled with deformable material and the load applied through the support anchors to the adjacent vertebrae.

A spinal motion preservation assembly adapted for an assembly sequence allowing selective adjustment after anchoring in two adjacent vertebral bodies and placement of a volume of prosthetic nucleus material between the two adjacent vertebral bodies wherein the adjustment imposes a distraction to increase the distance between the two adjacent vertebral bodies.

A spinal motion preservation assembly adapted for an assembly sequence allowing selective adjustment after anchoring in two adjacent vertebral bodies and placement of a volume of prosthetic nucleus material between the two adjacent vertebral bodies wherein the adjustment increases the length of the spinal motion preservation assembly along an cephalad/caudal axis.

A spinal motion preservation assembly with a pivoting element located between two anchor assemblies, the spinal motion preservation assembly adapted for an assembly sequence so that after the spinal motion preservation assembly has been anchored to two adjacent vertebrae, provided with a prosthetic nucleus, and provided with the pivoting element such that the spinal motion preservation assembly may be selectively adjusted to alter the distribution of physiologic load between the load borne by prosthetic nucleus and load borne by the two anchor assemblies through the pivoting element.

A spinal implant assembly comprising:

• a first bone anchor placed in a first vertebral body, and
• a prosthetic nucleus placed into an intervertebral disc space adjacent to the first vertebral body, the prosthetic nucleus including an outer membrane and delivered prosthetic nucleus material placed into the outer membrane before the outer membrane detachment from a membrane delivery tool during removal of the membrane delivery tool from proximity to the intervertebral disc space.

The bone anchor of 30 wherein the engagable surface includes a set of slots accessible from the end of the bone anchor that receives the insert.

An insert for a bone anchor, the insert comprising:

• a first end that is inserted first into the bone anchor;
• a second end on the opposite end from the first end, the second end having a bearing surface for a pivot body;
• an elastically deformable component located between the first end and the second end so that the insert may be elastically deformed to temporarily reduce the distance from the first end to the second end.

The insert of 41 wherein the elastically deformable component is a spring.

The insert of 41 wherein the elastically deformable component is an elastomeric component.