DUAL ANCHOR PROSTHETIC NUCLEUS APPARATUS
A spinal mobility preservation apparatus and methods are disclosed. The spinal mobility preservation apparatus may include a proximal body, an intermediate body, a distal body, and an expandable membrane. The proximal body and the distal body secure the mobility preservation apparatus to adjacent vertebral bodies. At least one of an intermediate body and an expandable membrane secure the proximal body to the distal body and provide a degree of support to a spinal motion segment defined by the adjacent vertebral bodies. A single proximal body and an expandable membrane may also compose a spinal mobility preservation apparatus. The proximal body secured to one of a superior or an inferior vertebral body and the expandable membrane extending into the intervertebral disc space to support the spinal motion segment.
1 . An implantable spinal mobility preservation apparatus, comprising:
a proximal body defining a proximal lumen, the proximal body having a first retention structure configured to be secured in a caudad vertebral body;
a distal body having a second retention structure configured to be secured in a cephalad vertebral body; and
an expandable membrane having a proximal end and a distal end and defining an expansion chamber, with the proximal end of the expandable membrane secured to the proximal body and the distal end of the expandable membrane secured to the distal body, and the expandable membrane expandable from an unexpanded position to an expanded position, the expanded membrane in the expanded position defining a radial surface, a superior surface and an inferior surface the superior surface configured to support adjacent, superior vertebral body and the inferior surface configured to support an adjacent, inferior vertebral body.
2 . An implantable spinal mobility preservation apparatus, as in claim 1 , further comprising the expandable membrane having a greater diameter in the expanded position than the unexpanded position.
3 . An implantable spinal mobility preservation apparatus, as in claim 1 , further comprising the proximal body, the distal body and the expandable membrane defining and aligned along a longitudinal axis to facilitate the axial implantation.
4 . An implantable spinal mobility preservation apparatus, as in claim 3 , further comprising the combination of the proximal body, the distal body and the expandable membrane having an aspect ratio of greater than 1.
5 . An implantable spinal mobility preservation apparatus, as in claim 1 , further comprising a first ring positioned around the proximal end of the expandable membrane and the proximal body to secure the proximal end of the expandable membrane to the proximal body and a second ring positioned around the distal end of the expandable membrane and the distal body to secure the distal end of the expandable membrane to the distal body.
6 . An implantable spinal mobility preservation apparatus, as in claim 1 , further comprising the first retention structure formed as first threads and the second retention structure formed as second threads.
7 . An implantable spinal mobility preservation apparatus, as in claim 1 , further comprising a prosthetic nucleus material secured within the expansion chamber defined by the expandable membrane.
8 . An implantable spinal mobility preservation apparatus, as in claim 7 , further comprising a plug secured within the proximal lumen
9 . An implantable spinal mobility preservation apparatus, as in claim 7 , further comprising the expandable membrane is at least partially filled with the prosthetic nucleus material to position the expandable membrane in the expanded position.
10 . An implantable spinal mobility preservation apparatus, as in claim 9 , further comprising the combination of the expandable membrane and the prosthetic nucleus material enable the expandable membrane to transfer a component of axial compression into lateral force for absorption by the annulus.
11 . An implantable spinal mobility preservation apparatus, as in claim 1 , further comprising the proximal body configured in the shape of a rod and the distal body configured in the shape of a rod, the distal body substantially coaxial with the proximal body.