Patent ID: 7491236

Claim:
An implantable spinal mobility preservation apparatus, comprising: the proximal body having a first retention structure comprising external threads configured to be secured in a caudad vertebral body and, the proximal body having internal threading within the proximal lumen; the distal body having a second retention structure comprising external threads 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, the proximal body, the distal body and the expandable membrane defining a longitudinal axis and the first retention structure substantially coaxially aligned with the longitudinal axis and the second retentions structure substantially coaxially aligned with the longitudinal axis to facilitate the axial implantation and with the combination of the proximal body, the distal body and the expandable membrane having an aspect ratio of greater than 1.