Spinal motion preservation assemblies adapted for use in a spinal motion
segment are disclosed including the process for delivering and assembling
the spinal motion preservation assemblies in the spinal motion segment
via an axial channel created with a trans-sacral approach. The spinal
motion preservation assemblies make use of a dual pivot. A number of
different embodiments of spinal motion preservation assemblies are
disclosed which include at least one component adapted for elastic
deformation under compressive loads. The disclosed mobility preservation
assemblies provide for dynamic stabilization (DS) of the spinal motion
segment.