Patent ID: 8109975

Claim:
An assembly for dynamic stabilization of a spine, comprising: at least one mounting collar comprising a bore therethrough along a longitudinal axis; the collar having an outer surface that is longitudinally non-curving; the collar having first and second longitudinally-end faces facing in generally opposite directions; a spinal rod slidably extending through said bore; wherein the bore is defined by an interior wall with a continuously convexly curved profile with a medial first section of reduced size that tapers both inwardly and outwardly relative to the axis and respective end sections of relatively larger size; a first elastic element disposed on a first longitudinal side of the mounting collar and disposed beyond the first longitudinally-end face with respect to the medial first section; a second elastic element disposed on a second longitudinal side of the mounting collar opposite the first longitudinal side and disposed beyond the second longitudinally-end face with respect to the medial first section; wherein the mounting collar, first elastic element, and second elastic element are disposed such that longitudinal displacement of the mounting collar relative to the spinal rod causes the first or second elastic element to be longitudinally compressed.