Patent ID: 8425562
Filing Date: 2013-04-23
Classification: A61B

Abstract:
1. A bone anchor-based spinal dynamic stabilization system, comprising: a. a first bone anchor assembly engageable with a first vertebra and comprising a cavity; b. a second bone anchor assembly engageable with a second vertebra and having an outer surface defining a semi-spherical articulation surface, the articulation surface being free of any gaps or protrusions; c. a resilient element comprising a resilient portion with a planar face that contacts the semispherical articulation surface and an end portion defined by an elongated protrusion configured for disposal in the cavity to engage the resilient element with the first bone anchor assembly; and d. at least one sheath having a proximal end and a distal end at least partially circumferentially surrounding and spaced from the articulation surface; wherein the sheath and the end portion are monolithic wherein the resilient element is configured to be separably engageable with the articulation surface of the second bone anchor assembly and is positioned between the first bone anchor assembly and the articulation surface of the second bone anchor assembly to resiliently resist the movement of the first bone anchor assembly and the second bone anchor assembly towards each other, wherein said bone anchor-based spinal dynamic stabilization system is configured to permit movement of said semi-spherical articulation surface between first, second and third positions; wherein in said first position said semi-spherical articulation surface is freely disengaged from said resilient element; wherein in said second position said semi-spherical articulation surface contacts said resilient element permitting movement between said first bone anchor and said second bone anchor relative to each other without compression of said resilient element, and wherein in said third position said semi-spherical articulation surface compresses said resilient element.