Posterior functionally dynamic stabilization system

摘要

A functionally dynamic stabilization unit and system for treatment of spinal instability are provided. Each unit, and collectively, the system, is configured to control flexion, extension and translation of the affected unstable vertebral area, thereby stabilizing the vertebral segments by restoring normal function. This is achieved by providing a unit and system that allow for lateral bending, axial compression, rotation, anterior segmental height adjustment, and posterior segmental height adjustment. The unit and system provide sufficient segmental stiffness, while also limiting, or controlling, the range of motion (i.e., sufficient stiffness in the neutral or active zone, while limiting or preventing motion outside of the active zone) to stabilize the vertebral segments. In use, the system mimics the natural movement of the normal spine. Furthermore, the system includes a rigid, fusion-promoting coupler configured for use in an adjacent level, or as a substitute for the functionally dynamic unit. The modularity of the system allows adjustment over time and easier revision surgery, and is configured for minimally-invasive, delivery or implantation.

主权项

1. A spinal stabilization unit, comprising:
a flexible coupler having a body, a pair of arms, the arms being located at opposed ends of the coupler, and a range-of-motion limiting mechanism configured to control an amount of bending, an amount of compression, and an amount of extension of the coupler; and an anchoring system including a plurality of bone anchors configured to cooperate with the arms of the flexible coupler to attach the coupler to bone; wherein the range-of-motion limiting mechanism comprises a sleeve extending internally from a first end of the coupler towards a second end of the coupler and having a narrowed distal opening, and an elongated body extending internally from the second end of the coupler towards the first end of the coupler and having an enlarged end disposed within the sleeve and dimensioned such that the enlarged end abuts the wall of the narrowed opening when the coupler is elongated or bent, and the sleeve abuts the second end of the coupler when the coupler is compressed.