System for stabilizing the vertebral column including deployment instruments and variable expansion inserts therefore

Abstract

A system is provided for stabilizing adjacent vertebra without excision of bone or resection of ligaments comprising an expansion device and a deployment system which includes a hollow expandable insert and an expansion insert. The expandable insert includes a cylindrical body having a pair of slots having a threaded outer surface. The expandable insert is located with the slots oriented perpendicular to the vertebral column between the vertebrae. The thread cuts into the cortical bone contiguous to the intervertebral space but not substantially into the cancellous bone. The expandable insert is internally threaded. The expansion insert is externally threaded and arranged to be screwed into a bore in the expandable insert by the deployment system, whereupon the slots open to spread the vertebrae apart. The deployment system includes a tool having projecting fingers located within the slots to enable the expandable insert to be screwed into the intervertebral space.