Spinal fixator

Abstract

An adjustable spinal fixator for insertion between adjacent vertebrae comprises a contoured housing defining convex edges to fit within the concavity of the vertebral body. An externally threaded core extends through the housing, and a pair of internally threaded nut assemblies attach to the core member. Four crown members with teeth are separately mounted within the housing and retract and variably extend with the movement of the movable nuts on the core member. Two of the crown members extend and retract from the top of the housing, and the remaining two crown members extend and retract from the bottom of the housing. The spinal fixator is positioned between adjacent vertebrae with the crown members retracted so that the teeth are below the convex edges of the housing. Following placement, the crown members are extended outwardly from the top and bottom of the housing by rotation of the core member which causes the teeth to penetrate the bone at an angle to secure the spinal fixator in position. Preferably, a bone graft surrounds the implanted spinal fixator which defines apertures for bony ingrowth. Several sizes of spinal fixators exist to accommodate differing anatomies of the spine.

Dependencies are inferred from the claim text.