A posterior vertebral stabilizer has a resilient member such as a linear spring, which operates in tension and compression. The resilient member may be kept straight by a stabilization rod extending through the spring, or by a telescoping assembly that encases the resilient member. The ends of the stabilizer are attachable to pedicles of adjacent vertebrae so that the stabilizer adds stiffness to control flexion and extension of the vertebrae. Two such stabilizers may be used, and may be connected together by a crosslink designed to limit relative rotation of the stabilizers. Thus, the stabilizers may restrict axial rotation and lateral bending between the vertebrae, while permitting stiffened flexion and extension. Such stabilizers help provide the stiffness of a healthy intervertebral disc. In the event that fusion of the joint becomes necessary, a set screw or other component may be used to further restrict flexion and extension.