An improved flexible component used for dynamic stabilization of spinal segments for the treatment of vertebrae deformities and injuries and for the replacement of a complete or segment of the body of a vertebra in the spine is described. The flexible component is comprised of a solid, suitable implant material with a longitudinal bore the entire length and an appropriately formed slot which extends spirally around the shaft either continuously or segmentally. The flexible component may be encapsulated, fully or partially, in a suitable implant grade elastomeric resilient material. When used for a dynamic stabilization device, the component is attached to the vertebral bodies by pedicle screws know to those in the art. When used as a vertebral replacement device, attached to the components opposite ends are members for attachment to the adjacent vertebra that allow for height and angular adjustment.