[Cross stabilization of the internal fixator of the spine].

The "Internal Fixator" for stabilizing the dorso-lumbar spine represents an effective and meanwhile established device to neutralize flexion-bending and sagittal shearing forces. Because of the possible movement of the Schanz' screws in the bone and within the connection clamps, this device does not withstand torsional and frontal plane shearing forces after postinjury or postlaminectomy instability. Therefore, a cross-link device, adaptable to the "Internal Fixator" has been developed. Biomechanical testing against torsion and frontal plane bending moments have shown very low stability resulting in lateral displacement of the fixation device without cross-linking. The diagonal bracing with two wire cerclages does not significantly increase the stability. The recently developed cantilever cross-link device completes the two longitudinal bars to a frame construction and increases therefore the torsional and frontal plane stability for over 70%. This supplementary device is easy to apply to the "Internal Fixator" and has been successful in clinical practise.