[Mechanical principle of external fixation for dorsal stabilization of thoracic and lumbar vertebrae].

The mechanical principle of function of the Harrington instruments or of the spinal stabilization by means of plates does not meet the anatomical and mechanical conditions in instable fractures of the thoracic and lumbar spine sufficiently. The requested qualities in regard to fixation of the material, shortness of fusion distance, possibility of reduction and variability according to individual situations can be met only by the fixateur externe. Magerl was able to verify the correctness of this thesis by means of the fixateur externe constructed by himself. It was logic for us to practice the mechanical principle of the fixateur externe in using the implantation instruments which were positioned directly to the spine. The first instruments of this kind were introduced by Dick in 1983 and were used in Bad Wildungen since November 1983 successfully. The practical experiences of more than 40 operations using the Dick fixateur interne resulted in the development of own instruments applied by us since the beginning of 1985 as preliminary prototypes.