[Arthrodesis of the sub-occipital spine by screwed occipito-cervical plate. Clinical case and technical notes]

The authors report a new technique in arthrodesis of the sub-occipital spine which has been experienced since 1973 in case of metastases at CI-C2 level. An occipitovertebral metal plate, inverted Y shaped has been realised after anatomical and biomecanical studies. It is adapted to the occipito-vertebral curvature and screwed in the articular processes of C3 and C4 (14 mm screw), and in the pedicles of C2 (32 mm screw). At the upper part, the occiptal ridge offers fixation by 12 and 14 mm Muller's screw. In addition CI is attached to the plate, by a nylon thread. After the report of the first clinical case with a nine month period of follow up technical features of the material as well as practical problems are exposed. Tomograms of the cervical spine as well as bilateral brachial angiography are of paramount value. The latter investigation may reveal anomalies of the vertebral artery that can hinder of forbid the pedicular fixation. Finally the authors discuss the extension of this technique to complexe trauma of the suboccipital column.