Indications and technique for the operative treatment of hypoplastic deformities of the odontoid process.

On the basis of four typical cases of congenital hypoplastic deformities of the odontoid process the clinical significance, symptoms, diagnosis and the indications for operative treatment of the malformations are described. It is further shown that these malformations lead to clinical manifestations only when associated with a primarily existing, or a later acquired inadequacy of the ligaments with movement-induced changes in the position of the atlas. The operative treatment recommended involves a special technique for a bilateral dorsal fixation with tibial grafts. By this operative technique a substantial or even completely stable fixation of the atlas can be achieved, in the acute phase by the stability of the tibial grafts and in the long term by the bony fusion which occurs.