Atlanto-axial instability and spinal cord compression in children--diagnosis by computerized tomography.

Five children who were at risk for atlanto-axial instability underwent computerized tomography scanning of the cervical spine in flexion and extension to document the degree of bone instability and the presence or absence of spinal cord compression. Two patients had Morquio's syndrome, two had os odontoideum , and one had Klippel-Feil syndrome, and in all five the lateral radiographs of the cervical spine in flexion and extension were equivocal with regard to instability or were difficult to interpret because of the bone anomalies. The computerized tomography scan then provided a diagnosis by a non-invasion technique and quantitated the amount of compromise of the spinal cord by delineating flattening of the cord. The scan therefore helped the surgeon to decide if the spinal cord was at significant risk and if atlanto-axial fusion was advisable.