The definition of instability by Posner's method proved useful for selecting elderly patients with instability for fusion treatment. Fusion with instrumentation should be performed on elderly patients with instability after decompression.

No abstract

Occipitocervical fusion with a rectangular rod is useful for treating atlantoaxial dislocation in children and yields excellent results because of the firm internal fixation it achieves. This surgery induced no apparent postoperative spinal deformations.

We investigated the usefulness of magnetic resonance imaging (MRI) in assessing cervical spinal cord injury in patients where there was no evidence of bone injury on radiographs, and examined the relationship between the MRI findings and the clinical prognosis of this injury. MRI allowed us to confirm directly the cause and severity of spinal cord compression in 30 of 31 cases. The patients with severe spinal cord compression demonstrated by MRI showed poor neurological improvement. In regard to the signal changes in the spinal cord, the patients who showed no signal change on T1-and T2-weighted images had a better prognosis. MRI is a very useful non-invasive adjunctive imaging modality for diagnosis of this injury and for the evaluation of the compressed spinal cord. It also demonstrates potential in predicting neurological recovery.