Atlantoaxial fixation for craniovertebral anomaly associated with absent posterior elements of the axial vertebra: report of 3 cases.

This is a report of 3 relatively rare clinical cases in which the absence of posterior elements of the axis was associated with basilar invagination and multiple other craniovertebral junction musculoskeletal and neural abnormalities. Atlantoaxial fixation resulted in remarkable clinical recovery in all 3 cases. C2-3 fixation was not done, and bone decompression was not done. On the basis of their experience, the authors conclude that atlantoaxial fixation is a satisfactory form of surgical treatment in patients having an association of basilar invagination with absent posterior elements of axis.