Cervical myelopathy caused by anomalies at the level of atlas.

Study Design. Case report. Objective. To report a case of cervical myelopathy due to simultanous anomalies at the level of atlas involving hypoplasia of the posterior arch of the atlas, partial ossification of the transverse atlantal ligament, and hypertrophy of the dens. Summary of Background Data. Hypoplasia of the posterior arch of the atlas, ossification of the transverse atlantal ligament, and hypertropthy of the dens are all individually very rare clinical entities. We are not aware of previous reports describing the association of hypoplasia of the posterior arch of the atlas, partial ossification of the transverse atlantal ligament, and hypertrophy of the dens. Methods. The patient's medical history, physical examination, and radiographic evaluation are examined. Surgical treatment and clinical outcome are reported. In addition, available literature is also reviewed. Results. The patient's neurologic symptoms significantly improved after posterior decompressive surgery. Conclusion. We believe this is the first case of cervical myelopathy caused by simultaneous anomalies at the level of atlas involving hypoplasia of the posterior arch of the atlas, partial ossification of the transverse atlantal ligament, and hypertrophy of the dens. Surgical intervention improved the neurologic impairment.