Myelopathy due to hypoplasia of the atlas. A case report.

The authors report a 73-year-old woman who had spinal cord compression develop because of hypoplasia of the atlas associated with a retroodontoid pseudotumor diagnosed by magnetic resonance imaging. Radiographs of the cervical spine showed narrowing of the spinal canal at the level of the atlas and severe osteoarthrosis of the atlantoaxial joint without atlantoaxial subluxation. A remarkable neurologic recovery followed decompressive laminectomy of the atlas with posterior occipitocervical fusion. Postoperative magnetic resonance imaging showed significant reduction of the retroodontoid pseudotumor by fusion alone. The magnetic resonance imaging finding of spontaneous reduction of retroodontoid pseudotumor after posterior fusion argues against a need for transoral removal, which has a significant complication rate.