The lateral atlanto-axial joint as a source of headache in congenital atlanto-occipital fusion.

A 47-yr-old woman presented with severe right-sided neck pain and headache, predominantly in the right-occipital region, for 3 yrs. The symptoms persisted despite using nonsteroidal antiinflammatory medications and undergoing physical therapy. The patient's examination was unremarkable except for reduced neck motion and prominent right-occipital tenderness. Imaging showed congenital fusion of the atlanto-occipital joints bilaterally. A fluoroscopically guided diagnostic right-lateral atlanto-axial joint injection was positive. We are reporting the first case of clinically proven lateral atlanto-axial joint arthropathy with neck pain and headache in a patient with congenital atlanto-occipital joint fusion. Subsequently, the patient received a set of two therapeutic lateral atlanto-axial joint injections. She had remarkable improvement of her headache and neck pain. At 1-yr follow-up, the patient continued to have significant improvement of the right-sided neck pain and headache.