AIM: Neck pain is a common problem that may result from abnormalities in the soft tissues, bones and joints of the spine. However, upper neck and occipital pain syndrome due to unilateral idiopathic arthrosis of a C1-2 lateral articulation is a very rare condition.

MATERIAL and METHODS: We describe two patients with unilateral arthrosis of a C1-2 lateral articulation who were successfully treated with C1-2 fusion.

RESULTS: The patients presented with severe headache and/or neck pain. The diagnosis was made with a careful history and imaging studies, including X-ray films, CT scans, and MRI studies. Posterior atlanto-axial transfacet screw fixation was performed in both patients. There were no surgical complications.

CONCLUSION: C1-2 fusion is necessary to relieve intractable pain after failure of conservative treatment and/or invasive pain procedures in unilateral C1-2 arthrosis.