Fusion of spine, occipito-atlanto-axial region

This code describes a pathological fusion of the vertebrae in the uppermost cervical spine, specifically involving the occiput (base of the skull), atlas (C1), and axis (C2). This can be congenital or acquired, leading to restricted neck movement and potential neurological compromise.

Use this code when documentation clearly indicates a diagnosis of abnormal fusion within the occipito-atlanto-axial complex. This often presents with symptoms like torticollis, limited range of motion, or signs of spinal cord compression. Supporting documentation includes imaging reports (X-ray, CT, MRI) confirming the fusion.

• Differentiate from surgical fusion; this code is for a pathological fusion.
• Specify laterality if applicable and documented, though this region is typically midline.
• Consider additional codes for any associated neurological deficits or congenital anomalies.