Occipitocervical (craniocervical) fusion

What it is

Occipitocervical (craniocervical) fusion is a surgery that joins the skull (occiput) to the upper cervical spine using hardware and bone graft. In Chiari malformation, it is used when there is craniocervical instability — abnormal movement between the skull and the upper spine.

Understanding Occipitocervical (craniocervical) fusion

When the connection between the skull and the upper spine is unstable (as can occur with connective-tissue conditions, certain bony abnormalities, or after extensive bony removal), fusion stabilizes the junction by permanently joining the bones, using screws, rods, and bone graft that heals into a solid union. This prevents the abnormal movement that can compress the brainstem or spinal cord and contribute to symptoms. Fusion is often a component of complex Chiari surgery, where it may be combined with decompression and, sometimes, procedures to relieve front-side compression (such as odontoidectomy). Because fusion permanently limits motion at the joined levels, it is reserved for cases where instability is significant. The decision is individualized. Understanding occipitocervical fusion clarifies a stabilizing surgery used when instability accompanies Chiari.

Why it matters

Understanding occipitocervical fusion helps families see how, when instability accompanies Chiari, joining the skull to the upper spine stabilizes the junction — often as part of complex Chiari surgery — though it permanently limits some neck motion.