Occipitocervical Fusion

Indications

• Occipitocervical fusion is performed for craniovertebral junction (CVJ) instability.

• Posttraumatic: Atlantooccipital dislocation, complex fractures involving CVJ, unstable odontoid fractures with incompetence of the posterior ring of C1.

• Acquired instability secondary to infectious or inflammatory disease: rheumatoid arthritis, ankylosing spondylitis, Down syndrome, inflammatory bowel disease–associated arthropathy, pseudogout, ossification of posterior longitudinal ligament, chronic Grisel syndrome, CVJ tuberculosis, CVJ osteomyelitis.

• Neoplastic: Primary tumors of CVJ such as chordomas, chondromas, and osteoblastomas; metastatic CVJ disease.

• Congenital or developmental: anterior and posterior bifid arches of C1, congenital basilar invagination, Chiari malformation–associated basilar invagination, absent occipital condyles or absent C1 lateral masses, os odontoideum, unilateral atlas assimilation with chronic occipitocervical rotatory subluxation.

• Iatrogenic: Unstable craniocervical junction after transoral or endonasal endoscopic CVJ decompression, C1-2 pseudarthrosis, suboccipital craniectomy for Chiari malformation, extreme lateral transcondylar approach.