Craniocervical junction disorders are abnormalities of the bones that join the skull with the cervical spine.
The craniocervical junction is made up of the occipital bone and the first two cervical vertebrae: the atlas (C1) and the axis (C2). These abnormalities are especially concerning due to the important neurological structures that exist in this region, such as the brain stem and the cranial nerves as well as important blood vessels.
Craniocervical junction abnormalities might be caused by congenital disorders (present at birth), trauma or some bone diseases.
In general, the patient presents with headache and neck pain. If the spinal cord or the brain stem are compressed, other symptoms may appear like the feeling of electric shock or cramp down the back with neck flexion, muscle weakness, impaired sensation, difficulty in walking, difficulty in swallowing and other neurological symptoms.
Upon clinical suspicion, MRI, CT and dynamic imaging of the craniocervical junction should be requested to confirm the diagnosis.
Specific Disorders: they affect only the craniocervical junction such as platybasia, basilar invagination, atlas assimilation, atlanto-axial subluxation, atlas hypoplasia, Chiari malformation and os odontoideum.
General disorders: they may affect other parts of the body such as achondroplasia, Down syndrome, mucopolysaccharidosis and osteogenesis imperfecta.
Acquired disorders s:
Occur in adulthood as a result of trauma (accidents or falls) or other diseases (rheumatoid arthritis, Paget´s disease or bone tumors).
Surgery is necessary if there is instability of the craniocervical junction or neurological impairment. The goal of the surgery is to correct the deformity, decompress the neural structures and stabilize the craniocervical junction.
Realignment usually requires traction. Sometimes it is necessary to place a device attached to the skull called ‘halo vest’ for several weeks. Then after placing the device, x-rays must be taken to confirm stability and correct realignment of the structures.
If traction or manipulation are not effective or instability persists, a surgical procedure is required with the attempt to stabilize the bone structures and achieve spinal cord decompression. Several devices such as screws, rods, and metal plates could be used to stabilize temporarily the bone structures in their position until bone fusion occurs. The use of spinal navigation and intraoperative neurophysiological monitoring guarantees the maximum safety in this type of interventions.