Craniocervical instability


Craniocervical instability is a medical condition where there is excessive laxity of the ligaments at the atlanto-occipital joint and the atlanto-axial joint, between the skull and the top two vertebrae. This results in excessive movement of the vertebrae which can cause neuronal injury and compression of nearby structures including the spinal cord, vertebral artery or vagus nerve, causing a constellation of symptoms. It is frequently co-morbid with atlanto-axial instability, Chiari malformation and tethered cord syndrome.
It is more common in people with a connective tissue disease, notably Ehlers-Danlos Syndrome, osteogenesis imperfecta and rheumatoid arthritis. It is often brought on by a trauma, frequently whiplash.

Symptoms and signs

The impact of craniocervical instability can range from minor symptoms to severe disability, with some patients being bed-bound. The constellation of symptoms caused by craniocervical instability has been labelled the cervico-medullary syndrome. Common symptoms include:
Symptoms are frequently worsened by a Valsalva maneuver or by being upright for long periods of time. Lying supine can bring short-term relief.

Diagnosis

Craniocervical instability is usually diagnosed through neuro-anatomical measurement using radiography. Upright magnetic resonance imaging is considered the most accurate method, and supine magnetic resonance imaging, CT scan or digital motion X-ray, or Digital X-ray are also used.
The measurements to diagnose craniocervical instability are:
Alternatively, craniocervical instability can be diagnosed if a trial of cervical traction, typically using a halo fixation device, results in a significant alleviation of symptoms.

Treatment

Conservative treatment of craniocervical instability includes physical therapy and the use of a cervical collar to keep the neck stable. Cervical spinal fusion is performed on patients with more severe symptoms. Prolotherapy, including with stem cells, is another treatment option used but there is limited scientific evidence to date.