What is Craniocervical Instability?

Craniocervical Instability (CCI) is a structural instability of the craniocervical junction.  This can lead to pathological deformity of the brainstem, spinal cord and cerebellum (hind brainstem).

It is thought that 1 in 15 people with Ehlers-Danlos syndrome go on to develop CCI due to lack of connective tissue support at the craniocervical junction.

How is CCI diagnosed?

One of the biggest hurdles is diagnosing CCI within the EDS community.  Often it is not found on regular supine (laying down) imaging and requires an upright MRI in flexion, extension and rotation.  A supine MRI may detect abnormalities and indicators of CCI however to obtain a full and accurate diagnosis upright imaging is required. The upright imaging allows gravity to take hold thus giving a clearer indication of the structures and by flexing and extending again you are getting a clear picture of how lax the ligaments are, range of movement and whether any compression of the brainstem and spinal cord is taking place.  At present in the UK there is only one upright scanner facility suitable for diagnosing CCI  which is based in London.  Please click the link which will take you directly to the facilities website.

Click the link for upright MRI facility website

In EDS patients CCI can be caused by an injury such as whiplash however often it has occurred gradually over the course of many years through repetitive stretch injuries often unbeknown to the sufferer until symptoms present and progress.

Having such loose ligaments in this crucial junction gives rise to numerous abnormalities-

  • A pannus formation can develop whereby pannus tissue invades the space between  a joint and articular cartilage.  This is often seen on the heads axis otherwise known as the Odontoid bone/peg.  This can grow in a tumor like fashion and compress the brainstem.
  • The very same bone (Odontoid) can become retroflexed.  Essentially the ligaments are not strong enough to hold the bone in place and become misaligned causing it to push backwards, compressing the brainstem.
  • Nerve dysfunction and cell death can occur due to the deformative stress of the cranio-cervical nerves.
  • Chiari malformation can occur whereby a part of the brain called the cerebellar tonsils herniate putting increased pressure on the brainstem and cerebellum , damaging them over time and potentially blocking the flow of cerebral spinal fluid.
  • Cranial settling can occur whereby the skull sinks downward onto the spine and in serious cases the tip of the odontoid projects above the opening of the bottom of the skull (foramen magnum).  The correct name for this is basilar invagination.


The symptoms of CCI can be broadranging and differ from one sufferer to another.  The symptoms can also be exaserbated by such things as bending, being upright for too long, turning your head, motion travel and much more.  Below is a list of some of the symptoms of CCI.

  • A constant to near constant headache.  You will hear patients with CCI describe this as a “headache like no other”. The head feels too heavy to carry and the analogy is often used of feeling like a bowling ball is balancing on a tooth pick or bobble head.
  • Neuralgia pain which particularly focuses on the back of the head (occiput) but can branch forward and irritate other cranial nerves effecting the teeth, face and other areas on the head.
  • A pressure headache which is aggravated by bending over, coughing, sneezing and such like.  This is caused by impaired CSF flow, the ‘proper’name for it being intracranial hypertension.
  • Nerve pain, muscle spasms and pain within the neck.
  • Vertigo and dizziness.
  • Dysautonomia- Due to the compression of the brainstem the autonomic nervous system can dysfunction giving rise to rapid heart rate, fainting, fatigue, blood pressure irregularities, heat intolerance, nausea and much more.
  • Facial pain and numbness.
  • Stroke-like symptoms and even stroke can occur.
  • Vision problems.
  • Impaired coordination and balance problems.
  • Ringing in the ears and hearing loss.
  • Choking.
  • Sleep apnea.
  • Paralysis
  • The list goes on……………

How is CCI treated?

After the diagnosis of CCI the immediate advice is to wear a hard supportive cervical brace, particularly when out and about and during travel when serious injury can occur.  In some parts of the world traction is carried out which involves your skull being pulled upward taking the pressure off the spinal cord and nerves to monitor symptom relief.  The mainstay of treatment for CCI is a craniocervical fusion which involves fusing the skull-C1-C2 with rigid hardware and bone matrix usually taken from your hip and/or illiac crest to support the fusion process. Your neck will then be immobilised for a period of time to allow the occipital and cervical bones to fuse together.

Further reading is available from the links below written by one of the worlds leading neurosurgeons Dr Fraser Hendseron.

Link 1- further information on CCI

Link 2- further reading on CCI

Link 3- further information on CCI

*I will discuss Craniocervical Instability in more depth throughout my blog from my experience living with it, testing, measurements and much more.  These blog posts will be quickly assessable from the category section in the sidebar*