What is Cervical Instability?

Cervical instability is a condition in which the vertebrae in the cervical spine move excessively compared to what is normal. This excessive motion is due mostly to loose or damaged ligaments in the cervical spine, which are failing to keep the vertebrae in alignment when the cervical spine is placed under stress and mobilized into various directions.

Cervical instability can be due to a number of medical conditions, but oftentimes is due to connective tissue disorders such as Ehlers-Danlos syndrome, an injury involving the cervical spine, or it can also occur as various structures in the cervical spine degenerate over time.

Cervical instability is typically diagnosed with a ‘dynamic’ scan. ‘Dynamic’ in this context simply means an imaging modality that allows you to see the bones and how the ligaments are performing while the bones are moving.

The Importance of Dynamic Imaging
Establishing a baseline with a flexion-extension MRI or digital motion X-ray is a vital part of the work-up in a cervical instability patient because it gives the provider a baseline to work with. These scans provide specific measurements of how much the ligaments are allowing the bones to move (which indirectly gauges ligament integrity).

Without the specific measurements that these scans provide, there is no way to confirm whether or not the patient has cervical instability. While symptoms and physical exam can give clues, actual measurements of bone translation (or movement) are the the most reliable way to confirm the diagnosis. These results can then be interpreted in context of the patient's symptoms and the physical exam.

Knowing the Type of Instability
If no dynamic diagnostic measurements are made, there is also no way to know what type of cervical instability a patient has. In a follow-up article, we will go into more detail on this, but it is important to understand that ligaments in the cervical spine protect the spine from excessive motion in certain directions.

Seeing which bones are moving excessively in the context of which direction the cervical spine is moving gives us good indicators of which ligaments are failing. Knowing which ligaments are failing to perform their job is critical to a successful workup. By deciphering this vital information, the physician is then able to more accurately determine which specific structures are likely causing symptoms for the patient.

Associated Symptoms
If cervical instability is confirmed, the subsequent symptoms that can be associated with this condition can include, but are not limited to:

• Neck pain
• Brain fog
• Headaches
• Fatigue
• Anxiety
• Tinnitus
• Dizziness/balance issues/syncope
• Elevated heart rate
• Visual disturbances

These symptoms derive from the fact that many vital structures are encased and protected by the cervical vertebrae, most notably the upper cervical vertebrae (C0–C2).

If these vertebrae are misaligned or experience excessive motion, they can place pressure on vital structures such as the:

• Brain stem
• Jugular vein
• Carotid artery
• Vagus nerve
• As well as many others

Each of these individual structures can influence the symptoms of the patient and change the presentation based off of which structures are being affected.

Citations: 

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