Called AAD for short, atlanto axial dislocation is a fracture of a joint that supports the vertebrae. A major risk in the case of AAD is spinal cord compression, which can cause severe neurological injuries.
What is AAD?
The first vertebra of the spine is the C1 cervical vertebra. This vertebra is also known as the atlas. Below the atlas is the second cervical vertebra C2, also known as the axis. The axis has a unique bony protrusion in the front called the odontoid process, which makes this joint more stable. However, under certain circumstances, the odontoid process can get fractured, resulting in a weaker joint between the atlas and the axis, held only by ligaments. This problem is referred to as atlanto-axial dislocation, AAD in short.
Causes for AAD:
Direct significant trauma, usually caused by traffic accidents account for majority of atlanto axial dislocations, that is when the odontoid process is fractured.
Atlanto axial dislocations can also occur without trauma in patients with rheumatoid arthritis, juvenile rheumatoid arthritis, or ankylosing spondylitis.
Symptoms of AAD:
- Pain in the neck area, especially in the back area is felt.
- Movement is painful and restricted. Spinal cord compression is a major risk in this event. The odontoid process may compress the spinal cord, causing severe neurological injuries and even death.
- Neurological damage may cause change in walking ability, weakness in the arms and legs, loss of bladder or bowel control and difficulty in breathing. Displacement and neck movements must be avoided at all costs.
To observe the odontoid process, an X-ray done with the mouth open is usually required.
Suspicious X-rays may require CT scan to further confirm the diagnosis. Here, medical history and physical examination offer little or no help. Great care must be taken not to move the neck.
If X-rays are normal and subluxation is still suspected, MRI, which is more sensitive, should be done. MRI also provides the most sensitive evaluation of spinal cord compression and is done immediately if cord compression is suspected.
Treatment for AAD:
- Strict immobilisation of the neck is paramount.
- Treatment includes symptomatic measures and cervical immobilisation, usually beginning with a rigid cervical collar.
- Close monitoring of the patient is essential due to the risk of displacement of the neck bones, potentially causing spinal cord compression and neurological damage.
- Pain killers are advised for the pain.
- Surgery may be needed to stabilise the spine.
Photograph via sxc.hu