Atlantoaxial dislocation

The most frequent abnormalities are: Lumbosacral transitional anomalies Scoliosis Hyperyphosis Hyperlordosis Rectification Spondylolysis Spondylolisthesis Vertebral arthritis Facet arthritis Spinal stenosis Fissure, protrusion and disc herniation Postoperative fibrosis Dislocation of the coccyx Atlantoaxial Dislocation Sprain Whiplash Syndrome

Description

The second cervical vertebra (known as the "axis") has a bony protrusion in the front (known as "odontoid process"), which is raised until it forms a joint with the first cervical vertebra ( or "atlas").

The atlantoaxial dislocation is a fracture of the odontoid process, in such a way that the end which forms a joint with the atlas is separated from its base and kept in position only by the ligaments, which are not strong, joining it to the atlas.

As a result, an atlantoaxial dislocation is not really a form of common back pain, as it is due to a bone fracture caused by direct trauma.

How it happens

An atlantoaxial dislocation is a result of significant trauma, and is most frequently caused by traffic accidents.

Symptoms

Pain in the cervical area, sometimes with pain in the back of the neck or painful restriction of mobility.

Risks

Given that one end of the odontoid process is left free and is only joined by several ligaments which are not very strong, it may become displaced and thus compress the spinal cord. The compression of the spinal cord in this first cervical segment may produce severe neurological injuries or even death.

Hence, it is essential to avoid the possibility of displacement.

Diagnosis

In cases of atlantoaxial dislocation, medical history and physical examination provide very vague information and are not sufficient to arrive at a diagnosis. If the existence of an odontoid fracture and an atlantoaxial dislocation are suspected, physical examination must be performed with great care to avoid movement of the neck.

Radiography might be the method of choice, since it allows observation of the odontoid fracture, usually with a radiography performed with the mouth open.

If the fracture is very recent, it may not be revealed by radiography and may require a bone gammagraphy. Radiographical images which appear suspicious but not conclusive may require a Computerized Axial Tomography (CT Scan ) in order to confirm the diagnosis.

Treatment

Given that this is a fracture with a risk of displacement, it requires immobilization and, in light of the risk of possible displacement, its progress should be closely monitored.

Medication may be given for the pain. Vertebral manipulation is absolutely not-recommended.