Atlantoaxial instability / AA Luxation

What is AA luxation?

AA luxation is also called atlanto-axial malalignment and it is commonly a congenital abnormality (birth defect), however traumatic causes can also be seen. The malalignment is between the cervical vertebra 1 and vertebra 2 and causes spinal cord impingement.

Which breeds are commonly affected?

Small breeds toy dogs are most commonly affected, with Toy Poodles, Pekinese, Chihuahuas, and Yorkshires been over-represented. The clinical signs are commonly noted in congenital cases at less then one year of age, and for patients with traumatic cause, the signs can occur at any age.

What are the clinical signs for AA luxation?

Neck pain is the most common clinical signs, and commonly progresses to wobbliness and incoordination. Some patients, depending on the degree of spinal compression can develop complete paralysis.

How is AA luxation diagnosed?

The diagnosis of AA luxation is based on radiography (x-rays), history, clinical signs and breed of the patient.

How is AA luxation treated?

There are two different therapeutical approaches for AA luxation, conservative (medical management) and surgical.

The nonsurgical management includes exercise restriction, neck braces and pain medications for several months, with the goal to build up scar tissues. Full recovery has been seen with medical management, however there is always a risk for sudden dislocation of the vertebrae C1-2, which could lead to sudden death from trauma.

Due to the risk of recurrence of spinal cord trauma with medical management, surgery is the best option. The ultimate goal with surgery is to stabilize the C1-C2 or AA region permanently by relieving spinal cord compression. Implants are used to stabilize the two vertebrae.