Overview of Atlantoaxial Instability (Luxation) in Dogs
Atlantoaxial instability is a condition in which the first two cervical (neck) vertebrae are not firmly attached which can occur in dogs. Normally, the atlas (the first cervical vertebra) and the axis (the second cervical vertebra) are attached by a group of ligaments. They are further stabilized by a prominence on the axis called the dens that protrudes into a hole in the atlas.
Dogs with congenital atlantoaxial instability are born without ligament support to their atlantoaxial joint, and may also be born without a dens. Trauma to the neck can also cause tearing of the ligaments or fracture of the dens, resulting in atlantoaxial instability.
Atlantoaxial instability can lead to cervical spinal cord injury, the symptoms of which include: neck pain; a drunken, staggering gait; paralysis of all four legs; or sudden death.
Causes of Atlantoaxial Instability (Luxation) in Dogs
Breeds at risk for congenital atlantoaxial instability include all toy breeds, especially Chihuahuas, Pomeranians, Pekingese, toy poodles, and Yorkshire terriers. These dogs usually show signs at less than one year of age, and symptoms can occur after very mild trauma, such as jumping off furniture, which would be considered normal activity.
Any dog, young or old and of any breed, is at risk for atlantoaxial instability after a traumatic event, such as being hit by a car or being an unrestrained passenger in a car accident.
Diagnosis of Atlantoaxial Instability (Luxation) in Dogs
Treatment of Atlantoaxial Instability (Luxation) in Dogs
After surgery, the pet should be cage-rested and restricted from activity for about 4 to 6 weeks. Frequent re-check examinations by your surgeon are necessary to identify potential problems and correct them as soon as possible.
Dogs with this condition should not be bred, since there may be a genetic component to this condition.
In-depth Information on Atlantoaxial Instability (Luxation) in Dogs
The neck is made of seven vertebral bones, or cervical vertebrae, which are connected by ligaments. Each vertebra fits precisely with its neighbor to form a joint. The spinal cord is located in a tunnel within the vertebrae, where it is protected from injury.
The first cervical vertebra is called the atlas; it holds up the head like Atlas held up the world. The second cervical vertebra is called the axis. The atlantoaxial joint is held in place by several ligaments and by a bony prominence of the axis called the dens, which fits in a hole in the atlas.
If the ligaments or the dens do not develop correctly or are injured, the atlantoaxial joint becomes unstable. This places the delicate spinal cord at risk for injury. Symptoms of spinal cord injury vary with the severity of the injury. Dogs with mild cases may only show neck pain. Those with more severe cases can have an unstable, wobbly, drunken gait. And those with very severe cases can be completely paralyzed in all four legs, or suddenly die. Death is often due to injury to the respiratory center in the spinal cord, making the animal stop breathing.
Congenital atlantoaxial instability is usually seen in toy breeds less than one year of age. Breeds most often seen for this problem include the Chihuahua, Pomeranian, Pekingese, toy poodle, and Yorkshire terrier.
Dogs with congenital atlantoaxial instability are born without proper ligament support of their atlantoaxial joint, or are born without a dens, or both. The instability that is present can predispose the dog to a major spinal cord injury with only a minor incident, such as jumping off a piece of furniture.
Atlantoaxial instability can also develop in any dog after a major traumatic event, such as getting hit by a car or being an unrestrained passenger in a car accident.