What is cervical vertebral instability?
Cervical vertebral instability, also known as cervical stenosis, cervical spondylopathy, or wobbler syndrome, is caused by compression of the spinal cord, usually at the base of the neck.
How does it affect dogs?
Although spinal cord compression occurs in the neck, the hind legs are often affected first. The mildest form of cervical vertebral instability results in stumbling or irregular walking or running. This incoordination can progress to a wobbly gait, hence the term wobbler syndrome. In severe cases, the dog may suddenly develop total paralysis of all four limbs.
What causes cervical vertebral instability?
One or more of the vertebrae at the base of the neck (cervical vertebrae) may be deformed or otherwise develop instability, putting abnormal pressure on the spinal cord. This pressure compresses and damages the nerves that transmit information to the limbs, causing paresis (weakness) or paralysis to sometimes occur.
My dog suddenly became paralyzed. Is this part of the disease?
Initially, the pressure affects your dog's ability to move normally, but this slight incoordination may be difficult to detect. The incoordination, however slight, can put extra stress on the intervertebral discs that act as shock absorbers. If these discs rupture, they put sudden and excessive pressure on the spinal cord and sudden paralysis may result.
I am told that only large-breed dogs are affected. Is this true?
Yes, the condition is most prevalent in Great Danes and the doberman pinschers, but basset hounds, Saint Bernards, old English sheepdogs, borzois, and pointers are also commonly affected.
There appears to be variation in the age of onset based on breed. For example, Great Danes are usually affected when they are young, about 1 to 3 years of age, whereas doberman pinschers and other breeds are usually 6 to 9 years old before any signs are apparent.
How is the condition diagnosed?
Breed and clinical signs are good indicators of cervical vertebral instability. With your dog anesthetized or sedated, your veterinarian will take X-rays (radiographs) of their neck, which often reveal abnormalities affecting the vertebrae at the base of the cervical spine. Definitive diagnosis requires myelography, computed tomography (CT) scans, or magnetic resonance imaging (MRI).
Myelography is another diagnostic test that can be performed. For this procedure, a special radiopaque solution is injected into the fluid surrounding the spinal cord and a series of X-rays are then taken of the spine. The area of compression is indicated by a thinning of the column of dye at the pressure points.
What is the treatment for cervical vertebral instability?
Anti-inflammatory drugs, analgesics and muscle relaxants may relieve the initial discomfort, but the greatest chance of success lies with surgery, particularly if performed early in the course of disease. Although some dogs respond well to medication alone, its continued long-term use may create undesirable side effects. Medical treatment alone is effective in 40%-54% of cases.
What does surgical treatment involve?
It is important that pressure on the spinal cord be relieved as soon as possible. Medical treatment with anti-inflammatory drugs reduces the pressure due to inflammation, but does not resolve the problem if there is a deformed vertebra or disc material pressing on the spinal cord.
Various surgical techniques can be used to relieve the pressure. If the surgery is performed at an early stage, before irreversible damage has occurred, the outlook can be quite good. Normally, this surgery is performed by a board-certified veterinary surgeon. The surgeon will determine the most appropriate technique for your pet and will discuss your options, the risks, and the long-term prognosis. Approximately 80% of surgically treated cases improve.
What is the post-operative care?
Most surgeons insist on hospitalization for several days following surgery. After discharge, it is important that the dog receives help with walking. The dog must not be allowed to climb steps or stairs for some time once at home. Your pet’s surgeon will give you detailed instructions on what your pet should and shouldn’t physically do, and they may recommend your pet be evaluated by a veterinary rehabilitation therapist for follow-up during their recovery.
Is the condition likely to occur again after surgery?
Whether the condition occurs again depends on your pet's specific condition. If there is inherent weakness in the spine, it is possible for the condition to recur. However, with modern surgical techniques, recurrence is not common and most pets enjoy a relatively normal lifestyle following surgery.
