Cervical Spondylomyelopathy / Wobbler’s Syndrome
What is Wobbler Syndrome?
There are various phrases that have been used to describe the same syndrome in dogs including cervical spondylomyelopathy, cervical malformation-malarticulation, cervical vertebral instability and cervical spondylolisthesis. It is a problem of the spine (including the spinal cord and nerves) of the neck, resulting in poor transmission of nerve signals between the brain and the body. It is seen almost exclusively in large breed dogs (often Doberman’s or Great Danes).
The precise cause of the problem varies between different dogs, but usually involves one or more of the following:
- abnormalities in the shape of the vertebrae as a congenital problem
- bulging (protrusion) of the intervertebral disc
- rupture (extrusion) of the intervertebral disc
- instability between the two vertebrae
- proliferations of bone or soft tissues around the vertebrae
Why does the disease develop?
We do not know fully why the disease happens. We think that genetic or hereditary factors are the major cause, although it is not a simple hereditary disease. Nutritional and hormonal disorders may also play a role, as may trauma or mechanical factors, although this is largely unproven.
What are the symptoms?
Dogs can start to show symptoms at almost any age, but most are young adults (approximately 1-5 years).
Symptoms can vary depending on the site of the problem, the severity of spinal cord or nerve root compression, and the duration of this compression. Symptoms often develop over a long period of time, although occasionally we will see dogs where symptoms develop very suddenly.
The most common symptom is an un-coordinated walking style, ranging from occasional stumbling or scuffing of the toes, to a stiff, “prancing” gait. The fore limbs are usually most severely affected, but the hind limbs are usually also affected. Occasionally, affected dogs will have obvious lameness of one forelimb caused by compression of the nerve supply to that leg. We also occasionally see dogs that are so severely affected that they are almost paralysed, with difficulty standing or walking. Many dogs have neck pain but this is not a feature in all patients.
How is Wobbler syndrome diagnosed?
Achieving an accurate diagnosis is essential. Various other diseases can cause similar symptoms, including fractures of the vertebral bones, tumours of the spinal cord, other congenital abnormalities, clotting disorders, meningitis and even certain parasite infections so these problems must be ruled out before deciding on a treatment plan.
The site of the problem must first be identified based on a detailed examination by an experienced neurologist or neurosurgeon. The diagnosis is usually made based on an x-ray dye study (myelogram), a CT scan or more commonly an MRI scan of the suspect area of the spinal cord, which may be performed with the neck in different positions to detect changes that might occur with movement of the neck. In some dogs, additional tests such as blood tests, spinal fluid taps or biopsy samples may be needed to confirm the diagnosis.
