Wobbler Syndrome

Also known as cervical spondylomyelopathy or wobbler syndrome, this condition is caused by compression of the spinal cord at the neck. Wobbler syndrome progresses slowly and has multiple possible causes.

There's still a lot we don't know about the causes and disruptions involved in this disorder, but it requires veterinary care and either conservative or surgical treatment. Let's take a detailed look at everything related to this curious syndrome.

Why does wobbler syndrome occur?

This disease is characterized by dynamic and static compression at the neck of the spinal cord, the nerve roots, or both. It can happen for several reasons, with varying severity.

In most cases, it's usually due to protrusion of an intervertebral disc, typically located between C5-C6 or C6-C7, vertebral malformations along with severe thickening of the dorsal longitudinal ligament, foraminal stenosis (narrowing of the spinal canal), or osteoarthritic changes in the joint processes.

Either way, it's not clear what triggers it, but a genetic origin is suspected, along with body conformation, nutrition, or the result of some improper movement or exercise.

Symptoms of wobbler syndrome

We should suspect our dog has wobbler syndrome if we notice one or more of these symptoms. In any case, it should always be the vet who confirms the diagnosis.

• Wobbly gait, characterized by short steps.
• Ataxic gait (lack of coordination).
• Paresis mainly in the hind limbs, which is partial or mild paralysis.
• Neck pain, mainly present in acute presentations.
• Chronic limping, suggesting nerve root entrapment.
• Muscle atrophy.
• Proprioceptive positioning deficits (postural reaction deficit).

Which breeds get wobbler syndrome?

Although it can affect any breed, it has a certain predisposition toward large breeds or giant breeds, most often in two breeds in particular, the Doberman and Great Dane, which account for 60-70% of all affected dogs. It usually affects dogs between 3 and 7 years old, and there doesn't seem to be a sex-based predisposition.

Approximately 50% of large-breed dogs have a single site of compression, and 50% have two or more. In giant breed dogs, on the other hand, only 20% have a single compression site, making multiple compressive lesions much more common (80%) in these cases.

How is wobbler syndrome diagnosed?

The diagnostic process starts by taking a full medical history of the dog, including their age and breed, and when the clinical picture began and how it's progressed.

Next, it's a good idea to observe the animal and carry out a proper clinical exam, but always very carefully and in the hands of a professional, since rough handling of the neck is unnecessary and can lead to further injury.

In cases with movement-triggered pain, it's recommended to use food to encourage the patient to make the movements on their own — this way, if there's pain, they won't turn their head.

Beyond that, there are many thorough neurological and orthopedic exams that can be done. X-rays can help, mainly to rule out other differential diagnoses, such as fractures, vertebral dislocations, discospondylitis, or vertebral tumors.

A myelogram can also be done, injecting contrast dye into the subarachnoid space to visualize the spinal cord's outline. This method used to be the go-to option. Nowadays we also have CT scans (computed axial tomography), which is more specific and doesn't provide much more information than a myelogram, but does offer higher resolution. That's why a combination of both techniques, called myelo-CT, is preferred. This combines the diagnostic advantages of both techniques.

However, today the test of choice is an MRI, since by visualizing changes in the intensity of the spinal cord images, information can be gathered about the severity, chronicity, and prognosis of the condition. What's more, no contrast injection is needed, which reduces the risk of complications.

Treating cervical spondylomyelopathy

Treatment for this disease is tailored to the symptoms it's caused and how the clinical picture has progressed. So there's no single treatment that applies to every case. Either a conservative or surgical approach can be chosen.

Conservative treatment for cervical spondylomyelopathy

This is based on keeping the dog resting, restricting exercise to minimize high-impact activities that would worsen the dynamic component of the compression. It should also be paired with proper medication, led by corticosteroids or, secondarily, NSAIDs (non-steroidal anti-inflammatory drugs).

This approach is recommended when the dog's symptoms began after minor trauma, and also for dogs still growing. On the other hand, this treatment isn't recommended if the dog shows neurological abnormalities in all four limbs or if bone problems have been detected. Recent studies on this treatment show an improvement rate of around 50%.

Surgical treatment for cervical spondylomyelopathy

If surgery is chosen, the vet will need to assess which surgical technique is most appropriate, since several are available. The decision is made based on symptoms, the neurological exam, and imaging test results. In any case, the success rate is high — around 80% of dogs improve after surgery.

However, post-op complications and recurrence can occur. What's more, recovery can take up to four months, and management isn't simple, especially since these are usually large dogs. The goal of all these approaches is decompression, both direct and indirect, but if it isn't achieved sufficiently, the dog won't improve. Complications from surgery for cervical spondylomyelopathy

Complications can arise from the surgery itself, since all procedures under general anesthesia carry risks. Breathing difficulty, heart problems, or bleeding are among the most common complications. During recovery, infections, abscesses, seromas, implant migration or failure, and so on can appear.

However, the average complication rate is around 15%, with only a 3% mortality rate. It's worth noting that this percentage sometimes rises in the Doberman breed, due to the clotting disorders and dilated cardiomyopathy associated with the breed.

What's the prognosis for cervical spondylomyelopathy?

This disease isn't fatal, but it does significantly affect quality of life, which is what needs to be weighed. Early detection and choosing the right treatment are essential, since this way the outcome can be quite positive, and the recurrence rate drops to 24%. So, at any suspicious or abnormal symptom in your dog, don't hesitate to see the vet so they can properly assess it.