Wobblers Syndrome

Cervical Spondylomyelopathy is a neurological disease affecting the neck region. This is commonly known as "Wobblers Syndrome", as affected dogs have a characteristic wobbly gait (walk), especially on their hind limbs, as this is a degenerative, progressive illness.

So, what is Wobblers Syndrome?

Wobblers syndrome results from a malformation of the last three cervical vertebrae in the neck leading to disk rupture and spinal cord compression resulting in pain and neurological problems. Most dogs show signs of spinal cord compression as young to middle-aged adults, for example, four to six years. Occasionally dogs with severe deformities of their vertebrae will develop problems when they are immature (five to ten months old).

The exact cause of Wobblers is unknown; however, with the high incidence of certain breeds being affected, heredity is a contributing factor and over-nutrition.

Signs of Wobblers Syndrome

Clinical signs in dogs with Wobblers Syndrome are progressive and can take months or even years to develop/show. Still, they may also appear acutely (suddenly) if there has been a traumatic episode or after strenuous exercise.

Signs include:

• Weakness and uncoordinated gait (known as ataxia), usually first seen in the pelvic limbs
• Wide limb stance
• Lameness/stiffness in the thoracic limbs
• Difficulty around the home – unable to climb steps, for example
• Difficulty getting up from lying down
• Dragging or knuckling of the toes
• Neck pain and/or stiffness with reluctance to raise or lower the head
• Partial or complete paralysis

Diagnosis

There could be numerous causes of the clinical signs exhibited by Wobblers Syndrome. After a complete examination, including a neurological examination by your Veterinary Surgeon, a referral may be necessary to a specialist hospital where a diagnosis can be achieved under general anaesthetic. Tests include:

• MRI scan to examine the spinal cord and the discs between the cervical vertebrae.
• CT scan will also be used to examine the shape of the bones of the vertebral column.
• A Myelography may also be included where a small volume of a dye (contrast agent) is injected around the spinal cord to see if the flow of dye is interrupted due to the pressure on the spinal cord.
• In some dogs, extra tests such as blood tests or spinal fluid collection may be indicated to help confirm the diagnosis.

Treatment

The treatment for Wobblers Syndrome very much depends on each case individually and the severity of the condition.

Non-surgical management

Non-surgical management may allow some stabilisation of the condition, at least in the short term. It is only recommended for dogs with mild pathology (small disc bulges) and very slow disease progression.

The following non-surgical treatments are available:

• Exercise modification – absolute rest in the short-term and modified exercise in the long-term such as avoiding jumping or climbing stairs
• Harness walks
• Anti-inflammatory medications
• Physical therapies -  massage, physio, laser
• Hydrotherapy

Surgical management

Surgery aims to relieve the compression of the spinal cord. This may be performed in the following ways:

The abnormal tissue, such as the thickened disc, can be removed from the spinal cord (direct decompression). For dogs affected only by extrusion or protrusion of the intervertebral disc with no evidence of instability or compression of the nerve roots, surgical decompression by the ventral slot may be appropriate. This involves the removal of a window of bone within the casing of the spinal canal, allowing us to remove any bulging or ruptured intervertebral disc material that might be compressing the spinal cord.

Alternatively, the abnormal tissue, soft tissue and not bone, may be stretched to reduce compression on the spinal cord (termed indirect decompression). Stabilisation (or fusion) of the abnormal vertebrae may be necessary.

Vertebral distraction-stabilisation procedures are often indicated in dogs with cervical Spondylomyelopathy-associated disc protrusions.

Outlook

The outlook for dogs with Wobblers Syndrome is variable and, again, very much case-dependent.

In severe cases managed conservatively,  the progressive spinal cord compression often results in deterioration in strength and coordination, leaving some dogs unable to walk. Unfortunately, the progression of clinical signs may be gradual or acute (sudden).

According to Willows Specialist Referral Service based in Solihull,  the success rate with surgery depends on the nature of the spinal cord compression, the number of areas of reduction and whether or not the compression(s) respond to traction. The best scenario is generally a single, traction-responsive disc protrusion. In these cases, the outlook is often favourable, although weakness and incoordination may persist.

Unfortunately, with Wobblers Syndrome, the spinal cord has often been compressed for an extended period before treatment, resulting in some nerve injuries being irreversible.