Spondylosis deformans is a progressive disease of the cat’s spine characterised by the formation of bony spurs (osteophytes) on the edges of the vertebrae, which are the small bones that make up the backbone.
The cat’s spine is made up of vertebrae (small bones), sandwiched between each vertebra are pads of tough, fibrous cartilage called intervertebral discs. Ligaments hold the vertebrae together, protect the intervertebral discs and stabilise the spine. The intervertebral discs separate the vertebrae, act as a shock absorber, providing a cushion and allow the spine to move.
The bony spurs on the vertebrae of cats with spondylosis can range in size from small spurs to bridges that form across the intervertebral disc space.
Spondylosis deformans is a disease that affects middle-aged to senior cats; in fact, it is thought that all cats will develop spondylosis deformans if they live long enough.
Causes
As a cat ages, the vertebral discs begin to thin, which reduces the space between each vertebra which causes the joints between the discs to become unstable. In an attempt to stop the instability, the spine grows bony spurs in an attempt to reinforce the weakened joint.
Other possible causes include:
- Genetic predisposition
- Major trauma
- Repeated microtrauma
- Vitamin A toxicosis can lead to spondylosis of the cervical vertebrae in the neck
Symptoms
The most common location is the thoracic vertebrae of the upper back (T4 to T10); however, they can develop further down, and often produce more severe symptoms.
The formation of osteophytes should not cause pain, and many cats will remain asymptomatic. However, it can put pressure on and compress the spinal cord or spinal nerve roots, which will cause pain. Cats are exceptional at hiding pain, and the only change may be behavioural, such as aggression, especially when touched.
Compression of the spinal cord can cause impaired neuromuscular function such as weakness of the limbs, and loss of urinary or bowel control.
Inflexibility of the spine can develop as the bone growth enlarges. Pet owners may notice a reluctance to jump, or stiffness.
Other symptoms can include lameness and muscle atrophy (wasting).
Diagnosis
Your veterinarian will perform a complete physical examination of your cat and obtain a medical history. It may be possible to feel bony growths during the physical exam.
Diagnostic workup:
Xray: Which will reveal bone spurs on the vertebrae. Due to the nature of this disease, it is not uncommon for spondylosis deformans to be an incidental finding, secondary to other conditions which necessitated the x-ray.
Myelography: This test involves injecting contrast material into the space around the spinal cord, followed by an x-ray to evaluate the spinal cord and spinal nerve roots.
MRI or CT scans: These advanced imaging techniques can provide highly detailed images which provide the veterinarian with a more detailed view of the vertebrae, discs, ligaments and nerve structures. This can show the degree of bone spur growth and determine if the spinal cord or spinal nerve roots are affected.
The veterinarian will grade the severity of the growths from 1 (minimal) to 4 (severe).
In some cases, your veterinarian may refer you to an orthopedic specialist.
Treatment
Treatment of spondylosis deformans depends on whether the cat is displaying clinical signs.
NSAIDs: The most common treatment is non-steroidal anti-inflammatory drugs (NSAIDs) to relieve pain. Administer with food.
Corticosteroids: If painkillers don’t work, the veterinarian may prescribe corticosteroids.
Surgery: If spinal cord compression has occurred, it may be necessary to perform surgery to remove spurs and relieve pressure.
Neutraceuticals: Glucosamine, a sugar produced by the body and a building block of cartilage. Glucosamine supplements can help to slow the breakdown of cartilage and improve flexibility.
Home care
Administer all medications as prescribed. Speak to your veterinarian if you notice any symptoms such as gastrointestinal upset, loss of appetite, or if symptoms don’t resolve.
If the cat is experiencing a range of motion, it can help to make some modifications around the home.
- Provide steps or ramps for the cat to climb.
- Ensure litter trays and food bowls are within easy reach.
- Provide litter trays with low sides.
- A comfortable and warm bed, slightly raised from the floor.