Have you heard of spondylosis deformans? This condition affects the spine of older dogs and causes the bones (vertebrae) of the back to fuse together.
And if you are glazing over already, keep reading: Experts believe every dog who lives long enough will eventually develop this condition.
Think of spondylosis like arthritis of the spine.
The spine is made up of 30 small bones called vertebrae — plus a variable number of tail vertebrae. These are separated from one another by discs and joined together flexibly with ligaments. This clever system allows the spine to bend and flex rather than exist ramrod-straight like a broom handle.
Over time, those shock-absorbing discs start to show signs of wear and tear (a bit like brake discs in a car wearing out). This makes bending and stretching painful, and more serious than that, it leads to instability, which could put pressure on the spinal cord.
We sometimes lose sight of just how clever the body is, and this is one of those times. To stabilize the spine and provide a natural brace, the vertebrae grow bony spurs that reach out to one another, like the hands of acrobats on the high trapeze, and join together to form a bony bridge. It is this bony bridge linking vertebrae together that is the condition called spondylosis deformans.
Dogs Most Affected
Spondylosis used to be considered a condition mainly affecting large dogs, but we now know that any dog can be affected. However, genetics come into play with predisposed boxers, Airedale Terriers and German Shepherds, but that’s balanced against age.
I’ve seen dogs ranging from Cairn Terriers to Labrador crosses and Great Danes who had particularly dramatic-looking fused spines on X-ray.
Spondylosis develops in response to degeneration of the backbone, and so the signs are related to back pain. You are most likely to notice your dog is stiff and perhaps has difficulty stretching, jumping up or putting his head down to a food bowl.
Some dogs become hyperasethetic, which means oversensitive to pain. These dogs yelp piteously before you touch them, or they move slightly and scream as if someone had trapped their paw in a door. Their response is out of proportion to the action because pinched nerves amplify the pain.
To understand this, think of the pain as a noise and how it sounds with the naked ear as compared to what it sounds like through headphones with the volume turned up to the max.
Spondylosis is often picked up as an incidental finding when the dog is radiographed for another problem. The reason it’s an “incidental” is that spondylosis is painful only if it pinches nerve roots. The rest of the time, it’s doing a useful job of supporting the backbone (like scaffolding).
Spondylosis can look dramatic on X-ray and yet not cause pain, so don’t be depressed if your veterinarian shows you some impressive-looking arthritic lesions of the spine. However, it may be necessary to run further tests (MRI scan or myelography) to check if the decayed discs are pressing on the spinal cord or the extra bone has trapped nerve roots (both of which can be painful).
This happy Doberman got a second chance at life after abandonment and a diagnosis of spondylosis deformans:
Usually no action is necessary other than pain relief (a catch-all because the dog probably also has arthritis in other joints as well). Again, if nerve roots are being pinched, then special painkillers, such as gabapentin, that ease nerve-generated discomfort may be prescribed.
As a rule of thumb, surgery to de-bulk the extra bone is not recommended. This not only weakens the spine but also is a fool’s errand because the bone is liable to grow back again.
Confusion With Another Condition
And finally, a brief word about a different condition with a similar name: spondylitis.
Spondylosis and spondylitis may share 7 of their 11 letters, but it’s those final 4 letters that are important. The “-itis” part of spondylitis means “inflammation”; in this case, the inflammation is caused by a blood-borne infection that gets into the bones of the spine.
Whereas spondylosis is largely painless, a dog with spondylitis is unwell, feverish and in a lot of pain. The treatment is also very different, requiring weeks of strong antibiotics and pain relief. However, the good news is spondylitis is rare, so your dog is much more likely to get spondylosis rather than a more serious disease.
This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed April 29, 2016.