Intervertebral Disc Disease (IVDD) in Dogs
When dogs suddenly don’t want to lift their head, cry out when their back is touched, knuckle on their paws, or drag their legs, this can be a sign that they ruptured an intervertebral disc. Discs are supposed to be soft cushions between the vertebrae of the spine, but with IVDD, they are prone to becoming brittle and breaking open. This can cause swelling and pain at the site, as well as causing the inability of a dog to use its legs. Sometimes signs of a "slipped disc" are so mild owners don’t even notice, and other times dogs can become permanently paralyzed.
Although any dog (or person) can rupture an intervertebral disc by getting hit by a car, slipping on the ice and landing on their back, being obese and carrying too much weight on the spine, and many other causes, intervertebral disc disease is an inherited condition. IVDD means an animal can, and probably will, rupture one or more discs throughout their lifetime. In fact, veterinarians often see calcified evidence of a previous disc rupture on x-ray in dogs who present for a newly ruptured disc (not immediately visible on x-ray).
Causes of Disc Disease in Dogs
- Genetics/hereditary/high-risk breed
- Age-related degeneration
Signs of IVDD in Dogs
Because the contents of the ruptured disc spill out and press on the spinal cord, spinal nerve, or nerve root, the dog is often neurologically affected. They are also painful due to inflammation at the site of the ruptured disc. Muscle spasms around the area cause further pain.
Milder signs may be a hunched posture and/or holding their head down, stiff neck, unwilling to turn head, unwilling to chew bones/hard treats, back pain, unwillingness to go up and down stairs, run or even walk.
More severe signs may be knuckling (walking on the top part of the paws, not flipping them over properly to walk on the underside), dragging legs as if unable to move them, or not able to stand or walk at all. These signs may affect the back legs only, front legs only, all legs, or front and back legs on the right or left side only. Paresis is weakness and instability, whereas paralysis is the complete inability to move the legs at all. Urinary incontinence will often occur with paralysis of the back legs.
How is disc disease diagnosed in dogs?
The most common areas for disc rupture are in the cervical (neck) and thoracolumbar (mid-to-lower-back) regions of the spine. MRI or CT is the best imaging modality with which to see a ruptured disc, as x-rays can only show a narrowed space between vertebrae, which is arguably subjective, or old ruptured discs that have already calcified.
Diagnosis is often made by general practice veterinarians based on a neurologic and orthopedic exam, so this condition is often treated without imaging. As the spinal cord gets compressed, the first thing to go is proprioception (placing paw appropriately), then motor (moving the limb), then superficial pain (ability to feel light touch), and finally deep pain (ability to feel painful stimulus). If your pet can’t place their paw correctly, can’t even move their leg, and doesn’t respond to light touch/petting the limb, your vet will test for deep pain, using a hemostat to gently and then more firmly pinch your dog’s toe. If they can feel this deep pain stimulus, they have a better chance of recovering than if there is no response.
Dogs whose signs worsen rapidly within the first 24 hours often need surgery to remove the spilled-out contents of the ruptured disc, thereby removing the cause of the pressure on the spinal cord. If the cord has not been damaged, the dog will likely fully recover, especially if the dog can still feel pain. If the cord has been damaged, and especially if the dog cannot feel deep pain, there may be residual deficits or permanent paralysis. Paralysis is often permanent in severe cases that do not have surgery within 24 hours of the disc rupture.
In dogs prone to IVDD (see below), discs begin degenerating as young as 1-2 months of age and have been seen to rupture as young as 1-2 years old. In older, large breed dogs, degeneration tends to cause disc rupture after 5 years of age on average.
- Stage I disc disease produces mild pain and is usually self-correcting in a few days.
- Stage II disc disease causes moderate to severe pain in the neck or lumbar (lower back) area.
- Stage III disc disease causes partial paralysis (paresis) and results in the dog walking in staggering or uncoordinated movements.
- Stage IV disc disease causes paralysis but the ability to feel is present.
- Stage V disc disease causes paralysis and loss of feeling.
Other causes showing the same clinical signs are due to blood clots, pieces of disc contents getting into the blood vessels (fibrocartilaginous embolism), tumors, degeneration of the spinal cord itself (Degenerative Myelopathy), or trauma. Advanced imaging is often necessary to differentiate between these.
Treatment Options for Dogs with Disc Disease
Medical management: NSAIDs (non-steroidal anti-inflammatory pain medication) or steroids are often prescribed, along with muscle relaxants and nerve pain medications. Plenty of rest is required to allow healing time, as a disc technically takes up to 30 days to heal. Dogs should be on a leash to go out to urinate and defecate only, and not be allowed to run, jump or exercise until fully healed, and then eased back into it.
Surgical management: Hemilaminectomy is a procedure in which a ‘window’ is cut into the adjacent vertebrae to access and remove the material which came out of the ruptured disc. This surgery is performed by board-certified surgeons or neurologists. Your dog will stay in the hospital for several days after this procedure to begin physical therapy, aid in emptying the bladder, monitoring and documenting their progress in regaining use of their limbs, etc. Follow-up physical therapy is necessary, as well as assisting in voiding the bladder if necessary.
Can IVDD be prevented?
Remember, any dog with IVDD can rupture a disc at any time, so it’s wise to keep these dogs exercised on a leash and to limit high-impact activity (like jumping to catch a frisbee). You cannot prevent IVDD, but you can be armed with the information that it is most common in the following breeds:
- Miniature Dachshund
- Shih Tzu
- Lhasa Apso
When should you contact a vet?
It’s important to have your dog assessed IMMEDIATELY if you suspect a disc rupture, as it can progress quite quickly from mild to severe. The best chance of making sure your dog does not lose their ability to use their legs is to have your dog seen by a vet AS SOON AS POSSIBLE. Waiting even just a few hours can sometimes prove devastatingly irreversible.
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