spiny situation: intervertebral disc disease
Intervertebral disc disease (IVDD) is a common condition affecting dogs. Intervertebral discs are cushions between the bones in the spine. They act like shock absorbers and allow for mobility of the spine.
Understanding disc disease requires a little bit of an anatomy lesson regarding the discs themselves. Each disc has two parts - the inner part (called the nucleus propulsis) and the outer fibrous ring (called the annulus fibrosis). Think of each disc as a jelly donut. The nucleus propulsis is the inner jelly filling and the annulus fibrosis is the surrounding donut.
Degenerative changes in the disc structure allows for herniation of nucleus propulsis (jelly) through the annulus fibrosis (donut). When this happens, the herniated material can push up into the spinal canal and push up on the spine, causing discomfort and, if severe enough, paralysis.
Though it can occur in any breed, most commonly this condition occurs in breeds with short legs, such as the Corgi and Dachshund. In these breeds, clinical signs generally show up between 3 and 6 years of age. In taller breeds, the disease most often shows up in 6- to 8-year-old dogs.
Seventy-five percent of IVDD cases occur in the part of the spine known as the thoracolumbar spine, which is the space between the front and hind limbs. Clinical signs of severe disc disease in this area include sudden hind limb weakness or paralysis. Mild disease may show up as a generally painful appearance in your pet, with specific pain in the back. He may walk in a crouched stance and find it hard to get comfortable.
The second most common area for disc herniation occurs in the cervical spine, or the spine in the neck. This condition is known as Wobbler Disease or Wobbler Syndrome, and will be discussed in detail in a future blog.
Diagnosing IVDD can be a little bit tricky. Sometimes simple X-rays will clearly show disc herniation, though sometimes additional testing is needed. Generally, if severe disc herniation is suspected, the patient will be transferred to the nearest neurologist or surgical referral practice. There, a myelogram or MRI can help pinpoint the exact problem.
Once IVDD has been diagnosed, treatment will depend on clinical signs. Mild cases will respond well to anti-inflammatories and muscle relaxers. More severe cases, however, will require surgery to allow the affected pet to return to normal function, which can be costly. Petplan pet insurance recently paid out a claim for over $3,000 for a 12-year-old German Shepherd who needed treatment for IVDD. Prognosis is poor for pets who have been “down in the rear” or paralyzed in the hind limbs for over 24 hours.
If you feel like your pet is having spinal pain, or worse, is acutely weak in the hind or front limbs, contact your veterinarian right away, as IVDD may be to blame.