The disc degeneration associated with IVD can start within the first year of life. This together causes the disc to become less elastic and, in a sense, more brittle. If a force is placed on the diseased disc greater than that disc can withstand, the disc can rupture. The rupturing disc hits the spinal cord, causing swelling and a disruption of the normal blood flow to the cord. This disrupts the function of the nerves traveling through the spinal cord.
Clinical signs are related to how many nerves are affected.
Clinical signs range from mild back pain only to complete paralysis of the hind legs. Surgery is the treatment of choice in dogs whose ruptured disc causes paralysis. Surgical treatment for IVD disease is a step-wise process. Normally, neither the disc nor the spinal cord can be seen on regular x-rays. To determine if a disc has ruptured, and to identify which disc has ruptured, a myelogram must be performed.