What are Intervertebral Disks? The intervertebral disks exist between the vertebrae in the spine. They act like shock-absorbers to help absorb the forces placed on the spine. They have two portions, an outside fibrous covering ( the annulus fibrosis) and an inside, more gelatinous portion, the nucleus pulposis. In this way they kind of resemble a water ballon. The outside of the water ballon is the annulus, and the water on the inside is like the nucleus pulposis. Related anatomy When the intervertebral disks become damaged, this is referred to as intervertebral disk disease ("Disk disease", "Slipped disk"). As disks age, they lose water content, and become less able to withstand compressive forces. If too much force is placed on them, they can be squeezed and expand or rupture. This rupture usually occurs in an upward direction, and the inner disk material extrudes into the spinal canal where the spinal cord is. Signs develop either because of the impact of the disk material hitting the cord, or due to the disk material compressing the spinal cord. Intervertebral disk disease can occur in any area of the spinal cord. Dachshunds appear predisposed, as their disks age or degenerate quicker than most dogs. Young to middle-aged dogs are most commonly affected. Dogs less than 1 year of age rarely have intervertebral disc disease. Geriatric dogs are occasionally affected. Clinical signs of disk disease are rare in cats. Signs of a disk problem range from being painful to being unable to move. The more spinal cord damage, the worse the clinical signs. Animals with the worse spinal cord damage lose the ability to move and to feel their limbs. To know if an animal can consciously feel, we have to pinch the toes and see if the animal vocalizes or tries to bite us. While this test may seem harsh, it is very important. If an animal can still feel it's legs, even if he or she can't move, there is a 85 -95% chance or greater that the animal can walk again if surgery is performed. The diagnosis of disk disease is based on clinical signs initially. To prove that a disk is pressing on the spinal cord, a special X-ray study known as a myelogram is often necessary. To perform a myelogram, first a spinal tap is done. Next, a dye or contrast agent is injected around the spinal cord to outline it. This usually shows where the disk has ruptured and this allows your surgeon to know exactly where the surgery should be performed. Recent guidelines have been established for therapy depending upon severity of clinical signs. Dogs without neurological sign or those that exhibit only back pain may be managed without surgical intervention ( Strict cage confinement for at least two weeks and NSAIDs). The use of steroids is strongly discouraged since it can lead to intestinal ulceration and even death. Neurologically affected animals (those who are unable to stand and or had a wobbly walk) are candidates for surgery. The surgery is performed to remove extruded disk material from around the spinal cord, relieving the compression and giving the spinal cord the best chance at healing. Dogs will usually be able to walk again about 14 days after the surgery, but it can sometimes take longer. Dogs that go home following surgery need good nursing care and lots of TLC. You can print out our handout on Nursing Care of the Paralysed Pet. If you have any questions or concerns about this or any other condition please feel free to call our office anytime. (626) 403-6824 |
Intervertebral Disk Disease
