Back and Disc Problems
Your pet is unable to speak, but she can communicate well with body language. She may be hunched over, or have her spine twisted to one side. She will be in pain and may have trouble moving or cry when you pick her up.
Back pain is particularly common in low, long dogs, such as Dachshunds. We also see it in the highly active dogs that do a lot of jumping, such as Border Collies. Anything that puts undo pressure on the spine can cause a back spasm.
The spinal cord is one of the most important and sensitive organs in the body. If it is damaged, the nerve cells do not regenerate but are replaced with fibrous or scar tissue. Spinal cord injuries usually result in permanent damage. Therefore, the spinal cord is protected in a very special fashion. It goes through a bony canal within the spine and is surrounded by protective bone everywhere except the junction of two vertebrae. These junctions are filled by rubber-like cushions called intervertebral discs. They allow the back to move up and down and sideways without allowing contact between the bones of the spinal column. This extreme protection of the spinal cord reflects its importance and fragility.
The disc is composed of two parts. The outer covering is much like a thick shell. It is comprised of tough fibers that protect and contain the central part. The disc is thinnest at the top. This thin area is located just below the spinal cord. The central part of the disc is much softer than the outer part and has the consistency of thick toothpaste.
When the outer shell degenerates, it allows the central part of the disc to escape. This is called a disc rupture or a "slipped" disc. Since the disc is thinnest near the spinal cord, disc material that escapes through the tear usually goes upward, putting pressure on the spinal cord. Because the spinal cord is encased within its bony canal, it cannot move away from the pressure and it becomes "pinched".
Degenerative disc disease causes spontaneous degeneration of the outer part of the disc, resulting in disc rupture. It may not be related to injury, although trauma is a common cause. It is also not related to age. Most dogs with degenerative disc disease are 3-7 years old. It is a sudden event most likely due to genetic factors. Certain breeds, especially the Dachshund, Poodle, Pekinese, Lhaso Apso, German Shepherd, Doberman and Cocker Spaniel have a high incidence of disc disease.
Most owners report that a disc rupture occurred following some kind of traumatic event, such as a relatively small jump or fall. Although this act is frequently blamed for the disc rupture, the injury actually occurred due to chronic disc degeneration.
The spinal cord is like a telephone cable carrying thousands of tiny wires. When it is crushed, transmission of information through the wires is slowed or stopped. When the disc degenerates and ruptures, a similar event in the spinal cord occurs. The central part is forced upward, putting pressure on the spinal cord and the nerves that leave the spinal cord over the discs (i.e. spinal nerves). Pressure on the spinal nerves results in pain. Pressure on the spinal cord results in pain and/or loss of information transmission causing partial or complete paralysis.
Most disc ruptures occur in the middle to lower part of the back. However, they may also occur in the neck. Back injuries often cause paralysis without severe pain while neck injuries usually cause severe pain without paralysis. If paralysis affects all four legs, the disc rupture must be in the neck. Due to the way nerve tracts are arranged in the spinal cord, disc ruptures in the neck may affect the rear legs first and may not involve the front limbs.
Disc degeneration usually occurs relatively slowly, usually over several days or weeks. The dog often experiences pain and becomes reluctant to move. It may lie around for a few days allowing the body to try to heal the injury, often without the owner being aware that a problem existed. However, discs may also rupture very acutely. Some dogs will go from normal walking to total paralysis in less than one hour.
A presumptive diagnosis of disc disease is made based on the dog's history of neck or back pain, uncoordinated walking, or paralysis when there is no history of trauma. The physical examination will indicate that the problem originates from the spinal cord, giving further evidence to disc disease. Another important factor is the breed. If the dog is one of the high incidence breeds, the diagnosis is even more likely.
In some cases, plain radiographs (x-rays) may assist the diagnosis, but they may also be normal since neither the disc nor the spinal cord is visible on an x-ray. If the diagnosis is in doubt or if surgery is to be performed, a myelogram may be done. This procedure involves injecting a special dye around the spinal cord while the dog is anesthetized. When radiographs are taken, the dye will be seen outlining the spinal cord. A break in the dye column means that there is pressure on the spinal cord at that point.
It is possible that the pressure is due to a blood clot or tumor. Both are possible but rare, especially when compared to disc ruptures. If the patient is a high-risk breed and there has been a sudden onset without trauma, there is an approximately 95% chance that a disc rupture is causing the clinical signs. However, the diagnosis is not definite until the time of surgery.
PAIN RELIEF. For immediate help ASA (Aspirin) may be safe to give to your dog. Consult your veterinarian for a dose.
WATCH THE WEIGHT. For long-term prevention, keep your pet in shape. If you can't easily feel your pet's ribs, then he is probably overweight. Start your pet on a calorie-reduced food and begin more regular exercise.
SEE YOUR VETERINARIAN. If your pet is in severe pain or has signs such as wobbly walking, or partial paralysis, it's a situation for your veterinarian. This type of back condition is considered an emergency.