Disc herniation

What is a disc herniation? First of all, you need to understand what is a vertebra and an intervertebral disc.
The spinal column is made up of vertebrae that are joined together by the intervertebral discs that are between them, and serve as absorbers which give the spinal column its mobility.
An intervertebral disc is formed of 1) the nucleus pulposus (softer) and 2) the annulus fibrosis (more solid).

So what is disc herniation? The cartilaginous disc found in the spinal canal between each vertebra, acts as an absorber. It ages prematurely, hardens, deforms itself and may compress and injure the spinal cord. The disc herniations will form mostly at the different hinges of the spinal column, the cervico-thoracic hinge (at the neck) and especially the thoracolumbar (between the last rib and the base of the tail), though it may occur at all the other areas.

There exists 2 types of disc herniations ;

Hansen type 1 : This type is seen especially in small sized dogs. A sudden rupture occurs in the dorsal annulus fibrosis. It is caused by an early degeneration of the intervertebral discs, causing them to lose their capacity of absorbing shocks. Once the degeneration has reached a certain point, the annulus fibrosis may spontaneously rupture during physical activity or by a “sudden” movement and the nucleus pulposus material finds itself in the spinal canal, most of the time it does it “explosively”.

This creates an acute shock to the spinal cord. Long term, the herniated material will organize itself, but will not be re-absorbed. Therefore the pain may lessen, but will often persist to the point of causing discomfort. This may make it difficult when evaluating and measuring. Furthermore, the annulus fibrosis will not repair itself and more material may herniate, thus causing the animal’s condition to worsen.

Disc Herniation Type 2; this type of herniation especially affects large breeds. This type of herniation develops slowly as the dog grows older. The nucleus pulposus progressively deforms the annulus fibrosis without passing any disc material, so the compression to the spinal cord is slower.

The first signs to appear, most of the time, following a disc herniation are a reluctance to climb up or down the stairs, to jump and to play. Your dog may also complain or cry out when doing a sudden movement or when being picked up. He may also tremble, refuse to eat and may show signs of aggression caused by the pain and anxiety.

The first signs may appear suddenly without any history and may vary from mild to severe. However, in many cases there was a history of one or more episodes of pain, a few months or even a few years before.

Surgery is the only treatment that will fix the problem at its origin, and, avoid recurrences, no matter what, the degree of severity of the clinical signs. This will remove pressure on the spinal cord, relieving the pain and preventing recurrences. The surgery is performed by a specialist, and done as quickly as possible for better results.

The second option to help relieve your dog of pain is medical treatment. It only treats the pain and inflammation, however, the herniated material remains and may generate chronic pain. Long term, the consequences can be serious (recurrences, weakness, irreversible paralysis…). The treatment consists of strict rest for a minimum of 3 weeks( the dog must be taken outside with a leash to do his business a maximum of 3-4 times a day), ideally, placing your dog in a cage will prevent all possibility of jumping, running, playing… Then, he can progressively return to limited exercise, which will consist of small walks on a leash for 4 to 6 weeks. An inflammatory drug and muscle relaxant may be prescribed to reduce pain and inflammation depending of the symptoms. Care must be taken since the anti-inflammatory will rapidly increase your dog’s comfort even though the lesions still remain. So, he might seriously injure himself if you do not restrain his level of activity.

Diagnostic testing:

The breed, age, history and clinical signs are often very suggestive of a disc herniation. X-rays might be done at the clinic to exclude any possibility of a fracture, a luxation, of a tumor or bone tumor.

To have a precise diagnosis as to where, the type and the number of herniations, a magnetic resonance, a topographic image or a myelography should be done. It is necessary if surgery is considered.

Following a disc herniation diagnosis, it is important that you make sure your pet can urinate, have bowel movements and eats well. If this is not the case, it is imperative that you call us. If you have chosen the surgical treatment, follow-ups with the surgeon should be done to insure a good progression in your dog’s recovery.

For type 1 herniation, the prognosis is always better with surgical treatment and is excellent for cervical disc herniation.

For thoracolombar herniation, the prognosis will depend of the initial clinical signs;

-whether or not the dog can still walk, if there is still voluntary movement, and the animal will walk quickly and well.
-if your animal is paralyzed but still feels pain, the period of time necessary for your dog to walk again and the degree of his final deficits will depend of the amount of time he’s had the problem. The sooner surgery is done, the better the results are.
-If there is no perception of pain within less than 24-48 hours, the prognosis is very guarded. There is still some chance that the animal will recover his functional neurological function.
-If perception of pain is absent for longer than 48 hours then prognosis is poor.

For type 2 herniations, no matter the chosen treatment, prognosis is always poor.

Chondrodystropic breeds are predisposed to type 1 herniations. Breeds such as the Teckel, beagle, toy,miniature poodle, cocker spaniel, Shih Tzu, l’hasa apso and Welsh corgi.

The Labrador and German Sheppard are predisposed to type 2 herniations.