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INTERVERTEBRAL DISC COLLAPSE & PROTUSION

Humans and dogs share back problems, although the damage can be more severe in long dogs e.g. Daschunds.

The invertebral discs are positioned between each of the bones that make up the spine (vertebrae). They are soft and tough, and act a bit like "spacers" in keeping the vertebrae apart from each other. The vertebra can then bend and flex without crunching into each other.

Normal appearance of a spine	A collapsed intervertebral disc placing pressure on the spinal cord

When discs wear out, the centre (nucleus) sometimes erupts out of its central position and travels upwards where it collides with the spinal cord and/or one of the major nerves exiting the spinal cord. This is called a "prolapsed disc".

In people, this may be to one side, and for example, it may hit the right sciatic nerve giving the person a sharp shooting pain down the back of their right leg.

In dogs, the normal sequence of events is compression on the lower half of the spinal cord as a whole. If the disc has prolapsed slowly, then the dog may just feel lower back pain, much like in people. Sometimes it goes off to one side, so only one side of the spinal cord ids affected.

If the disc prolapses with a little more force, it may cause enough pressure on the lower spinal cord to interfere with messages travelling up and down the spinal cord between the feet and brain. The messages get slowed down and by the time the brain receives information about where the hind foot is, the foot has already moved.

The result is inco-ordination (ataxia) . Affected dogs are wobbly in the hind legs and knuckle over very easily.

Sometimes, the disc prolapse can be explosive, and it can literally cut the spinal cord in half. This is quite common in dogs with long low backs e.g. Dachshunds, Basset hounds. It goes off a bit like someone squeezing an orange pip between their fingers.

These dogs are paralysed and the prognosis is very poor.

Treatment

Mild cases need strict confined cage rest and physiotherapy 3-4 times a day to keep the muscle tone up.

We use cortisone (e.g. Prednisolone) to try and reduce swelling associated with the prolapsed disc.

Moderate to severe cases need referral to a specialist centre ASAP if they are to have any chance of recovery. The surgeons place a special dye in the spinal cord to see which disc(s) is causing the problem. Surgery involves removing bone surrounding the spinal cord so it can move away from the prolapsed disc below it, and relieve the pressure. The offending disc is sometimes removed at the same time.