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MEDICINE 101

BACK PAIN - DISC DISEASE

It is hard to believe, but this is not a piece of avant-garde sculpture. In spite of the symmetry and wonderful shape, this is simply a bone. It's a vertebra, one of the backbones, from a thin-backed whale, found on a beach in Newfoundland.

I am not sure about whales, but, in humans, problems with bones and other structures in the back are among the commonest complaints that doctors have to deal with.

The word vertebra comes from the Latin meaning jointed. Vertebrae, or backbones, are stacked one on top of the other to form the spinal column. The bones of the spine give support to the bones of the legs, arms and head but they also protect the spinal cord. It's a delicate and critically-important outpouching of the brain. Inside its own protective bony ring, it runs down through all the vertebrae. The spinal cord carries messages from the brain to the rest of the body.

Between each of the vertebra lies a disc, a shock-absorbing flexible pad. This makes good sense - otherwise the spine could not move. The pads, like this foam rubber model, allow for some compression and expansion and also movement, because the gristle that makes up the disc gives much more than the bone could.

The discs themselves have a fibrous or gristle-like ring on the outside and a more liquid, almost jelly-like centre.

The discs deteriorate as we get older, and sometimes, as a result of injury or simply bad genes, they break open - they explode really - pushing the damaged pieces of the gristle backwards into the spinal cord. This happens most commonly where there is most movement in the spinal column, in the lower back or in the lower neck. The pieces of degenerated disc put pressure on the nerves from the spinal cord. Oddly enough, if you have such a disc problem you often don't feel as much pain in your back as you do where the nerves come to the surface - down the legs and into the foot. This situation is what the chiropractor refers to as a "slipped disk" - a misnomer, as the disc has not slipped, but rather "exploded". Quite commonly, the disc fragments put pressure on the large nerve that exits at the lower end of your back and goes down the back of your leg - a pain known as sciatica.

Though manipulation, anti-inflammatory drugs and rest often help the problem, the specific treatment is surgery. A small incision is made in the back and the surgeons go through the muscle layers and pick away the pieces of the shattered discs that are putting pressure on the nerve roots. Relief of the pain is almost immediate, and you're BACK to feeling like your old self.