Our spine consists of a stack of bones called vertebra. Each one is shaped like a ring; when stacked, the central holes line up and form a tube or spinal canal. Your spinal cord sits in that canal. In between the vertebrae are discs which act as cushions, absorbing the shock of each footstep or cushioning the weight of whatever you lift.
What happens over time
The discs are 70% water. They are made of a tough fibrous outer ring called an annulus, that encloses a jelly inside called the nucleus pulposus. As we age, the water content in the nucleus decreases causing the disc to literally shrink. Imagine a wet sponge that is allowed to dry out; it becomes smaller. The disc become stiffer and less able to provide shock absorption. As a result, the vertebral bones feel more of the stress from our daily activities; they react by developing spurs or calcifications along their margins.
Over time these changes can lead to a condition called spinal stenosis. This is where the thinning of the discs and the calcific spurs cause narrowing of the channels that your spinal nerves pass through, “pinching the nerve", and leading possibly to sciatica.
Is the disc painful?
The discs do have nerves in the outer ring or annulus. So we do have some sensation there. But it is uncommon for the disc itself to be the primary cause or source of back pain. Everyone gets degenerative discs. There are plenty of people with back pain who have normal appearing discs on an MRI; almost everyone over 40 is going to have disc degeneration to some degree. As we age, the disc degenerates further and more discs become involved. It is usually something else that causes the back pain. Either stenosis as described above, a disc herniation, mechanical pain related to improper movement of the spine, or muscular pain.
The first part of solving a problem is identifying the problem. That’s where a medical evaluation, by a physiatrist or physical medicine and rehabilitation specialist, is very useful. Specialists in bones, muscles, nerves, and human movement, they can “weed” out all the potential causes of neck or back pain, define the cause of your specific problem, and then design a unique treatment plan for you. If you would like help with your neck pain, back pain, or have concerns about degenerative disc disease, contact the office of Frank Y. Wei, M.D., PLLC for an evaluation.