A worn-down disk in your spine can create back pain due to nerve pinches, bone spurs, and inflammation.

Cushiony pads called disks are nestled between the individual bones of your spine and help keep your back highly flexible and capable of absorbing stress and strain. Unfortunately, as you age, those back disks can wear down. This is called degenerative disk disease. In fact, it is not an actual disease but the normal aging of the spine. And this degeneration of the back disks can sometimes lead to back pain.

"The disk is like a tire between the vertebrae, or bones in the spine," says Nick Shamie, MD, associate professor of spine surgery at UCLA School of Medicine, director of spinal deformity surgery at Santa Monica-UCLA Medical Center and Orthopaedic Hospital, and spokesman for the American Academy of Orthopaedic Surgeons. "It acts as a shock absorber. But with the passage of time and the aging process, everyone's tire will wear out."

By the age of 50, 85 percent of the population begins to show evidence of disk degeneration. For most people, the deterioration of their back disks creates no back pain at all. However, some will suffer back pain through inflammation, nerve pinches, or osteoarthritis.

How Back Disks Deteriorate

Spinal disks consist of a tough outer layer filled with a thick, jellylike fluid. There are several ways the disks can deteriorate and potentially cause back pain. These include:

• Tears that can form in the outer layer over time, through wear associated with everyday activities.
• Aging that causes the jelly inside a disk to dry out, reducing its ability to absorb shocks.
• Injuries that can rip a disk apart or cause a significant tear. These injuries can be caused by sports, improper lifting, or a severe strain placed on the spine.

Most everyone will experience some degree of disk degeneration, but some people are born with a susceptibility to back pain. "Some people are born with less resilient tissue, so their disks tend to wear out quicker," Dr. Shamie says.

How Bad Disks Cause Back Pain

Since disks are a support for both the spine and the nervous system, there are several ways in which the deterioration of these disks can lead to back pain. These include:

• Inflammation. "Basically, an inflammation occurs in the area surrounding the disk," Shamie says. "The body is trying to repair itself because tissues that aren't normally under stress are now being stressed. Whenever there's inflammation, there's going to be pain. The back pain can come from surrounding muscles or from the outer layer of the disk, which contains nerves.”
• Spinal stenosis. A deflating disk can cause pressure either on the spinal cord or one of the major nerve roots branching out from the spinal cord. "As the disk deflates, it bulges out to the side, like a tire sometimes does as it goes flat," Shamie says. "In the spine, there are important neural structures. A little bit of a bulge can impinge on those nerves and press upon those nerves and signal pain in those neural structures." Because the brain can't differentiate where the pressure is being applied, this pain is often felt through the back or neck, or through one of the person's limbs — along an arm if the pressure is happening in the upper back, or along a leg if the pinch is in the lower back.
• Herniated disk. This is often called a bulging disk, ruptured disk, slipped disk, or pinched nerve. It happens when a disk tears and the inside jelly part pushes through the tear and presses on the spinal nerves. Having a herniated disk is painful and can lead to other symptoms, such as shooting pains down the legs, numbness, and weakness.
• Osteoarthritis. As the disk breaks down, the bones of the spine will begin to rub together, creating back pain through arthritis.

If you are experiencing back pain or tingling or pain through your arms or legs, you should ask your family doctor whether you could be experiencing the effects of back disk deterioration. A specialized imaging test, such as a computed tomography (CT) scan or magnetic resonance imaging (MRI) scan, is usually used to determine the health of your spinal disks.