Nearly everyone shows some signs of wear and tear on the spinal discs as they age. Not everyone, however, will have symptoms described as degenerative disc disease. Not actually a disease, degenerative disc disease refers to a condition in which pain is caused from a damaged disc. A wide range of symptoms and severity is associated with this condition.
The discs are like shock absorbers between the bones of the spine and are designed to help the back stay flexible while resisting terrific forces in many different planes of motion. Each disc has two parts:
A firm, tough outer layer (anulus fibrosus). The outer portion of this layer contains nerves. If the disc tears in this area, it can become quite painful.
A soft, jelly-like core (nucleus pulposus). This part of the disc contains proteins that can cause the tissues they touch to become swollen and tender. If these proteins leak out to the nerves of the outer layer of disc they can cause a great deal of pain.
Unlike other tissues of the body, there is very little blood supply to the disc. Once a disc is injured, it cannot repair itself, and a spiral of degeneration can set in with three stages that appear to occur over 20 to 30 years:
Acute pain makes normal movement of the back difficult
The bone where the injury occurred becomes relatively unstable. Over a long period of time, the patient will have back pain that comes and goes.
The body restabilizes the injured segment of the back. The patient experiences fewer bouts of back pain.
The typical person with degenerative disc disease is active, otherwise healthy and in his or her 30s or 40s.
- Pain that is worse when sitting. While seated, the discs of the lower back have three times more load on them than when standing.
- Pain that gets worse when bending, lifting or twisting
- Feeling better while walking or even running than while sitting or standing for long periods of time
- Feeling better changing positions often or lying down
- Periods of severe pain that come and go. These last from a few days to a few months before getting better. They can range from nagging pain to severe, disabling pain.
- Pain can affect the low back, buttocks and thighs or the neck, depending on where the affected disc is, radiating to the arms and hands
- Numbness and tingling in the extremities
- Weakness in the leg muscles or foot drop may be a sign that there is damage to the nerve root
A diagnosis is based on a medical history and a physical examination, as well as the symptoms and the circumstances where the pain started. MRI can show damage to discs, but it alone cannot confirm degenerative disc disease.
A diagnostic study commonly performed is discography. A discogram is a diagnostic procedure to determine if your vertebral disc(s) is/are your source of back pain.
A discogram is an invasive test that generally isn’t used for an initial evaluation of back pain. But your doctor may suggest a discogram if your back pain persists despite conservative treatments, such as medication and physical therapy.
Some doctors use a discogram before spinal fusion surgery to help identify which disks need to be removed. However, discograms are not always accurate in pinpointing which disks, if any, are causing back pain. Many doctors instead rely on other tests, such as MRI and CT scanning, to diagnose disk problems and guide treatment.