Degenerate disc disease is the name for the age-related breakdown of intervertebral discs over time.
It can lead to weakness, numbness and pain that radiates down the leg.
Despite its name, degenerative disc disease is not a disease, but a natural occurrence that comes with aging.
The rubbery discs between the vertebrae normally allow for flexing and bending of the back, like shock absorbers. In time, they become worn, and they no longer offer as much protection as before.
Contents of this article:
What is degenerative disc disease?
Degenerative disc disease is an age-related condition leading to discogenic pain, or pain caused by damaged discs between the vertebrae.
Intervertebral discs, also known as intervertebral fibrocartilage or spinal discs, provide the padding between the vertebrae of the spine. They have an elastic structure, made of fibrocartilage tissue.
The outer part of the disc is known as the annulus fibrosus. It is tough and fibrous, and it consists of several overlapping layers.
The inner core of the disc is the nucleus pulposus. It is soft and gelatinous.
The intervertebral discs cushion the stress when the spine moves or bears weight. They also help the spine to bend.
As people age, the repeated daily stresses on the spine and occasional injuries, including minor, unnoticed ones, can damage the discs in the back.
- the breakdown of cartilage, the tissue that cushions the joints
- a bulging or broken disc, known as a herniated disc
- the narrowing of the spinal canal, or spinal stenosis
These changes can affect the nerves, leading to pain, weakness, and numbness.
Signs and symptoms
The disc will sometimes bulge between the vertebrae. This is known as a herniated disc.
Disc degeneration may cause no symptoms, or the pain may be so intense that the individual cannot continue with their daily activities.
The discomfort can range from mild to be severe and debilitating. It can lead to osteoarthritis, with pain and stiffness in the back.
The most common early symptom is usually pain and weakness in the back that radiates to another area.
If the damage is in the lower back, or lumbar spine, the discomfort will radiate to the buttocks and upper thighs. There may also be tingling, numbness, or both, in the leg or foot.
If the damage is in the neck area, or cervical spine, the pain may spread to the shoulder, arm, and hand.
There may also be instability in the spine, leading to muscle spasms in the lower back or neck, as the body tries to stabilize the vertebrae. This can be painful.
There may be flareups of intense pain.
The pain may be worse when sitting, bending, lifting, or twisting. Walking, lying down, and changing position may help relieve it.
The term degenerative disc disease usually refers to a combination of spinal problems that start with damage to the disc, and eventually spread to other parts of the spine. It usually gets worse with age.
- Loss of fluid: the intervertebral discs of a healthy young adult consist of up to 90 percent fluid. With age, the fluid content decreases, making the disc thinner. The distance between vertebrae becomes smaller, and it becomes less effective as a cushion, or shock-absorber.
- Disc structure: very small tears or cracks develop in the outer layer of the disc. The soft and gelatinous material in the inner part may seep through the cracks or tears, resulting in a bulging or rupturing disc. The disc may break into fragments.
Factors that can speed up this process include:
- strenuous physical work
- tobacco smoking
- an acute, or sudden, injury, such as a fall
When the vertebrae have less padding between them, the spine becomes less stable.
To compensate, the body builds osteophytes, or bone spurs, small bony projections that develop along the edge of bones. These projections can press against the spinal cord or spinal nerve roots. They can undermine nerve function and cause pain.
When the bone spurs grow into the spinal canal and press into the spinal cord and nerves, this is known as spinal stenosis.
Tests and diagnosis
The doctor will ask about symptoms, when and where the individual feels pain, tingling or numbness, and which situations cause the most pain. They will also ask about any falls, injuries, or accidents.
A physical examination may assess for:
- Muscle strength: The doctor may check for atrophy, wasting, or abnormal movements.
- Pain with motion or in response to touch: The patient will be asked to move in specific ways. If pressure applied to the lower back causes pain, there may be a degenerated disc.
- Nerve function: The physician taps different areas with a reflex hammer. Poor or no reaction could indicate a compressed nerve root. Hot and cold stimuli may be used to see how well the nerves react to temperature changes.
The doctor may order the following diagnostic tests:
- Imaging scans, such as CT or MRI, to gather information about the state of the spinal nerves, the discs, and how they are aligned.
- A discogram, which involves injecting a dye into the soft center of the disc, or several discs. The aim is to see whether the disc is painful. The dye shows up on a CT scan or X-ray. Discogram usage may be controversial, however, because cracked discs do not always cause symptoms.
The doctor may also test for other conditions, such as a tumor or other kinds of damage, to ensure a correct diagnosis.
Treatment may include occupational therapy, physical therapy, or both, special exercises, medications, losing weight, and surgery.
Patients can help themselves in a number of ways, especially if symptoms are mild.
Physical therapy and exercise that strengthens the core like yoga or pilates can help to manage degenerative disc disease.
- Some positions can help relieve symptoms. Kneeling or reclining, for example, may be less painful than sitting.
- Lifting weights may help. This must be done under guidance and without bending the body.
- Medications include painkillers, such as Tylenol, and non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen. Steroids and muscle relaxers may also be prescribed.
- A corset or brace can offer support for the back.
- Exercises that build the back and stomach muscles include core strengthening programs, yoga, pilates, and swimming.
A doctor can inject the joints next to the damaged disc with steroids and a local anesthetic. These are called facet joint injections. They can provide effective pain relief.
Facet rhizotomy is a radiofrequency current that deadens the nerves around the facet joint, preventing pain signals from reaching the brain. Patients who respond well to facet joint injections may benefit from these. Pain relief may last for more than a year.
Intradiscal electrothermal annuloplasty (IDET) involves inserting a catheter into the disc and heating it. This appears to reduce pain, possibly by causing collagen to contract so that it repairs damage in the disc. The exact mechanism remains unclear.
Patients who do not respond to conservative therapies within about 3 months may consider surgery.
This may be an option if there is:
- back or leg pain that stops the patient from carrying out regular activities
- numbness or weakness in the legs
- difficulty standing or walking
The following surgical options are available:
If conservative management does not have the intended effect, spinal surgery may be required to correct the degenerated disc.
Stabilization surgery or spinal fusion: two vertebrae are fused together, to provide stability for the spine.
This can be done anywhere in the spine but is more common in the lower back and the neck area. These are the most movable parts of the spine.
This can relieve extreme pain in patients whose spine can no longer bear their weight, but it can also speed up the degeneration of the discs next to the fused vertebrae.
Decompression surgery: Various options to remove part of the joint of the disc can relieve the pressure on the nerves.
A patient who develops osteoarthritis, a herniated disc or spinal stenosis may need other types of treatment.
Stem cell therapy
Researchers at the University of Queensland, Australia, have had some success with a tissue engineering-based approach using stem cells.
The aim is to encourage functional cartilage to generate itself, using an injectable hydrogel system. The researchers concluded that stem cell therapy might be useful for intervertebral disc regeneration.