Degenerative Disc Disease
Degenerative disc disease (DDD) is part of the natural process of
growing older. Unfortunately, as we age, our intervertebral discs
lose their flexibility, elasticity, and shock absorbing characteristics.
The ligaments that surround the disc called the annulus fibrosis,
become brittle and they are more easily torn. At the same time,
the soft gel-like center of the disc, called the nucleus pulposus,
starts to dry out and shrink. The combination of damage to the intervertebral
discs, the development of bone spurs, and a gradual thickening of
the ligaments that support the spine can all contribute to degenerative
arthritis of the lumbar spine.
Degenerative disc disease is as certain as death and taxes, and
to a certain degree this process happens to everyone. However,
not everyone who has degenerative changes in their lumbar spine
has pain. Many people who have "normal" backs have MRIs
that show disc herniations, degenerative changes, and narrowed
spinal canals. Every patient is different, and it is important
to realize that not everyone develops symptoms as a result of
degenerative disc disease.
When degenerative disc disease becomes painful or symptomatic,
it can cause several different symptoms, including back pain,
leg pain, and weakness that are due to compression of the nerve
roots. These symptoms are caused by the fact that worn out discs
are a source of pain because they do not function as well as they
once did, and as they shrink, the space available for the nerve
roots also shrinks. As the discs between the intervertebral bodies
start to wear out, the entire lumbar spine becomes less flexible.
As a result, people complain of back pain and stiffness, especially
towards the end of the day.
Symptoms
The most common symptom of degenerative disc disease is back pain.
When DDD causes compression of the nerve roots, the pain often
radiates down the legs or into the feet, and may be associated
with numbness and tingling. In severe cases of lumbar DDD, where
there is evidence of nerve root compression, individuals may experience
symptoms of sciatica and back pain, and sometimes even lower extremity
weakness.
Diagnosis
The diagnosis of degenerative disc disease begins with a complete
physical examination of the body, with special attention paid
to the back and lower extremities. Your doctor will examine your
back for flexibility, range of motion, and the presence of certain
signs that suggest that your nerve roots are being affected by
degenerative changes in your back. This often involves testing
the strength of your muscles and your reflexes to make sure that
they are still working normally. You will often be asked to fill
out a diagram that asks you where your symptoms of pain, numbness,
tingling and weakness are occurring.
A routine set of x-rays is also usually ordered when a patient
with back pain goes to see a doctor. If degenerative disc disease
is present, the x-rays will often show a narrowing of the spaces
between the vertebral bodies, which indicates that the disc has
become very thin or has collapsed. Bone spurs begin to form around
the edges of the vertebral bodies and also around the edges of
the facet joints in the spine. These bone spurs can be seen on
an x-ray, where they are called osteophytes. As the disc collapses
and bone spurs form, the space available for the nerve roots starts
to shrink. The nerve roots exit the spinal canal through a bony
tunnel called the neuroforamen, and it is at this point that the
nerve roots are especially vulnerable to compression.
In many situations, doctors will order a MRI or a CT scan (CAT
scan) in order to evaluate the degenerative changes in the lumbar
spine more completely. A MRI scan is very useful for determining
where disc herniations have occurred and where the nerve roots
are being compressed. A CT scan is often used to evaluate the
bony anatomy in the spine, which can show how much space is available
for the nerve roots and within the neuroforamen and spinal canal.
Treatment
Your doctor will be able to discuss with you what your diagnosis
means in terms of treatment options. For most people who do not
have evidence of nerve root compression with muscle weakness,
the first line of therapy includes non-steroidal anti-inflammatory
drugs and physical therapy. A soft lumbar corset is often prescribed
in order to allow the back to have a chance to rest. Surgery is
offered only after physical therapy, rest, and medications have
failed to adequately relieve the symptoms of pain, numbness and
weakness over a significant period of time.
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