Lumbar degenerative disc disease
Degenerative disc disease refers to a syndrome in which
a painful disc causes chronic low back pain. The condition
generally starts with a torsional (twisting) injury
to the disc space. The injury weakens the disc and creates
excessive micro-motionat the corresponding vertebral
level because the disc cannot hold the vertebral segment
together as well as it used to. The excessive micro-motion,
combined with the inflammatory proteins inside the disc
that become exposed and irritate the local area, produces
low back pain. (See
Figure 1)
Unlike the muscles in the back, the disc does not have
a blood supply and therefore cannot heal itself and
the painful symptoms of degenerative disc disease can
become chronic. While it is rare that low back pain
from degenerative disc disease will progress or increase,
the pain will tend to fluctuate and at times may become
significantly worse.
The degenerative process
It is important to note that disc degeneration
is part of the natural process of aging and does not
necessarily lead to low back pain. MRI scans have
documented that approximately 30% of 30 year olds have
signs of disc degeneration on MRI scans even though
they have no back pain symptoms. It must therefore be
stressed that not all degenerated discs that are seen
on MRI scans are pain generators.
As the population ages, it is even more common for
individuals to have signs of disc degeneration without
pain, and by the time an individual reaches 60 years
old, disc degeneration is an expected finding on an
MRI scan. In fact, the incidence of low back pain actually
declines as we age, despite the fact that our discs
are degenerating.
A fully degenerated disc no longer has any inflammatory
proteins (that can cause pain) and usually collapses
into a stable position (see Figure
2). While many people over the age of 60 have degenerated
discs, it is highly uncommon for them to suffer from
degenerative disc disease.
Treatment options
For most people, degenerative disc disease can be
successfully treated with conservative care. Most patients
will experience low-grade continuous but tolerable pain
that will occasionally flare (intensify). The frequency
and intensity of the flares can be managed with an exercise
program that consists of:
- hamstring stretching
- dynamic lumbar stabilization exercises
- low-impact aerobic conditioning
Non-prescription medications, such as NSAID's and acetaminophen,
may be helpful in alleviating low back pain, and stronger
therapies, such as oral steroids or epidurals, may be
prescribed to treat severe flares.
For patients who are unable to function because of
the pain, or who are frustrated with their activity
limitations, lumbar spinal fusion surgery is an option.
Fusion surgery works because it stops the motion at
a painful motion segment.
A one-level fusion does not significantly change the
mechanics in the back, and a two-level fusion may also
be considered for patients with severe, disabling pain.
Three-level fusions change the mechanics of the back
substantially and are not recommended (the back is designed
for movement, and limiting the movement and altering
the muscle composition can in and of itself cause pain).
When performed judiciously by an experienced surgeon
trained in doing fusion surgery, a fusion surgery can
be an effective option for patients to enhance their
activity level and overall quality of life. Particularly
now that minimally invasive techniques (ALIF with anterior
interbody cages) are available to do the fusion, the
surgery carries little morbidity (eg. post-operative
discomfort), saves more of the normal anatomy of the
low back, and has a high rate of fusion.
By: Peter
F. Ullrich, Jr., MD
September 8, 1999
Updated February 28, 2000
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