 As
can be seen in the above illustration, a bulging disc is
a herniated disc which is still contained by it's annulus.
This is an important distinction to make. If given enough time
and appropriate therapy, these will--more often than not--get
better! This is attributed the the disc "going back in," or with
time drying out and shrinking. If the nerve has enough space to
exit the spinal canal, then there will be minimal or no pain,
thus obviating the need for surgery.
But what if the disc annulus is too weak to repair itself,
despite time, medications, and therapy? This may result in
continued pain, or intermittent pain which only interferes with
specific activities. Often in this latter case, the disc moves
in and out compressing the nerve and thus causing sciatica. This
type of disc bulge is described as an incompetent disc.
Often the only way to demonstrate this condition is with a dynamic
or motion study of the spine with X-rays. The traditional test
for this is the myelogram.
Osteoarthritis and Stenosis
Often a disc bulge occurs in a patient with "degenerative arthritis"
known as Osteoarthritis. (This is to be distinguished from Osteoporosis,
which is the thinning of bones due to loss of calcium, and which
usually occurs in genetically predisposed post-menopausal women.)
In the illustration below, the facet joint has become large (hypertrophied)
and developed bony spurs, i.e. it is osteoarthritic.
 Now
the nerve no longer has enough room to exit the spinal
canal, and sciatica with varying degrees of pain, numbness, and
weakness will be present.
Stenosis occurs whenever the spinal canal or the hole a
nerve root exits (foramina) the spinal canal is narrowed.
In the above illustration, the foramina was tight (i.e., stenotic!)
prior to the disc herniation. Thus a person with stenosis is more
likely to be symptomatic from even mild disk herniations.
|
