material which is attached to nerve roots, the dura, and the
side walls of the epidural space. Such scar tissue may form
as a consequence of spine surgery in which the epidural
space is entered (discectomy, laminectomy, Brantigan cage
fusion), as a sequelae of spine trauma, as a consequence of
a disc herniation with leakage of enzymes onto nerve roots
creating scar tissue, or potentially from injections into the
spine (although this has not been demonstrated). Such scar
tissue is not uniformly painful, but its presence is seen in
many patients who have continued or new pain after spine
surgery. Dense scar tissue is visible on MRI whereas thin
scar tissue strands are not. Since there is no way to directly
correlate the pain with the scar tissue through testing, the
diagnosis is a presumptive one after ruling out other causes
of spinal origin pain.
MRI demonstrates scar tissue as a compression of the
spinal sac (dura) or nerve tissue. The MRI images can lead to
confusion between scar tissue and a new disc herniation, and
often gadolinium contrast is injected IV to permit
differentiation between scar tissue and new or recurrent disc
herniation. Also new fat suppression modes MRI settings
coupled with IV gadolinium make the presence of scar tissue
quite clear.
Epidurography is the injection of the epidural space under
x-ray with contrast material which shows scar tissue as a
"filling defect". The area where contrast does not go (but
should) is presumptively scar tissue or some other
obstruction. Often during epidurography, the nerve roots can
be evaluated as to whether contrast flows freely down the
nerve root or whether there is an obstruction.
Finally, epiduroscopy can be used to evaluate scar tissue.
Epiduroscopy uses an endoscope placed in the caudal canal
in the sacrum (tailbone) and the endoscope is advanced in the
spine while assessment of scar tissue is undertaken. Some
scar tissue may be easily broken up by the endoscope, while
dense scar tissue cannot.
In the past, surgeons would operate on scar tissue in the
spine over and over again attempting to remove it, but the
scar tissue grows back. Because of increasing risks of
damage to the spine with more surgeries and because of the
short term relief provided by such surgeries, most surgeons
do not perform scar tissue excision surgeries any longer.
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