The
Anatomy of Adhesive Arachnoiditis
Provided by
Charles V. Burton.
M.D., and
The Burton Report®
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According to Dr.
Charles V. Burton,
one of the primary difficulties in addressing the subject of
adhesive arachnoiditis is the great amount of confusion regarding
nomenclature. Adhesive arachnoiditis is an advanced form of
arachnoiditis (a common entity) and is most often confused with the
latter. Some of the other terms by which it has been referred to
have been:
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 Serosa Circumscripta Spinalis
Intraspinal Granulomatosis
Obliterative Arachnoiditis
Chronic Arachnoiditis
Spinal Meningitis
Chronic Spinal Meningitis
Chemical Meningitis
Sterile Meningitis
Granulomatous Meningitis
Failed Back Syndrome
Failed Back Surgery Syndrome
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Once identified,
Adhesive Arachnoiditis can be better understood by appreciating the
normal anatomy of the spinal column, the dural membranes, and the
subarachnoid space. In the image, to the left, the nerve rootlets of
the cauda equina, which are in motor and sensory pairs, are shown as
single nerves for simplification. If a lumbar puncture were to be
performed the needle would simply push the nerve roots, floating in
cerebrospinal fluid, out of the way. If a similar procedure were
attempted in a patient with Class III Adhesive Arachnoiditis, where
the nerve roots were fixed to each other and to the dura mater, the
needle could easily injure or sever the nerves. |
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Adhesive Arachnoiditis comes about as a progression of inflammatory
change secondary to insult or injury occurring over a period of
time. This progression involves: |
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Acute Inflammatory Phase (Class I)
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Beginning of Chronic Phase (Class II) |
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Chronic Scar Phase (Class III) |
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Arachnoiditis Ossificans |
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Adhesive
Arachnoiditis: Acute Inflammatory Phase (Class I) |
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In the
illustrations of the first, or acute inflammatory phase, shown
above, the nerve roots are swollen and hyperemic (vascular
dilatation). Pathologic specimens show acute inflammatory cells
predominating. |
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Adhesive Arachnoiditis:
Beginning of Chronic Phase (Class II) |
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In the illustrations of the second phase, shown above, the nerve
root swelling has progressively decreased (the nerves are beginning
to be encased in collagenous scar tissue). Pathologic specimens show
a mix of acute and chronic inflammatory cells. |
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Adhesive Arachnoiditis: Chronic Scar Phase (Class III) |
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By the time the process has reached the chronic phase there is
prominent collagenous scar deposition. The nerve roots are adherent
to each other and to the meninges. Surgically opening the dura
often shows what appears to be an empty sac because the nerves are
now actually part of the dural membrane. By the Class III stage the
inflammatory cells seen document a chronic process. The nerves
themselves have been progressively deprived of nourishment as the
nutrient blood vessels have atrophied and the "percolating"
nourishment derived from the cerebrospinal fluid has markedly
decreased. It is, in fact, a tribute to the human nervous system
that in the face of such adversity, in can, in the great majority of
cases, continue to maintain "normal" function. The only way this
can happen is if the adverse process occurs slowly enough to allow
the system to adapt and acclimate. The acclimization is, however,
fragile. Because function is maintained precariously any additional
insult (i.e. trauma, surgery, myelography, etc.) can tip the balance
and cause onset of clinical disability and incapacitation. |
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By far the greatest number of cases of adhesive
arachnoiditis which have occurred throughout the world during the
20th century resulted from oil myelography with either Pantopaque®
or Myodil®. Because these substances are hyperbaric once they were
placed in the subarachnoid space they would migrate to the distal
portion, where they remained, producing progressive scarring. |
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The patterns of adhesive
arachnoiditis scar are typically quite variable in their patterns.
Sown above are drawings of variable scar patterns in three actual
cases. These are patterns reflecting diffuse, multi-level
involvement, characteristic of the introduction of a toxic foreign
body substance into the sub-arachnoid space. The last illustrations
to the right shows how residual droplets of foreign body substance
(in this case Pantopaque®) are surrounded by encapsulating scar
reflecting the body's defense against foreign body substances.
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The illustrations to the
left demonstrate an example of focal adhesive arachnoiditis. In
this case it is due to the local inflammatory effect of a
hypertrophic facet joint intruding into the central spinal canal.
Focal inflammation is also typical following segmental spinal trauma
or focal spinal surgery. |
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Adhesive Arachnoiditis: Arachnoiditis Ossificans
The image to the left is a year 2000 CT scan performed on a 71 year
old woman who developed clinically significant adhesive
arachnoiditis following a 1971
Pantopaque®
myelogram. Control of her constant pain required implantation of a
spinal cord neurostimulator which provided good pain control
allowing the patient return to normal function. In 1990 she began
to experience progressive bowel and bladder dysfunction. The CT
scan shows classic arachnoiditis ossificans where the scar tissue
has calcified. |
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The red dots represent the
spaces occupied by the nerve roots. These nerves are being
progressively strangled by the progression of scar calcification. |
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