PREVALENCE OF CHIARI MALFORMATION, AND
CERVICAL STENOSIS, IN
Daniel J Clauw, Robert M Bennett, Frank Petzke, Michael J
Introduction. There has been a recent recognition that the
clinical features of fibromyalgia
(FM) may overlap significantly with those of Chiari
malformation and/or cervical spinal stenosis (CM/CS). The evidence
supporting this relationship includes: 1) a large case series
published by Milhorat demonstrating the clinical similarities
between CM and FM (Neurosurgery 44:1005,1999), 2) the observation
of Rosner and others that some patients labeled as having FM have
CM/CS and may benefit from decompressive surgery.
Subjects and Methods. This prospective study examined the
prevalence of CM/CS in individuals who had been diagnosed with FM.
39 consecutive patients fulfilling ACR criteria for FM at two
tertiary care centers served as the FM cohort, and a group of
23gender-matched asymptomatic individuals served as the control
group. All subjects completed symptom questionnaires, had an
extensive neurological examination, and underwent a MRI of the
posterior fossa and cervical spine. The MRIs were first screened
for technical adequacy and were read by two blinded radiologists
who evaluated the diameter of the cervical canal and cord at each
level from C1- C7, and the level of the cerebellar tonsils
relative to the foramen magnum.
Results. 38 FM pts. and 23controls had adequate studies to
evaluate their cervical region for CS. There were no consistent
differences between groups in the mean diameter, or in the number
of individuals who would be judged to have "stenosis",
at any cervical level. Of the subjects who had technically
adequate studies of the posterior fossa 8/26 FM and 11/15 controls
had evidence of cerebellar tonsils in the foramen magnum. Finally,
a neurosurgeon who rated the overall MRI in a blinded fashion
judged 47% of FM and 50% of controls as possibly a surgical
Summary. This study does not support the notion that there
is an increased prevalence of CM or CS in individuals with FM.
However, this small sample size would not detect a small increase
in prevalence of CM or CS in FM, and these findings cannot be
extrapolated to other settings where individuals might be labelled
as having FM without a careful diagnostic evaluation. Larger
studies are necessary to help address this complex issue.
D.J., Petzke, F., Rosner, M.J., Bennett, R.M.
Prevalence of Chiari malformation and cervical spine stenosis in
Fibromyalgia. Arth. Rheum. 43: S173, 2000
Disclosure: This study was funded by the National Fibromyalgia