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Abstracts

Is There an Association Between Cervical Myelopathy and Fibromyalgia?

Dan S Heffez MD, Ruth E Ross PhD, Von Shade-Zeldow PhD, Konstantino Kostas PhD, Sagar Shah BS, Robert Gottschalk ND/FNP, Dean Elias MD, Alan Shepard MD, Sue E Leurgans PhD, Charity Moore PhD

Introduction: Cervical myelopathy and fibromyalgia have a number of symptoms in common. It has been suggested that fibromyalgia may be incorrectly diagnosed in some patients who actually have cervical myelopathy or perhaps that cervical spinal cord dysfunction is the underlying cause of the fibromyalgia syndrome. In order to examine the possible relationship between cervical myelopathy and fibromyalgia, we undertook a prospective nonrandomized, case control outcome study of operative versus non-operative treatment of cervical myelopathy in patients who had previously been diagnosed with fibromyalgia.

Methods: Patients carrying the diagnosis of fibromyalgia were referred for neurological evaluation in order to exclude the possibility of myelopathy. Patients underwent a highly structured evaluation, which included a neurological examination by a neurologist and a neurosurgeon, a psychological interview and detailed neuroradiological imaging of the brain and cervical spine. The radiological evaluation included MRI of the cervical spine, MRI of the brain with axial cuts through the plane of the foramen magnum and dynamic contrast enhanced CT of the cervical spine. Patients also completed a HADS and a SF-36 outcome questionnaire. All data was gathered prospectively and entered into a relational database. Patients were followed up every 3 months using a uniform mail-in questionnaire regardless of treatment prescribed.

Cervical myelopathy was diagnosed in the face of symptoms consistent with myelopathy and in the presence of neurological signs indicative of cervical spinal cord dysfunction. Both symptoms and signs of myelopathy were required for inclusion in the outcome study.

Cervical stenosis was diagnosed if the anteroposterior (AP) mid-sagittal spinal canal diameter measured 10mm or less at 1 or more levels as determined from MRI or dynamic CT imaging of the cervical spine. Chiari 1 malformation was diagnosed if tonsillar herniation equaled or exceeded 5 mm as measured on the mid-sagittal MRI image.

Surgical candidates met the following criteria: 1) the neurological examination was abnormal and localized to the cervical spine or cervicomedullary junction, 2) the neuroradiological findings were consistent with compression of the cervical spinal cord or caudal brain stem and 3) non-operative measures if appropriate had failed over 3-6 months.
Non-operative treatment consisted of analgesics, use of a cervical collar and posture and body mechanics training. Non-operative therapy was offered as primary treatment if the patient was unwilling to undergo surgery or if the radiological findings suggested that external cervical immobilization might be effective in minimizing spinal cord compression.

Results: There were 64 patients in the surgical group and 44 patients in the non-surgical group. While the patients were not randomized to the treatment arms, the 2 groups were virtually identical with regards to sex ratio, mean age, mean duration of illness, history of craniospinal trauma, level of education and work history.

The prevalence of those symptoms commonly associated with both cervical myelopathy and fibromyalgia, including pain, headache, numbness, tingling, instability of gait, dizziness and grip weakness was identical in the 2 groups of patients. The prevalence of those symptoms commonly associated with fibromyalgia but not with cervical myelopathy such as fatigue, cognitive difficulties, irritable bowel syndrome, insomnia and depression did not differ between the 2 groups.

The findings on neurological examination did not differ between the 2 groups. The most prevalent findings were high thoracic spinothalamic sensory level to a cold or pinprick stimulus, hyper-reflexia, recruitment of reflexes, Hoffman sign, ankle clonus and absent gag reflex. In both surgical and non-surgical patients, the pyramidal tract findings became more pathological when the patient was examined with the neck positioned in flexion or extension.

There was no difference between the 2 groups in their initial responses to the SF36 quality of life questionnaire, nor in their level of anxiety or depression (HADS questionnaire).

The mid-sagittal AP spinal canal diameter in both the surgical and non-surgical patients was distinctly smaller than that reported in the literature for normal men and women using similar imaging techniques. In both the surgical and non-surgical groups, 23% of patients had a mid-sagittal spinal canal diameter 10mm or less at the c5/6 disc space as measured on CT or MRI images. With the neck positioned in extension, 46% of surgical and non-surgical patients were found to have a mid-sagittal AP spinal canal diameter 10mm or less at the c5/6 disc space as measured on CT images.

Forty percent of patients in the surgical group had 3mm or more of tonsillar ectopia (mean 5.6mm) while 27% of the patients in the non-surgical group had a similar finding (mean 4.0mm) as measured in the traditional manner on the mid-sagittal T1 weighted MRI image.

No single structural cause for myelopathy was identified and therefore no single surgical procedure was performed. The surgical treatment of myelopathy included suboccipital decompression, anterior cervical discectomy and fusion or cervical laminectomy with or without instrumented fusion as indicated by the neuroradiological findings.

While we diagnosed and treated myelopathy, we monitored all symptoms. At the six month follow-up, there was a statistically significant improvement in the surgical group as compared to the non-surgical group with regards to patient reported dizziness, limb numbness, pain, impaired balance and grip weakness (p=0.04 - p=0.000, Chi squared analysis). Improvement was noted in a number of symptoms associated with fibromyalgia and not usually associated with cervical myelopathy such as irritable bowel syndrome (p=0.003) and, impaired memory (p=0.007), impaired concentration (p=0.03) and disorientation (p=0.002). Headache improved in 90% of the surgical group and 45% of the non-surgical group (p=0.06). Patients in the surgical group were more likely to report an improvement in fatigue, depression, insomnia, limb paresthesiae, clumsiness and cold intolerance than were patients in the non-surgical group but the differences were not statistically significant.
There was an improvement in all 9 subscales of the SF36 in the surgical as compared with the non-surgical group, (p=0.037 - p<0.0001,Wilcoxon rank sum test and Fisher's exact test).

Surgical treatment of cervical myelopathy associated with spondylotic cervical stenosis and/or the Chiari 1 malformation may result in the improvement of a vast array of symptoms usually attributed to fibromyalgia, with an associated improvement in patient quality of life. Despite non-randomization, the surgical and non-surgical patients were virtually identical in all measured parameters at the time of initial evaluation. However, as the patients were not randomized, the observed difference in outcome cannot be definitively or exclusively attributed to surgery. Nevertheless, our outcomes implicate a potential association between cervical myelopathy and fibromyalgia in some patients.