Fibromyalgia & Chronic Pain LIFE Mar/Apr 2013, Issue 8 - Page 23

women, depending on disc level and patient size.) Compression or abutment of the cord was often intermittent, and consistent with prior studies, with PC3 much more evident in extension rather than in flexion. features, including thermoregulatory, cardio-vascular, gastrointestinal, and urological issues as well as mood disturbances . t least for the FM population, these findings have been supported independently. Hryciw found that 54% of her clinic patients with FM had PC3 by flexion-extension MRI.18 She also reported that 50% of those with PC3 had obstructive sleep apnea (OSA), a linkage of the cervical myelopathy with OSA also suggested by others. Parenthetically, 7 months after surgical decompression for Chiari malformation (without FM), the apnea hypopnea index was reduced significantly (80%) in 16 patients with an overlapping mixture of central and obstructive sleep apnea.19 A F rom a database that now exceeds 3,000 patients, a random two-month experience was reported in The Journal of Pain in 2008.16 Of 107 referrals to a suburban rheumatology office, 53 had FM by 2001 American College of Rheumatology (ACR) classification criteria,17 32 had an autoimmune or connective tissue disease, and 22 had chronic widespread pain (CWP) without sufficient allodynia (tender points) to confirm FM. PC3 was identified by flexion-extension C-spine MRI in 71% of the FM group and in 85% of the CWP group. Also, in only 15 of 52 patients identified with PC3 (21%) could the cord compression be visualized on the traditional, neutral sagittal MRI view. Thus, 80% of patients in this study with PC3 would not have been diagnosed using the MRI protocol available to most practicing clinicians. variety of symptoms suggestive of a myelopathic process were described by Heffez and were later seen in Seattle, WA, and in Portland, at Oregon Health and Sciences University. In addition to pain in an extended cervical position, patients reported having poor balance, variable dysesthesias, weakness, muscular cramping , headaches, wide- spread and migratory regional pains, fatigue, and poor sleep in both studies. Examination findings often revealed motor and sensory deficits. Patients also characteristically reported dysautonomic Unfortunately, available data are insufficient to be conclusive. Yet, in animal models, intermittent abutment of the cervical cord (without injury or ischemia) is a potent trigger of autonomic arousal. 22 And of note, similar abutment to thoracic and lumbar levels are not. Hence, there appears to be a curious connection between autonomic arousal and cervical cord irritation, and this observation may provide a rationale as to why FM—a potent dysautonomic (malfunction of the autonomic nervous system), hyperexcitatory (overstimulation) state—often is temporally related to cervical spine trauma.23, 24 Summary N A eurologic deficits also have been repor ted in a controlled FM study, and PC3 was proposed as a reasonable explanation. 20 In fact, these authors later suggested that in patients with FM, only a f lexion-extension C- spine MRI protocol is acceptable, especially when a patient is being evaluated for a Chiari malformation. 21 uch obser vations raise the prospect that while it is visually and, in many ways, clinically similar to CSM, PC3 may offer a twist. The intermittent component of compression documented by a flexion-extension MRI may add a dimension worth studying and discriminate PC3 from CSM. Certainly, there are many important clinical and therapeutic features that distinguish intermittent from chronic nerve entrapment. The same may very well be true for the cervical spinal cord. R S egardless of whether there is a true connection between autonomic arousal and cervical cord irritation, dynamic imaging of structures confers more information and may assist in elucidating why there seem to be so many discrepancies between anatomy (as we see it so far) and symptoms. Application of enhanced imaging has had profound implications for many other areas of medicine. Those first steps were taken just as gingerly and sometimes as skeptically received. Yet, with further independent evaluation, the f lexion-extension C-spine MRI may help ferret out a bit more of the mystical conundrum that is the cervical spine. To learn about how to do a f lexionextension C-spine MRI, call Pacific Rheumatolog y A ssociates for video i n s t r u c t i o n . M R I te c h n i c a l s e t tin g s are g iven in R e ference 16. R eferences can be found at www. fmcpaware.org/pc3. Mar/Apr 2013 Fibromyalgia & Chronic Pain Life 23