The variable presentation and treatment response of fibromyalgia (FM) may be related to comorbidities, including positional cervical cord compression (PC3). Prevalence of PC3 among routine referrals for rheumatology consultation was assessed over 2 random months (January and February 2006) from a 4-year experience of 1100 patients. PC3 was defined as cord abutment, compression or flattening with a spinal canal diameter of <10 mm by magnetic resonance sagittal flexion, neutral, and extension images. Of 107 referrals, 53 had FM, 32 had a connective tissue disease (CTD) without FM, and 22 had chronic widespread pain (CWP) without FM criteria. The dynamic cervical spine images were obtained in 70 patients: 49 of 53 with FM, 20 of 22 with CWP and 1 of 32 with CTD, based on history and examination. Among those who received magnetic resonance imaging [MRI], 52 patients met PC3 criteria (71% of FM group [35/49], 85% of CWP group [17/20]). Two patients had a Chiari malformation (FM), 1 had multiple sclerosis (CWP), and 1 had multiple myeloma (CWP). Extension views were required for diagnosis for 37 of these 52 (71%) subjects, as well as for 8 patients who also had cervical spinal cord flattening. The pilot data suggest that further evaluation of PC3 in a controlled trial is warranted among patients with FM and CWP.
Perspective: Fibromyalgia is complex and poorly understood. Recognition of unsuspected, comorbid cervical cord compression may provide new insight into its variable presentation, leading to novel treatment considerations. Also, dissemination of this dynamic MRI protocol may promote further study of this emerging concept of cervical cord irritation.