Fibromyalgia & Chronic Pain LIFE Mar/Apr 2013, Issue 8 - Page 19

Research Update Using Dynamic MRI to Diagnose Neck Pain: The Importance of Positional Cervical Cord Compression (PC3) Editorial Note: Andrew Holman, MD, Pacific Rheumatology Associates, is a Seattle area rheumatologist and fibromyalgia researcher. In the following article he describes a type of flexion MRI and its importance in identifying positional cervical spinal cord compression (PC3). In this article he discusses research that has led to the discovery that positional cervical spinal cord compression plays a role in many patients diagnosed with FM. I t has become universally accepted that cervical (neck) spine pain and regional imaging often correlate poorly. Both degenerative disc disease and cer vical pain are common among chronic pain patients. Yet, many have one apparently without the other. One diagnostic response is to discount the informative value of cervical imaging and rely more on histor y, symptoms, and physical signs. Another is to consider how to better image this area of complex anatomy, without discounting the primar y importance of clinical findings. Neck Pain and the Spinal Cord G eneral medical reviews describing “neck pain” often leave out mention of any role attributable to the cervical spinal cord. Defects of discs, facet joints, ligaments, ner ve roots, and muscles are contemplated, but irregularities of the cord itself generally are not. where the cer vical spinal cord was compressed at 2 disc levels; after decompression, the cord was freed and there was evidence of cerebral spinal f luid f lowing unimpeded within a widened cervical canal. If these images can be accepted as proof of—or at least consistent with—CSM followed by resolution of its symptoms, then we may be compelled to similarly judge identical images obtained through dynamic imaging. T s a dynamic structure, the cervical spine anatomy may be suspected of differing in conformation, depending on its orientation in f lexion, extension, rotation, and lateral bending (normal movement). Current accepted diagnostic imag ing , especially by magnetic resonance imaging (MRI), often has been static and limited to the patient’s neutral positioning in the machine (laying f lat). Such standards may prove deceptive and filled with bias. A hese abnormalities are discussed in scientific reviews on cervical spondylotic myelopathy (CSM) – spinal cord compression. Malcolm eloquently reviewed five different CSM syndromes: “the transverse lesion syndrome, the motor system syndrome, the central cord syndrome, the Brown Sequard syndrome, and the brachalgia and cord syndrome.” 1 Each is associated with a different set of clinical signs and symptoms. Figure 1 provides an excellent example of cord compression using a traditional, static, neutral C-spine MRI protocol. In Dr. Malcolm’s re v ie w, he de s c r i b e s a c a s e O ve r h a l f a ce n t u r y a g o , Olsson reported how position inf luenced cer vical spinal canal diameter in the canine model. 2 Penning expanded this e valu at ion to hum an s pin al co rd co m p re s s i o n i n 1 9 9 6 . 3 Much later, after the discovery of MRI, Muhle et al examined a cohort of 46 patients to assess the effect of confor mational changes to the cer vical canal in extension (30°) and f lexion (50°). 4 Cer vical spinal stenosis was more commonly found at extension (48%) compared to f lexion (24%). Further, 11% of the 46 patients had cord compression in f lexion compared to Mar/Apr 2013 Fibromyalgia & Chronic Pain Life 19