Potential thresholds of critically increased cardiac-related spinal cord motion in degenerative cervical myelopathy

Introduction New diagnostic techniques are a substantial research focus in degenerative cervical myelopathy (DCM). This cross-sectional study determined the significance of cardiac-related spinal cord motion and the extent of spinal stenosis as indicators of mechanical strain on the cord. Methods Eighty-four DCM patients underwent MRI/clinical assessments and were classified as MRI+ T2-weighted (T2w) hyperintense lesion in MRI or MRI− (no T2w-hyperintense lesion). Cord motion (displacement assessed by phase-contrast MRI) and spinal stenosis adapted spinal canal occupation ratio (aSCOR) were related to neurological (sensory/motor) and neurophysiological readouts contact heat evoked potentials (CHEPs) by receiver operating characteristic (ROC) analysis. Results MRI+ patients (N = 31; 36. 9%) were more impaired compared to MRI− patients (N = 53; 63. 1%) based on the modified Japanese Orthopedic Association (mJOA) subscores for upper MRI+ median (Interquartile range): 4 (4–5) ; MRI−: 5 (5–5) ; p 0. 01 and lower extremity MRI+: 6 (6–7) ; MRI−: 7 (6–7) ; p = 0. 03 motor dysfunction and the monofilament score MRI+: 21 (18–23) ; MRI−: 24 (22 - 24) ; p 0. 01. Both patient groups showed similar extent of cord motion and stenosis. Only in the MRI− group displacement identified patients with pathologic assessments trunk/lower extremity pin prick score (T/LEPP): AUC = 0. 67, p = 0. 03; CHEPs: AUC = 0. 73, p = 0. 01. Cord motion thresholds: T/LEPP: 1. 67 mm (sensitivity 84. 6%, specificity 52. 5%) ; CHEPs: 1. 96 mm (sensitivity 83. 3%, specificity 65. 6%). The aSCOR failed to show any relation to the clinical assessments. Discussion These findings affirm cord motion measurements as a promising additional biomarker to improve the clinical workup and to enable timely surgical treatment particularly in MRI− DCM patients. Clinical trial registration www. clinicaltrials. gov, NCT 02170155.