Clinical significance of high intramedullary signal on T2-weighted cervical flexion–extension magnetic resonance imaging in cervical myelopathy

Background: In cervical myelopathy, significant findings are seen in flexion–extension MRI due to the increased likelihood of cord compression during neck extension. In addition, a high intramedullary signal on T2-weighted MR images has been reported to be a prognostic factor in this condition. However, the relationship between Japanese Orthopaedic Association (JOA) scores and the signal intensity in preoperative cervical flexion–extension T2-weighted images has not been evaluated. The purpose of this study was to evaluate whether preoperative flexion–extension MRI may be used to predict surgical outcomes in patients with cervical myelopathy. Methods: A total of 121 patients who underwent surgery for cervical myelopathy were included. All patients underwent preoperative cervical flexion–extension MRI followed by cervical decompression surgery, with or without spinal fusion, and postoperative follow-up for at least 2 years. Pre- and postoperative (2 years after surgery) JOA scores were recorded, and the degree of postoperative improvement was calculated. The relationship between intramedullary signal intensity on preoperative cervical dynamic MRI findings and degree of clinical recovery was examined. Results: Patients with a high intramedullary signal on the extension MRI had significantly better neurological recovery than those with a high signal on the flexion MRI (p < 0.000005). There was no significant difference in neurological recovery between patients with and without a high intramedullary signal on extension MRI. Conclusions: A preoperative high intramedullary signal on flexion MRI was associated with a poor surgical outcome, while no such association was seen with extension MRI.