Magnetic resonance imaging of the spinal cord in cervical ossification of the posterior longitudinal ligament

Study Design. Magnetic resonance imaging findings of an increased signal in the cervical cord in patients undergoing surgery for ossification of the posterior longitudinal ligament were analyzed to determined whether an increased signal on T2-weighted images correlated with a poorer outcome. Objectives. To clarify whether preoperative magnetic resonance imaging findings of a high signal in the cord constitute a poor prognostic factor. Summary of Background Data. The importance of a high, T2-weighted, intramedullary signal on preoperative magnetic resonance studies in patients undergoing surgery for ossification of the posterior longitudinal ligament requires further clarification. Methods. Of 91 patients having cervical surgery for ossification of the posterior longitudinal ligament, 26 had a history of minor trauma. High, T2-weighted signals in the cord were note din 23 patients who had sustained trauma and in 39 patients who had no history of trauma. Patients were divided into four groups according to the presence or absence of a high cord signal and/or a trauma history. Pre- and postoperative Japanese Orthopaedic Association scores and recovery ratios then were evaluated. Results. The pre-and postoperative Japanese Orthopaedic Association scores and recovery ratios of the patients with a high signal and a trauma history were significantly less than those with no high signal but with a trauma history. Among the patients with no history of trauma, however, there were no significant differences in the pre- and postoperative JOA scores and recovery ratios between the patients with a high signal and those with no high signal. Conclusion. A high preoperative cord signal on T2- weighted magnetic resonance images for patients undergoing surgery for ossification of the posterior longitudinal ligament constitutes a poor prognostic factor, when trauma has placed a role.