Risk Factors for Rapidly Progressive Neurological Deterioration in Cervical Spondylotic Myelopathy.

STUDY DESIGN A retrospective single-center study. OBJECTIVE This study sought to clarify the risk factors and to evaluate the surgical outcome in patients with rapidly progressive cervical spondylotic myelopathy (rp-CSM). SUMMARY OF BACKGROUND DATA CSM is a degenerative spine disease presenting a slow development of myelopathy. Some patients, however, show rapidly progressive neurological deterioration (especially gait disturbances) without any trauma. At present, there is little information about this condition. METHODS We studied 71 consecutive CSM patients (52 men, 19 women) with a mean age of 67.1 years, and the follow-up period was 1 year. Patients were divided into two groups: rp-CSM and chronic-CSM (c-CSM) groups. The Japanese Orthopaedic Association score and various clinical differences, including age, sex, comorbidity, the waiting period from symptomatic onset to surgery, cervical range of motion, and intramedullary MR T2-hyperintensity were analyzed, and independent risk factors were determined using a logistic regression analysis. RESULTS Eighteen of 71 patients (25.4%) were diagnosed with rp-CSM. There were no significant differences between the two groups with regard to age, sex, or cervical range of motion. In the rp-CSM group, the preoperative upper/lower extremities and bladder functions were worse, and the waiting period for surgery was shorter (rp-CSM 1.2 mo, c-CSM 25.7 mo). Patients with rp-CSM had a history of cardiovascular event (CVE) (rp-CSM 44.4%, c-CSM 15.1%) and presented with MR T2-hyperintensity (rp-CSM 94.4%, c-CSM 58.5%), especially at the C4/5 disc level. Independent risk factors were a history of CVE (odds ratio = 4.7) and MR T2-hyperintensity (odds ratio  = 12.5). The rp-CSM group showed a better neurological recovery after decompression surgery (the Japanese Orthopaedic Association recovery rate: rp-CSM 64.5%, c-CSM 40.7%). CONCLUSION A history of CVE and MR T2-hyperintensity were risk factors for rp-CSM. Despite rapid neurological deterioration, rp-CSM patients showed a good neurological recovery after surgery, and thus indicating that rp-CSM is a reversible condition. LEVEL OF EVIDENCE 4.