Prognostic factors for deterioration of patients with cervical spondylotic myelopathy after nonsurgical treatment

Study Design. A prospective study involving 56 patients with cervical spondylotic myelopathy (CSM) was conducted. Objective. To investigate the outcomes and prognostic factors for CSM after nonsurgical treatment. Summary of Background Data. The superiority of surgical treatment over nonsurgical treatment has not been confirmed in mild forms of CSM. Outcomes and prognostic factors for nonsurgical treatment of mild forms of CSM are not well understood. Methods. Clinical signs and symptoms of CSM were assessed by Japanese Orthopedic Association (JOA) scores. Nonsurgical treatment was selected for patients with mild forms of CSM ( JOA >= 13 patients). Seventy patients with mild forms of CSM were enrolled in the study between 1995 and 2003. The follow-up rate was 80.0%. Prognostic factors that exacerbate clinical symptoms of CSM were examined, such as age, gender, follow-up period, developmental or dynamic factors on plain lateral radiograph, high signal intensity area on T2-weighted sagittal MRI, and the extent of maximum cord compression; partial or circumferential spinal cord compression, on axial MRI. Univariate and multivariate logistic regression analysis were carried out to test for significant prognostic factors. Results. There was, on average, no statistically significant deterioration in JOA scores after nonsurgical treatment. However, 11 of 56 patients deteriorated after nonsurgical treatment. The only factor that significantly exacerbated clinical symptoms of CSM was circumferential spinal cord compression in the maximum compression segment on axial MRI. Indeed, 10 of 33 CSM patients with circumferential spinal cord compression on axial MRI deteriorated after nonsurgical treatment. Conclusion. Outcomes of mild forms of CSM during nonsurgical treatment were generally good as shown by average JOA scores. The only prognostic factor for mild forms of CSM was circumferential spinal cord compression in the maximum compression segment on axial MRI. Surgical treatment can be considered for patients with this prognostic factor.