10-Second Step Test for Quantitative Evaluation of the Severity of Thoracic Compressive Myelopathy

Study Design. A clinical and cohort study. Objective. To evaluate the efficacy of the 10-second step test as a measure of the severity of thoracic compressive myelopathy. Summary of Background Data. Objective measurement is essential for determining the severity of thoracic compressive myelopathy. Some useful measurements for cervical myelopathy have been identified; however, few reports have addressed the measurement of severity of thoracic myelopathy. Methods. Twenty-five presurgical patients with thoracic compressive myelopathy were included. Patients with cervical myelopathy and concomitant lumbar canal stenosis were excluded from this analysis. The subjects included 14 males and 11 females, with a mean age of 58.8 years (range, 36-81). The 10-second step test was performed, and the number of steps in 10 seconds was recorded. The Japanese Orthopedic Association (JOA) score for thoracic myelopathy, which was adapted from the JOA score for cervical myelopathy, was also used for assessment. Results. The average 10-second step test score in all patients was 9.6 +/- 1.3 before surgery, which significantly correlated with the total JOA score (r = 0.69, P < 0.01) and its lower extremity motor function score (r = 0.92, P < 0.01). They were retested 12 months after surgery, but the postoperative scores for 5 patients were not available. The average preoperative 10-second step test score of the remaining 20 patients was 9.5 +/- 1.5, which significantly improved to 15.1 +/- 1.2 12 months after surgery. The step test score in those 20 patients significantly correlated with the total JOA score and lower extremity motor function score before and after surgery (P < 0.01). Conclusion. The 10-second step test reflected the severity of thoracic compressive myelopathy. Moreover, this test was useful for evaluating surgical outcome in patients with thoracic compressive myelopathy.