Abstract
Cervical compressive myelopathy (CCM) is one of the common neurological disorders seen in the geriatric population. The 10-s Grip and Release ("G and R") Test and the 30-m Walking ("Walking") Test are widely known as quantifiable physical assessments for the severity of cervical myelopathy. We developed the 10-s Step ("Step") Test as another easily performable quantifiable measure for this. However, it is not clear if the Step test can adequately reveal the severity of myelopathy like the other established tests, given its simple method. The purpose of this study was to verify the practical effectiveness of this Step Test as a quantifiable parameter of CCM in comparison with the other two established tests. 168 consecutive patients with CCM were selected. Only 101 patients having >12-month postoperative follow-up were included. All were treated with cervical expansive laminoplasty. The three above mentioned quantitative tests and two assessment questionnaires (Japanese Orthopedic Association [JOA] Score, and lower-limb-function section of the Japanese Orthopedic Association cervical myelopathy evaluation questionnaire [JOACMEQ-L]) for CCM were prospectively administered, and the results of the three tests were evaluated using linear regression models to determine which quantitative test best reflected the results of the JOA score and JOACMEQ-L. Each quantitative test was carried out twice, just before and 1 year after surgery. The intraobserver reproducibility of the 10-s Step Test was found to be as high as that of the other tests both before and after surgery. Linear regression analyses showed that the results of the Step Test correlated with JOA scores to the same degree as the Walking Test results did, and to a greater degree than the G and R Test results did. Moreover, the results of the Step Test showed a significant degree of correlation with JOACMEQ-L. In view of these findings, our conclusion was that the easily performed Step Test is an useful test for assessing the severity of cervical myelopathy, especially for the lower limb dysfunction secondary to CCM.