Dynamic MRI Findings and the mJOA Scale: Establishing Correlations in the Clinical Assessment

To investigate the correlation between the score on the modified Japanese Orthopaedic Association (mJOA) scale and the dynamic magnetic resonance (DMR) findings in patients diagnosed with degenerative cervical myelopathy (DCM).

We conducted a retrospective cohort study. All patients underwent a DMR examination of the cervical spine using the same device. The anatomic parameters evaluated were the spinal canal diameter (SCD) and the spinal canal width (SCW). The SCD was measured as the distance between the midpoint of the posterior portion of the intervertebral disc and the anterior margin of the yellow ligament. The SCW was measured as the distance between the anterior and posterior margins of the spinal cord at the exact point used to assess the SCD. The mJOA scale was chosen to assess the functional status. The intra and interobserver reliability of the morphometric parameters of the magnetic resonance imaging (MRI) were calculated using the intraclass correlation coefficient (ICC), and values of p  < 0.05 were considered statistically significant.

Regarding the intraobserver evaluation of the SCD, an almost perfect agreement was achieved, and the SCW's interobserver evaluation presented a strong agreement. The mJOA score ranged from 6 to 18, and there was a weak, non-statistically significant correlation between the SCD and SCW parameters.

We could not identify a correlation involving the cervical spinal canal measurements obtained from DMR exams and the clinical severity of patients with DCM measured using the mJOA score. Due to the small sample size, these findings should be interpreted with caution.