Does Spinal Cord-Canal Mismatch Adversely Affect the Clinical Outcomes of Anterior Cervical Discectomy and Fusion for the Treatment of Cervical Myelopathy?

Study Design. Retrospective cohort study. Objective. To clarify whether clinical outcomes of anterior cervical discectomy and fusion (ACDF), is affected by presence of spinal canal-cord mismatch (SCCM). Summary of Background Data. SCCM is considered a factor that would moderately influence surgeons to perform posterior surgery since it could widen the spinal canal, while an anterior approach could only remove degenerative pathologies grown into the spinal canal. Materials and Methods. We retrospectively reviewed 186 patients who underwent ACDF and had been followed-up for more than two years. Patients with spinal cord occupation ratio (SCOR) of ≥0.7 were classified into the SCCM group, while those with a SCOR of <0.7 were included in the no-SCCM group. Patient demographics, cervical sagittal parameters, neck pain visual analog scale (VAS), arm pain VAS, and Japanese Orthopedic Association (JOA) score were assessed. JOA score was the primary outcome of the study. Results. One hundred and forty-seven patients (79.0%) were included into the no-SCCM group, while 39 patients (21.0%) were classified into the SCCM group. Postoperative radiographic parameters including C2–C7 lordosis, C2–C7 sagittal vertical axis, and range of motion did not significantly differ between the two groups. Neck pain VAS, arm pain VAS, and JOA score (no-SCCM group, from 13.7±2.5 to 14.6±2.3, P <0.001; SCCM group, from 13.8±1.6 to 15.0±2.0, P <0.001) significantly improved after the operation in both groups, and results were not significantly different between the two groups. Furthermore, SCOR was not significantly associated with JOA recovery rate at two years postoperatively in linear regression analysis. Conclusion. Clinical and radiographic outcomes of ACDF were not affected by the presence of SCCM. Furthermore, SCOR was not significantly associated with neurological recovery at two years of follow-up. Therefore, ACDF can be safely and effectively applied for treating cervical myelopathy, regardless of the presence of SCCM, when other factors favor the anterior approach. Level of evidence. Level III.