Is Facet Joint Distraction Associated with Functional Outcome in Patients with Cervical Spondylotic Radiculopathy Treated with Single-Segment Anterior Cervical Discectomy and Fusion?

To explore 1) whether the degree of facet joint distraction during single-segment anterior cervical discectomy and fusion for cervical spondylotic radiculopathy affects functional outcome and 2) whether the degree of facet joint distraction is related to cervical sagittal parameters. This study retrospectively analyzed data from 72 patients with single-segment cervical spondylotic radiculopathy from January 2013 to December 2018. Lateral cervical radiographs were performed preoperatively and 12 months postoperatively. Disc height, interfacet distance, and segmental angle were measured from the lateral cervical radiographs to evaluate facet joint distraction, and cervical sagittal parameters were measured. The outcome measures included visual analog scale (VAS) and Neck Disability Index scores. Sixty-eight patients were included. ΔInterfacet distance was statistically significant in relation to ΔVAS score (P < 0.01). In a receiver operating characteristic curve analysis, less than the mean ΔVAS score for all patients was set as a positive result, and the critical value of Δinterfacet distance was 0.7 mm (P = 0.024, area under the curve = 0.659, sensitivity = 46.8%, specificity = 78.8%). According to the critical value determined by the receiver operating characteristic curve, all patients were divided into the appropriate distraction group or the excessive distraction group. There was a significant difference in VAS scores between the 2 groups (P < 0.05). After undergoing single-segment ACDF for the treatment of cervical spondylotic radiculopathy, patients with an interfacet distance of 0.7 mm or more had worse VAS pain scores. However, this was not related to the improvement in postoperative Neck Disability Index scores; changes in the interfacet distance were not associated with changes in the cervical sagittal parameters.