Abstract
OBJECTIVE: To analyze the predictive factors for neck pain and cervical spine function after laminoplasty for degenerative cervical myelopathy (DCM) using K-means for longitudinal data (KML). METHODS: In this prospective cohort study, we collected clinical and radiographic data from patients with DCM who underwent cervical laminoplasty. A novel index of surgical outcome, "neck function," which comprises neck pain and cervical spine function according to the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire, was proposed. We treated surgical outcomes as longitudinal rather than cross-sectional data and used KML for analysis. Patients were categorized as having good or poor outcomes based on the KML graph of neck pain and cervical spine function. RESULTS: From 2016 to 2020, 104 patients underwent laminoplasty for DCM; however, 35 patients were excluded because of loss to follow-up or incomplete data. The authors found that central canal stenosis (odds ratio [OR], 17.93; 95% confidence interval [CI], 1.26-254.73; p=0.03) and preoperative neck pain (OR per 1 point increase=1.49; 95% CI, 1.12-1.99; p=0.006) were 2 negative predictive factors and that a positive K-line during flexion was a positive predictive factor (OR, 0.11; 95% CI, 0.01-0.87; p=0.036) for neck function after laminoplasty. CONCLUSION: Central canal stenosis, preoperative neck pain and a K-line during flexion were found to be predictive of postoperative neck pain and cervical spine function after laminoplasty. To achieve better surgical outcomes for neck function, the authors suggest the utilization of these determinants as a guiding framework for the selection of surgical approaches for DCM.