BACKGROUND: There were no precise researches showing which parameters with regard to degree of cervical stenosis and sagittal cervical alignment are the most crucial for surgical outcomes after laminoplasty for cervical spondylotic myelopathy (CSM). The objectives of this study were to investigate to what extent the preoperative parameters may have a direct influence on postoperative neurologic recovery, and to determine the crucial determinants of prognosis. METHODS: A retrospective review of 83 patients with CSM after laminoplasty was conducted. Magnetic resonance imaging parameters evaluation included presence/absence of signal change on T1 and T2 and anatomic measurements, including cervical canal compromise and cervical alignment. Data analysis involved logistic regressions and Spearman rank correlation coefficients. Receiver operator characteristic (ROC) curves were computed to evaluate the contribution of the original model. RESULTS: Univariate logistic regression showed that age (odds ratio = 0.822; 95% confidence interval, 0.729-0.927; P = 0.001), baseline Japanese Orthopedic Association (JOA) score (odds ratio = 1.700; 95% confidence interval, 1.158-2.496; P = 0.007), cervical curvature index (Ishihara) score (CCI) (odds ratio = 1.123; 95% confidence interval, 1.030-1.225; P = 0.008), maximum canal compromise (MCC) (odds ratio = 0.940; 95% confidence interval, 0.885-0.998; P = 0.041), and signal intensity (odds ratio = 0.139; 95% confidence interval, 0.033-0.580; P = 0.007) were independent prognostic indicators after laminoplasty. A ROC curve was computed based on the probability of the five predictors, with an area under the curve of 0.929 ± 0.028. CONCLUSIONS: Age and baseline JOA scores were crucial clinical predictors of outcome after laminoplasty for patients with CSM. Regarding the predictive value, CCI, MCC, and patterns of signal intensity changes on T1-/T2-weighted images were crucial determinants of prognosis of neurologic outcome.