Abstract:[Objective] To explore the factors impacting clinical outcomes of posterior open-door cervical laminoplasty for ossification of the posterior longitudinal ligament (OPLL). [Methods] A retrospective study was done on 67 patients who underwent C3~C7 open-door lamino- plasty for cervical OPLL in General Hospital of Ningxia Medical University from 2015 to 2022. Univariate comparison and multiple logistic re- gression were used to analyze the related factors impacting the clinical consequences. [Results] All patients had operation completed success- fully, and were followed up for more than 24 months. According to the improvement rate of JOA score <60% or ≥60% at the last follow-up, 33 patients were termed as the poor group, accounting for 49.3%, while the remaining 34 patients fell into the good group, accounting for 50.7%. As results of univariate comparison, the poor group proved significantly greater than the good group in terms of age [(59.1± 9.9) years vs (52.9± 9.8) years, P=0.010], the occupying rate of cervical canal preoperatively [(50.1±15.2)% vs (41.7±12.2)%, P=0.036], T1 slop (T1S) [(26.8±8.7)° vs (21.5±5.8)°, P=0.013], K line negative ratio [negative /positive, (11/22) vs (4/30), P=0.034] and intramedullary high signal ratio [yes/no, (20/ 13) vs (10/24), P=0.010]. Regarding to multivariate logistic regression, the canal occupying rate (OR=83.54, P=0.006), intramedullary high signal on MRI (OR=3.13, P=0.004) and T1S (OR=1.11, P=0.036) were independent risk factors for poor clinical outcomes. The area under curve (AUC) of the predicting model analyzed by ROC was of 0.80, 95%CI 0.70~0.91, P=0.001, with the slope of the calibration curve close to 1, indicating good accuracy of the prediction model. [Conclusion] The high spinal canal occupying rate, high intramedullary signal intensity and high T1S are independent risk factors for poor surgical outcomes of open-door cervical laminoplasty for OPLL.