Abstract:[Objective] To explore the predictive factors of clinical recovery in cervical unilateral open-door laminoplasty (UODL) for the cervical ossification of the posterior longitudinal ligament (C-OPLL). [Methods] A retrospective analysis was conducted on 316 patients who underwent UODL for C-OPLL in our department from January 2013 to January 2021. The posterior compression score of spinal cord (PCS) created by us was used to evaluate MRI images before surgery. Univariate omparison and multiple stepwise regression analysis were used to evaluate the factors related to clinical recovery. [Results] All patients had UODL performed successfully without serious nerve injury, infection and other complications. The mean follow-up time of patients was of (53.7±23.3) months. According to the recovery rate of JOA score 2 years after surgery, 160 patients with J0A score recovery rate ≥50% were considered as good recovery group (the GR), while other 156 patients with JOA score recovery rate <50% were considered as poor recovery group (the PR). The GR group proved a significantly shorter duration of the disease [(20.3±7.6) months vs (29.2±8.7) months, P<0.001], significantly lower incidence of high signal on MRI preoperatively [yes/no, (36/124) vs (70/86), P<0.001], whereas significantly higher PCS score [(10.7±3.4) vs (5.7±2.6), P<0.001] than the PR group. However, there were no significant differences in terms of age, gender composition, body mass index (BMI), previous hypertension, diabetes, smoking and stroke histories, preoperative C2~7 Cobb angle, C2~7 SVA, T1 slope, K-line, number of vertebra involved in ossification, ossification occupying rate, ossification thickness, and postoperative rehabilitation training ratio between the two groups (P>0.05). As result of multiple linear stepwise regression, the equation was as follows: Y=7.395-0.306×disease course +5.832× preoperative PCS score, which meaned long disease course (B=-0.306, P<0.001), while low preoperative PCS score (B=5,832, P<0.001) were the main factors related to poor postoperative recovery. [Conclusion] Long disease course is a risk factor for poor postoperative recovery, while high preoperative PCS score is a positive factor for good postoperative recovery.