What Are the Important Predictors of Postoperative Functional Recovery in Patients With Cervical OPLL? Results of a Multivariate Analysis

A retrospective cohort study. The objective of this study was to identify important predictors of poor functional recovery in patients undergoing surgery for cervical ossification of the posterior longitudinal ligament (OPLL). This was a retrospective cohort study of 142 OPLL patients with laminoplasty; 135 had complete radiographical data and were followed up for ≥2 years. The following OPLL characteristics were compared between patients with “good” and “poor” outcomes (Japanese Orthopedic Association [JOA] recovery rate ≥50% and <50%, respectively): number of ossified levels, OPLL classification, ossification shape, K-line, canal-occupying ratio, and increased magnetic resonance imaging (MRI) signal intensity. Predictors of functional recovery were identified. Pre- and postoperative (2 years following surgery) JOA scores were 10.6 ± 2.9 and 14.1 ± 2.2, respectively, indicating significant improvement following laminoplasty (P < .001). The average JOA recovery rate was 53.4% ± 34.7%, with 81 (60.0%) and 54 (40.0%) patients in the better and poorer neurological outcome groups, respectively. The canal occupation ratio of OPLL ≤60%/>60% were 117 (86.7%) and 18 (13.3%) patients, respectively. In the stepwise logistic regression analysis, an occupation ratio greater than 60% was identified as a significant factor for poor postoperative neurological outcome (relative risk, 4.82; 95% confidential interval, 1.61-14.46, P = .005). This multivariate analysis demonstrated a large size OPLL (occupying ratio >60%) was associated with a risk of poor neurological recovery roughly 5 times greater, and therefore other types of surgery are recommended in cases with such a ratio