Risk factors for segmental ossification volume progression in cervical ossification of the posterior longitudinal...

This study aimed to analyze the risk factors for segmental ossification volume progression in cervical ossification of the posterior longitudinal ligament (OPLL) after laminoplasty (LP).

Patients with OPLL who underwent LP at our institution and were followed for more than 12 months were enrolled. Three-dimensional models were reconstructed using CT images to measure the OPLL volume preoperatively and at final follow-up, and the ossification volume of each segment was calculated. The annual volume growth rate (AVGR) of OPLL was calculated by dividing the volume change by the follow-up duration. OPLL segmental ossification volume with an AVGR greater than 12.24% were classified into the progression group. Variables were categorized into segmental ossification-level factors and patient-level factors. Segmental ossification-level factors included facet tropism (FT), facet angle (FA), and segmental range of motion (SROM), among others. Patient-level factors included age, body mass index (BMI), intraoperative blood loss, follow-up duration, and smoking status, among others. Correlation analyses were performed to assess the associations between segmental ossification-level factors, patient-level factors and segmental ossification AVGR. Factors with P < 0.05 were entered into a generalized linear mixed model (GLMM) to identify risk factors for segmental ossification volume progression in OPLL after LP.

A total of 37 patients (172 segments) were included. The mean age was 55.19 ± 10.53 years, and the mean follow-up duration was 23.11 ± 14.01 months. There were 114 segments in the progression group and 58 segments in the non-progression group, with no significant difference in the distribution of ossified segments between the two groups. Correlation analyses showed that FT (P = 0.002), ROM (P < 0.001), smoking (P = 0.029), alcohol consumption (P = 0.025), and operative time (P = 0.031) were significantly positively correlated with AVGR, whereas age (P = 0.040), follow-up duration (P = 0.007), and diabetes mellitus (P < 0.001) were significantly negatively correlated with AVGR. The GLMM demonstrated that FT (OR = 2.169, P = 0.012) and greater SROM (OR = 3.182, P < 0.001) were independent risk factors for segmental ossification volume progression of OPLL after LP. The area under the curve (AUC) of the model was 0.933.

SROM and FT are risk factors for segmental ossification volume progression of OPLL. Measurement and consideration of SROM and FT are necessary when planning LP for patients with OPLL.