[Radiological characteristics and associated factors of single-level cervical disc herniation combining with focal ossification of posterior longitudinal ligament].

OBJECTIVE

To investigate the correlation between cervical sagittal imbalance, disc morphology, and localized ossification of the posterior longitudinal ligament (LOP) in patients with single-level cervical disc herniation.

METHODS

A cross-sectional study was conducted on 150 patients with single-level cervical disc herniation and complete imaging data (including standard X-ray film, CT, and MRI). Patients were divided into the LOP(+) group ( n=76, with LOP at the herniated segment) and the LOP (-) group ( n=74, without LOP) based on the presence of LOP. Univariate and logistic regression analyses were performed to identify factors associated with LOP, including gender, age, body mass index, C-reactive protein, fasting blood glucose, serum uric acid, maximum diameter of herniated disc, the maximum base width of herniated disc, spinal canal occupancy rate, height of intervertebral space, Pfirrmann grade of disc degeneration, C 2-7 Cobb angle, T 1 slope, cervical sagittal vertical axis (cSVA), C 2-7 Cobb angle in extension/flexion, global cervical range of motion (ROM), and extension/flexion angle and ROM at the index level. Pearson or Spearman correlation was used to analyze the correlation of the main imaging parameters between the two groups.

RESULTS

Univariate analysis showed that Pfirrmann grade, maximum base width of herniated disc, spinal canal occupancy rate, height of intervertebral space, C 2-7 Cobb angle, extension angle and ROM at the index level were the influencing factors of LOP ( P<0.05). Further logistic regression analysis revealed that the increase of the maximum base width of the herniated disc and the decrease of the spinal canal occupancy rate were the independent influencing factors of LOP ( P<0.05). Correlation analysis showed that the correlation patterns among the main radiological parameters were not identical between the LOP (-) and LOP (+) groups. In both groups, the C 2-7 Cobb angle was positively correlated with T 1 slope ( P<0.05), and some segmental motion parameters were correlated with global cervical ROM and dynamic C 2-7 Cobb parameters ( P<0.05). In the LOP (+) group, spinal canal occupancy rate, cSVA, OPLL thickness, and disc morphological parameters also showed certain correlations ( P<0.05).

CONCLUSION

Cervical sagittal imbalance (characterized by reduced lordosis and segmental mobility) and disc base expansion are significantly associated with LOP coexistence in single-level cervical disc herniation patients. These imaging markers may aid early identification of high-risk populations in clinical settings.