Bone Density of Vertebral Bodies and Ossified Masses in Cervical Ossification of the Posterior Longitudinal Ligament: An Imaging Study Based on MRI, CT, and DEXA.

Complications from anterior decompression fusion for cervical ossification of the posterior longitudinal ligament (OPLL) are often related to the bone mineral density (BMD) of vertebral bodies and ossified masses. The aim of this study was to clarify whether dual-energy X-ray absorptiometry (DEXA) T-scores reliably predict BMD in these structures, and whether vertebral bone quality (VBQ) and Hounsfield units (HU) can be effectively used to screen for osteopenia and osteoporosis. A total of 122 patients with cervical OPLL and 105 non-OPLL patients were included. Vertebral BMD was assessed by VBQ and HU, and ossified mass BMD was assessed by ossified mass bone quality (OMBQ) and ossification mass HU (OMHU). Overall, VBQ scores and HU values demonstrated weaker correlations with T-scores in the OPLL group compared with the non-OPLL group. Receiver operating characteristic curve analyses showed that VBQ and HU effectively discriminated osteopenia/osteoporosis in the OPLL cohort, with area under the curve values ranging from 0.763 to 0.827, similar to the non-OPLL. No significant differences in BMD were observed between the OPLL and non-OPLL groups based on the common assessment of VBQ, HU and DEXA-derived BMD (p > 0.05). Both OMBQ and OMHU showed good reliability and were significantly correlated with T-scores (p < 0.05). In patients with cervical OPLL, VBQ and HU remain effective screening tools for osteopenia/osteoporosis, potentially guiding or obviating the need for further DEXA scans. Additionally, our findings suggest that patients with lower T-scores may exhibit reduced BMD in both vertebral bodies and ossified masses.