Purpose <p>Hounsfield units (HU), vertebral body quality (VBQ), and T-scores serve as bone mineral density (BMD) indicators. This study aimed to investigate the utility of HU values and VBQ scores in assessing BMD in patients with cervical ossification of the posterior longitudinal ligament (OPLL), and based on this, compare BMD between cervical OPLL and cervical spondylotic myelopathy (CSM) using VBQ scores, HU values and T-scores, and explore the relationship among cervical segmental HU values and VBQ scores in patients with cervical OPLL.</p> Methods <p>In this study, we enrolled 309 patients who underwent posterior cervical single-door laminoplasty for cervical spondylosis at single medical institution. Participants were divided into two groups: the OPLL group and the CSM group. We utilized propensity score matching (PSM) to equate groups. Data collected included demographic characteristics, clinical data, T-scores, cervical VBQ scores and HU values. Correlations among cervical VBQ scores, HU values, and T-scores were assessed. Receiver-operating characteristic (ROC) curves were constructed to compare the diagnostic performance of VBQ scores versus HU values for osteoporosis. T-scores, VBQ scores, and HU values were compared between the matched cohort to elucidate the intergroup in BMD. In addition, cervical variations in cervical VBQ scores and HU values were systematically compared among the OPLL. The matched cohort was compared using the Wilcoxon signed-rank test, while VBQ scores and HU values across cervical segments were analyzed with the Kruskal-Wallis test.</p> Results <p>We analyzed 106 successfully matched pairs of patients with OPLL and CSM. In the OPLL group, both the correlation between VBQ scores and T-scores and the correlation between HU values and T-scores were weaker compared to the control group. Notably, within the OPLL cohort, the association between HU values and T-scores exhibited greater strength than the correlation between VBQ scores and T-scores. Furthermore, HU values demonstrated greater predictive value for the prevalence of osteoporosis compared to VBQ scores(AUC, 0.891 VS 0.731). The OPLL exhibited a lower prevalence of osteoporosis and higher T-scores in the hip and lumbar spine compared to CSM. Elevated cervical HU values and reduced VBQ scores were observed. Our analysis revealed heterogeneity in VBQ scores and HU values across cervical spine segments. The VBQ scores and HU values of C6 and C7 were significantly lower than those of C2-C4.</p> Conclusion <p>VBQ scores and HU values are both useful for evaluating BMD in cervical OPLL patients, but HU values provide a more reliable prediction. OPLL patients demonstrate increased BMD in the cervical, lumbar, and hip regions. HU values are more suitable for assessing BMD differences among cervical vertebrae.</p>