The Canal Bone Ratio: A Novel Indicator for Opportunistic Osteoporosis Screening in Adult Spinal Deformity Patients through Radiographs.

STUDY DESIGN: Retrospective diagnostic study.

OBJECTIVES: To evaluate the utility of quantitative assessment of bone density using proximal femoral morphological parameters based on full-spine X-rays.

SUMMARY OF BACKGROUND DATA: CT and MRI are commonly utilized methods for opportunistic assessment of bone density. However, there is currently a lack of means to quantitatively assess bone density in adult spinal deformity (ASD) patients through radiographs.

METHODS: Data collection involved medical records of ASD patients treated at our hospital. Patients were categorized into osteoporotic and non-osteoporotic groups based on DEXA T-scores. Demographic information, radiographic parameters (canal bone ratio, CBR; cortical bone thickness, CBT), Hounsfield units (HUs) and vertebral body quality (VBQ) score were compared. Pearson correlation analysis was conducted to assess the correlation between CBR, CBT, and T-scores. Multiple linear regression analysis identified independent predictors of bone density T-scores. Receiver operating characteristic (ROC) curves and area under the curve (AUC) calculations were performed to investigate the predictive performance for osteoporosis.

RESULTS: A total of 102 patients were included, with the osteoporotic group showing larger CBR and smaller CBT compared to the non-osteoporotic group. Proximal femoral morphological parameters exhibited the strongest correlation with total hip T-scores. Advanced age (β=-0.028, 95%CI=-0.054 to -0.002, P=0.032), low BMI (β=0.07, 95%CI=0.014 to 0.126, P=0.015), and high CBR (β=-7.772, 95%CI=-10.519 to -5.025, P<0.001) were identified as independent predictors of low bone density. ROC analysis demonstrated that CBR had a similar osteoporosis screening capability as HUs, followed by CBT and VBQ score.

CONCLUSION: The utilization of CBR from full-spine X-rays is a simple and effective osteoporosis screening indicator for ASD patients, facilitating bone density assessments by spine surgeons for all attending patients.