Canal Bone Ratio for Predicting Bone Mineral Density in Lumbar Degenerative Diseases

Despite its clinical importance, osteoporosis remains underdiagnosed, particularly in spinal surgery patients, where bone quality affects surgical outcomes. Existing screening methods are often costly or inaccessible, highlighting the need for a simpler alternative.

The purpose of the present study was to assess the canal bone ratio (CBR) as a predictive tool for bone mineral density (BMD) in patients with lumbar degenerative diseases and establish a specific cutoff value for diagnosing osteoporosis.

A retrospective analysis was conducted of 102 patients older than 50 years who underwent lumbar spine surgery at our institution from 2016 to 2024. Eligible patients underwent dual-energy x-ray absorptiometry (DXA), full-spine x-ray imaging, and computed tomography within 3 months before their surgery. CBR measurements were obtained by analyzing x-ray images for the inner and outer diameters of the femoral shaft 7 cm below the lesser trochanter. The Youden index based on T score thresholds from DXA scans determined the optimal cutoff value for diagnosing osteoporosis using CBR.

The cutoff value for CBR was 0.501, which was identified by analyzing BMD data from the lumbar spine and femoral neck regions. This cutoff demonstrated a strong correlation with low BMD scores, exhibiting a sensitivity of 0.656 and a specificity of 0.671 for identifying osteoporosis among the included patients. Additionally, CBR values negatively correlated with T scores and computed tomography-based Hounsfield units values obtained from lumbar and femoral regions, reinforcing its validity as a screening tool.

CBR correlates with T scores from DXA and Hounsfield units values, establishing itself as a feasible and practical screening tool for osteoporosis in patients with lumbar degenerative disease.

CBR facilitates early intervention and improves management in populations at high risk for bone fragility.