Impact of Lumbar Degenerative Changes on Vertebral Bone Strength: A Finite Element Analysis

Assessing the bone condition in patients with spinal disease is clinically valuable. However, evaluating bone strength in the presence of spine degenerative changes is challenging. Quantitative computed tomography (QCT) and finite element analysis (FEA) have been proposed as methods for more accurate bone quality assessment. This study investigates the relationship between bone strength predicted by FEA and other relevant biological parameters. This retrospective cross-sectional study included 127 patients with spinal disease who underwent preoperative CT scans between 2014 and 2020. Baseline patient characteristics, volumetric bone mineral density (vBMD) measured by QCT, and vertebral bone strength predicted by FEA were collected. The degree of degeneration was evaluated by classifying osteophyte formation, disc height narrowing, vertebral sclerosis, and spondylolisthesis into a grading scale ranging from 0 to 2. Multiple linear regression analysis was conducted to assess the effect of each factor on bone strength predicted by FEA. Of 127 patients, 120 patients (median age was 62 years) were included. The median vBMD and vertebral strength were 114.3 mg/cm³ and 7892.9 N, respectively. After adjusting for age, sex, body mass index, smoking status, diabetes mellitus, vBMD, and degenerative changes, multiple linear regression analysis revealed that sex, vBMD, and degree of degeneration independently increased the vertebral strength measured by FEA. This study suggests that in patients with spinal disease, vertebral bone strength is affected not only by sex and bone mineral density but also by degenerative changes. Thus, bone strength could be predicted more accurately in patients with spinal disease using FEA.