Risk factors for cage subsidence following anterior–posterior spinal fixation in osteoporotic vertebral fractures: a multicenter retrospective study

Study Design: Retrospective multicenter cohort study. Purpose: This study aimed to evaluate the incidence of cage subsidence and its impact on the clinical outcomes of anterior-posterior spinal fixation (APSF) for osteoporotic vertebral fractures (OVFs). It also aimed to identify the risk factors for cage subsidence. Overview of Literature: The risk factors for cage subsidence after APSF for OVFs remain unclear. Methods: This multicenter retrospective cohort study included patients who underwent combined APSF using an expandable cage system, with a minimum 1-year follow-up at multiple centers. Patients were divided into cage subsidence (n=53) and non-subsidence (n=47) groups. Demographic data, surgery-related factors, and radiographic parameters were analyzed. After univariate analysis of factors associated with cage subsidence, multivariate logistic regression was used to identify related factors. Results: The demographic data showed a significant difference in Hounsfield unit (HU) (102.6±28.3 vs. 80.0±30.6, p=0.005) and endplate injury (p