Cage subsidence in anterior spinal reconstruction and its clinical outcomes following anterior and posterior stabilization in thoracolumbar fractures

Abstract

Background Using expandable cages through the anterior approach is a well-established method for treating thoracolumbar burst fractures. We aim to identify factors associated with cage subsidence and their impact on clinical outcomes in patients treated with corpectomy via a complementary anterior approach. Methods We included adult patients with thoracolumbar burst fractures who were treated using the complementary anterior approach at our institution between 2015 and 2021. Our analysis considered factors related to the fracture, implant, subsidence, and functional outcomes (measured by the SF-36). Hounsfield units were measured using the XERO Viewer System on CT scans, and statistical analysis was conducted using R.v4.1 and Rstudio v2021.09.1 + 372. Results thirty-one patients were included. A significant difference was found in subsidence magnitude between the "UH < 110" and "UH > 180" groups (p = 0.0468). Patients who received non-modular cylindrical cages had markedly more subsidence and poorer physical outcomes on the SF-36. If the complementary anterior approach was performed six months after the posterior stabilization, all components of the SF-36 were diminished. Conclusions To optimize the management of thoracolumbar burst fractures, it is essential to evaluate bone quality before using an anterior approach. Rectangular base modular cages lead to less subsidence and better health outcomes, while non-modular cylindrical cages may decrease physical function. An anterior approach after six months leads to worst functional results. The results provide valuable insights into the use of expandable cages in addressing burst fractures in the lumbar spine.