Predictors of Mechanical Failure Following Lateral Access Corpecto-my: The Impact of Posterior Fixation Range

Objective: This study aims to evaluate the radiologic outcomes of lateral access corpectomy to identify perioperative predictors associated with mechanical failure. Methods: We retrospectively reviewed 42 patients who underwent single-level lateral access corpectomy with posterior instrumentation between January 2019 and July 2024. Clinical indications included osteoporotic vertebral fractures (n = 23), spinal metastases (n = 10), and destructive spondylitis (n = 9). Radiologic parameters including total interbody height (TIH) and local segmental angle (SA) were assessed at each time point. Univariate and logistic regression analyses were performed to identify risk factors for mechanical failure. Results: Postoperatively, the mean TIH gain was 8.42 mm and the mean kyphosis correction was 9.85°. Mechanical failure occurred in 6 cases (14.3%), including pedicle screw pullout (n = 3), rod fracture (n = 1), and severe endplate destruction (n = 2). Logistic regression analysis identified short-segment fixation as a significant risk factor for mechanical failure (OR 8.00, 95% CI 1.19-53.93, p = 0.033). All mechanical failure cases occurred in patients with expandable cages. While expandable cages achieved greater initial TIH gain and kyphosis correction compared with mesh cages, they also demonstrated a greater degree of correction loss at final follow-up (TIH loss 6.62 mm vs. 3.93 mm, p = 0.061). Conclusion: Among patients undergoing lateral access corpectomy, short-segment fixation was the only factor significantly associated with mechanical failure, and its combination with an expandable cage carried the highest failure rate. Given the small number of failure events, these findings are hypothesis-generating and suggest that long-segment fixation should be prioritized whenever clinically feasible.