Dynamic Bone Metabolism and Inflammatory-Immune Markers for Postoperative Outcome Assessment in Thoracolumbar Burst Fractures.

Abstract

Postoperative failure after thoracolumbar burst-fracture fixation is difficult to anticipate using imaging alone. We tested whether early inflammatory biomarkers and bone-formation markers improve risk stratification. A prospective cohort of consecutive adults undergoing fixation for T10-L2 burst fractures with 24-month follow-up. The primary endpoint was treatment failure. Secondary endpoints were ≥10% vertebral height loss and ≥10° kyphosis progression. Biomarkers (C-reactive protein [CRP], interleukin-6 [IL-6], bone-specific alkaline phosphatase, osteocalcin, and erythrocyte sedimentation rate) were measured serially. Primary analyses used the posterior-only cohort; full-cohort models adjusting for approach served as sensitivity checks. Forced-entry multivariable logistic regression quantified associations; performance was assessed with area under the receiver operating characteristic curve (AUC) and calibration. Prespecified sensitivities adjusted for infections ≤3 months and nonsteroidal anti‑inflammatory drug/steroid exposure near the two-week draw. Of 196 screened, 174 were analyzed (posterior-only n = 138); 50 of 174 (28.7%) met the primary endpoint. In posterior-only patients, two-week CRP (7.8 vs. 4.1 mg/L; P = 0.006) and IL-6 (16.8 vs. 12.5 pg/mL; P = 0.028) were higher in failures. Adjusted models showed Thoracolumbar Injury Classification and Severity Score (TLICS) ≥5 (odds ratio [OR] 2.35, 95% confidence interval [CI] 1.02-5.42), CRP ≥5 mg/L (OR 2.12, 95% CI 1.22-3.70), and IL-6 ≥7 pg/mL (OR 1.63, 95% CI 1.01-2.67) predicted failure; AUC = 0.75 (optimism-corrected 0.73) with good calibration. Two-week CRP/IL-6 provided peak discrimination (AUCs 0.73/0.70) and increased a baseline clinical AUC from 0.66 to 0.75. Associations persisted after infection and medication adjustments. Radiographic progression was more frequent in failures and associated with TLICS and, for height loss, CRP. Two-week CRP and IL-6, combined with TLICS, identify patients at risk of postoperative treatment failure after thoracolumbar burst-fracture fixation and support biomarker-guided surveillance.