Risk factors for revision surgery due to construct failure after instrumented treatment of pyogenic spondylodiscitis.

OBJECTIVE: Construct failure following instrumented treatment for pyogenic spondylodiscitis remains a significant clinical challenge and is often associated with persistent pain or neurological deterioration requiring revision surgery. This study aimed to identify risk factors for construct failure requiring revision surgery after instrumented treatment of pyogenic spondylodiscitis. METHODS: This retrospective single-center cohort study included 355 patients who underwent dorsal spinal instrumentation with or without anterior reconstruction for pyogenic spondylodiscitis at the University Medical Center Göttingen between 2013 and 2022. Construct failure requiring revision surgery was defined as the primary endpoint. Time-to-event analyses were performed using Kaplan-Meier survival estimates and Cox proportional hazards regression models. Baseline predictors included age, Charlson Comorbidity Index (CCI), preoperative C-reactive protein (CRP), and osteoporosis. An extended model additionally incorporated postoperative relapse infection and wound infection. RESULTS: During a mean follow-up of 27 ± 9 months, 48 of 355 patients (13.8%) underwent revision surgery due to construct failure. Revision-free survival was 86.9% at 1 year, 82.7% at 2 years, and 80.9% at 3 years. In the baseline Cox proportional hazards model, a higher CCI (HR 1.08 per point increase, 95% CI 1.00-1.16; p = 0.048) and elevated CRP (HR 1.004 per mg/L increase, 95% CI 1.001-1.007; p = 0.018) were independently associated with an increased hazard of revision surgery due to construct failure.In the extended model, relapse infection emerged as the strongest predictor of revision surgery due to construct failure (HR 11.54, 95% CI 5.05-26.36; p < 0.001), while CCI and preoperative CRP remained significant. Age, osteoporosis, and wound infection were not independently associated with revision surgery due to construct failure. CONCLUSION: Greater comorbidity burden and elevated preoperative CRP were associated with an increased risk of revision surgery due to construct failure, whereas postoperative relapse infection was strongly associated to revision surgery. Optimized risk stratification and stringent infection control may help to reduce revision risk.