Two-Year Outcomes of Postoperative Spine Infection: Implant Retention and Predictors of Treatment Failure

Abstract Background Postoperative Spine Infection (PSI) after surgery occurs in approximately 1–2% of cases and is associated with significant morbidity. High-quality evidence to guide optimal prevention and management of PSI is limited. Methods We retrospectively identified all adult patients over a three-year period (2020-2023) who required reoperation for PSI. Clinical, microbiological therapy, and 24-month outcome data were collected. Treatment failure was defined as unplanned return to theatre secondary to persistent infection or infection related implant failure requiring removal. Descriptive statistics and univariate logistic regression were used to identify factors associated with failure. Results Sixty-three deep PSI cases were identified (range 18–91 years, median 59 years, 56% female). Onset of infection ranged from 4 days to 30 weeks postoperatively (median 20 days). Staphylococcus aureus and Enterobacterales were the most common pathogens, followed by coagulase-negative staphylococci and Cutibacterium acnes. Treatment failure occurred in 13 cases (21%). In cases where implants were present (81% of total cohort), antibiotic durations of either 12 weeks or 24 weeks demonstrated similar success rates (p=0.76). Infections involving Cutibacterium acnes were more likely associated with implant removal (p = 0.04). No other significant risk factors for failure were identified. Conclusions Most PSI were effectively managed in this cohort with surgical debridement and targeted antibiotics, allowing implant retention in most patients with instrumentation.