Prophylactic use of topical vancomycin reduces the incidence of postoperative wound infection in surgery for spinal metastases.

Abstract

PURPOSE: Oncologic spine surgery carries a high risk of surgical site infection (SSI). We assessed the impact of intraoperative topical vancomycin on SSI rates and its economic impact in patients undergoing surgery for spinal metastases. METHODS: We retrospectively reviewed 97 patients treated surgically for spinal metastases between 2022 and 2025. Local vancomycin powder was applied to the wound in 32 patients (32%). SSI rates, clinical outcomes, and costs were compared between groups. An exploratory LASSO-penalized logistic regression model was developed to identify predictors of SSI. RESULTS: SSI occurred in 8 patients (8.2%; five deep). No infections were observed in the vancomycin group (0/32), whereas 8 of 65 patients (12.3%) without vancomycin developed SSI (p = 0.0496), corresponding to an absolute risk reduction of 12.3% points (NNT = 9). Due to a zero-event cell, the odds ratio was estimated using a continuity correction (Haldane–Anscombe; OR = 0.10, 95% CI 0.006–1.86); the relative risk was RR = 0.12 (95% CI 0.007–1.98). Patients with SSI had longer hospital stays (19.1 ± 8.6 vs. 8.6 ± 5.6 days; p < 0.001). The estimated prophylaxis cost to prevent one SSI was 19–59 EUR versus an average SSI management cost of ~ 3,500 EUR, suggesting a favorable cost profile. In the LASSO model, vancomycin was selected as a protective feature, although discrimination was modest. CONCLUSIONS: Topical vancomycin appears to reduce SSI risk and is a safe, inexpensive prophylactic option in metastatic spine surgery, with a likely cost-saving effect under local cost assumptions.