Intra-wound Vancomycin Powder for Surgical Site Infection Prophylaxis in Spinal Surgery: A Systematic Review and Meta-analysis

Surgical site infection remains a consequential complication of spinal surgery despite intravenous antibiotic prophylaxis, maintenance of normothermia, glycemic control, and meticulous surgical technique. Applying vancomycin powder directly into the wound before closure achieves high local drug concentrations with minimal systemic absorption and was hypothesized to lower surgical site infection rates compared with standard intravenous prophylaxis alone. Five databases were searched through May 2026 for comparative studies of patients undergoing spinal surgery in which one group received intra-wound vancomycin powder at wound closure and a concurrent control group did not. Of 2,765 records, 700 remained after duplicate removal, 96 full texts were assessed, and 14 studies met all eligibility criteria, comprising 9,802 patients: 4,516 received vancomycin powder and 5,286 served as controls. Four studies were randomized trials and ten were nonrandomized cohorts. Odds ratios were pooled using the Mantel-Haenszel fixed-effect method, with random-effects estimates reported alongside. Risk of bias was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool and Risk Of Bias In Non-randomized Studies - of Interventions (ROBINS-I), and certainty using Grading of Recommendations Assessment, Development and Evaluation (GRADE). Vancomycin powder was associated with lower odds of overall surgical site infection (odds ratio 0.55; 95% confidence interval 0.44 to 0.70), deep infection (0.50; 0.37 to 0.68), and superficial infection (0.55; 0.32 to 0.93). The direction of effect persisted across seven sensitivity analyses and a leave-one-out analysis, with no funnel plot asymmetry detected. However, the association was driven by nonrandomized studies; when restricted to the four randomized trials, it was no longer statistically significant (0.73; 0.45 to 1.18). Intra-wound vancomycin powder is therefore associated with fewer surgical site infections in spinal surgery, but the evidence is of moderate certainty, and adequately powered randomized trials remain necessary.