Comparison of postoperative infection risk with and without topical vancomycin in adult posterior spinal fusion: a propensity-matched cohort study of 126,910 patients

PURPOSE: Surgical site infections (SSIs) are the third most common complication following spine surgery. The effect of topical vancomycin in addition to perioperative systemic cefazolin remains uncertain. This study sought to investigate the effect of topical vancomycin administration on 90-day postoperative infection risk following adult posterior spinal fusion (PSF). METHODS: The TriNetX Global Collaborative database was queried to identify adult patients undergoing PSF. Patients were stratified into two cohorts based on documented administration of topical vancomycin and systemic cefazolin (topical cohort) versus systemic cefazolin alone (control cohort). Patients underwent 1:1 propensity matching based on demographics and relevant comorbidities. The primary outcomes of interest included 90-day rates of infection-related complications. Subgroup analyses were performed to identify the influence of neuromuscular scoliosis, PSF with osteotomies, pelvic fixation, or fusion of greater than six levels on infection rates. Infectious complication rates were also compared between patients receiving topical vancomycin with and without topical gentamicin or tobramycin. RESULTS: After propensity matching, 63,455 patients were included in each cohort. Patients in the topical cohort demonstrated comparable rates of overall infection (3.0% vs. 3.1%, p = 0.794), superficial surgical site infection (SSI) (0.9% vs. 0.8%, p = 0.151), deep SSI (0.6% vs. 0.6%, p = 0.070) and all other infectious complications when compared to the control cohort. Subgroup analysis revealed decreased rate of deep SSI when using topical gentamicin or tobramycin with vancomycin versus topical vancomycin alone (0.7% vs. 1.7%, p = 0.019). No other between-group differences were observed. CONCLUSION: This study found no significant difference in 90-day postoperative infectious complications following PSF when topical vancomycin was added to standard systemic cefazolin prophylaxis compared to cefazolin prophylaxis alone. Vancomycin with the addition of gentamicin or tobramycin, however, was associated with decreased rates of deep SSI. LEVEL OF EVIDENCE: Level III, retrospective cohort study.