Use of Vancomycin Powder in the Surgical Treatment of Early Onset Scoliosis Is Associated with Different Microbiology Cultures after Surgical Site Infection

Background: The use of vancomycin powder has been shown to decrease risk of surgical site infection (SSI) in early onset scoliosis (EOS). While there is potential benefit in SSI reduction, there is also theoretical risk in creating increased bacterial resistance to standard treatment regimens. However, the effects of topical vancomycin powder on microbiology in these patients has not been studied. Methods: A multicenter database for EOS patients was retrospectively analyzed. All patients that underwent surgical treatment with traditional growing rods, magnetically controlled growing rods, vertical expandable prosthetic titanium rib, and Shilla for EOS performed after 2010 were identified (n=1115). Patients that sustained at least 1 SSI after guided growth surgery were assessed (n=104, 9.3%). Patients with culture and antibiotic details were included (n=55). Patients that received vancomycin powder at index surgery were compared with patients that did not. A multivariate regression model was used to control for potential confounders. Results: There were 55 patients included in this study, including 26 males (47%) and 29 females (53%). Mean age at index surgery was 7.2±6.9 years. Vancomycin powder was utilized in 18 cases (33%). Mean time from index surgery to SSI was 2.0±1.3 years. There were 2 cases of wound dehiscence (4%), 7 cases of superficial infection (13%), and 46 cases of deep infection (84%). There were significant differences in overall microbiology results between vancomycin and no vancomycin cohorts (P=0.047). On univariate analysis, the vancomycin powder cohort had a significantly high incidence of cultures without growth (n=7, 39% vs. n=4, 11%, relative risk: 2.063, 95% confidence interval: 0.927-4.591, P=0.028). This association remained significant on multivariate analysis (adjusted odds ratio: 9.656, 95% confidence interval: 1.743-53.494, P=0.009). Conclusions: In EOS patients undergoing procedures complicated by SSI, the use of vancomycin powder was independently associated with increased risk of no culture growth. Surgeons and infectious disease physicians should be aware and adjust diagnostic and treatment strategies appropriately. Level of Evidence: Level III - retrospective cohort study.