This report is a retrospective analysis of prospectively collected data from the STaphylococcus aureus suRgical Inpatient Vaccine Efficacy (STRIVE) trial. The analysis re-evaluated the use of intrawound vancomycin powder as a preventive strategy for surgical site infection (SSI) in patients undergoing posterior spinal fusion (PSF) surgery. The investigators hypothesized that SSI rates would be similar between patients who did and did not receive intrawound vancomycin.
Data were drawn from 3,595 patients enrolled in the STRIVE trial. A total of 3,311 patients underwent surgery and were included in this analysis. Patients were stratified by intrawound antibiotic usage. Specifically, 847 patients (26%) received only intrawound vancomycin, and 1,534 patients (46%) received no intrawound antibiotics. Multivariate logistic regression was used to assess the association between intrawound vancomycin use and SSI while adjusting for patient demographics and known SSI-associated risk factors. Secondary outcomes evaluated included critical care stay, reoperation, sepsis, and hospital readmission.
Among the surgical cohort, 60 patients developed a postoperative SSI (reported as 8% in the subgroup presenting with SSI). Of those 60 patients with SSI, 20 (33%) had received intrawound vancomycin. In adjusted analyses, receiving intrawound vancomycin was not associated with a statistically significant difference in SSI incidence compared with no intrawound antibiotics (odds ratio [OR] 0.77; 95% confidence interval [CI]: 0.42–1.42). The authors concluded that intrawound vancomycin use was not associated with a reduction in SSI after PSF surgery.
The analysis also examined secondary clinical outcomes. Intrawound vancomycin was not associated with differences in the odds of critical care stay (OR 0.94; 95% CI: 0.78–1.12) or sepsis (OR 2.04; 95% CI: 0.62–6.73).
However, intrawound vancomycin use was associated with higher odds of two important postoperative events:
These associations indicate that, in this dataset, intrawound vancomycin was linked to increased rates of readmission and reoperation despite no observed reduction in SSI incidence.
The authors identified variables associated with the likelihood of receiving intrawound vancomycin. Intraoperative antibiotic readministration was associated with higher odds of vancomycin use (OR 2.97; 95% CI: 1.36–6.5; P = 0.006). Geographic location was also strongly associated with differing use patterns: compared with North America, the odds of intrawound vancomycin use were lower in Europe (OR 0.13; 95% CI: 0.06–0.29; P < 0.001) and Asia (OR 0.02; 95% CI: 0–0.08; P < 0.001).
In this retrospective analysis of prospectively collected STRIVE trial data, intraoperative vancomycin powder was not associated with a reduced incidence of surgical site infection after posterior spinal fusion surgery when compared with no intrawound antibiotics. Intrawound vancomycin was associated with increased odds of hospital readmission and reoperation but showed no significant association with critical care stay or sepsis. The study is reported as Level II evidence.
Disclosures reported in the source document include: A.J. is a paid consultant for DePuy, Globus Medical, and Stryker. K.K. reports royalties from DePuy, Stryker, and Orthofix; paid consultancy and speaking roles for DePuy, Orthofix, and K2 Medical; research support from DePuy; and membership on the Scoliosis Research Society board or committee. H.H. is a paid consultant/speaker with stock/stock options for Globus Medical, and receives research support and speaking fees from Orthofix. The remaining authors reported no conflicts of interest.
Note: all numerical results, odds ratios, confidence intervals, and P values reported here are taken directly from the source article abstract. No additional outcomes, subgroup analyses, or external data were inferred or added.