Does intra-wound vancomycin application during spinal surgery increase rates of surgical wound infection and disruption?

Author(s):
Victor R. Vakayil; James Glover; Jeremiah Atkinson; Ty Kanstrup; James Harmon; Catherine Statz; Robert Bulander

Background:

Surgical site infection (SSI) following spinal surgery is associated with increased morbidity, mortality and healthcare costs. The application of intra-wound vancomycin powder prior to closure during spinal surgery is not FDA approved; the lack of randomized clinical trials and concerns for accelerated antibiotic resistance have raised questions about the safety and efficacy of this intervention.

Hypothesis:

The use of intra-wound vancomycin powder is associated with decreased postoperative rates of SSI and wound disruption.

Methods:

We performed a single-institution, one year, observational cohort analysis of all patients undergoing spinal surgery. Patients were stratified into those who received intra-wound vancomycin powder: the vancomycin group (VG), and those who did not (nVG). We assessed demographics, baseline comorbidities and perioperative variables. Our primary outcome of interest was 90-day SSI rate and rates of wound disruption. We constructed multivariate regression models to evaluate the independent effect of vancomycin application on 90-day outcomes. Additionally, we reviewed culture antibiograms to evaluate vancomycin resistance.

Results:

Of the 1081 patients analyzed, 47.2% (N=510) received intra-wound vancomycin powder while 52.8% (N = 571) did not. On univariate analysis, SSI was significantly higher in the VG (4.9%, N=25) when compared to the nVG (2.6%, N=15, P = 0.048). Similarly, rates of wound disruption were also higher in the VG (3.1%, N = 16) than the nVG (0.9%, N = 5, P = 0.007). On multivariate analysis, vancomycin application was independently associated with an increased rate of wound disruption (OR 3.2, P = 0.038, Table 1), however, the rates of SSI were equivocal. Antibiograms of culture isolates demonstrated the growth of vancomycin-resistant Enterococci in the VG (4%, N=1).

Conclusions:

The application of intra-wound vancomycin powder during spinal surgery failed to demonstrate improved protection against developing SSI. Moreover, vancomycin administration significantly increased rates of wound disruption and may be associated with increased antimicrobial resistance. Our results question the safety and efficacy of this practice. Randomized clinical trials are required to demonstrate a benefit to the intra-wound application of vancomycin powder.