Intrawound Vancomycin Decreases the Risk of Surgical Site Infection After Posterior Spine Surgery: A Multicenter Analysis

Spine 2018;43:65–71

Study Design. Secondary analysis of data from a prospective multicenter observational study.

Objective. The aim of this study was to evaluate the occurrence of surgical site infection (SSI) in patients with and without intrawound vancomycin application controlling for confounding factors associated with higher SSI after elective spine surgery.

Summary of Background Data. SSI is a morbid and expensive complication associated with spine surgery. The application of intrawound vancomycin is rapidly emerging as a solution to reduce SSI following spine surgery. The impact of intrawound vancomycin has not been systematically studied in a welldesigned multicenter study.

Methods. Patients undergoing elective spine surgery over a period of 4 years at seven spine surgery centers across the United States were included in the study. Patients were dichotomized on the basis of whether intrawound vancomycin was applied. Outcomes were occurrence of SSI within postoperative 30 days and SSI that required return to the operating room (OR). Multivariable random-effect log-binomial regression analyses were conducted to determine the relative risk of having an SSI and an SSI with return to OR.

Results. A total of 2056 patients were included in the analysis. Intrawound vancomycin was utilized in 47% (n=966) of patients. The prevalence of SSI was higher in patients with no vancomycin use (5.1%) than those with use of intrawound vancomycin (2.2%). The risk of SSI was higher in patients in whom intrawound vancomycin was not used (relative risk (RR) – 2.5, P<0.001), increased number of levels exposed (RR -1.1, P=0.01), and those admitted postoperatively to intensive care unit (ICU) (RR -2.1, P=0.005). Patients in whom intrawound vancomycin was not used (RR -5.9, P<0.001), increased number of levels were exposed (RR-1.1, P=0.001), and postoperative ICU admission (RR -3.3, P<0.001) were significant risk factors for SSI requiring a return to the OR.

Conclusion. The intrawound application of vancomycin after posterior approach spine surgery was associated with a reduced risk of SSI and return to OR associated with SSI.

Level of Evidence: 2

Does Intrawound Vancomycin Application During Spine Surgery Create Vancomycin-Resistant Organism?

Neurosurgery (2017) 80 (5): 746-753

Surgical site infection (SSI) following spine surgery is a morbid and expensive complication. The use of intrawound vancomycin is emerging as a solution to reduce SSI. The development of vancomycin-resistant pathogens is an understandable concern.

OBJECTIVE: To determine the occurrence of vancomycin-resistant SSI in patients with and without use of intrawound vancomycin.

METHODS: Patients undergoing elective spine surgery were dichotomized based on whether intrawound vancomycin was applied. Outcome was occurrence of SSI requiring return to the operating room within postoperative 90 days. The intrawound culture and vancomycin minimal inhibitory concentrations (MIC) were reviewed. Analyses were conducted to compare the pathogen profile and MIC for vancomycin in patients who received vancomycin and those who did not.

RESULTS: Of the total 2802 patients, 43% (n = 1215) had intrawound vancomycin application during the index surgery. The use of vancomycin was associated with significantly lower deep SSI rates (1.6% [n = 20] vs 2.5% [n = 40], P = .02). The occurrence of Staphylococcus aureus SSI was significantly lower in the patients who had application of intrawound vancomycin (32% vs 65%, P = .003). None of the patients who had application of intrawound vancomycin powder, and subsequently developed an S aureus SSI, demonstrated pathogens with resistance to vancomycin. All patients had MIC < 2 μg/mL, the vancomycin susceptibility threshold. The occurrence of gram-negative SSI (28% vs 7%) and culture negative fluid collection (16% vs 5%) was higher in the vancomycin cohort.

CONCLUSIONS: The use of intrawound vancomycin during the index spine surgery was protective against SSI following spine surgery. The application of intrawound vancomycin during index surgery does not appear to create vancomycin-resistant organisms in the event of an SSI.