Lopez W, et al. - Data were collected and analyzed over the course of 2005 to 2009 and 2011 to 2015 to assess the consequence of vancomycin and cefazolin as standard preoperative antibiotic prevention on surgical site infections (SSI) after instrumented spinal fusion. A reduction in performed revision surgeries to diagnose infection from a rate of 4% in the period 2005 to 2009 to 2% from 2011 to 2015. They also recorded a decline in the incidence of revision surgeries for any cause ie, 14% in 2005–2009 vs 9% in 2011–2015. They also found that the odds of a revision procedure for SSI were decreased by 50% after introducing the protocol. They observed no significant variation in the organisms effective of SSI between 2005 and 2009 and 2011 and 2015.