Introduction: Surgical site infections (SSIs) in patients who have undergone lumbar fusion surgery can be a devastating complication. The aim of this study was to examine the relationship between timing of preoperative antibiotic prophylaxis and adverse outcomes such as SSIs with subgroup analysis stratified by antibiotic type.
Methods: This retrospective cohort included patients having undergone a 1-3 level lumbar fusion who were allocated into 5 groups based on the time from antibiotic administration to incision (Group A = 0-15 min, Group B = 16-30 min, Group C = 31-45 min, Group D = 46 – 60 min, and Group E = 61+ min). The primary outcome was SSIs, with secondary outcomes including: 90-day readmission and revision surgery. Statistical analysis, including a logistic regression model, was used to examine the relationship between patient/case characteristics, preoperative antibiotic timing, and postoperative outcomes.
Results: From 1,131 patients, 26 SSIs were identified. Logistic regression analysis revealed that Group E patients were 1.4 times more likely to develop an SSI and 7.2 times more likely to be readmitted within 90 days compared to Group A. Furthermore, Groups B-D did not have significantly higher odds of infection compared to Group A. Patients treated with vancomycin showed the lowest incidence of SSI when administered between 16-30 minutes, however cefazolin showed the lowest incidence when administered between 0-15 minutes.
Discussion: Preoperative antibiotic administration beyond one hour is associated with higher rates of SSI. Furthermore, vancomycin use is optimal when administered between 16 and 30 minutes prior to incision. While antibiotic prophylaxis effects depend on patient characteristics and varying pharmacokinetics, an effective regimen can significantly improve patient outcomes
