Timing of Preoperative Surgical Antibiotic Prophylaxis After Primary One-Level to Three-Level Lumbar Fusion.

Objective The purpose of this study was to examine the relationship between timing of preoperative surgical antibiotic prophylaxis and postoperative surgical site infections (SSIs) among patients with 1-level to 3-level lumbar fusion. Methods Patients having undergone a primary 1-level to 3-level lumbar fusion at a single institution were allocated into 5 groups based on the time from preoperative antibiotic administration to incision (group A, 0-15 minutes; group B, 16-30 minutes; group C, 31-45 minutes; group D, 46–60 minutes; and group E, 61+ minutes). Timing of antibiotic administration as a continuous variable was also analyzed. All patients received irrigation with 3 L of normal saline containing bacitracin as well as local administration of vancomycin powder. SSIs were identified by the definition set forth by the 2017 Centers for Disease Control and Prevention guidelines. Results Among 1131 patients, 27 (2.4%) were found to have an SSI. Compared with patients with antibiotic administration within 0–15 minutes before incision, patients with administration 61+ minutes before incision (group 4) had significantly higher odds of developing an SSI (P Conclusions Our results show that preoperative antibiotic administration beyond 1 hour in patients who have undergone lumbar fusion is associated with higher rates of SSI.