Comparison of Intrawound Vancomycin Utility in Posterior Instrumented Spine Surgeries Between Patients With Tumor and Nontumor Patients.

Abstract

Retrospective cohort study of consecutive patients. To compare the efficacy of intrawound vancomycin to prevent postoperative surgical site infection (SSI) between patients with spinal tumor and nontumor spine patients. Recent studies have suggested that intrawound vancomycin is a promising method for reducing the SSI rate in spine surgery. However, the patient population in which it is most effective remains unknown. Medical records of a consecutive series of patients with tumor and nontumor spine patients who underwent open posterior instrumented surgeries at our institution between October 2011 and June 2014 were reviewed. 1 gram of vancomycin powder was evenly sprayed into the surgical site before drain placement. The SSI rates before and after vancomycin use were compared. Changes in SSI rates, which reflected the utility of vancomycin, were compared between patients with tumor and nontumor patients. A total of 334 patients were enrolled including 25 patients with tumor and 129 nontumor patients in the "before" period, and 27 patients with tumor and 153 nontumor patients in the "after" period. Baseline characteristics in both patients with tumor and nontumor patients did not differ between periods. The SSI rate of nontumor patients was significantly reduced with intrawound vancomycin application (7.0% [9/129] vs. 0.7% [1/153], P = 0.011). However, the SSI rate in patients with tumor was not reduced (8.0% [2/25] vs. 14.8% [4/27], P = 0.442). 3 of the 4 patients with tumor who developed SSI after vancomycin use had previous radiotherapy, whereas only 1 SSI occurred in 14 patients with tumor without radiotherapy in the same period. Intrawound vancomycin may be beneficial for nontumor spine patients who undergo open posterior instrumented surgeries, but may not for those with spinal tumors. The poor physical health status, major surgical trauma, and tumor-related adjuvant treatments of patients with spinal tumor may contribute to this disparity.