Effect of intrasite vancomycin powder on development of epidural fibrosis

Placement of vancomycin powder into the surgical wound prior to closure has been shown to reduce postoperative infections in spine surgery. This study examines the effect of vancomycin powder on formation of epidural fibrosis (EF). Twenty-two rats underwent a two-level lumbar laminectomy. A control group, a low-dose and a high dose vancomycin powder (applied prior to closure) group was formed. Rats were sacrificed at 30 days and a blinded fellowshiptrained pathologist evaluated the laminectomy segments for EF. 50% of the samples in the high-dose vancomycin group were EF grade 3, compared to 20% of the low-dose and 16.7% of control samples. The average fibrosis grade for the high dose, low dose and control groups were 2.4, 1.4 and 1.8, respectively. There were more grade 3 EF specimens in the high dose vancomycin group. While the average EF grade was also higher in this group, there was not a statistical difference compared with the other groups.