This study has been designed as a single-blinded, multi-center, randomized clinical trial at New York Presbyterian Hospital Columbia and New York Presbyterian Hospital Cornell. The study population includes all adult craniotomies performed at each institution over a 4 year and 9 month time period. The treatment variable is the application of topical vancomycin to the surgical site. If a craniotomy is performed, a paste made from vancomycin powder and sterile solution will be applied to the edges and outer surface of the craniotomy.