The purpose of this study was to evaluate the efficacy, in preventing Spinal Surgical Infection, of intraoperative pulsatile irrigation with a 2000-ml saline solution of PVP-Iodine in a group of patients undergoing complex spine surgery with a posterior approach. To confirm and better assess the efficacy of intraoperative irrigation on the infection rate in spinal surgery, specimens for bacterial culture were harvested by swabs from muscular tissue before and after irrigation of the wounds