Antimicrobial prophylaxis for spinal surgery

The concept of antimicrobial prophylaxis (AMP) did not exist in Japan until recently. Therefore, postoperative administration of antimicrobial drugs has long been practiced under the pretext of prophylaxis against surgical site infection (SSI). In recent years, however, the concept of AMP and prophylactic countermeasures against SSI, based on evidence of the effectiveness of AMP, has gradually spread in Japan. From 2000 onward, we have undertaken prophylactic countermeasures against SSI in patients undergoing spinal surgery referring to the Guideline for Prevention of Surgical Site Infection published by the Centers for Disease Control and Prevention in 1999. The purpose of this study was to investigate the type of AMP that would be appropriate for spinal surgery and the manner in which it should be used. The subjects were 1415 patients who underwent spinal surgery at our department from January 1990 to March 2008. The patients were classified into four groups according to the method of AMP administration: group 1, AMP was employed for 7 days, only postoperatively; group 2, initial AMP dosing was administered at the time of anesthesia induction, followed by administration of AMP for 5 days, including the day of the operation; group 3, initial AMP dosing was administered at the time of anesthesia induction, and AMP was administered for 3 days, including the day of the operation; group 4, the initial dosing was administered at the time of anesthesia induction, and AMP was administered for 2 days, including the day of the operation. The frequency of SSI was assessed in the four groups. The frequencies of SSI in groups 1−4 were 2.6% (14/539), 0.9% (5/536), 0% (0/257), and 0% (0/83), respectively. Thus, the frequency of SSI decreased as the duration of the AMP administration period decreased. As a result of thorough implementation of preventive measures against perioperative occurrence of infections, which included additional preoperative and intraoperative administration of AMP, the incidence of SSI could be decreased despite shortening the duration of AMP administration to 2 days.