Intraoperative bacterial contamination in operations for craniotomy

Abstract

Abstract Background: Intraoperative wound sterility in neurosurgical patients were rarely reported. This study used swab samples to prospectively assess the surgical field sterility of craniotomy. Methods: Forty patients admitted for craniotomy were included for surgical field bacterial contamination study during 15 months period. The specimens for bacterial culture were from the skin before cleansing (craniotomy specimen (CS) 1), (CS2) the skin after antiseptic cleansing but before dressing, (CS3) skull immediately after exposure, (CS4) dura immediately after exposure, (CS5) dura immediately before wound closure, (CS6) skull immediately before wound closure, and (CS7) uncovered blood agar plates placed near the instrument table at the marginal laminar air flow (LAF) area for 30 minutes after dura exposure. The culture was conducted on blood agar plates for 5 days to allow for bacterial growth. Results:The culture was positive in CS1 in 34 patients (85.0%), CS5 in 1 patients (2.5%), CS6 in 1 patient (2.5%), and CS7 in 8 patients (20%). No bacterial growth was observed in all CS2-CS4. The frequency of positive cultures in CS5 is significantly higher than that in CS5 and CS6 (P=0.007). The detected bacterial species were indigenous bacteria of the skin. Conclusions:Our study demonstrated low rate of wound contamination during craniotomy. Cultures were more frequently positive in specimens obtained in the marginal LAF area than those in the surgical field.