Surgical site infection surveillance for neurosurgical procedures: a comparison of passive surveillance by surgeons to active surveillance by infection control professionals.

Issue: Surveillance methods for surgical site infections (SSIs) range from patient self-report to active surveillance by infection control professionals (ICPs). Surgeon questionnaires surveying SSIs are typically suboptimal due to bias, lack of standardized criteria to diagnose infection, and poor response rate. Although concurrent surveillance of SSIs by ICPs at our medical center documented an incidence of 2.2 SSIs per 100 procedures, the neurosurgeons perceived a much higher rate of SSIs.

Project: The neurosurgeons provided a list of patients they had clinically identified with SSIs over a 7 month period. This list was compared with a line listing of SSIs independently identified by ICPs via concurrent surveillance utilizing the Centers for Disease Control and Prevention (CDC) definitions.

Results: A total of 766 procedures were performed. Active surveillance by ICPs detected 17 infections (2.2/100 procedures). Of the 14 cases identified by the neurosurgeons, 3 did not meet the CDC definition of a nosocomial infection. The ICPs identified 6 SSIs not documented by the neurosurgeons. Compared to active surveillance by ICPs, the sensitivity and specificity of the neurosurgeon's identification of SSIs was 64% and 99.6%, respectively. The positive predictive value was 78.6% and the negative predictive value was 99.2%.

Lessons Learned: An active surveillance program is necessary for accurate identification of SSIs. The primary problem with passive surveillance by surgeons is failure to capture cases; surgeons missed 36% of cases compared to active surveillance by ICPs.