Surgical site infections after elective neurosurgery: A survey of 1747 patients

OBJECTIVE: To evaluate the incidence and risk factors of postsurgical site infections (SSIs) in elective neurosurgical procedures in patients treated with an ultrashort antibiotic protocol. METHODS: In this consecutive series of 1747 patients treated with elective neurosurgery and ultrashort prophylactic antibiotic therapy at the Fondazione Istituto Nazionale Neurologico "Carlo Besta" in Milan, the rate of SSIs was 0.7% (13 patients). When only clean neurosurgery was considered, there were 11 such SSIs (1.52%) in 726 craniotomies and one SSI (0.15) in 663 spinal operations. The antibiotic protocol was prolonged in every case of external communication as cerebrospinal fluid leaks or external drainages. RESULTS: The infection rate of the whole series was low (0.72%), and a risk factor identified for SSIs in clean neurosurgery was longer surgery duration. The relative risk estimate was 12.6 for surgeries lasting 2 hours and 24.3 for surgeries lasting 3 or more hours. Patients aged older than 50 years had a lower risk of developing SSI with a relative risk of 0.23 when compared with patients aged younger than 50 years. CONCLUSION: The present series reports a low incidence of SSIs for elective neurosurgery, even for high-risk complex craniotomies performed for tumor removal. Given that an antibiotic protocol prolongation was used to pretreat any early signs of infection and external communication, the protocol was appropriate for the case mix. The two identified risk factors (surgical duration > 2 hours and middle-aged patients [16-50 yr]) may be indicators of other factors, such as the level of surgical complexity and poor neurological outcome.