OBJECTIVES: Neurosurgical surgical site infections (SSI) are life-threatening complications, requiring medical treatment and additional surgeries and remain a substantial cause of morbidity. In order to identify the incidence and the main risk factors for SSI, we developed the Prophylaxis with Antibiotic protocol for neuroSurgical Site Infections Study (PASSIS), a prospective observational multicenter cohort study for examining a large number of neurosurgical procedures.
METHODS: The study PASSIS involved four Italian Neurosurgical Departments applying the same antibiotic prophylaxis (ABP) protocol on 6359 consecutive neurosurgical procedures. In high-risk conditions (intra-operative contamination and/or post-operative cerebro-spinal fluid (CSF), and/or subcutaneous drainage and/or post-operative hyperpyrexia), and in presence of wound complication (CSF leak and/or CSF collection and/or wound diastasis), a prolongation protocol was prescribed.
RESULTS: The crude rate of SSI in the whole series was and 1.7% for patient and 1.5% for procedure. Patient related SSI risk factors: Younger patients (≤14 years) had a significantly higher SSI risk compared with older patients (RR: 2.17; CI 95%: 1.13- 4.14). Patients underwent two surgeries were at increased SSI risk (RR: 3.80; CI 95% 2.33-6.18), and the risk increased with the number of surgeries. Surgeries lasting longer than 3 hours (RR: 2.27; CI 95% 1.15-4.50), undergoing two or more surgeries and the presence of prosthetic implants (RR: 2.40; CI 95% 1.53- 3.77) were procedure related SSI risk factors positively associated with SSI. In high-risk conditions and in wound complication as defined previously, ABP prolongation showed limited efficacy (RR:1.97; CI 95% 1.21-3.22 and 9.31; CI 95% 5.90-14.68 respectively).
CONCLUSIONS: The subjects submitted to complicated, repeated, long lasting craniotomies, especially if experiencing postoperative deterioration, display the higher risk of SSIs, as a final life threatening complication. In order to reduce the SSI rate, further studies should address to design tailored prophylaxis protocols for each high risk situation as hereby defined; the wound complications deserve an increased microbiological surveillance, focusing the attention on the timing and source of infections.