The association of meningitis with postoperative cerebrospinal fluid fistula

Objective: To determine the risk factors for and the clinical course of postoperative meningitis following lateral skull base surgery and to determine its relationship to cerebrospinal fluid (CSF) fistula. Patients: Patients undergoing lateral skull base surgery between July 1999 and February 2010 at an academic tertiary referral center. All subjects had culture-proven meningitis or suspected bacterial meningitis in the postoperative period. Medical records were compared with the lateral skull base patients who did not develop meningitis. Results: Of 508 procedures, 16 patients developed meningitis (3.1%). The most common diagnosis was acoustic neuroma in 81.3%; 68.8% of patients had a CSF leak prior to onset of meningitis, and 50% received a lumbar drain. The median time from surgery to the onset ofmeningitis was 12 days with a range of 2 to 880 days. The relative risk of developing meningitis in the setting of postoperative CSF fistula is 10.2 (p<0.0001). No meningitis-associated mortality was observed. Conclusions: Postoperative meningitis occurred in a small number of patients undergoing lateral skull base surgery. A postoperative CSF fistula leads to an increased risk of meningitis by a factor of 10.2.