Postoperative CSF Characteristics After Extended Endoscopic Skull Base Surgery: Case Series and Review of the Literature

Extended endoscopic endonasal approaches (EEA) to the skull base are associated with a greater risk of CSF leak and infection than standard trans-sellar cases. Postoperative CSF characteristics such as intracranial pressure, cytology, and microbiology are closely associated with this risk but have not previously been described. Consecutive patients undergoing extended EEA at our tertiary center underwent lumbar puncture 3 to 5 days after surgery in accordance with local protocol. Opening pressure (OP) and CSF characteristics were obtained from the medical record and reported descriptively. The incidence of CSF leak, meningitis, and any predictive factors of these complications were then evaluated. A total of 43 patients met inclusion criteria, of which 36 were female (83.7%) and 24 (55.8%) underwent EEA for anterior fossa meningioma. Out of 43 patients, 28 (65.1%) had a recorded OP (median 16 cmH2O [11–20]) and, notably, one-third (32.1%) had an elevated pressure greater than 20 cmH2O. Two cases (4.7%) of CSF leak were observed and the need for perioperative CSF diversion was a statistically significant predictor of leak (p = 0.004). The cohort had a single case of microbiologically proven meningitis as well as two additional cases of asymptomatic CSF pleocytosis that prompted additional empirical antibiotic therapy. The risk of CSF leak and meningitis in a modern cohort of patients undergoing extended EEA is low. However, 32.1% of patients in this cohort had an elevated opening pressure and 4.7% had unexpected CSF pleocytosis. Careful consideration of these factors and their possible impact on postoperative morbidity is essential.