Comparison of Spontaneous Temporal Bone Cerebrospinal Fluid Leaks From the Middle and Posterior Fossa.

OBJECTIVES:To compare patients surgically managed for spontaneous cerebrospinal fluid (CSF) leaks of the temporal bone arising from the middle cranial fossa (MCF) and posterior cranial fossa (PCF) and to describe the surgical management of posterior fossa CSF leaks. STUDY DESIGN:Retrospective case review. SETTING:Academic tertiary center. PATIENTS:Adult patients presenting with spontaneous temporal bone CSF leaks undergoing operative repair between January 2010 and August 2018. Patients with a history of trauma, previous mastoid surgery, and iatrogenic CSF leaks were excluded. INTERVENTION:Transmastoid or MCF CSF leak repair. MAIN OUTCOME MEASURES:Patient demographics, body mass index (BMI), comorbidities, presenting features, and lumbar puncture opening pressures were compared between groups and the management of the PCF CSF leaks described. RESULTS:Forty-six patients (26 women, 20 men) were included. The mean age at the time of repair was 58.0 ± 12.9 years (±SD). The origin of the CSF leak was from the PCF in three patients and MCF in 43 patients. All three patients with PCF leaks presented with an acute history of meningitis compared with only seven (16%) in the MCF group. This difference was statistically significant (p = 0.01, Fisher's exact test). There were no statistically significant differences in age, sex, BMI, or lumbar puncture opening pressures. The PCF leaks were repaired using a transmastoid approach with multilayer closure of the bony defect and fat graft obliteration of the mastoid. CONCLUSIONS:Spontaneous CSF leaks arising from the PCF are rare and may present more commonly with meningitis. Identification requires careful review of imaging.