Temporal Bone Encephalocele and Cerebrospinal Fluid Leak Repair via the Middle Cranial Fossa Approach

Objectives: (1) To report the clinical presentation, radiographic findings, operative strategy, and outcomes among patients with temporal bone encephaloceles and cerebrospinal fluid (CSF) fistulae; (2) to identify clinical variables associated with surgical outcomes following middle cranial fossa (MCF) repair. Methods: Retrospective review of 75 consecutive patients who underwent repair via an MCF or combined MCF-transmastoid approach at one of two tertiary academic medical centers. Results: Seventy-five patients were reviewed. The mean age at diagnosis was 50.8 years (median, 54 years; SD, 16.2). Fifty-five percent of patients were men, and surgery was performed on the left side in 51% of cases. The mean body mass index was 34 kg/m 2 . Presenting symptoms included hearing loss (75%), otorrhea (71%), rhinorrhea (12%), and recent meningitis (11%); 4% of lesions were discovered incidentally following head and neck imaging for seemingly unrelated complaints. Fifteen patients (20%) reported a history of major trauma, 8 (11%) defects were associated with extensive cholesteatoma, and 8 (11%) occurred following prior surgery; the remaining 44 (59%) lesions occurred without antecedent trauma, chronic ear disease, or surgery. The majority of defects (83%) were repaired using a multilayer autologous tissue technique including temporalis fascia, fascia lata, auricular cartilage, bone and or bone pâté; 13 temporal bone repairs incorporated artificial mesh. Six (8%) patients experienced a recurrent CSF leak, three of which developed meningitis. The use of artificial mesh was statistically associated with the development of postoperative meningitis ( P = 0.004). Additionally, there was a fivefold increased risk of recurrent CSF leak with artificial mesh, although this difference did not reach statistical significance ( P = 0.06). Conclusions : Patients with temporal bone encephaloceles and CSF leaks commonly present with persistent otorrhea and conductive hearing loss mimicking chronic middle ear disease. There is a high prevalence of obesity among this patient population, which may play a role in the pathogenesis of primary and recurrent disease. An MCF approach incorporating a multilayer autologous tissue technique provides a safe and reliable method of repair that may be particularly useful for large or multifocal defects. Artificial mesh should be avoided given an increased risk of postoperative meningitis.