Introduction: Temporal bone encephaloceles are a complex problem of the skull base, often requiring surgical intervention with a multidisciplinary approach between neurosurgeons and neurotologists. While the incidence of spontaneous encephaloceles has increased in most recent years due to factors such as idiopathic intracranial hypertension, other causes exist. Namely, chronic otitis media with and without cholesteatoma are an associated and perhaps unrecognized cause of middle fossa encephaloceles. This study examines the association of temporal bone encephaloceles and chronic otitis media.
Methods & Results: This study examines the association of temporal bone encephaloceles and chronic otitis media. A retrospective analysis includes 55 repaired encephaloceles repaired through multidisciplinary team approach including neurosurgery and neurotology. Of this group, 58% of patients had chronic otitis media and 18% had cholesteatoma. For the remainder, 29% of encephaloceles were spontaneous and 9% were traumatic/iatrogenic. 19% had prior recent tympanostomy tube for presumed middle ear effusion. None had prior middle ear, mastoid, or middle fossa surgery.
Interventions: 93% of patients underwent exclusively transmastoid approach, for encephalocele repair and 7% had combined middle cranial fossa and transmastoid approach. 56% had ear drum repair (tympanoplasty) simultaneous with encephalocele repair. Most likely causes were perforation or retraction with cholesteatoma. 12% also had ossicular chain reconstruction at the same time, often due to cholesteatoma erosion or osteitis.
Discussion: For patients with encephaloceles, the diagnosis of chronic otitis media must be considered. COM was present in over half (56%) of the patients in this encephalocele group. While spontaneous/idiopathic causes of encephalocele exist, skull base surgeons should be aware of COM as a related entity. This has implications for surgical approach selection (transmastoid approach vs middle fossa craniotomy alone), employment of simultaneous procedures (tympanoplasty and or ossicular chain reconstruction), and managing patient expectations about longterm management.