Brain herniation into the middle ear: two idiopathic cases treated by a combined intracranial-mastoid approach.

One hundred thirty-nine cases of brain herniation into the middle ear and mastoid have been reported in the world literature during the last 40 years. In 29 cases the herniation was idiopathic. In idiopathic cases, intermittent CSF otorhinorrhea, a history of intermittent "serous otitis media," and a conductive hearing loss were the main clinical findings. Polytomography or CT-scan revealed a tegmen antri or tympani defect in some patients. There are three surgical approaches for treatment of brain herniation into the middle ear: neurosurgical, otological, and combined.