Surgical management of brain tissue herniation into the middle ear and mastoid

In the well pneumatized temporal bone, the temporal lobe of the brain is separated from the middle ear and mastoid process by a thin layer of bone known as the tegmen. Congenital defects, infection, and trauma can alter this structure in such a way that cerebral tissue herniates into the ear. This unusual condition may precipitate numerous otologic problems such as hearing loss, trapped squamous epithelium, and the potential for meningitis or encephalitis. The purpose of this paper is to define the problem as well as discuss the diagnosis and surgical management. The authors feel this should be a team effort, in many cases employing the assistance of a neurosurgeon, as the repair must often be intradural. Case histories and an extensive review of the literature are to be included.