Brain herniation and chronic otitis media: diagnosis and surgical management.

Herniation of the brain into the middle ear is a rare, but potentially life-threatening complication of chronic otitis media. Fifty patients with a tegmen defect associated with chronic otitis media were operated on between 1985 and 1998. Among these 50, 15 patients presented brain herniation associated with the bony defect. Fourteen patients had undergone previous mastoid surgery for chronic otitis media. Neurological symptoms were encountered in five patients. In 10, magnetic resonance imaging (MRI) was performed before surgery, and a diagnosis of brain herniation could be made. The hernia was repaired in all patients using a middle fossa craniotomy, combined with a transmastoid approach in 11 cases where a large hernia, and/or inflammatory tissues were present in the mastoid. The herniated brain tissue was resected in all, and the dural and bony defects were closed with fascia and bone. No complication or recurrence occurred, during a mean follow-up of 2 years. In conclusion, the occurrence of severe neurological complications as a consequence of brain herniation emphasizes the necessity for recognition and appropriate management of this disease. Computerized tomography (CT) scanning allows the suspicion of brain herniation, but a definitive diagnosis can best be established with an MRI study. The hernia should be repaired using a middle fossa craniotomy, combined with a transmastoid approach in one or two stages, when necessary.