Surgery of the facial nerve

The diagnosis and management of facial nerve disorders are challenging aspects of neurotological practice. In Bell's palsy and Herpes Zoster oticus facial nerve decompression is indicated in approximately 10 per cent of cases within the first three weeks if 90-95 per cent degeneration has occurred. The presence of a dry eye determines whether the lesion is proximal to the geniculate ganglion and a middle fossa approach is necessary. Injury to the facial nerve occurs most commonly as a result of temporal bone fractures, from either blunt trauma or penetrating wounds. Occasionally iatrogenic injury occurs during ear surgery. Injury resulting in immediate and total facial paralysis with degeneration confirmed by appropriate electrical testing requires facial nerve exploration. In the presence of an injury proximal to the geniculate ganglion and hearing preservation, exploration of the nerve via middle fossa approach is indicated. If the hearing is lost then the translabyrinthine approach is appropriate. In the event the entire interosseous segment requires exposure, both mastoid and middle fossa exposures are required. If the traumatized facial nerve has not been divided it is decompressed proximal and distal to the injury site. In the event the nerve is divided, a direct anastomosis is the ideal treatment. Rerouting is necessary to achieve adequate length for the anastomosis. Nerve grafting is done when required.