The clinical picture may vary depending upon the location of the tumour and their proximity to the middle or inner ear. Slowly progressive or sudden facial weakness, often preceded by facial twitching, is a common presenting complaint. However, one quarter of patients have normal facial nerve function. Depending on its site of origin, either proximal or distal to the geniculate ganglion, the patient may have sensorineural or conductive hearing loss. As for the diagnosis of facial nerve neuroma, high-resolution CT should be performed to visualize the facial canal followed by MRI to demonstrate the actual tumor.
Surgical excision is the definitive treatment for facial nerve neuromas. If possible, the neuroma should be dissected of the nerve. These tumors usually must be resected with the affected portion of the nerve because they are diagnosed after facial palsy is present, or in advanced stages because of their insidious progression. Thus, the nerve should be repaired immediately by primary repair or by a nerve interposition graft. Regardless of the type of repair, patients can expect no better recovery than an eventual House-Brackmann Grade III palsy.
The surgical approach should be chosen based on the anatomic location and extension of the tumor. A middle fossa craniotomy is used for patients with intracanalicular neuromas and useful hearing. The translabyrinthine or transpetrosal route is useful for patients without useful hearing and a facial nerve neuroma in the internal acoustic canal. Tumours involving tympanic segment or vertical mastoid segment, tympanomastoid approach is indicated to remove the tumour and to reconstruct the ossicular chain destroyed by the tumour.
