Surgical treatment of facial nerve schwannomas.

Facial nerve schwannomas are rare. They occur all along the nerve's course from the cerebellopontine angle to the parotid region. Clinically, intracranial facial nerve schwannomas often present with facial nerve paralysis or hearing loss and may initially be misdiagnosed as vestibular schwannomas. Modern imaging techniques allow diagnosis and evaluate tumor location, size and extension. Functional tests evaluate facial nerve and hearing function. All this information results in an individual management plan. Microsurgery, stereotactic radiosurgery and observation are the therapeutic options. Surgery is planned depending on tumor features and the preoperative functional status. Subtemporal, transmastoid, translabyrinthine and retrosigmoid approaches are the principal routes. Preservation of facial nerve function is the main surgical difficulty. Anatomical nerve conservation, nerve resection with immediate grafting or delayed hypoglosso-facial nerve anastomosis are possible. The main predicting factors of postoperative facial function are the degree and duration of facial paralysis before surgery. Observation is an option for small tumors and asymptomatic patients. In these cases, a close follow-up is mandatory. The optimal timing for surgery is critical: waiting maximizes the time with good facial function, but increases the risk of hearing loss by cochlea erosion and lowers the chances of postoperative facial nerve recovery once paralysis has occurred. The role of radiosurgery is still to be determined: it seems suitable for inoperable patients and recurrent tumors.