Transmastoid trans-facial canal approach to facial nerve tumors

Abstract

Facial nerve tumors within the temporal bone present several surgical challenges due to the tortuous course of the facial nerve and the nerve’s close relationship to other important structures. Surgical approaches often have either sacrificed hearing/vestibular function or involved brain retraction. We present a case of a patient who was diagnosed with a facial nerve schwannoma (House-Brackmann IV/VI). Magnetic resonance imaging (MRI) showed the tumor was limited to the middle ear. The patient had already undergone facial reanimation procedures and elected to have the tumor removed. A transmastoid trans-facial canal surgical approach was used to remove the tumor without disturbing the ossicular chain. The patient’s hearing and vestibular function remained intact. Operating from within the facial canal provides the surgeon additional room to dissect facial nerve tumors from the middle ear to the geniculate ganglion when using a transmastoid approach. This surgical approach is similar to the previously described transmastoid/supralabyrinthine approach to excise facial nerve tumors within the temporal bone but modified to keep the ossicles intact. While the described approach has a limited application, in certain cases of facial nerve tumors within the temporal bone when surgery is warranted, a transmastoid trans-facial canal approach may have advantages over previously-described approaches.

Keywords

• schwannoma
• skull base
• facial nerve
• otology
• adenoid cystic carcinoma