Temporal Lobe Retraction Provides Better Surgical Exposure of the Peri-Geniculate Ganglion for Facial Nerve Decompression via Transmastoid Approach

For the exposure of the labyrinthine segment of the facial nerve, transmastoid approach is not usually considered due to being situated behind the superior semicircular canal. To obtain a better view and bigger field for manipulation in the peri-geniculate area during facial nerve decompression, retraction of temporal lobe after bony removal of tegmen mastoideum was designed via transmastoid approach. Fifteen patients with traumatic facial paralysis [House-Brackmann (HB) grade IV-VI], 3 patients with Bell's palsy (HB grade V-VI), and 2 patients with herpes zoster oticus (HB grade V-VI) underwent facial nerve decompression surgery between January 2008 and July 2014. In all patients, we performed temporal lobe retraction for facial nerve decompression via the transmastoid approach. Patients were examined using pre operative tests including high-resolution computed tomography, temporal magnetic resonance imaging, audiometry, and electroneurography (degenerative ratio >90%). Facial function was evaluated by HB grading scale before and 6 months after the surgery. After the surgery, facial function recovered to HB grade I in 9 patients and to grade II in 11 patients. No problems due to surgical retraction of the temporal lobe were noted. Compared to the standard transmastoid approach, our method helped achieve a wider surgical view for improved manipulation in the peri-geniculate ganglion in all cases. Facial nerve decompression via the transmastoid approach with temporal lobe retraction provides better exposure to the key areas around the geniculate ganglion without complications.