[Clinical diagnosis and surgical management of 110 cases of facial nerve schwannomas].

Objective: To elucidate the clinical behavior, causes of misdiagnosis, surgical management, and outcomes of facial nerve schwannomas (FNS). Methods: A retrospective review in Chinese People's Liberation Army General Hospital from January 1, 2002 to December 31, 2015 was carried out and evaluated 110 patients with FNS, including 50 males and 60 females, aged 16-67 years old. The appropriate surgical strategy was selected based on each patient's clinical manifestations, facial nerve function, and imaging characteristics. After surgery, patients received follow-up visits to assess their facial nerve functions, with the effect of treatment compared to the reality before surgery. The Kruskal-Wallis H test was used to distinguish between the pre- and post-operation facial nerve functions in patients who had different facial nerve functions before the operations. Results: 110 cases of FNS mainly presented with facial paralysis, hearing loss, tinnitus, otalgia, dizziness, and facial spasm. 20 of the cases were misdiagnosed as Bell's Palsy, 6 were mistaken for chronic otitis media/cholesteatoma with radical mastoidectomy, 3 were mistaken for Meniere's disease, 1 was misdiagnosed as petrous bone cholesteatoma, and 4 were mistaken for acoustic neuroma. 81.8 % (90/110) of the patients had multiple segments of the facial nerve, including the vertical segment of the facial nerve, accounting for 65.5% (72/110), followed by the labyrinthine/geniculate segment, for 61.8% (68/110), and the horizontal segment, for 55.5% (61/110). The appropriate surgical approaches were chosed based on the sizes and scopes of the tumors evaluated by imaging: transmastoid approach in 73 cases, translabyrinthe approach in 14 cases, middle cranial fossa approach in 13 cases, retrosigmoid approach in 3 cases, transmastoid-middle cranial fossa approach in 3 cases, and transmastoid-neck approach in 4 cases, with all the patients undergoing a total/subtotal resection of the tumor. Eighty-seven patients had their facial nerves reconstructed. Among them, 6 received facial nerve end-to-end anastomosis, 55 received great auricular nerve graft, and 26 were subjected to facial nerve-hypoglossal nerve anastomosis. Because of long histories, facial muscle atrophies, or other reasons, the remaining patients were not received facial nerve reconstruction. The House-Brackmann(H-B) grading scale was used to evaluate the facial nerve function pre- and post-operation. Patients with better facial nerve functions and shorter history of facial paralysis before operation would get relatively better facial nerve function. The before and after operation comparisons revealed that the recovery of the facial nerve functions in patients with H-B Ⅰ-Ⅲ was better than the improvement in patients with H-B Ⅳ-Ⅴ. The difference was statistically significant (Kruskal-Wallis H test, H=8.508, P<0.05). Conclusions: The diagnosis of patients with unknown facial paralysis, hearing loss, and tinnitus should take into account the possibility of FNS. CT and other imaging examinations of the temporal bone can avoid misdiagnosis and determine the tumor size and extent of lesions, as well as provide the basis for the choice of the surgical approach. After tumors have been completely resected, facial nerve reconstruction can be performed simultaneously, according to the defect of the nerve.