Preoperative Facial Nerve Palsy in Patients With Vestibular Schwannoma: Clinical Features and Postoperative Functional Prognosis in a Case Series of 34 Among 1228 Consecutive Patients

Abstract

BACKGROUND: Facial nerve palsy is a rare presenting symptom of vestibular schwannomas and has not been investigated in detail. OBJECTIVE: To investigate the incidence, clinical features, and postoperative long-term outcomes of facial nerve function in patients with vestibular schwannomas causing preoperative facial nerve palsy. METHODS: After excluding patients with neurofibromatosis type 2 and those with prior treatment, 1228 consecutive patients who underwent vestibular schwannoma surgery were retrospectively investigated. Patients with and without preoperative facial nerve palsy were compared statistically to clarify their clinical features. RESULTS: Preoperative tumoral facial nerve palsy was seen in 34 patients (2.8%). Their clinical features included older age, having large cystic tumors with significant meatal extension, and showing abnormal electrogustometric responses, compared with patients without preoperative facial nerve palsy. Owing to the frequent insufficient intraoperative responses on facial nerve electromyography, the tumor resection ratewas lower in the group with preoperative facial nerve palsy (mean: 95.2%). Among the 33 patients with sufficient follow-up data (mean: 63.9mo), additional treatmentwas required only in 1 patient and facial nerve function improved in 25 patients (75.8%) within 2 yr postoperatively. CONCLUSION: Facial nerve palsy is a rare preoperative symptom that occurs in less than 3% of patients with vestibular schwannoma. Tumor resection in such patients tends to be challenging owing to their advanced age, having large cystic tumors with significant meatal extension, and difficulties in intraoperative facial nerve monitoring, but surgical decompression of the facial nerve can assist in the improvement of their long-term functions.