Influence of clinical and neurophysiological parameters on the function outcome of the facial nerve after vestibular schwannoma surgery

Introduction: Vestibular schwannomas are benign neoplasms of the nerve seath, and they represent the third most common endocranial tumour, following the meningioma and the pituitary adenomas. The primary symptoms of vestibular schwannomas are hearing loss, tinnitus as well as a balance disorder. The therapy of vestibular schwannoma consists of observation, surgery and radiosurgery. The majority of patients who are good candidates for surgery are already affected by significant hearing impairment, thus one of the primary goals of the surgery is the preservation of facial nerve function. Aim: To analyze the outcome of facial nerve function one-year post-surgery using clinical and neuropsychological parameters. Material and methods: This study analyzed the patient's clinical status on admission along with the neuroradiological characteristics of tumours and the neurophysiological intraoperative parameters and their effect on the facial nerve function in the early postoperative period as well as one year after the surgery using the House–Brackmann scale. Results: A total of 30 patients who underwent surgery from January 1st 2015 to December 31st 2018 at the Clinical Centre of Serbia, Neurosurgery Clinic for vestibular schwannomas were examined. The median age of the patients was 51 years. Hearing loss was present in all patients. Sensitivity drop in the innervation region of n. trigeminus was present in 7 (23.3%) patients, as was tinnitus. Cerebellar symptomatology (76%) was present in the highest percentage of patients. Conclusion: We can conclude that the most important aspects of the facial nerve function are the preoperative state of the facial nerve and the electrophysiological parameters. Although the radical procedure of surgery led to an immediate postoperative outcome, it was not significant for the ultimate outcome of treatment. Thus, radical surgery may be considered to carry the same risk of definitive impairment of the facial nerve function, just like a combination treatment with subtotal resection and stereotaxic radiosurgery