Facial nerve function after microsurgical removal of the vestibular schwannoma

Technological development in microsurgery during the 20th century has led to a significant decline in mortality and morbidity of surgical management of vestibular schwannoma. Postoperative facial nerve function is among the main criteria of success. A retrospective analysis focused on 90 patients undergoing retrosigmoid-transmeatal surgery of vestibular schwannoma during 2010-2012. The aim of the study was to evaluate perioperative factors associated with postoperative facial nerve function. Facial nerve was discontinued in nine cases (10%) and was subsequently reconstructed. The position of the facial nerve to the tumor, morphological changes (e.g. elongation and splaying), cystic component of a tumor and an extent of tumor growth into the fundus of the internal acoustic meatus were among the parameters affecting facial nerve preservation. Definitive excellent to good function (House-Brackmann grade 1-3) was achieved in 96% of patients in the group with preserved facial nerve continuity. There was 67% of patients with good definitive postoperative function in the facial nerve reconstruction group. Stimulation threshold at the end of the surgery brought no significant information about definitive function of the facial nerve but it predicted early postoperative outcome. At present, the facial nerve continuity can be preserved in the vast majority of surgically managed vestibular schwannomas cases. It is crucial to define prognostic factors influencing the facial nerve injury outcome and include them into a decision-making protocol. Equally, it is necessary to define factors leading to unfavorable outcomes of the facial nerve function despite its anatomical preservation.