Facial nerve aberrations encountered during cochlear implantation

Abstract

Conclusion: In patients with cochleovestibular malformations, surgeons should always consider the possibility of an aberrant course or shape of the facial nerve (FN). In our series, the majority of cases could be successfully implanted without major complications through careful handling of the FN and ossicles. Objectives: To assess the frequency, type, and surgical implications of FN aberrations encountered during cochlear implantation (CI). Methods: Medical records and radiologic findings of 972 patients who underwent CI from 1988 to 2009 were reviewed retrospectively. Radiologic and intraoperative findings demonstrating malformations of the FN, ossicles, and inner ear were evaluated. Intraoperative events and postoperative FN outcome were reviewed. Results: Seven patients (0.7%) had an aberrant course or shape of the FN during CI. All these patients were pediatric. Four showed abnormal anterior or inferior location of the vertical segment, two had a bifurcated horizontal or vertical segment, and one had an inferiorly located horizontal segment. All seven patients displayed combined malformations of the cochlea and had malformed or missing ossicles. CIs were successfully performed via the facial recess approach and cochleostomy. There was no postoperative FN paralysis except in one case with immediate iatrogenic FN paralysis that recovered completely 1 month after FN decompression.