Facial palsy following cochlear implantation

Owing to its anatomical location, the facial nerve (FN) is at risk of damage during cochlear implantation, especially during posterior tympanotomy. The aim of this study was, therefore, to evaluate the risk of FN palsy following cochlear implantation surgery via mastoidectomy and posterior tympanotomy approach (facial recess). This is a retrospective study. The data bank of patients who received a cochlear implant between 2000 and 2012 was analyzed. 3403 surgeries were done during this period. Records of the patients who had suffered from FN palsy were evaluated and the type of FN palsy, the severity, time of onset, and need for revision surgery were recorded. 0.76 % (26/3403) of the patients had FN palsy and were, therefore, included in the study. 76.9 % (20/26) subjects were 18 years or older. 0.15 % (5 subjects) suffered from immediate FN palsy and 0.62 % (21 subjects) from delayed FN palsy. Intraoperative FN injury was documented in only three subjects of the immediate FN palsy group. In two subjects with immediate FN palsy, the FN was intraoperatively exposed but not injured, despite these individuals’ experiencing FN palsy. In 100 % of the immediate onset FN palsy group a part of the FN was exposed during surgery, whereas it was exposed only in 9.5 % of the delay onset FN palsy group. Although the FN was bone protected in 19 subjects, they had FN palsy. Most of the subjects presented House-Brackmann grade III or IV (69.2 %). All of the subjects were treated initially with a conservative therapy, only 42.3 % (11 subjects) underwent revision surgery. The recovery rate was 80.8 % (in immediate onset palsy 40 %, in delayed onset palsy 90.5 %). Cochlear implantation entails only a minimal risk of FN palsy and that FN palsy is chiefly a transient problem.