Facial nerve stimulation associated with cochlear implant use following temporal bone fractures

Objective: To describe the incidence and management of patients with facial nerve stimulation (FNS) associated with cochlear implant (CI) use in the setting of a prior temporal bone fracture.

Patients: One adult CI recipient is reported who experienced implant associated FNS with a history of a temporal bone fracture. Additionally, a literature search was performed to identify similar patients from previous descriptions of CI related FNS.

Main outcome measures: Presence of FNS after implantation and ability to modify implant programming to avoid FNS.

Results: The patient in the present report experienced FNS for middle and basal electrodes during intraoperative neural response telemetry (NRT) in the absence of any surgical exposure or manipulation of the facial nerve. FNS was absent during device activation, but it recurred during follow-up programming sessions. However, additional programming has prevented further FNS during regular implant use. Four other patients with FNS after temporal bone fracture were identified from the literature, and the present case represents the one of two cases in which reprogramming allowed for implant use without FNS.

Conclusions: CI associated FNS is uncommon in patients with a history of a temporal bone fracture, but it is likely that fracture lines provide a lower impedance pathway to the adjacent facial nerve and thus reduce the threshold for FNS. The present report suggests that, in the setting of a prior temporal bone fracture, NRT is not always a reliable predictor of FNS during implant use, and programming changes can help to mitigate FNS when it occurs.