Is Serial Electroneuronography Indicated Following Temporal Bone Trauma?

OBJECTIVE: Contemporary guidelines advise facial nerve (FN) decompression within 2 weeks of temporal bone trauma if a single electroneuronography (ENoG) demonstrates more than 90% degeneration of the FN. We report a case series demonstrating the potential of serial ENoG to guide FN management more than 2 weeks following injury.

PATIENTS: Adults with traumatic temporal bone fractures and resultant ipsilateral FN paresis.

INTERVENTION: Serial ENoG followed by observation or decompression of the FN.

MAIN OUTCOME MEASURE: House-Brackmann (HB) graded FN function.

RESULTS: Nine cases of blunt temporal bone trauma resulting in ispilateral FN paralysis were identified and reviewed. Two patients were women, and average age at the time of trauma was 30 years (range, 17-52). Immediate paralysis occurred in four cases, while five were delayed. A single ENoG was performed in seven patients and was predictive of final function in six, while one patient had an initially reassuring ENoG but did not obtain full recovery of FN function (HB 4). Two patients underwent serial ENoG on a weekly basis which, while initially reassuring, demonstrated declining FN function on subsequent testing. Decompression was performed in both patients with excellent recovery of FN function (HB1 and HB2).

CONCLUSIONS: The majority of ENoGs performed within 2 weeks of temporal bone trauma provide sufficient prognostic data for treatment decisions; however, in selected cases, a single ENoG may not adequately predict long-term FN outcomes. For patients failing to improve with observation alone, serial ENoG may capture declining FN function, identifying patients that may benefit from late decompression.