Facial F wave recording: A novel and effective technique for extra- and intraoperative diagnosis of facial nerve function in acoustic tumor disease

Abstract

OBJECTIVE: To investigate the diagnostic yield of facial F wave recording in patients with acoustic neurinomas intraoperatively and extraoperatively.

STUDY DESIGN AND SETTING: Prospective study, comparative evaluation of facial F waves, transcranial magnetic stimulation of the facial motor cortex, blink reflex, and intraoperative online electromyographic activity. The study was performed in the neurosurgical department of a university hospital.

RESULTS: Extraoperatively, only F wave latencies were closely correlated to tumor diameter as an independent variable. Intraoperatively, loss of F waves was specific for the development of a severe to total facial paresis postoperatively. A transient loss of F waves heralds an imminent danger of severe facial dysfunction.

CONCLUSION: Facial F wave recording provides valuable information on the functional status of the nerve intra- and extraoperatively.

SIGNIFICANCE: Facial F wave recording should be used as a standard electrodiagnostic technique in addition to transcranial magnetic stimulation and blink reflex recording. It seems particularly useful for intraoperative facial nerve monitoring.