We aim to present a reliable method of obtaining the blink reflex potential in the intraoperative setting to monitor for facial nerve injury throughout surgical procedures that risk facial nerve injury.

Surgical procedures conducted near the brainstem carry a significant risk of injury to the facial nerve. Existing intraoperative monitoring techniques, including electromyography and transcranial motor evoked potentials, lack specificity for the facial nerve and can only be employed intermittently. Stimulation of the ophthalmic trigeminal nerve facilitates a neural pathway that influences the facial nucleus, triggering a blink response through the facial nerve. Establishing a dependable and continuous method for monitoring this response could enhance the early detection and prevention of facial nerve injury during surgery.

We reviewed 20 cases involving skull base or cerebellopontine angle pathology where a reproducible blink reflex potential was obtained. In each case, blink reflex potentials were obtained with either 1) single trial of double train stimulation and recording the response, or 2) multiple trials with a single stimulation and averaging the responses. We evaluated the consistently of the response obtained with each method throughout each case.

Patients had an average age of 48 years. The averaged blink response showed a higher signal-to-noise ratio and greater subjective consistent waveform morphology across cases.

The blink reflex potential can be reliably recorded intraoperatively using either double train or single stimulation. The averaged response of single stimulation is more consistent, supporting its broader application. Further studies are needed to establish alarm criteria in various anesthetic environments.