Journal of clinical neurophysiology : official publication of the American Electroencephalographic Society, sa.0, 2020 (SCI-Expanded)
ABSTRACT
Introduction: Blink reflex (BR) under general anesthesia as an intraoperative neuromonitoring method was used to monitor facial nerves in few studies. This study aimed to test the utility of intraoperative BR during cerebellopontine angle and skull base surgeries, assess its prognostic value for facial nerve functions, and compare it to facial corticobulbar motor evoked potentials (CoMEPs).
Methods: BR and facial CoMEPs were recorded from 40 patients undergoing skull base surgeries. Subdermal needles were placed in the supraorbital notch for stimulation and in the orbicularis oculi muscle for recording the BR. A double train of 20-40 V intensity with an intertrain interval of 40-60 ms, interstimulus interval (ISI) of 2.5ms, a stimulus duration of 0.5ms were applied. Facial nerve functions were assessed with the House-Brackmann (HB) grading system in the postoperative day one and 3rd month period and correlated with intraoperative BR and CoMEPs measurements.
Results: BR was recordable on the affected side in 32 (80%) and contralateral side in 35 (87,5%) out of 40 patients. According to our statistical results, BR had a slightly better sensitivity than facial CoMEPs in predicting impairment of facial nerve functions for both postoperative and 3rd month time points. BR showed better accuracy for predicting postoperative nerve functions, whereas CoMEPs correlated better in predicting 3rd month outcome.
Conclusions: We suggest that BR is a valuable intraoperative neuromonitoring method that can be used in addition to facial CoMEPs during skull base surgeries to assess real-time facial nerve integrity and predict prognosis.
ABSTRACT
Introduction: Blink reflex (BR) under general anesthesia as an intraoperative neuromonitoring method was used to monitor facial nerves in few studies. This study aimed to test the utility of intraoperative BR during cerebellopontine angle and skull base surgeries, assess its prognostic value for facial nerve functions, and compare it to facial corticobulbar motor evoked potentials (CoMEPs).
Methods: BR and facial CoMEPs were recorded from 40 patients undergoing skull base surgeries. Subdermal needles were placed in the supraorbital notch for stimulation and in the orbicularis oculi muscle for recording the BR. A double train of 20-40 V intensity with an intertrain interval of 40-60 ms, interstimulus interval (ISI) of 2.5ms, a stimulus duration of 0.5ms were applied. Facial nerve functions were assessed with the House-Brackmann (HB) grading system in the postoperative day one and 3rd month period and correlated with intraoperative BR and CoMEPs measurements.
Results: BR was recordable on the affected side in 32 (80%) and contralateral side in 35 (87,5%) out of 40 patients. According to our statistical results, BR had a slightly better sensitivity than facial CoMEPs in predicting impairment of facial nerve functions for both postoperative and 3rd month time points. BR showed better accuracy for predicting postoperative nerve functions, whereas CoMEPs correlated better in predicting 3rd month outcome.
Conclusions: We suggest that BR is a valuable intraoperative neuromonitoring method that can be used in addition to facial CoMEPs during skull base surgeries to assess real-time facial nerve integrity and predict prognosis.