Intraoperative Neuromonitoring of Blink Reflex During Posterior Fossa Surgeries and Its Correlation With Clinical Outcome

Abstract

Purpose: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 with facial corticobulbar motor evoked potentials (CoMEPs).Methods:Blink reflex 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 to 40 V intensity with an intertrain interval of 40 to 60 milliseconds, an interstimulus interval of 2.5 milliseconds, and a stimulus duration of 0.5 milliseconds were applied. Facial nerve functions were assessed with the House–Brackmann grading system in the postoperative day 1 and third-month period and correlated with intraoperative BR and CoMEPs measurements.Results:Of 40 patients, BR was recordable on the affected side in 32 (80%) and contralateral side in 35 (87.5%) 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 third-month time points. Blink reflex showed better accuracy for predicting postoperative nerve functions, whereas CoMEPs correlated better in predicting third-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.

Blink reflex: A practical test to evaluate the trigeminal nerve injury following percutaneous balloon compression for the treatment of trigeminal neuralgia

“…This intraoperative BR recording method has been used in several studies to monitor trigeminal or facial nerve function during MVD and posterior fossa surgeries. [47][48][49] In this study, we found that the absence of R1 post was significantly associated with complete pain relief and facial numbness following PBC. Therefore, we consider that intraoperative monitoring of BR would be feasible during PBC, and that the absence of R1 may provide real-time feedback on the surgical effect and provide a reference point for terminating the compression.…”

The Role of Neurophysiology in Managing Patients with Chiari Malformations

“…BR is useful in the study of trigeminal and facial nerve lesions, peripheral neuropathy, posterior fossa lesions, multiple sclerosis, and extrapyramidal diseases [51]. Under general anesthesia in the operating room, only the R1 response can be recorded [52][53][54][55].…”