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Updated: May 9, 2026
Facial Nerve Surgery in the Rat Model to Study Axonal Inhibition and Regeneration
Published on: May 5, 2020
Effectiveness of C5 or C6-Cz assembly in predicting immediate post operative facial nerve deficit
Silvia Mazzali Verst1, Andrea Caivano Sucena, Marcos Vinicius Calfat Maldaun
1Post-Graduation Department, São Paulo Medical School, University of Sao Paulo, São Paulo, Brazil, silviaverst@terra.com.br.
Background:
Intraoperative neurophysiology monitoring (IOM) is a valuable tool in cerebellopontine angle (CPA) surgeries posing risk to the cranial nerves. Transcranial electrical stimulation (TES) for cranial nerves has been performed in the last 7 years, for obtaining the facial nerve motor evoked potential (MEP), using either C3/C4-Cz or C3-C4 (or inverse) stimulating points, which have been correlated with facial nerve functional outcome.
Method:
Intraoperative surgical and electrophysiological findings were documented prospectively. Patient files were reviewed for clinical data. We studied 23 patients undergoing CPA tumor resection using C5 or C6-Cz montage for TES, and were able to determine the correlation between facial nerve functional outcome and the amplitude drop of facial MEP above 50 %. Patients were evaluated for immediate facial nerve outcome and 6 months after the surgery. Follow-up was performed by structured telephone interviews with local physicians.
Results:
The sensibility of the studied parameters was 92.8 % for amplitude drop of facial nerve MEP, with positive predictive value of 81.2 %. The absence of changes during IOM has shown a negative predictive value of 100 %.
Conclusion:
In this series, the used montage was effective in predicting new facial deficit.
