Reliability of Percutaneous Test for Facial Nerve Function

To evaluate the reliability of conventional tests for facial nerve denervation, comparisons of the thresholds and relationship with prognosis were made between the conventional percutaneous and direct stimulation methods in 11 cases of facial palsy decompressed and followed up for more than 6 months. Although all cases showed complete or severe nerve degeneration in the preoperative percutaneous stimulation test, the threshold for the direct intraoperative stimulation test varied from 4 V (normal) to more than 30 V. The results of the direct intraoperative stimulation test correlated well with prognosis (degree of improvement of palsy score). Our results indicate that the direct stimulation method is better than the percutaneous stimulation method as an electrodiagnostic test for nerve degeneration.