Methods
For groups A, B, and C, we compared the electrical potential in response to stimulation of the facial nerve trunk before and after tumor resection. We also compared the electrical potential in response to stimulation of the facial nerve trunk and stimulation of each branch after tumor resection. From these results, we calculated the amplitude response ratio (ARR) for each patient and compared each group. In other words, the ratio of electrical potential in response to trunk stimulation before and after tumor resection (after / before resection) was determined as ARR1, and the ratio of electrical potential in response to trunk stimulation and branch stimulation after tumor resection (trunk / periphery) was determined as ARR2. Furthermore, in group C, the time to recovery of paralyzed branches and ARR1 and ARR2 were compared. The House-Brackmann scale was used to assess paralysis.
Statistical processing was carried out using the Chi-squared test, Wilcoxon signed-rank sum test, and the Mann-Whitney U test, with p < 0.05 considered statistically significant. We used Spearman’s rank correlation coefficients to examine correlations.