Results
Electrical potential in response to trunk stimulation before and after resection, and their ratio (ARR1) (Fig. 2A, 2B)
In each group, the potentials to the trunk stimulation before and after resection were measured. In group A, all branches showed significantly higher potentials after resection than before resection. In group B, there was no significant difference in the response potentials of all branches before and after resection. In group C, MB had lower potentials after resection. In groups A and B, AAR 1 was higher than 1 in all branches. In group C, AAR 1 was lower than 0.5 in all branches.
Electrical potential in response to trunk and peripheral stimulation after tumor resection, and their ratio (ARR2) (Fig. 3A, Fig. 3B)
In each group, the potentials to the trunk and peripheral stimulation after resection were measured. In groups A and B, the response potentials to trunk and peripheral stimulation after tumor resection were similar. In groups A and B, ARR2 was approximately 1. In group C, the potential for trunk stimulation was lower than that for peripheral stimulation. ARR2 of the C group was lower than 0.5 in all branches.
Relationship between ARR and recovery time (Fig. 4A, Fig.4B)
We observed the recovery time in patients with facial nerve palsy (group C). The median recovery time was 98 (30–150) days for TB, 7 (4–70) days for ZB, 20 (4–30) days for BB, and 60 (3–180) days for MB. There was no correlation between recovery period of facial paralysis and AAR 1 and AAR 2.