Shan et al (2014) analyzed the benefits of facial nerve EMG monitoring during parotid tumor surgery. In this study, 92 patients with parotid tumor who underwent surgery were surveyed. The study group consisted of 46 patients who underwent intra-operative EMG monitoring, and 46 patients served as the control group. The incidence of post-operative facial nerve weakness and the operation time were recorded. In primary parotid tumor resection, the operation time of the study group (6 cases) was ( ± ) mins, that of control group (7 cases) was ( ± ) mins (p = ) when the facial nerve needed no dissecting; the operation time of the study group (32 cases) was ( ± ) mins, that of control group (33 cases) was ( ± ) mins (p = ) when the facial nerve needed dissecting. For patients with revision surgery, the mean operation time in the study group [( ± ) mins] was significantly lower than that of the control group [( ± ) mins], p < . In the study group, 8 patients suffered from post-operative facial nerve weakness because of tumor characteristics; in the control group, 6 patients suffered from post-operative facial nerve weakness, with 4 cases because of tumor characteristic, and 2 cases because of operator error. The authors concluded that these findings suggested that continuous EMG monitoring of facial nerve during parotidectomy reduces the mean operation time in patients with revision surgery, but not the incidence of post-operative facial paralysis.