Intraoperative Monitoring of Motor Evoked Potential for the Facial Nerve Using a Cranial Peg-Screw Electrode and a “Threshold-level” Stimulation Method - Goto, Tetsuya; Muraoka, Hisashi; Kodama, Kunihiko; Hara, Yosuke; Yako, Takehiro; Hongo, Kazuhiro (Skull Base, 2010)