Intraoperative transcranial facial motor evoked potential monitoring in surgery of cerebellopontine angle tumors predicts early and late postoperative facial nerve function

We propose a novel method that predicts facial nerve function (FNF) calculated from the drop and recovery of motor evoked potential (FMEP) amplitude ratio during surgery cerebellopontine angle tumors. enrolled 73 patients with tumor, used biphasic, constant current, suprathreshold stimulation (BCS) protocol to record FMEP orbicularis oris. measured intraoperative minimum-to-baseline (MBR), final-to-baseline (FBR), value (RV). RV was by subtracting MBR FBR. Using those values, we evaluated FNF both at early postoperative (EP) late (LP) periods. successfully obtained 62 readings. Facial palsies occurred in 22 EP period, 14 recovered LP period. Both FBR showed significant correlation good predictive power period for first time. is new useful predictor recovery. can be an outcome periods predicted FMEP.