Intraoperative facial motor evoked potentials monitoring with transcranial electrical stimulation for preservation of facial nerve function in patients with large acoustic neuroma

摘要

＜正＞ Background Although various monitoring techniques have been used routinely in the treatment of the lesions in theskull base,iatrogenic facial paresis or paralysis remains a significant clinical problem.The aim of this study was toinvestigate the effect of intraoperative facial motor evoked potentials monitoring with transcranial electrical stimulation onpreservation of facial nerve function.Method From January to November 2005,19 patients with large acoustic neuroma were treated using intraoperativefacial motor evoked potentials monitoring with transcranial electrical stimulation（TCEMEP）for preservation of facialnerve function.The relationship between the decrease of MEP amplitude after tumor removal and the postoperativefunction of the facial nerve was analyzed.Results MEP amplitude decreased more than 75% in 11 patients,of which 6 presented significant facial paralysis（H-Bgrade 3）,and 5 had mild facial paralysis（H-B grade 2）.In the other 8 patients,whose MEP amplitude decreased lessthan 75%,1 experienced significant facial paralysis,5 had mild facial paralysis,and 2 were normal.Conclusions Intraoperative TCEMEP can be used to predict postoperative function of the facial nerve.The decreasedMEP amplitude above 75 % is an alarm point for possible severe facial paralysis.Chin Med J 2007;120 （4）:323-325