title: The value of intraoperative facial nerve electromyography in predicting facial nerve function after vestibular schwannoma surgery.
abstract: The prognostic significance of intraoperative facial nerve electromyography (EMG) changes is not well-established in vestibular schwannoma (VS) surgery. We studied facial nerve EMG with a threshold >0.05mA and performed subgroup analyses based on tumor size, resection approach, and extent of resection, for prediction of long-term facial nerve outcome. A total of 477 surgically treated VS patients were included. Elevated stimulation threshold exceeding >0.05mA is a highly specific (90%), but very insensitive (29%) finding in this cohort. The positive predictive value and negative predictive values (NPV) of facial nerve EMG for detection of permanent facial palsy are 68% and 63%, respectively. The NPV decreased with increasing tumor size (72% versus [vs.] 64% vs. 53%) due to the increasing prevalence of post-operative facial nerve palsy in these patients. In conclusion, while facial nerve EMG is a critical adjunct for locating the facial nerve intraoperatively, its predictive value for facial nerve function remains to be determined.
authors.affiliation: Department of Neurological Surgery, University of California at San Francisco, San Francisco, CA 94143, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Sughrue
authors.forename: Rajwant
authors.initials: R
authors.lastname: Kaur
authors.forename: Ari J
authors.initials: AJ
authors.lastname: Kane
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Rutkowski
authors.forename: Gurvinder
authors.initials: G
authors.lastname: Kaur
authors.forename: Isaac
authors.initials: I
authors.lastname: Yang
authors.forename: Lawrence H
authors.initials: LH
authors.lastname: Pitts
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Parsa
mesh_terms: D015331:Cohort Studies; D004576:Electromyography / Q000379:methods; D005154:Facial Nerve / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D009464:Neuroma, Acoustic / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D011183:Postoperative Complications / Q000175:diagnosis / Q000503:physiopathology*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies