• Sanjiv K Bhimrao, Trung N Le, Charles C Dong, Serge Makarenko, Sarin Wongprasartsuk, Brian D Westerberg, and Ryojo Akagami.
• *Division of Otolaryngology-Head & Neck Surgery†Division of Neurosurgery, Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada.
• Otol. Neurotol. 2016 Sep 1; 37 (8): 1162-7.

ObjectiveTo determine whether transcranial electrical stimulation-induced facial motor-evoked potential (FMEP) monitoring of the facial nerve (FN) during vestibular schwannoma (VS) tumor resection can predict both immediate and 1 year postoperative FN functional outcome.DesignProspective consecutive non-comparative observational case series.SettingTertiary referral center.Main Outcome MeasuresFacial function, immediate post operation and at 1 year using House-Brackmann (HB) grading scale.MethodsThe study included 367 consecutive patients (men 178; women 189; age 13-81 years) monitored during primary sporadic VS microsurgery between November 2002 and April 2015. Neurofibromatosis type II, revision surgery, previous radiotherapy treatment, preoperative facial nerve weakness, and non-VS cases were excluded retrospectively during analysis of data. Data of facial function were missing from eight patients at 1 year and were excluded. The correlation between the final-to-baseline FMEP ratio and immediate and 1 year facial nerve function was examined.ResultsUsing logistic regression model, the cut-off points of FMEP ratio were 0.62 (PPV 0.96) and 0.59 (PPV 0.98) which predicted satisfactory FN function (HB grades 1 or 2) immediately postoperative and at 1 year after surgery, respectively.ConclusionTranscranial electrical stimulation FMEP is a valuable tool for monitoring facial nerve function during resection of vestibular schwannoma. Maintaining a FMEP event-to-baseline ratio of 60% or greater is predictive of satisfactory long-term FN function.

29 keywords...

hide…