{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,5]],"date-time":"2026-07-05T04:38:57Z","timestamp":1783226337293,"version":"3.54.6"},"reference-count":40,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"3","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["FOC"],"published-print":{"date-parts":[[2013,3]]},"abstract":"\n Object<\/jats:title>\n During surgeries that put the facial nerve at risk for injury, its function can be continuously monitored by transcranial facial nerve motor evoked potentials (FNMEPs) in facial nerve target muscles. Despite their advantages, FNMEPs are not yet widely used. While most authors use a 50% reduction in FNMEP response amplitudes as a warning criterion, in this paper the authors' approach was to keep the response amplitude constant by increasing the stimulation intensity and to establish a warning criterion based on the \u201cthreshold-level\u201d method.<\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n The authors included 34 consecutive procedures involving 33 adult patients (median age 47 years) in whom FNMEPs were monitored. A threshold increase greater than 20 mA for eliciting FNMEPs in the most reliable facial nerve target muscle was considered a prediction of reduced postoperative facial nerve function, and subsequently a warning was issued to the surgeon. Preoperative and early postoperative function was documented using the House-Brackmann grading system.<\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n Monitoring of FNMEPs was feasible in all 34 surgeries in at least one facial nerve target muscle. The mentalis muscle yielded the best results. The House-Brackmann grade deteriorated in 17 (50%) of 34 cases. The warning criterion was reached in 18 (53%) of 34 cases, which predicted an 83% risk of House-Brackmann grade deterioration. Sensitivity amounted to 88% (CI 64%\u201399%) and specificity to 82% (CI 57%\u201396%). Deterioration of FNMEPs and a worse House-Brackmann grade showed a high degree of association (p < 0.001). The impact of FNMEP monitoring on surgical strategy is exemplified in an illustrative case.<\/jats:p>\n <\/jats:sec>\n \n Conclusions<\/jats:title>\n In surgeries that put the facial nerve at risk, the intraoperative increase in FNMEP stimulation threshold was closely correlated to postoperative facial nerve dysfunction. Monitoring of FNMEPs is a valid indicator of facial nerve function in skull base surgery. It should be used as an adjunct to direct electrical facial nerve stimulation and continuous electromyographic monitoring of facial nerve target muscles.<\/jats:p>\n <\/jats:sec>","DOI":"10.3171\/2012.12.focus12386","type":"journal-article","created":{"date-parts":[[2013,3,1]],"date-time":"2013-03-01T17:10:52Z","timestamp":1362157852000},"page":"E7","source":"Crossref","is-referenced-by-count":36,"title":["Facial nerve motor evoked potentials during skull base surgery to monitor facial nerve function using the threshold-level method"],"prefix":"10.3171","volume":"34","author":[{"given":"Johannes","family":"Sarnthein","sequence":"first","affiliation":[{"name":"Kliniken f\u00fcr Neurochirurgie und"},{"name":"Center for Integrative Human Physiology, Universit\u00e4t Z\u00fcrich, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nader","family":"Hejrati","sequence":"additional","affiliation":[{"name":"Kliniken f\u00fcr Neurochirurgie und"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marian C.","family":"Neidert","sequence":"additional","affiliation":[{"name":"Kliniken f\u00fcr Neurochirurgie und"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alexander M.","family":"Huber","sequence":"additional","affiliation":[{"name":"Ohren-, Nasen-, Hals-, und Gesichtschirurgie, Universit\u00e4tsSpital Z\u00fcrich; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Niklaus","family":"Krayenb\u00fchl","sequence":"additional","affiliation":[{"name":"Kliniken f\u00fcr Neurochirurgie und"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"key":"b1-0340007","series-title":"Acta Neurochir (Wien)","first-page":"1169","article-title":"Quantitative parameters of facial motor evoked potential during vestibular schwannoma surgery predict postoperative facial nerve function","volume":"153","author":"Acioly","year":"2011"},{"issue":"6 Suppl Operative","key":"b2-0340007","series-title":"Neurosurgery","first-page":"354","article-title":"Transcranial electrocortical stimulation to monitor the facial nerve motor function during cerebellopontine angle surgery","volume":"66","author":"Acioly","year":"2010"},{"key":"b3-0340007","series-title":"World Neurosurg","article-title":"Facial nerve monitoring during cerebellopontine angle and skull base tumor surgery: a systematic review from description to current success on function prediction","author":"Acioly","year":"2011"},{"issue":"1 Suppl","key":"b4-0340007","series-title":"Neurosurgery","first-page":"78","article-title":"Localized transcranial electrical motor evoked potentials for monitoring cranial nerves in cranial base surgery","volume":"57","author":"Akagami","year":"2005"},{"issue":"2 Suppl","key":"b5-0340007","series-title":"J Neurosurg","first-page":"161","article-title":"Threshold-level repetitive transcranial electrical stimulation for intraoperative monitoring of central motor conduction","volume":"95","author":"Calancie","year":"2001"},{"key":"b6-0340007","series-title":"Spine (Phila Pa 1976)","first-page":"406","article-title":"Alarm criteria for motor-evoked potentials: what's wrong with the \u201cpresence-or-absence\u201d approach?","volume":"33","author":"Calancie","year":"2008"},{"key":"b7-0340007","series-title":"Clin Neurophysiol","first-page":"588","article-title":"Intraoperative facial motor evoked potential monitoring with transcranial electrical stimulation during skull base surgery","volume":"116","author":"Dong","year":"2005"},{"key":"b8-0340007","series-title":"J Neurol Neurosurg Psychiatry","first-page":"1066","article-title":"Facial nerve motor-evoked potential monitoring during skull base surgery predicts facial nerve outcome","volume":"79","author":"Fukuda","year":"2008"},{"key":"b9-0340007","series-title":"Skull Base","first-page":"429","article-title":"Intraoperative monitoring of motor evoked potential for the facial nerve using a cranial peg-screw electrode and a \u201cthreshold-level\u201d stimulation method","volume":"20","author":"Goto","year":"2010"},{"key":"b10-0340007","series-title":"Otolaryngol Head Neck Surg","first-page":"146","article-title":"Facial nerve grading system","volume":"93","author":"House","year":"1985"},{"key":"b11-0340007","series-title":"J Neurosurg Anesthesiol","first-page":"13","article-title":"Progressive suppression of motor evoked potentials during general anesthesia: the phenomenon of \u201canesthetic fade.\u201d","volume":"17","author":"Lyon","year":"2005"},{"key":"b12-0340007","series-title":"Clin Neurol Neurosurg","first-page":"872","article-title":"Facial motor evoked potentials in cerebellopontine angle surgery: technique, pitfalls and predictive value","volume":"113","author":"Matthies","year":"2011"},{"key":"b13-0340007","series-title":"Intraoperative Monitoring of Neural Function","first-page":"260","article-title":"Transcranial electrical MEP with muscle recording","volume":"8","author":"Mendiratta","year":"2008"},{"key":"b14-0340007","series-title":"J Neurol Neurosurg Psychiatry","first-page":"417","article-title":"Intraoperative preservation of corticospinal function in the brainstem","volume":"80","author":"Neuloh","year":"2009"},{"key":"b15-0340007","series-title":"Neurosurgery","first-page":"1061","article-title":"Motor evoked potential monitoring with supratentorial surgery","volume":"54","author":"Neuloh","year":"2004"},{"key":"b16-0340007","series-title":"Acta Neurochir (Wien)","first-page":"1753","article-title":"Motorevoked potentials (MEP) during brainstem surgery to preserve corticospinal function","volume":"153","author":"Sarnthein","year":"2011"},{"key":"b17-0340007","series-title":"Neurosurgery","first-page":"302","article-title":"Intraoperative motor evoked potential alteration in intracranial tumor surgery and its relation to signal alteration in postoperative magnetic resonance 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