Methodology for intraoperatively eliciting motor evoked potentials in the vocal muscles by electrical stimulation of the corticobulbar tract

Deletis, Vedran; Fernández-Conejero, Isabel; Ulkatan, Sedat; Costantino, Peter D.

doi:10.1016/j.clinph.2008.11.013

Cited by 66 publications

(43 citation statements)

References 13 publications

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“…in contrast, skull base tumor patients require a multiple pulse stimulation train to elicit facial Mep responses and the response thresholds in this group were much higher. the requirement for multipulse-induced facial Mep in non-hfS subjects confirms that previously described for corticobulbar Mep of the facial nerve as well as the vagus nerve [14][15][16]21 .…”

Section: Figure 1: Examples Of Facial Meps Elicited Using Single Pulssupporting

confidence: 73%

“…it has been argued that a facial muscle Mep response to single pulse transcranial stimulation must be artifactual because temporal summation is required to evoke "true" corticobulbar responses 13,14,16,21 . in the present analysis we rigorously excluded any results where there was even small degree of muscle depolarization occurring in advance of 10 ms. responses with latencies < 10 ms would indicate extracranial activation of the facial nerve 14,16,21 .…”

Section: Figure 1: Examples Of Facial Meps Elicited Using Single Pulsmentioning

confidence: 99%

“…in the present analysis we rigorously excluded any results where there was even small degree of muscle depolarization occurring in advance of 10 ms. responses with latencies < 10 ms would indicate extracranial activation of the facial nerve 14,16,21 . however, when we applied a single pulse stimulation paradigm in hfS patients we observed facial Mep responses 76% of the time using the C3/C4-Cz stimulation montage and 86% of the time using the C3/C4 montage.…”

Section: Figure 1: Examples Of Facial Meps Elicited Using Single Pulsmentioning

confidence: 99%

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Facial Motor Neuron Excitability in Hemifacial Spasm: A Facial MEP Study

Wilkinson

Kaufmann

2014

Can. J. Neurol. Sci.

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hemifacial spasm (hfS) is an involuntary and irregular spasm of the facial muscles innervated by the Vii cranial nerve that typically progresses in severity and extent over time. the etiology of hfS has been attributed to vascular compression of the facial nerve at the root exit zone (reZ) 1 . this led to the development of surgical microvascular decompression (MVd) of this cranial nerve by Jannetta and colleagues 2 for the treatment of hfS. this group also advocated the use of intraoperative neurophysiological monitoring to minimize iatrogenic injuries as well as an aid to the surgical procedure. Specifically, Moller and Janetta described the lateral spread (lS) response, an electromyographic hallmark specific to hfS [3][4][5] . this lS response is produced by electrical stimulation of one branch of the facial nerve and observing the electromyographic response in the facial musculature innervated by a different branch of the nerve.the neurophysiological mechanism of the lS response has been hotly debated between those that favor a peripheral mechanism 6,7 versus a centrally mediated hypothesis [3][4][5] . We sought to explore this debate by observing facial motor evoked potentials and lS responses during MVd surgeries for hfS 8 . We found that facial motor evoked potential (Mep) amplitude and duration became markedly reduced, coincident with the lS response, following the surgical microvascular decompression AbStRAct: Introduction: hemifacial spasm (hfS) may be due to peripheral axon ephapsis or central motor neuron hyperexcitability. low facial motor evoked potential (Mep) thresholds or Mep responses to single pulse stimulation (normally multipulse stimulation is needed) may support the central hypothesis. Methods: We retrospectively compared response thresholds for facial Meps in 65 patients undergoing surgical microvascular decompression (MVd) for hfS and 29 patients undergoing surgery for skull base tumors. Results: Single pulse stimulation elicited facial Mep in up to 87% of hfS patients whereas only 10% of tumor patients responded to single pulse stimulation. When comparing facial Mep thresholds using multi-pulse stimulus trains the voltage required in the hfS group were significantly lower then in skull base tumor patients (p < 0.001). the Mep latencies and amplitudes at threshold stimulation were similar between the two groups. Conclusions: these results suggest the facial corticobulbar pathway demonstrates enhanced excitability in hfS.RéSuMé: excitabilité du neurone moteur facial dans le spasme hémifacial : étude des PéM. Contexte : le spasme hémifacial (Shf) peut être dû à un éphapse au niveau d'axones périphériques ou à une hyperexcitabilité du neurone moteur central. le fondement de l'hypothèse centrale repose sur des seuils bas de potentiels évoqués moteurs (pÉM) faciaux ou des réponses pÉM à une impulsion unique (normalement, plusieurs impulsions sont nécessaires). Méthode : nous avons comparé rétrospectivement les seuils de réponse des pÉM faciaux chez 65 patients soumis à une chirurgie de décomp...

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Section: Figure 1: Examples Of Facial Meps Elicited Using Single Pulssupporting

confidence: 73%

Section: Figure 1: Examples Of Facial Meps Elicited Using Single Pulsmentioning

confidence: 99%

Section: Figure 1: Examples Of Facial Meps Elicited Using Single Pulsmentioning

confidence: 99%

See 1 more Smart Citation

Facial Motor Neuron Excitability in Hemifacial Spasm: A Facial MEP Study

Wilkinson

Kaufmann

2014

Can. J. Neurol. Sci.

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“…• The CoMEPs are elicited from the vocal and cricothyroid muscles during electrical and magnetic stimulation of the M1 for laryngeal muscles in a group of patients and healthy subjects [6,[9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…tumor process, arteriovascular malformations). Furthermore, future studies might correlate preoperative, intraoperative and postoperative speech status in patients operated on during awake brain surgery (with application of intraoperative methodology for eliciting CoMEPs and LLRs from laryngeal muscles while mapping M1 for laryngeal muscles and Broca's area) [7,[9][10][11] with and without preoperative nTMS mappings. Ultimately, future studies may correlate findings of fMRI protocols with this recent nTMS methodology for preoperative mapping of the M1 and Broca's area.…”

Section: Preoperative Mapping Of Primary Motor and Broca's Area With mentioning

confidence: 99%

Preoperative Mapping of Primary Motor and Broca’s Area with Transcranial Magnetic Stimulation (TMS) – Case Report

Vidaković¹,

Vujović²

2017

J Neurol Exp Neurosci

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Best Practices in Facial Nerve Monitoring

et al. 2021

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Objectives/HypothesisFacial nerve monitoring (FNM) has evolved into a widely used adjunct for many surgical procedures along the course of the facial nerve. Even though majority opinion holds that FNM reduces the incidence of iatrogenic nerve injury, there are few if any studies yielding high‐level evidence and no practice guidelines on which clinicians can rely. Instead, a review of the literature and medicolegal cases reveals significant variations in methodology, training, and clinical indications.Study DesignLiterature review and expert opinion.MethodsGiven the lack of standard references to serve as a resource for FNM, we assembled a multidisciplinary group of experts representing more than a century of combined monitoring experience to synthesize the literature and provide a rational basis to improve the quality of patient care during FNM.ResultsOver the years, two models of monitoring have become well‐established: 1) monitoring by the surgeon using a stand‐alone device that provides auditory feedback of facial electromyography directly to the surgeon, and 2) a team, typically consisting of surgeon, technologist, and interpreting neurophysiologist. Regardless of the setting and the number of people involved, the reliability of monitoring depends on the integration of proper technical performance, accurate interpretation of responses, and their timely application to the surgical procedure. We describe critical steps in the technical set‐up and provide a basis for context‐appropriate interpretation and troubleshooting of recorded signals.ConclusionsWe trust this initial attempt to describe best practices will serve as a basis for improving the quality of patient care while reducing inappropriate variations.Level of Evidence4 Laryngoscope, 131:S1–S42, 2021

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Methodology for intraoperatively eliciting motor evoked potentials in the vocal muscles by electrical stimulation of the corticobulbar tract

Cited by 66 publications

References 13 publications

Facial Motor Neuron Excitability in Hemifacial Spasm: A Facial MEP Study

Facial Motor Neuron Excitability in Hemifacial Spasm: A Facial MEP Study

Preoperative Mapping of Primary Motor and Broca’s Area with Transcranial Magnetic Stimulation (TMS) – Case Report

Best Practices in Facial Nerve Monitoring

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