scholarly journals Bilateral and Optimistic Warning Paradigms Improve the Predictive Power of Intraoperative Facial Motor Evoked Potentials during Vestibular Schwannoma Surgery

Cancers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 6196
Author(s):  
Tobias Greve ◽  
Liang Wang ◽  
Sophie Katzendobler ◽  
Lucas L. Geyer ◽  
Christian Schichor ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Vestibular Schwannoma ◽  
False Positive ◽  
Motor Evoked Potentials ◽  
False Positive Rate ◽  
Tumor Resection ◽  
Outcome Variable ◽  
Facial Muscle ◽  
Threshold Method ◽  
Warning Criteria

Facial muscle corticobulbar motor evoked potentials (FMcoMEPs) are used to monitor facial nerve integrity during vestibular schwannoma resections to increase maximal safe tumor resection. Established warning criteria, based on ipsilateral amplitude reduction, have the limitation that the rate of false positive alarms is high, in part because FMcoMEP changes occur on both sides, e.g., due to brain shift or pneumocephalus. We retrospectively compared the predictive value of ipsilateral-only warning criteria and actual intraoperative warnings with a novel candidate warning criterion, based on “ipsilateral versus contralateral difference in relative stimulation threshold increase, from baseline to end of resection” (BilatMT ≥ 20%), combined with an optimistic approach in which a warning would be triggered only if all facial muscles on the affected side deteriorated. We included 60 patients who underwent resection of vestibular schwannoma. The outcome variable was postoperative facial muscle function. Retrospectively applying BilatMT, with the optimistic approach, was found to have a significantly better false positive rate, which was much lower (9% at day 90) than the traditionally used ipsilateral warning criteria (>20%) and was also lower than actual intraoperative warnings. This is the first report combining the threshold method with an optimistic approach in a bilateral multi-facial muscle setup. This method could substantially reduce the rate of false positive alarms in FMcoMEP monitoring.

scholarly journals Sensitivity and Negative Predictive Value of Motor Evoked Potentials of the Facial Nerve

2021 ◽  
Author(s):  
Nicolas Bovo ◽  
Shahan Momjian ◽  
Renato Gondar ◽  
Philippe Bijlenga ◽  
Karl Schaller ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Evoked Potentials ◽  
Negative Predictive Value ◽  
Patient Group ◽  
Vestibular Schwannoma ◽  
Predictive Value ◽  
Cerebellopontine Angle ◽  
Motor Evoked Potentials ◽  
Vestibular Schwannomas ◽  
Predictive Values

Abstract Objective The objective of this study was to determine the performance of the standard alarm criterion of motor evoked potentials (MEPs) of the facial nerve in surgeries performed for resections of vestibular schwannomas or of other lesions of the cerebellopontine angle. Methods This retrospective study included 33 patients (16 with vestibular schwannomas and 17 with other lesions) who underwent the resection surgery with transcranial MEPs of the facial nerve. A reproducible 50% decrease in MEP amplitude, resistant to a 10% increase in stimulation intensity, was applied as the alarm criterion during surgery. Facial muscular function was clinically evaluated with the House–Brackmann score (HBS), pre- and postsurgery at 3 months. Results In the patient group with vestibular schwannoma, postoperatively, the highest sensitivity and negative predictive values were found for a 30% decrease in MEP amplitude, that is, a criterion stricter than the 50% decrease in MEP amplitude criterion, prone to trigger more warnings, used intraoperatively. With this new criterion, the sensitivity would be 88.9% and the negative predictive value would be 85.7%. In the patient group with other lesions of the cerebellopontine angle, the highest sensitivity and negative predictive values were found equally for 50, 60, or 70% decrease in MEP amplitude. With these criteria, the sensitivities and the negative predictive values would be 100.0%. Conclusion Different alarm criteria were found for surgeries for vestibular schwannomas and for other lesions of the cerebellopontine angle. The study consolidates the stricter alarm criterion, that is, a criterion prone to trigger early warnings, as found previously by others for vestibular schwannoma surgeries (30% decrease in MEP amplitude).

scholarly journals A novel threshold criterion in transcranial motor evoked potentials during surgery for gliomas close to the motor pathway

2016 ◽  
Vol 125 (4) ◽  
pp. 795-802 ◽  
Author(s):  
Tammam Abboud ◽  
Miriam Schaper ◽  
Lasse Dührsen ◽  
Cindy Schwarz ◽  
Nils Ole Schmidt ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Tumor Resection ◽  
Threshold Level ◽  
Neurological Deterioration ◽  
Motor Deficit ◽  
Percentage Increase ◽  
Glioma Surgery ◽  
Leg Muscles ◽  
Threshold Criterion

OBJECTIVE Warning criteria for monitoring of motor evoked potentials (MEP) after direct cortical stimulation during surgery for supratentorial tumors have been well described. However, little is known about the value of MEP after transcranial electrical stimulation (TES) in predicting postoperative motor deficit when monitoring threshold level. The authors aimed to evaluate the feasibility and value of this method in glioma surgery by using a new approach for interpreting changes in threshold level involving contra- and ipsilateral MEP. METHODS Between November 2013 and December 2014, 93 patients underwent TES-MEP monitoring during resection of gliomas located close to central motor pathways but not involving the primary motor cortex. The MEP were elicited by transcranial repetitive anodal train stimulation. Bilateral MEP were continuously evaluated to assess percentage increase of threshold level (minimum voltage needed to evoke a stable motor response from each of the muscles being monitored) from the baseline set before dural opening. An increase in threshold level on the contralateral side (facial, arm, or leg muscles contralateral to the affected hemisphere) of more than 20% beyond the percentage increase on the ipsilateral side (facial, arm, or leg muscles ipsilateral to the affected hemisphere) was considered a significant alteration. Recorded alterations were subsequently correlated with postoperative neurological deterioration and MRI findings. RESULTS TES-MEP could be elicited in all patients, including those with recurrent glioma (31 patients) and preoperative paresis (20 patients). Five of 73 patients without preoperative paresis showed a significant increase in threshold level, and all of them developed new paresis postoperatively (transient in 4 patients and permanent in 1 patient). Eight of 20 patients with preoperative paresis showed a significant increase in threshold level, and all of them developed postoperative neurological deterioration (transient in 4 patients and permanent in 4 patients). In 80 patients no significant change in threshold level was detected, and none of them showed postoperative neurological deterioration. The specificity and sensitivity in this series were estimated at 100%. Postoperative MRI revealed gross-total tumor resection in 56 of 82 patients (68%) in whom complete tumor resection was attainable; territorial ischemia was detected in 4 patients. CONCLUSIONS The novel threshold criterion has made TES-MEP a useful method for predicting postoperative motor deficit in patients who undergo glioma surgery, and has been feasible in patients with preoperative paresis as well as in patients with recurrent glioma. Including contra- and ipsilateral changes in threshold level has led to a high sensitivity and specificity.

Incidence of ischemic complications and technical nuances of arteries protection for insular gliomas resection.

2021 ◽  
Author(s):  
Zonggang Hou ◽  
Zhenxing Huang ◽  
Zhenye Li ◽  
Gen Li ◽  
Yaokai Xu ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Diffusion Weighted Imaging ◽  
Motor Evoked Potentials ◽  
Tumor Resection ◽  
Neurological Deficits ◽  
Motor Deficits ◽  
Acute Ischemia ◽  
Critical Ischemia ◽  
Diffusion Weighted ◽  
Ischemic Complications

Abstract Insular gliomas remain surgically challenge due to their complex anatomical position and microvascular supply. The incidence of ischemic complications is a risk that should not be ignored. The goal of this study was to analyze the incidence of ischemia and its risk factors, and also describe a single surgeon's arteries protection experience of insular gliomas resection. The authors studied 75 consecutive cases of insular gliomas that underwent transcortical tumor resection in their division. Analysis included pre- and postoperative demographic, clinical, radiological including diffusion weighted imaging (DWI), as well as intraoperative neurophysiology data, and functional outcomes. Strategies such as “Residual Triangle”, “Basal Ganglia Reconstruction” and “Sculpting Technique” were used to protect lateral lenticulostriate arteries and main branches of M2 for maximal tumor resection according to the different classification of Berger-Sinai. Postoperative diffusion-weighted imaging showed acute ischemia in 44 patients, only 9 of whom developed new motor deficits. Flat inner edge (OR 0.144 95% CI 0.024, 0.876), and motor evoked potentials (MEPs) (<50%) (OR 18.182, 95% CI 3.311, 100.00) were determined to have significant associations with postoperative Critical Ischemia, which located in the posterior limb of the internal capsule or corona radiata. For insular gliomas resection, the protection of main branches of MCA is important. Insular gliomas resection might be with high incidence of ischemia uncovered by DWI which not always result in neurological deficits. Their own strategies maybe the feasible technical nuances allow the surgeon to achieve a thorough and safe resection. Motor evoked potentials is essential for its resection.

Spinal Cord Monitoring

2016 ◽  
pp. 798-832
Author(s):  
Jeffrey A. Strommen ◽  
Andrea J. Boon
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Motor Evoked Potentials ◽  
Spinal Cord Tumor ◽  
Tumor Resection ◽  
Neurophysiological Monitoring ◽  
Spinal Root ◽  
Compound Muscle Action Potentials ◽  
Aneurysm Repair ◽  
Aortic Aneurysm Repair

Intraoperative neurophysiological monitoring is a valuable tool to preserve spinal cord and spinal root integrity during surgical procedures. A monitoring plan may include somatosensory evoked potentials (SEP), motor evoked potentials (MEP), compound muscle action potentials (CMAP), and electromyography (EMG). Such monitoring is individualized depending on the preoperative clinical deficit, the structures most at risk, and the surgical and anesthesia plan. The most common use of these techniques is in primary spine disease, where the spinal cord pathways will typically be monitored with both MEP and SEP. In cervical or lumbar spine surgeries, EMG monitoring will help protect the nerve root either during decompression or during pedicle screw placement. Monitoring during spinal cord tumor resection or vascular procedures (such as aortic aneurysm repair) not only helps prevent deficit, but also allows the surgeon to proceed with confidence and not unnecessarily terminate the procedure.

scholarly journals The influence of depth of anesthesia and blood pressure on muscle recorded motor evoked potentials in spinal surgery. A prospective observational study protocol

2021 ◽  
Author(s):  
Sebastiaan E. Dulfer ◽  
M. M. Sahinovic ◽  
F. Lange ◽  
F. H. Wapstra ◽  
D. Postmus ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Evoked Potentials ◽  
Study Protocol ◽  
False Positive ◽  
Motor Evoked Potentials ◽  
Neurological Injury ◽  
Neurophysiological Monitoring ◽  
Transcranial Electrical Stimulation ◽  
Depth Of Anesthesia ◽  
Registration Number

AbstractFor high-risk spinal surgeries, intraoperative neurophysiological monitoring (IONM) is used to detect and prevent intraoperative neurological injury. The motor tracts are monitored by recording and analyzing muscle transcranial electrical stimulation motor evoked potentials (mTc-MEPs). A mTc-MEP amplitude decrease of 50–80% is the most common warning criterion for possible neurological injury. However, these warning criteria often result in false positive warnings. False positives may be caused by inadequate depth of anesthesia and blood pressure on mTc-MEP amplitudes. The aim of this paper is to validate the study protocol in which the goal is to investigate the effects of depth of anesthesia (part 1) and blood pressure (part 2) on mTc-MEPs. Per part, 25 patients will be included. In order to investigate the effects of depth of anesthesia, a processed electroencephalogram (pEEG) monitor will be used. At pEEG values of 30, 40 and 50, mTc-MEP measurements will be performed. To examine the effect of blood pressure on mTc-MEPs the mean arterial pressure will be elevated from 60 to 100 mmHg during which mTc-MEP measurements will be performed. We hypothesize that by understanding the effects of depth of anesthesia and blood pressure on mTc-MEPs, the mTc-MEP monitoring can be interpreted more reliably. This may contribute to fewer false positive warnings. By performing this study after induction and prior to incision, this protocol provides a unique opportunity to study the effects of depths of anesthesia and blood pressure on mTc-MEPs alone with as little confounders as possible.Trial registration number NL7772.

scholarly journals Susceptibility of Transcranial Electric Motor-evoked Potentials to Varying Targeted Blood Levels of Dexmedetomidine during Spine Surgery

2010 ◽  
Vol 112 (6) ◽  
pp. 1364-1373 ◽  
Author(s):  
Mohamed Mahmoud ◽  
Senthilkumar Sadhasivam ◽  
Shelia Salisbury ◽  
Todd G. Nick ◽  
Beverly Schnell ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Electric Motor ◽  
Motor Evoked Potentials ◽  
Plasma Concentrations ◽  
Motor Evoked Potential ◽  
Secondary Outcome ◽  
Outcome Variable ◽  
Blood Levels ◽  
Dependent Manner ◽  
Significant Attenuation

Background Dexmedetomidine has been increasingly used as an adjunct to opioid-propofol total intravenous anesthesia (TIVA). The authors tested the hypothesis and found that clinically relevant blood levels of dexmedetomidine do not produce significant attenuation of the amplitude of transcranial electric motor-evoked potentials either independently or by interaction with propofol in a dose-dependent manner. Methods The authors planned to recruit 72 patients with idiopathic scoliosis who had posterior spine fusion surgery during propofol and remifentanil TIVA with dexmedetomidine as an adjunct. However, the authors terminated the study after enrolling 44 patients because of change in surgical technique. Before administering dexmedetomidine, baseline transcranial electric motor-evoked potentials were acquired during TIVA with remifentanil and propofol. Patients were randomized to varying targeted blood levels of dexmedetomidine (0.4, 0.6, and 0.8 ng/ml) and propofol (2.5, 3.75, and 5 microg/ml) using a factorial design. The primary outcome variable was amplitude of transcranial electric motor-evoked potential. The secondary outcome was amplitude of cortical somatosensory-evoked potentials. Results Of the 44 recruited patients, 40 completed the study, and their data were analyzed. The administration of dexmedetomidine in increasing doses as an adjunct to propofol-based TIVA caused a clinically and statistically significant attenuation of amplitudes of transcranial electric motor-evoked potentials. Conclusion The authors conclude that under the stimulation conditions used, dexmedetomidine as an anesthetic adjunct to propofol-based TIVA at clinically relevant target plasma concentrations (0.6-0.8 ng/ml) can significantly attenuate the amplitude of transcranial electric motor-evoked potentials.

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