Clinical and functional characteristics of intraoperative motor evoked potentials monitoring in microdiscectomy

Aim. To assess motor evoked potentials parameters in a complex of intraoperative neurophysiological monitoring at the time of discectomy for a herniated intervertebral disc under general anesthesia, to determine their dependence on age, sex, height.Methods. Intraoperative motor evoked potentials monitoring during microdiscectomy under inhalational anesthesia was conducted in 43 patients for the herniated disc at L4-L5 or L5-S1 levels. In all patients, the herniated disc diagnosis was confirmed by the magnetic resonance imaging data. Monitoring was performed using the «Neuro-IOM» device («Neurosoft», Russia). Latency and amplitude of muscle response for m. abductor hallucis and m. tibialis anterior were analyzed.Results.. The obtained data suggest that the motor evoked potentials allow to objectify the presence of motor disorders, which persist at the end of microdiscectomy. The data on the relationship between latency of muscles responses on the side of radiculopathy and the healthy side with patients’ age, body height and weight are obtained. The motor evoked potentials amplitude had a direct correlation with the patients’ body weight. Increase in latency of transcranial motor evoked potentials on the side of the clinical motor fall-out compared with the healthy limb was defined. Due to the expressed variability of motor evoked potentials responses amplitude under general anesthesia, significant differences for a given parameter were not obtained.Conclusion. There is relationship between latency of motor evoked potentials and patients’ age, body height and weight; an increase in the latency of transcranial motor evoked potentials on the side of the clinical motor fall-out compared with the healthy limb was revealed.

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Neuroanesthesia Guidelines for Optimizing Transcranial Motor Evoked Potentials Neuromonitoring During Deformity and Complex Spinal Surgery: A Delphi Consensus Study

Neurosurgery ◽

10.1093/neuros/nyz310_610 ◽

2019 ◽

Vol 66 (Supplement_1) ◽

Author(s):

Corey T Walker ◽

Han Jo Kim ◽

Paul Park ◽

Lawrence Lenke ◽

Justin S Smith ◽

...

Keyword(s):

Spinal Cord ◽

Evoked Potentials ◽

Motor Evoked Potentials ◽

Neurophysiological Monitoring ◽

Delphi Consensus ◽

Optimal Method ◽

Modified Delphi ◽

Spine Surgeon ◽

Transcranial Motor Evoked Potentials ◽

Inhaled Anesthetic

Abstract INTRODUCTION Intraoperative neurophysiological monitoring of transcranial motor evoked potentials (MEPs) provides the most reliable method for assessing spinal cord functional integrity during deformity and other complex spinal surgeries. MEPs are affected by pharmacological and physiological parameters. It is the responsibility of the spine surgeon and neuroanesthesia team to understand how they can best maintain high quality MEP signals throughout surgery. Nevertheless, varying approaches to neuroanesthesia are seen in clinical practice. METHODS We identified 19 international spinal deformity expert teams for participation in our study. A modified Delphi process utilizing 2 rounds of surveying was performed. Greater than 50% and 75% agreement on the final statements was considered achieving “agreement” and “consensus,” respectively. RESULTS Anesthesia regimens and protocols were obtained from the expert centers. A large amount of variability in these centers was witnessed. Two rounds of consensus surveying were then performed, and all centers participated in both rounds of the surveying. Consensus was obtained in 12 of 15 statements and majority agreement in 2 of the remaining. Agreement on specific safe neuroanesthesia practices in the setting of MEP monitoring was obtained. Total intravenous anesthesia (TIVA) was identified as the optimal method of maintenance with few centers allowing for low MAC concentrations of inhaled anesthetic. While no strict cutoff values of propofol concentrations or opioid doses were identified, most centers advocated for less than 150 mcg/kg/min of propofol with titration to the lowest dose that maintains appropriate anesthesia depth based on bispectral index or electroencephalography awareness monitoring. Utilization of adjuvant intravenous anesthetics, including ketamine and lidocaine, may help to reduce propofol and opioid requirements without negatively impacting MEP signals. Low-dose dexmedetomidine was also routinely used with the same purpose, but with knowledge that higher doses may be suppressive. Maintenance of blood pressure parameters near the patient's preoperative baseline or with mean arterial pressure greater than 80 mmHg ensures appropriate spinal cord perfusion and prevents loss of MEPs. CONCLUSION Spine surgeons and their neuroanesthesia teams should be familiar with the methods for optimizing IOM of MEPs during deformity and complex spinal cases. While variability in practices exist, consensus exists among international deformity centers regarding best practices.

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Improved potential quality of intraoperative transcranial motor-evoked potentials by navigated electrode placement compared to the conventional ten-twenty system

Neurosurgical Review ◽

10.1007/s10143-021-01568-4 ◽

2021 ◽

Author(s):

Arthur Wagner ◽

Sebastian Ille ◽

Caspar Liesenhoff ◽

Kaywan Aftahy ◽

Bernhard Meyer ◽

...

Keyword(s):

Evoked Potentials ◽

Intraoperative Monitoring ◽

Primary Motor Cortex ◽

Motor Evoked Potentials ◽

Vascular Lesions ◽

Electrode Placement ◽

Neurophysiological Monitoring ◽

Electrode Pair ◽

Significant Difference ◽

Transcranial Motor Evoked Potentials

AbstractIntraoperative neurophysiological monitoring of transcranial motor-evoked potentials (tcMEPs) may fail to produce a serviceable signal due to displacements by mass lesions. We hypothesize that navigated placement of stimulation electrodes yields superior potential quality for tcMEPs compared to the conventional 10–20 placement. We prospectively included patients undergoing elective cranial surgery with intraoperative monitoring of tcMEPs. In addition to electrode placement as per the 10–20 system, an electrode pair was placed at a location corresponding to the hand knob area of the primary motor cortex (M1) for every patient, localized by a navigation system during surgical setup. Twenty-five patients undergoing elective navigated surgery for intracranial tumors (n = 23; 92%) or vascular lesions (n = 2; 8%) under intraoperative monitoring of tcMEPs were included between June and August 2019 at our department. Stimulation and recording of tcMEPs was successful in every case for the navigated electrode pair, while stimulation by 10–20 electrodes did not yield baseline tcMEPs in two cases (8%) with anatomical displacement of the M1. While there was no significant difference between baseline amplitudes, mean potential quality decreased significantly by 88.3 µV (− 13.5%) for the 10–20 electrodes (p = 0.004) after durotomy, unlike for the navigated electrodes (− 28.6 µV [− 3.1%]; p = 0.055). For patients with an anatomically displaced M1, the navigated tcMEPs declined significantly less after durotomy (− 3.6% vs. 10–20: − 23.3%; p = 0.038). Navigated placement of tcMEP electrodes accounts for interindividual anatomical variance and pathological dislocation of the M1, yielding more consistent potentials and reliable potential quality.

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Tetanic Stimulation of the Peripheral Nerve before Transcranial Electrical Stimulation Can Enlarge Amplitudes of Myogenic Motor Evoked Potentials during General Anesthesia with Meeting Abstracts

Anesthesiology ◽

10.1097/00000542-200504000-00007 ◽

2005 ◽

Vol 102 (4) ◽

pp. 733-738 ◽

Cited By ~ 30

Author(s):

Meiko Kakimoto ◽

Masahiko Kawaguchi ◽

Yuri Yamamoto ◽

Satoki Inoue ◽

Toshinori Horiuchi ◽

...

Keyword(s):

Peripheral Nerve ◽

Evoked Potentials ◽

General Anesthesia ◽

Neuromuscular Blockade ◽

Motor Evoked Potentials ◽

Transcranial Electrical Stimulation ◽

Transcranial Stimulation ◽

Tetanic Stimulation ◽

Abductor Hallucis ◽

Abductor Hallucis Muscle

Background Neuromuscular blockade can suppress myogenic motor evoked potentials (MEPs). The authors hypothesized that tetanic stimulation (TS) of the peripheral nerve before transcranial stimulation may enhance myogenic MEPs during neuromuscular blockade. In the current study, the authors evaluated MEP augmentations by TS at different levels of duration, posttetanic interval, neuromuscular blockade, and stimulus intensity. Methods Thirty-two patients undergoing propofol-fentanyl-nitrous oxide anesthesia were examined. Train-of-five stimulation was delivered to C3-C4, and MEPs were recorded from the abductor hallucis muscle. In study 1, TS with a duration of 1, 3, or 5 s was delivered at 50 Hz to the tibial nerve 1, 3, or 5 s (interval) before transcranial stimulation, and the effects of TS on MEP amplitude were evaluated. In study 2, TS-induced MEP augmentations were evaluated at the neuromuscular blockade level (%T1) of 50% or 5%. In study 3, MEP augmentations by TS at stimulus intensities of 0, 5, 25, and 50 mA were evaluated. Results The application of TS significantly enlarged the amplitudes of MEPs at the combinations of duration (3, 5 s) and interval (1, 3, 5 s) compared with those without TS. TS-induced MEP augmentations were similarly observed at %T1 of both 50% and 5%. TS-induced MEP augmentations were observed at stimulus intensities of 25 and 50 mA. Conclusions The results indicate that TS of the peripheral nerve before transcranial stimulation can enlarge the amplitude of MEPs during general anesthesia with neuromuscular blockade. TS of the peripheral nerve can be intraoperatively applied as a method to augment myogenic MEP responses.

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Faculty Opinions recommendation of Transcranial Motor-Evoked Potentials Are More Readily Acquired Than Somatosensory-Evoked Potentials in Children Younger Than 6 Years.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.725891191.793534699 ◽

2017 ◽

Author(s):

John Bebawy

Keyword(s):

Evoked Potentials ◽

Somatosensory Evoked Potentials ◽

Motor Evoked Potentials ◽

Transcranial Motor Evoked Potentials

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Influence of hemorrhage and subsequent fluid resuscitation on transcranial motor-evoked potentials under desflurane anesthesia in a swine model

Journal of Clinical Monitoring and Computing ◽

10.1007/s10877-020-00644-2 ◽

2021 ◽

Author(s):

Tadayoshi Kurita ◽

Shingo Kawashima ◽

Mohamed Mathar Sahib Ibrahim Khaleelullah ◽

Yoshiki Nakajima

Keyword(s):

Evoked Potentials ◽

Fluid Resuscitation ◽

Motor Evoked Potentials ◽

Swine Model ◽

Transcranial Motor Evoked Potentials

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Sensitivity of Myogenic and Epidural Transcranial Motor Evoked Potentials for Detection of Acute Spinal Cord Ischemia

Anesthesiology ◽

10.1097/00000542-199409001-00894 ◽

1994 ◽

Vol 81 (SUPPLEMENT) ◽

pp. A895 ◽

Cited By ~ 1

Author(s):

P. de Haan ◽

C. J. Kalkman ◽

L. Ubags ◽

J. C. Drummond

Keyword(s):

Spinal Cord ◽

Evoked Potentials ◽

Motor Evoked Potentials ◽

Spinal Cord Ischemia ◽

Transcranial Motor Evoked Potentials

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Transesophageal versus transcranial motor evoked potentials to monitor spinal cord ischemia

Journal of Thoracic and Cardiovascular Surgery ◽

10.1016/j.jtcvs.2015.08.120 ◽

2016 ◽

Vol 151 (2) ◽

pp. 509-517 ◽

Cited By ~ 4

Author(s):

Kazumasa Tsuda ◽

Norihiko Shiiya ◽

Daisuke Takahashi ◽

Kazuhiro Ohkura ◽

Katsushi Yamashita ◽

...

Keyword(s):

Spinal Cord ◽

Evoked Potentials ◽

Motor Evoked Potentials ◽

Spinal Cord Ischemia ◽

Transcranial Motor Evoked Potentials

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Intra-operative neurophysiological monitoring

Journal of Neuroanaesthesiology and Critical Care ◽

10.4103/2348-0548.165035 ◽

2015 ◽

Vol 02 (03) ◽

pp. 179-192

Author(s):

Zulfiqar Ali ◽

Parmod Bithal

Keyword(s):

Evoked Potentials ◽

Surgical Procedures ◽

Complication Rate ◽

Motor Evoked Potentials ◽

Neurological Complication ◽

Intraoperative Neurophysiological Monitoring ◽

Neurophysiological Monitoring ◽

Sensory Evoked Potentials ◽

Sensory Evoked

AbstractIntraoperative neurophysiological monitoring has achieved importance due to complexity of cranio-spinal surgical procedures being performed frequently these days. Many studies have proven a decreased neurological complication rate after its introduction. It is broadly of two types: Sensory evoked potentials and motor evoked potentials which are further sub-divided. Its use during surgery requires a controlled anaesthesia technique with no or minimal influence on its recording. Its success depends upon three way communication among the surgeon the neurophysiologist and the anaesthesiologist.

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