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.

scholarly journals A comparison between threshold criterion and amplitude criterion in transcranial motor evoked potentials during surgery for supratentorial lesions

2019 ◽  
Vol 131 (3) ◽  
pp. 740-749 ◽  
Author(s):  
Tammam Abboud ◽  
Cindy Schwarz ◽  
Manfred Westphal ◽  
Tobias Martens
Keyword(s):  
Evoked Potentials ◽  
Sensitivity And Specificity ◽  
Motor Function ◽  
Stimulus Intensity ◽  
Motor Evoked Potentials ◽  
Threshold Level ◽  
Percentage Increase ◽  
Threshold Criterion ◽  
Amplitude Criterion ◽  
Significant Change

OBJECTIVEThe aim of this study was to compare sensitivity and specificity between the novel threshold and amplitude criteria for motor evoked potentials (MEPs) monitoring after transcranial electrical stimulation (TES) during surgery for supratentorial lesions in the same patient cohort.METHODSOne hundred twenty-six patients were included. All procedures were performed under general anesthesia. Craniotomies did not expose motor cortex, so that direct mapping was less suitable. After TES, MEPs were recorded bilaterally from abductor pollicis brevis (APB), from orbicularis oris (OO), and/or from tibialis anterior (TA). The percentage increase in the threshold level was assessed and considered significant if it exceeded by more than 20% on the affected side the percentage increase on the unaffected side. Amplitude on the affected side was measured with a stimulus intensity of 150% of the threshold level set for each muscle.RESULTSEighteen of 126 patients showed a significant change in the threshold level as well as an amplitude reduction of more than 50% in MEPs recorded from APB, and 15 of the patients had postoperative deterioration of motor function of the arm (temporary in 8 cases and permanent in 7 [true-positive and false-negative results]). Recording from TA was performed in 66 patients; 4 developed postoperative deterioration of motor function of the leg (temporary in 3 cases and permanent in 1), and showed a significant change in the threshold level, and an amplitude reduction of more than 50% occurred in 1 patient. An amplitude reduction of more than 50% occurred in another 10 patients, without a significant change in the threshold level or postoperative deterioration. Recording from OO was performed in 61 patients; 3 developed postoperative deterioration of motor function of facial muscles (temporary in 2 cases and permanent in 1) and had a significant change in the threshold level, and 2 of the patients had an amplitude reduction of more than 50%. Another 6 patients had an amplitude reduction of more than 50% but no significant change in the threshold level or postoperative deterioration.Sensitivity of the threshold criterion was 100% when MEPs were recorded from APB, OO, or TA, and its specificity was 97%, 100%, and 100%, respectively. Sensitivity of the amplitude criterion was 100%, 67%, and 25%, with a specificity of 97%, 90%, and 84%, respectively.CONCLUSIONSThe threshold criterion was comparable to the amplitude criterion with a stimulus intensity set at 150% of the threshold level regarding sensitivity and specificity when recording MEPs from APB, and superior to it when recording from TA or OO.

Predictive Value and Safety of Intraoperative Neurophysiological Monitoring With Motor Evoked Potentials in Glioma Surgery

Neurosurgery ◽  
2011 ◽  
Vol 70 (5) ◽  
pp. 1060-1071 ◽  
Author(s):  
Sandro M. Krieg ◽  
Ehab Shiban ◽  
Doris Droese ◽  
Jens Gempt ◽  
Niels Buchmann ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Predictive Value ◽  
Motor System ◽  
Motor Evoked Potentials ◽  
False Negative ◽  
Motor Deficit ◽  
Neurophysiological Monitoring ◽  
Glioma Surgery ◽  
Supratentorial Gliomas

Abstract BACKGROUND: Resection of gliomas in or adjacent to the motor system is widely performed with intraoperative neuromonitoring (IOM). Despite the fact that data on the safety of IOM are available, the significance and predictive value of the procedure are still under discussion. Moreover, cases of false-negative monitoring affect the surgeon's confidence in IOM. OBJECTIVE: To examine cases of false-negative IOM to reveal structural explanations. METHODS: Between 2007 and 2010, we resected 115 consecutive supratentorial gliomas in or close to eloquent motor areas using direct cortical stimulation for monitoring of motor evoked potentials (MEPs). The monitoring data were reviewed and related to new postoperative motor deficit and postoperative imaging. Clinical outcomes were assessed during follow-up. RESULTS: Monitoring of MEPs was successful in 112 cases (97.4%). Postoperatively, 30.3% of patients had a new motor deficit, which remained permanent in 12.5%. Progression-free follow-up was 9.7 months (range, 2 weeks-40.6 months). In 65.2% of all cases, MEPs were stable throughout the operation, but 8.9% showed a new temporary motor deficit, whereas 4.5% (5 patients) presented with permanently deteriorated motor function representing false-negative monitoring at first glance. However, these cases were caused by secondary hemorrhage, ischemia, or resection of the supplementary motor area. CONCLUSION: Continuous MEP monitoring provides reliable monitoring of the motor system, influences the course of operation in some cases, and has to be regarded as the standard for IOM of the motor system. In our series, we found no false-negative MEP results.

scholarly journals Long-term motor deficit in brain tumour surgery with preserved intra-operative motor-evoked potentials

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Davide Giampiccolo ◽  
Cristiano Parisi ◽  
Pietro Meneghelli ◽  
Vincenzo Tramontano ◽  
Federica Basaldella ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Brain Tumour ◽  
Evoked Potential ◽  
Corticospinal Tract ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Motor Deficit ◽  
Motor Deficits ◽  
Brain Tumour Surgery

Abstract Muscle motor-evoked potentials are commonly monitored during brain tumour surgery in motor areas, as these are assumed to reflect the integrity of descending motor pathways, including the corticospinal tract. However, while the loss of muscle motor-evoked potentials at the end of surgery is associated with long-term motor deficits (muscle motor-evoked potential-related deficits), there is increasing evidence that motor deficit can occur despite no change in muscle motor-evoked potentials (muscle motor-evoked potential-unrelated deficits), particularly after surgery of non-primary regions involved in motor control. In this study, we aimed to investigate the incidence of muscle motor-evoked potential-unrelated deficits and to identify the associated brain regions. We retrospectively reviewed 125 consecutive patients who underwent surgery for peri-Rolandic lesions using intra-operative neurophysiological monitoring. Intraoperative changes in muscle motor-evoked potentials were correlated with motor outcome, assessed by the Medical Research Council scale. We performed voxel–lesion–symptom mapping to identify which resected regions were associated with short- and long-term muscle motor-evoked potential-associated motor deficits. Muscle motor-evoked potentials reductions significantly predicted long-term motor deficits. However, in more than half of the patients who experienced long-term deficits (12/22 patients), no muscle motor-evoked potential reduction was reported during surgery. Lesion analysis showed that muscle motor-evoked potential-related long-term motor deficits were associated with direct or ischaemic damage to the corticospinal tract, whereas muscle motor-evoked potential-unrelated deficits occurred when supplementary motor areas were resected in conjunction with dorsal premotor regions and the anterior cingulate. Our results indicate that long-term motor deficits unrelated to the corticospinal tract can occur more often than currently reported. As these deficits cannot be predicted by muscle motor-evoked potentials, a combination of awake and/or novel asleep techniques other than muscle motor-evoked potentials monitoring should be implemented.

Reliability of Intraoperative Monitoring in Patients with a Preexisting Motor Deficit: Case Report and Literature Review

2020 ◽  
Author(s):  
Ravindran Visagan ◽  
José Pedro Lavrador ◽  
Shami Acharya ◽  
Noemia Pereira ◽  
Istvan Bodi ◽  
...  
Keyword(s):  
Intraoperative Monitoring ◽  
Aminolevulinic Acid ◽  
Clinical Course ◽  
Motor Evoked Potentials ◽  
Motor Deficit ◽  
Glioma Surgery ◽  
Cortical Motor ◽  
Full Power ◽  
Safe Zones

Abstract Background The use of intraoperative monitoring (IOM) in glioma surgery is a widely adopted and clinically validated adjunct to define safe zones of resection for the neurosurgeon. However, the role of IOM in cases of a significant preexisting motor deficit is questionable. Case Description We describe a case of a 25-year-old with a recurrent presentation of a left paracentral glioblastoma, admitted with intratumoral hemorrhage and subsequent acute severe right-sided weakness. The patient underwent a redo left parietal craniotomy and 5-aminolevulinic acid–guided resection with IOM. The severity of the weakness was not reflected by the pre- and intraoperative cortical motor evoked potentials (MEPs) that were reassuring. The patient's hemiparesis recovered to full power postoperatively. Conclusions Preoperative weakness is traditionally accepted as a relative contraindication to IOM and therefore its usefulness is questioned in this context. Our case challenges this assumption. We present the clinical course, review the cranial and spinal literature including the reliability of IOM in cases of preoperative motor deficit, and discuss the need for tailor-made IOM strategies.

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.

Electromagnetic Navigation Systems and Intraoperative Neuromonitoring: Reliability and Feasibility Study

2021 ◽  
Vol 20 (4) ◽  
pp. 373-382
Author(s):  
Hannah Keeble ◽  
José Pedro Lavrador ◽  
Noémia Pereira ◽  
Kornelius Lente ◽  
Christian Brogna ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Navigation System ◽  
Intraoperative Complications ◽  
Tumor Resection ◽  
Motor Deficit ◽  
Neurophysiological Monitoring ◽  
Navigation Systems ◽  
Electromagnetic Navigation ◽  
Significant Difference ◽  
Electromagnetic Navigation System

Abstract BACKGROUND A recent influx of intraoperative technology is being used in neurosurgery, but few reports investigate the accuracy and safety of these technologies when used simultaneously. OBJECTIVE To assess the ability to use an electromagnetic navigation system alongside multimodal intraoperative neurophysiological monitoring (IONM). METHODS Single-institution prospective cohort study of patients requiring craniotomy for brain tumor resection operated using an electromagnetic navigation system (AxiEM, Medtronic®). motor evoked potentials, somatosensory evoked potentials (SSEPs), electroencephalography, and electromyography were recorded and analyzed with AxiEM on (with/without filters) and off. The neurological outcomes of the patients were recorded. RESULTS A total of 15 patients were included (8 males/7 females, mean age 52.13 yr). Even though the raw acquisition is affected by the electromagnetic field (particularly SSEPs), no significant difference was detected in the morphology, amplitude, and latency of the different monitoring modalities (AxiEM off vs on) after the appropriate software filter application. Adjustments to the frequency of SSEP stimulation and number of averages, and reductions to the low-pass filters were applied. Notch filters were used appropriately and changes to the physical setup of the IONM and electromagnetic navigation system equipment reduced noise. Postoperatively, none of the patients developed new focal deficits; 7 patients showed improvement in their motor deficit (4 recovered fully). CONCLUSION The information provided by the IONM in intracranial neurosurgery patients whilst also using electromagnetic navigation systems is reliable for monitoring, mapping, and detecting intraoperative complications, provided that the appropriate software filters and tools are applied.

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