The warning-sign hierarchy between quantitative subcortical motor mapping and continuous motor evoked potential monitoring during resection of supratentorial brain tumors

2013 ◽  
Vol 118 (2) ◽  
pp. 287-296 ◽  
Author(s):  
Kathleen Seidel ◽  
Jürgen Beck ◽  
Lennart Stieglitz ◽  
Philippe Schucht ◽  
Andreas Raabe
Keyword(s):  
Evoked Potential ◽  
Tumor Resection ◽  
Motor Evoked Potential ◽  
Cortical Stimulation ◽  
Motor Deficits ◽  
Warning Sign ◽  
Motor Mapping ◽  
Direct Cortical Stimulation ◽  
Monopolar Stimulation ◽  
Signal Changes

Object Mapping and monitoring are believed to provide an early warning sign to determine when to stop tumor removal to avoid mechanical damage to the corticospinal tract (CST). The objective of this study was to systematically compare subcortical monopolar stimulation thresholds (1–20 mA) with direct cortical stimulation (DCS)–motor evoked potential (MEP) monitoring signal abnormalities and to correlate both with new postoperative motor deficits. The authors sought to define a mapping threshold and DCS-MEP monitoring signal changes indicating a minimal safe distance from the CST. Methods A consecutive cohort of 100 patients underwent tumor surgery adjacent to the CST while simultaneous subcortical motor mapping and DCS-MEP monitoring was used. Evaluation was done regarding the lowest subcortical mapping threshold (monopolar stimulation, train of 5 stimuli, interstimulus interval 4.0 msec, pulse duration 500 μsec) and signal changes in DCS-MEPs (same parameters, 4 contact strip electrode). Motor function was assessed 1 day after surgery, at discharge, and at 3 months postoperatively. Results The lowest individual motor thresholds (MTs) were as follows (MT in mA, number of patients): > 20 mA, n = 12; 11–20 mA, n = 13; 6–10 mA, n = 20; 4–5 mA, n = 30; and 1–3 mA, n = 25. Direct cortical stimulation showed stable signals in 70 patients, unspecific changes in 18, irreversible alterations in 8, and irreversible loss in 4 patients. At 3 months, 5 patients had a postoperative new or worsened motor deficit (lowest mapping MT 20 mA, 13 mA, 6 mA, 3 mA, and 1 mA). In all 5 patients DCS-MEP monitoring alterations were documented (2 sudden irreversible threshold increases and 3 sudden irreversible MEP losses). Of these 5 patients, 2 had vascular ischemic lesions (MT 20 mA, 13 mA) and 3 had mechanical CST damage (MT 1 mA, 3 mA, and 6 mA; in the latter 2 cases the resection continued after mapping and severe DCS-MEP alterations occurred thereafter). In 80% of patients with a mapping MT of 1–3 mA and in 75% of patients with a mapping MT of 1 mA, DCS-MEPs were stable or showed unspecific reversible changes, and none had a permanent motor worsening at 3 months. In contrast, 25% of patients with irreversible DCS-MEP changes and 75% of patients with irreversible DCS-MEP loss had permanent motor deficits. Conclusions Mapping should primarily guide tumor resection adjacent to the CST. DCS-MEP is a useful predictor of deficits, but its value as a warning sign is limited because signal alterations were reversible in only approximately 60% of the present cases and irreversibility is a post hoc definition. The true safe mapping MT is lower than previously thought. The authors postulate a mapping MT of 1 mA or less where irreversible DCS-MEP changes and motor deficits regularly occur. Therefore, they recommend stopping tumor resection at an MT of 2 mA at the latest. The limited spatial and temporal coverage of contemporary mapping may increase error and may contribute to false, higher MTs.

Direct cortical stimulation with cylindrical depth electrodes in the interhemispheric fissure for leg motor evoked potential monitoring

2020 ◽  
Vol 131 (1) ◽  
pp. 127-132
Author(s):  
Liberto Brage ◽  
Pedro Javier Pérez-Lorensu ◽  
Julio Plata-Bello ◽  
Ángel Saponaro-González ◽  
Luis Pérez-Orribo ◽  
...  
Keyword(s):  
Evoked Potential ◽  
Motor Evoked Potential ◽  
Cortical Stimulation ◽  
Direct Cortical Stimulation ◽  
Depth Electrodes ◽  
Interhemispheric Fissure ◽  
Evoked Potential Monitoring ◽  
Potential Monitoring

S2-3. Intraoperative monitoring of lower extremity motor-evoked potential by direct cortical stimulation

2013 ◽  
Vol 124 (8) ◽  
pp. e20
Author(s):  
Masami Fujii ◽  
Yuichi Maruta ◽  
Hirochika Imoto ◽  
Hisaharu Goto ◽  
Michiyasu Suzuki
Keyword(s):  
Lower Extremity ◽  
Intraoperative Monitoring ◽  
Evoked Potential ◽  
Motor Evoked Potential ◽  
Cortical Stimulation ◽  
Direct Cortical Stimulation

Transcranial Electrical Motor Evoked Potential Monitoring for Brain Tumor Resection

Neurosurgery ◽  
2001 ◽  
Vol 48 (5) ◽  
pp. 1075-1081 ◽  
Author(s):  
Henry H. Zhou ◽  
Patrick J. Kelly
Keyword(s):  
Brain Tumor ◽  
Evoked Potential ◽  
Tumor Resection ◽  
Motor Evoked Potential ◽  
Motor Deficits ◽  
Tumor Surgery ◽  
Brain Tumor Surgery ◽  
Stimulation Intensity ◽  
Potential System ◽  
Brain Tumor Resection

Abstract OBJECTIVE This study was designed to examine whether transcranial electrical motor evoked potential (MEP) monitoring is safe, feasible, and valuable for brain tumor surgery. METHODS Fifty consecutive patients undergoing brain tumor resection were studied, using nitrous oxide/propofol anesthesia. MEPs were continuously recorded throughout surgery, using a Sentinel 4 evoked potential system (Axon Systems, Inc., Hauppauge, NY). The MEPs were elicited by transcranial electrical stimulation (train of 5; stimulation rate, 0.5–2 Hz; square wave pulse with a time constant of 0.5 ms; stimulation intensity, 40–160 mA) through spiral electrodes placed over the primary motor cortex and were recorded by needle electrodes inserted into the contralateral orbicularis oris, biceps, abductor pollicis brevis, and anterior tibialis muscles. When MEP amplitudes decreased by more than 50%, MEP stimulation was repeated, with increased stimulation intensity, and MEP changes were reported to the surgeon. The motor function of each patient was examined before and after surgery, using a reproducible scale. The relationship between MEP amplitude decreases and worsening motor status was analyzed using linear regression. RESULTS Preoperative neurological examinations revealed mild to moderate motor deficits (2/5 to 4/5) for 38% of patients (19 of 50 patients). Most of the patients (96%) exhibited recordable baseline MEPs. Persistent MEP decreases of more than 50% were noted for eight patients (16%) (11 muscles). The MEPs were completely abolished in two patients (three muscles). The degree of postoperative worsening of motor status was correlated with the degree of intraoperative MEP amplitude reduction (r = −0.864; P < 0.001). CONCLUSION Persistent intraoperative MEP reductions of more than 50% were associated with postoperative motor deficits. The degree of MEP amplitude reduction was correlated with postoperative worsening of motor status. Transcranial electrical MEP monitoring is feasible, safe, and valuable for brain tumor surgery.

Intraoperative Seizures in Awake Craniotomy for Perirolandic Glioma Resections That Undergo Cortical Mapping

2018 ◽  
Vol 79 (03) ◽  
pp. 239-246 ◽  
Author(s):  
Chikezie Eseonu ◽  
Jordina Rincon-Torroella ◽  
Young Lee ◽  
Karim ReFaey ◽  
Punita Tripathi ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Cortical Stimulation ◽  
Awake Craniotomy ◽  
Motor Area ◽  
Perioperative Outcomes ◽  
Motor Deficits ◽  
Precentral Gyrus ◽  
Motor Mapping ◽  
Direct Cortical Stimulation ◽  
Motor Region

Background Perirolandic motor area gliomas present invasive eloquent region tumors within the precentral gyrus that are difficult to resect without causing neurologic deficits. Study Aims This study evaluates the role of awake craniotomy and motor mapping on neurologic outcome and extent of resection (EOR) of tumor in the perirolandic motor region. It also analyzes preoperative risk factors for intraoperative seizures. Methods We evaluated 57 patients who underwent an awake craniotomy for a perirolandic motor area eloquent region glioma. Patients who had positive mapping (PM) or intraoperative identification of motor regions in the cortex using direct cortical stimulation were compared with patients with no positive motor mapping following direct cortical stimulation and negative mapping (NM). Preoperative risks, intraoperative seizures, perioperative outcomes, tumor characteristics, and EOR were also compared. A logistic regression model was used to evaluate the predictors for intraoperative seizures in this patient cohort. Results Overall, 33 patients were in the PM cohort; 24 were in the NM cohort. Our study showed an 8.8% incidence of intraoperative seizures during cortical and subcortical mapping for awake craniotomies in the perirolandic motor area, none of which aborted the case. PM patients had significantly more intraoperative and postoperative seizures (15.5% and 30.3%, respectively) compared with the NM patients (0% and 8.3%, respectively; p = 0.046 and 0.044). New transient postoperative motor deficits were found more often in the PM group (51.5%) versus the NM group (12.5%; p = 0.002). A univariate logistic regression showed that PM (odds ratio [OR]: 1.16; 95% confidence interval [CI], 1.01–1.34; p = 0.035) and preoperative tumor volume (OR: 0.998; 95% CI, 0.996–0.999; p = 0.049) were significant predictors for intraoperative seizures in patients with perirolandic gliomas. Conclusion Awake craniotomies in the perirolandic motor region can be safely performed with a similar incidence of intraoperative seizures as reported for the language cortex. PM in this region may increase the likelihood of perioperative seizures or motor deficits compared with NM. Craniotomies that minimize cortical exposure for perirolandic gliomas that may not localize motor regions can still allow for extensive tumor resection with a good postoperative outcome.

Cutoff Points, Sensitivities, and Specificities of Intraoperative Motor-Evoked Potential Monitoring Determined Using Receiver Operating Characteristic Analysis

2018 ◽  
Vol 80 (02) ◽  
pp. 102-108
Author(s):  
Jiro Akimoto ◽  
Ryo Hashimoto ◽  
Junko Takanashi ◽  
Hidehiro Oka ◽  
Satoshi Tanaka
Keyword(s):  
Brain Tumor ◽  
Receiver Operating Characteristic ◽  
Sensitivity And Specificity ◽  
Evoked Potential ◽  
Operating Characteristic ◽  
Motor Evoked Potential ◽  
Cortical Stimulation ◽  
Transcranial Stimulation ◽  
Direct Cortical Stimulation ◽  
Cutoff Points

Background Although intraoperative motor-evoked potential (MEP) monitoring is widely performed during neurosurgical operations, evaluating its results is controversial. Study Aims The cutoff point of MEP monitoring should be determined not only to predict but also to prevent postoperative neurologic deficits. Material and Methods MEP monitoring was performed during 484 neurosurgical operations for patients without definitive preoperative motor palsy including 325 spinal operations, 102 cerebral aneurysmal operations, and 57 brain tumor operations, all monitored by transcranial stimulation, and 34 brain tumor operations monitored under direct cortical stimulation. To exclude the effects of muscle relaxants on MEP, the compound muscle action potential (CMAP), measured immediately after transcranial stimulation or direct cortical stimulation at supramaximal stimulation of the peripheral nerve, was used for normalization. The cutoff points, sensitivity, and specificity of MEP recorded during neurosurgery were examined by receiver operating characteristic (ROC) analyses and categorized according to the type of operation and stimulation. Results In spinal operations under transcranial stimulation, amplitude reduction of 77.9% and 80.6% as cutoff points for motor palsy with and without CMAP normalization, respectively, provided a sensitivity of 100% and specificity of 96.8% and 96.5%. In aneurysmal operations under transcranial stimulation, cutoff points of 70.7% and 69.6% offered specificities of 95.2% and 95.7% with and without CMAP normalization, respectively. The sensitivities for both were 100%. In brain tumor operations under direct stimulation, cutoff points were 83.5% and 86.3% with or without CMAP normalization, respectively, and the sensitivity and specificity for both were 100%. Conclusion An amplitude decrease of 80% in brain tumor operations, 75% in spinal operations, and 70% in aneurysmal operations should be used as the cutoff points.

Sign in / Sign up

Export Citation Format

Share Document