scholarly journals Continuous subcortical motor evoked potential stimulation using the tip of an ultrasonic aspirator for the resection of motor eloquent lesions

2015 ◽  
Vol 123 (2) ◽  
pp. 301-306 ◽  
Author(s):  
Ehab Shiban ◽  
Sandro M. Krieg ◽  
Thomas Obermueller ◽  
Maria Wostrack ◽  
Bernhard Meyer ◽  
...  
Keyword(s):  
Corticospinal Tract ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Neurophysiological Monitoring ◽  
Subtotal Resection ◽  
Motor Mapping ◽  
Monopolar Stimulation ◽  
Subcortical Stimulation ◽  
Stimulation Current ◽  
Stimulation Of

OBJECT Resection of a motor eloquent lesion has become safer because of intraoperative neurophysiological monitoring (IOM). Stimulation of subcortical motor evoked potentials (scMEPs) is increasingly used to optimize patient safety. So far, scMEP stimulation has been performed intermittently during resection of eloquently located lesions. Authors of the present study assessed the possibility of using a resection instrument for continuous stimulation of scMEPs. METHODS An ultrasonic surgical aspirator was attached to an IOM stimulator and was used as a monopolar subcortical stimulation probe. The effect of the aspirator’s use at different ultrasound power levels (0%, 25%, 50%, 75%, and 100%) on stimulation intensity was examined in a saline bath. Afterward monopolar stimulation with the surgical aspirator was used during the resection of subcortical lesions in the vicinity of the corticospinal tract in 14 patients in comparison with scMEP stimulation via a standard stimulation electrode. During resection, the stimulation current at which an MEP response was still measurable with subcortical stimulation using the surgical aspirator was compared with the corresponding stimulation current needed using a standard monopolar subcortical stimulation probe at the same location. RESULTS The use of ultrasound at different energy levels did result in a slight but irrelevant increase in stimulation energy via the tip of the surgical aspirator in the saline bath. Stimulation of scMEPs using the surgical aspirator or monopolar probe was successful and almost identical in all patients. One patient developed a new permanent neurological deficit. Transient new postoperative paresis was observed in 28% (4 of 14) of cases. Gross-total resection was achieved in 64% (9 of 14) cases and subtotal resection (> 80% of tumor mass) in 35% (5 of 14). CONCLUSIONS Continuous motor mapping using subcortical stimulation via a surgical aspirator, in comparison with the sequential use of a standard monopolar stimulation probe, is a feasible and safe method without any disadvantages. Compared with the standard probe, the aspirator offers continuous information on the distance to the corticospinal tract.

scholarly journals Intraoperative subcortical motor evoked potential stimulation: how close is the corticospinal tract?

2015 ◽  
Vol 123 (3) ◽  
pp. 711-720 ◽  
Author(s):  
Ehab Shiban ◽  
Sandro M. Krieg ◽  
Bernhard Haller ◽  
Niels Buchmann ◽  
Thomas Obermueller ◽  
...  
Keyword(s):  
Evoked Potential ◽  
Corticospinal Tract ◽  
Diffusion Tensor ◽  
Motor Evoked Potential ◽  
Motor Deficits ◽  
Subtotal Resection ◽  
Stimulation Intensity ◽  
Postoperative Mri ◽  
Subcortical Stimulation ◽  
Measured Distance

OBJECT Subcortical stimulation is a method used to evaluate the distance from the stimulation site to the corticospinal tract (CST) and to decide whether the resection of an adjacent lesion should be terminated to prevent damage to the CST. However, the correlation between stimulation intensity and distance to the CST has not yet been clearly assessed. The objective of this study was to investigate the appropriate correlation between the subcortical stimulation pattern and the distance to the CST. METHODS Monopolar subcortical motor evoked potential (MEP) mapping was performed in addition to continuous MEP monitoring in 37 consecutive patients with lesions located in motor-eloquent locations. The proximity of the resection cavity to the CST was identified by subcortical MEP mapping. At the end of resection, the point at which an MEP response was still measurable with minimal subcortical MEP intensity was marked with a titanium clip. At this location, different stimulation paradigms were executed with cathodal or anodal stimulation at 0.3-, 0.5-, and 0.7-msec pulse durations. Postoperatively, the distance between the CST as defined by postoperative diffusion tensor imaging fiber tracking and the titanium clip was measured. The correlation between this distance and the subcortical MEP electrical charge was calculated. RESULTS Subcortical MEP mapping was successful in all patients. There were no new permanent motor deficits. Transient new postoperative motor deficits were observed in 14% (5/36) of cases. Gross-total resection was achieved in 75% (27/36) and subtotal resection (> 80% of tumor mass) in 25% (9/36) of cases. Stimulation intensity with various pulse durations as well as current intensity was plotted against the measured distance between the CST and the titanium clip on postoperative MRI using diffusion-weighted imaging fiberitracking tractography. Correlational and regression analyses showed a nonlinear correlation between stimulation intensity and the distance to the CST. Cathodal stimulation appeared better suited for subcortical stimulation. CONCLUSIONS Subcortical MEP mapping is an excellent intraoperative method to determine the distance to the CST during resection of motor-eloquent lesions and is highly capable of further reducing the risk of a new neurological deficit.

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.

scholarly journals Intraoperative mapping of pre-central motor cortex and subcortex: a proposal for supplemental cortical and novel subcortical maps to Penfield’s motor homunculus

2021 ◽  
Author(s):  
Prajwal Ghimire ◽  
Jose Pedro Lavrador ◽  
Asfand Baig Mirza ◽  
Noemia Pereira ◽  
Hannah Keeble ◽  
...  
Keyword(s):  
Brain Mapping ◽  
Retrospective Cohort ◽  
Corticospinal Tract ◽  
Brain Lesions ◽  
Body Parts ◽  
Single Institution ◽  
Motor Representation ◽  
Motor Mapping ◽  
Subcortical Stimulation ◽  
Motor Maps

AbstractPenfield’s motor homunculus describes a caricaturised yet useful representation of the map of various body parts on the pre-central cortex. We propose a supplemental map of the clinically represented areas of human body in pre-central cortex and a novel subcortical corticospinal tract map. We believe this knowledge is essential for safe surgery in patients with eloquent brain lesions. A single-institution retrospective cohort study of patients who underwent craniotomy for motor eloquent lesions with intraoperative motor neuromonitoring (cortical and subcortical) between 2015 and 2020 was performed. All positive cortical and subcortical stimulation points were taken into account and cartographic maps were produced to demonstrate cortical and subcortical areas of motor representation and their configuration. A literature review in PubMed was performed. One hundred and eighty consecutive patients (58.4% male, 41.6% female) were included in the study with 81.6% asleep and 18.4% awake craniotomies for motor eloquent lesions (gliomas 80.7%, metastases 13.8%) with intraoperative cortical and subcortical motor mapping. Based on the data, we propose a supplemental clinical cortical and a novel subcortical motor map to the original Penfield’s motor homunculus, including demonstration of localisation of intercostal muscles both in the cortex and subcortex which has not been previously described. The supplementary clinical cortical and novel subcortical motor maps of the homunculus presented here have been derived from a large cohort of patients undergoing direct cortical and subcortical brain mapping. The information will have direct relevance for improving the safety and outcome of patients undergoing resection of motor eloquent brain lesions.

Increased corticospinal excitability prior to arm cycling is due to enhanced supraspinal but not spinal motoneurone excitability

2013 ◽  
Vol 38 (11) ◽  
pp. 1154-1161 ◽  
Author(s):  
Kevin E. Power ◽  
David B. Copithorne
Keyword(s):  
Magnetic Stimulation ◽  
Corticospinal Tract ◽  
Biceps Brachii ◽  
Motor Evoked Potentials ◽  
Corticospinal Excitability ◽  
Quiescent State ◽  
M Wave ◽  
Arm Cycling ◽  
Intention To Move ◽  
Stimulation Of

Human studies have not assessed supraspinal or spinal motoneurone excitability in the quiescent state prior to a rhythmic and alternating cyclical motor output. The purpose of the current study was to determine whether supraspinal and (or) spinal motoneurone excitability was modulated in humans prior to arm cycling when compared with rest with no intention to move. We hypothesized that corticospinal excitability would be enhanced prior to arm cycling due, in part, to increased spinal motoneurone excitability. Supraspinal and spinal motoneurone excitability were assessed via transcranial magnetic stimulation (TMS) of the motor cortex and transmastoid stimulation of the corticospinal tract, respectively. Surface electromyography recordings of TMS motor evoked potentials (MEPs) and cervicomedullary MEPs (CMEPs) were made from the relaxed biceps brachii muscle prior to rhythmic arm cycling and at rest with no intention to move. The amplitude of the MEPs was greater (mean increase: +9.8% of maximal M wave; p = 0.006) and their onset latencies were shorter (mean decrease: –1.5 ms; p < 0.05) prior to cycling when compared with rest. The amplitudes of the CMEPs at any of 3 stimulation intensities were not different between conditions. We conclude that premovement enhancement of corticospinal excitability is greater prior to arm cycling than at rest because of increases in supraspinal but not spinal motoneurone excitability.

Reproducible Measurement of Human Motoneuron Excitability With Magnetic Stimulation of the Corticospinal Tract

2009 ◽  
Vol 102 (1) ◽  
pp. 606-613 ◽  
Author(s):  
Peter G. Martin ◽  
Anna L. Hudson ◽  
Simon C. Gandevia ◽  
Janet L. Taylor
Keyword(s):  
Magnetic Stimulation ◽  
Corticospinal Tract ◽  
Motor Evoked Potentials ◽  
Compound Action Potential ◽  
Maximal Response ◽  
Response Curves ◽  
Stimulus Response ◽  
Maximal Output ◽  
Voluntary Contractions ◽  
Stimulation Of

It is difficult to test responses of human motoneurons in a controlled way or to make longitudinal assessments of adaptive changes at the motoneuron level. These studies assessed the reliability of responses produced by magnetic stimulation of the corticospinal tract. Cervicomedullary motor evoked potentials (CMEPs) were recorded in the first dorsal interosseus (FDI) on 2 separate days. On each day, four sets of stimuli were delivered at the maximal output of the stimulator, with the final two sets ≥10 min after the initial sets. Sets of stimuli were also delivered at different stimulus intensities to obtain stimulus-response curves. In addition, on the second day, responses at different stimulus intensities were evoked during weak voluntary contractions. Responses were normalized to the maximal muscle compound action potential ( Mmax). CMEPs evoked in the relaxed FDI were small, even when stimulus intensity was maximal (3.6 ± 2.5% Mmax) but much larger during a weak contraction (e.g., 26.2 ± 10.2% Mmax). CMEPs evoked in the relaxed muscle at the maximal output of the stimulator were highly reproducible both within (ICC = 0.83, session 1; ICC = 0.87, session 2) and between sessions (ICC = 0.87). ICCs for parameters of the input-output curves, which included measures of motor threshold, slope, and maximal response size, ranged between 0.87 and 0.62. These results suggest that responses to magnetic stimulation of the corticospinal tract can be assessed in relaxation and contraction and can be reliably obtained for longitudinal studies of motoneuronal excitability.

Motor Evoked Potentials from Transcranial Stimulation of the Motor Cortex in Humans

Neurosurgery ◽  
1984 ◽  
Vol 15 (3) ◽  
pp. 287-302 ◽  
Author(s):  
Walter J. Levy ◽  
Donald H. York ◽  
Michael McCaffrey ◽  
Fred Tanzer
Keyword(s):  
Spinal Cord ◽  
Motor Cortex ◽  
Evoked Potentials ◽  
Evoked Potential ◽  
Motor Evoked Potentials ◽  
Sensory Modality ◽  
Motor Evoked Potential ◽  
Transcranial Stimulation ◽  
Direct Stimulation ◽  
Stimulation Of

Abstract Electrical monitoring of the motor system offers the potential for the detection of injury, the diagnosis of disease, the evaluation of treatment, and the prediction of recovery from damage. Existing evoked potentials monitor one or another sensory modality, but no generally usable motor monitor exists. We have reported a motor evoked potential using direct stimulation of the spinal cord over the motor tracts in cats and in humans. To achieve a less invasive monitor, we used transcranial stimulation over the motor cortex in the cat, thus stimulating the motor cortex. We report here the initial application of this method to humans. A plate electrode over the motor cortex on the scalp and a second electrode on the palate direct a mild current through the motor cortex which will activate the motor pathways. This signal can be recorded over the spinal cord. It can elicit contralateral peripheral nerve and electromyographic signals in the limbs or movements when the appropriate stimulation parameters are used. In clinical use to date, this has been more reliable than the somatosensory evoked potential in predicting motor function in patients where the two tests differed. It offers a number of possibilities for the development of valuable brain and spinal cord monitoring techinques, but requires further animal studies and clinical experience. Studies to date have not demonstrated adverse effects, but evaluation is continuing.

Motor Evoked Potentials Elicited from Pyramidal Stimulation and Recorded from the Spinal Cord in the Rat

Neurosurgery ◽  
1991 ◽  
Vol 28 (4) ◽  
pp. 550-558 ◽  
Author(s):  
John Ryder ◽  
Rosario Zappulla ◽  
Julia Nieves
Keyword(s):  
Spinal Cord ◽  
Electrical Stimulation ◽  
Sensorimotor Cortex ◽  
Pyramidal Tract ◽  
Motor Evoked Potentials ◽  
Motor Evoked Potential ◽  
Evoked Response ◽  
Cord Injury ◽  
Latency Response ◽  
Stimulation Of

Abstract This study investigated the spinal evoked response to focal electrical stimulation of the sensorimotor cortex in 32 rats. The results demonstrate a long-latency response (beginning at 8 milliseconds); elicited by electrical stimulation, which is distinct from the short-latency motor evoked potential previously reported. The conduction velocity of this later response is similar to that reported for the pyramidal tract in the rat. Experiments confirm that the longer latency response depends upon the integrity of the pyramidal system. Focal stimulation outside the sensorimotor cortex failed to elicit a response. Experimental lesions of the pyramidal tract or ablating the sensorimotor cortex eliminated the spinal cord evoked response. The results demonstrate that focal stimulation of the sensorimotor cortex results in a spinal cord evoked response that represents activity within the pyramidal system. The utility of this response in the rat model for assessing experimental cord injury is discussed.

scholarly journals Arm posture-dependent changes in corticospinal excitability are largely spinal in origin

2016 ◽  
Vol 115 (4) ◽  
pp. 2076-2082 ◽  
Author(s):  
James L. Nuzzo ◽  
Gabriel S. Trajano ◽  
Benjamin K. Barry ◽  
Simon C. Gandevia ◽  
Janet L. Taylor
Keyword(s):  
Evoked Potentials ◽  
Biceps Brachii ◽  
Motor Evoked Potentials ◽  
Compound Muscle Action Potential ◽  
Corticospinal Excitability ◽  
Triceps Brachii ◽  
Upper Arm ◽  
Muscle Action Potential ◽  
Subcortical Stimulation ◽  
Stimulation Of

Biceps brachii motor evoked potentials (MEPs) from cortical stimulation are influenced by arm posture. We used subcortical stimulation of corticospinal axons to determine whether this postural effect is spinal in origin. While seated at rest, 12 subjects assumed several static arm postures, which varied in upper-arm (shoulder flexed, shoulder abducted, arm hanging to side) and forearm orientation (pronated, neutral, supinated). Transcranial magnetic stimulation over the contralateral motor cortex elicited MEPs in resting biceps and triceps brachii, and electrical stimulation of corticospinal tract axons at the cervicomedullary junction elicited cervicomedullary motor evoked potentials (CMEPs). MEPs and CMEPs were normalized to the maximal compound muscle action potential (Mmax). Responses in biceps were influenced by upper-arm and forearm orientation. For upper-arm orientation, biceps CMEPs were 68% smaller ( P = 0.001), and biceps MEPs 31% smaller ( P = 0.012), with the arm hanging to the side compared with when the shoulder was flexed. For forearm orientation, both biceps CMEPs and MEPs were 34% smaller (both P < 0.046) in pronation compared with supination. Responses in triceps were influenced by upper-arm, but not forearm, orientation. Triceps CMEPs were 46% smaller ( P = 0.007) with the arm hanging to the side compared with when the shoulder was flexed. Triceps MEPs and biceps and triceps MEP/CMEP ratios were unaffected by arm posture. The novel finding is that arm posture-dependent changes in corticospinal excitability in humans are largely spinal in origin. An interplay of multiple reflex inputs to motoneurons likely explains the results.

scholarly journals Modern Views on the Role of Intraoperative Neurophysiological Monitoring in Brain Tumour Surgery

2019 ◽  
Vol 26 (5) ◽  
pp. 105-115
Author(s):  
Vladislav Yu. Murunov ◽  
Lyudmila V. Kovalenko
Keyword(s):  
Cerebral Cortex ◽  
Motor Evoked Potentials ◽  
Conscious State ◽  
Historical Background ◽  
Intraoperative Neurophysiological Monitoring ◽  
Neurophysiological Monitoring ◽  
Subcortical Structures ◽  
Brain Tumour Surgery ◽  
Stimulation Of

The article defines the role of intraoperative neurophysiological monitoring (IONM) in neurosurgery, provides a brief historical background, as well as describes the main methods of IONM — somatosensory and motor evoked potentials. The authors describe electrical stimulation of the cerebral cortex and subcortical structures under general anaesthesia and in the conscious state. IONM is an integral part of neurosurgery, with its importance growing in orthopaedics and cavity surgery, where there is a risk of damaging nerve structures.

scholarly journals Intraoperative mapping of pre-central motor cortex and subcortex: a proposal for supplemental cortical and novel subcortical maps to Penfield’s motor homunculus

2020 ◽  
Author(s):  
Prajwal Ghimire ◽  
Jose Lavrador ◽  
Asfand Mirza ◽  
Noemia Pereira ◽  
Hannah Keeble ◽  
...  
Keyword(s):  
Brain Mapping ◽  
Retrospective Cohort ◽  
Corticospinal Tract ◽  
Brain Lesions ◽  
Body Parts ◽  
Single Institution ◽  
Motor Representation ◽  
Motor Mapping ◽  
Subcortical Stimulation ◽  
Motor Maps

Abstract Introduction: Penfield’s motor homunculus describes a caricaturised yet useful representation of the map of various body parts on the pre-central cortex. We propose a supplemental map of the clinically represented areas of human body in pre-central cortex and a novel subcortical corticospinal tract map that are accurate and essential for safe surgery in patients with eloquent brain lesions. Materials and methods: A single-institution retrospective cohort study of patients who underwent craniotomy for motor eloquent lesions with intraoperative motor neuromonitoring (cortical and subcortical) between 2015 and 2020 was performed. All positive cortical and subcortical stimulation points were taken into account and cartographic maps were produced to demonstrate cortical and subcortical areas of motor representation and their configuration. A literature review in PubMed was performed. Results: 180 patients (58.4% male, 41.6% female) were included in the study with 81.6% asleep and 18.4% awake craniotomies for motor eloquent lesions (gliomas 80.7%, metastases 13.8%) with intraoperative cortical and subcortical motor mapping. Based on the data, we propose a supplemental clinical cortical and a novel subcortical motor map to the original Penfield’s motor homunculus, including demonstration of localisation of intercostal muscles both in the cortex and subcortex which has not been previously described. Conclusion: The supplementary clinical cortical and novel subcortical motor maps of the homunculus presented here have been derived from a large cohort of patients undergoing direct cortical and subcortical brain mapping. The information will have direct relevance for improving the safety and outcome of patients undergoing resection of motor eloquent brain lesions.

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