Intraoperative seizures occurrence in cortical mapping of eloquent areas

The effect of structural epilepsy on the frequency of intraoperative convulsive seizures is assessed when mapping functionally significant areas of the cerebral cortex during resection of intracerebral neoplasms. The work is based on the analysis of the results of intraoperative neurophysiological studies at the Polenov Neurosurgical Institute. For the period 20192020 87 intraoperative mappings of eloquent cortex were carried out during resections of intracerebral neoplasms: 79 mappings of the motor cortex and 16 mappings of auditory-speech areas during operations with awakening. When mapping the motor zones of the cortex, the frequency of seizures was 5.1%, while mapping the auditory-speech zones with awakening 18.75%. The division of cases of intraoperative convulsive seizures into two groups: seizures arising from motor mapping and seizures associated with the mapping of auditory zones reflects differences in factors that affect the excitability of the cerebral cortex. In motor mapping, stimulation occurs against the background of general anesthesia, unlike waking operations. The intensity of stimulation in auditory mapping is higher than in motor mapping in motor mapping. Formally, the current used in motor mapping is significantly higher than in mapping auditory zones. In general, with the development of intraoperative convulsive seizures, the current intensity of cortical stimulation does not exceed the average values required to stimulate functionally significant cortical zones. The presence of epileptic syndrome in patients with intracerebral tumors cannot be considered as a predictor of intraoperative seizure development when performing motor mapping under general anesthesia as well as during surgery with awakening for mapping of motor or auditory verbal zones.

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AWAKE CRANIOTOMY FOR BRAIN TUMORS NEAR ELOQUENT CORTEX

Neurosurgery ◽

10.1227/01.neu.0000342405.80881.81 ◽

2009 ◽

Vol 64 (5) ◽

pp. 836-846 ◽

Cited By ~ 135

Author(s):

Stefan S. Kim ◽

Ian E. McCutcheon ◽

Dima Suki ◽

Jeffrey S. Weinberg ◽

Raymond Sawaya ◽

...

Keyword(s):

Surgical Resection ◽

Neurological Status ◽

Extent Of Resection ◽

Sensory Function ◽

Neurological Deficits ◽

Cortical Mapping ◽

Eloquent Areas ◽

Eloquent Cortex ◽

Low Incidence ◽

Intraoperative Localization

Abstract OBJECTIVE Intraoperative localization of cortical areas for motor and language function has been advocated to minimize postoperative neurological deficits. We report herein the results of a retrospective study of cortical mapping and subsequent clinical outcomes in a large series of patients. METHODS Patients with intracerebral tumors near and/or within eloquent cortices (n = 309) were clinically evaluated before surgery, immediately after, and 1 month and 3 months after surgery. Craniotomy was tailored to encompass tumor plus adjacent areas presumed to contain eloquent cortex. Intraoperative cortical stimulation for language, motor, and/or sensory function was performed in all patients to safely maximize surgical resection. RESULTS A gross total resection (≥95%) was obtained in 64%, and a resection of 85% or more was obtained in 77% of the procedures. Eloquent areas were identified in 65% of cases, and in that group, worsened neurological deficits were observed in 21% of patients, whereas only 9% with negative mapping sustained such deficits (P < 0.01). Intraoperative neurological deficits occurred in 64 patients (21%); of these, 25 (39%) experienced worsened neurological outcome at 1 month, whereas only 27 of 245 patients (11%) without intraoperative changes had such outcomes (P < 0.001). At 1 month, 83% overall showed improved or stable neurological status, whereas 17% had new or worse deficits; however, at 3 months, 7% of patients had a persistent neurological deficit. Extent of resection less than 95% also predicted worsening of neurological status (P < 0.025). CONCLUSION Negative mapping of eloquent areas provides a safe margin for surgical resection with a low incidence of neurological deficits. However, identification of eloquent areas not only failed to eliminate but rather increased the risk of postoperative deficits, likely indicating close proximity of functional cortex to tumor.

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Comparison of conscious sedation and general anesthesia for motor mapping and resection of tumors located near motor cortex

Neurosurgical FOCUS ◽

10.3171/foc.2003.15.1.8 ◽

2003 ◽

Vol 15 (1) ◽

pp. 1-5 ◽

Cited By ~ 9

Author(s):

Todd W. Vitaz ◽

William Marx ◽

Jonathan D. Victor ◽

Philip H. Gutin

Keyword(s):

Motor Cortex ◽

General Anesthesia ◽

Conscious Sedation ◽

Neurological Deficits ◽

Anesthetic Technique ◽

Neurophysiological Monitoring ◽

Motor Mapping ◽

Eloquent Cortex ◽

Group 2 ◽

Group 1

Object The surgical treatment of tumors located near eloquent cortex carries a high risk of inducing worsening neurological deficits. Intraoperative electrocorticography techniques have been developed to help identify these areas at the time of surgery in an effort to minimize such risks. The optimal anesthetic technique for conducting these procedures, however, has never been determined. Methods The authors conducted a retrospective study to compare patients who underwent intraoperative motor mapping between September 2000 and May 2002. Demographic and neurophysiological monitoring data were collected from the hospital records. Patients were divided into two groups based on the anesthetic technique used for surgery: in Group 1 general anesthesia was used, and in Group 2 conscious sedation. Group 1 comprised 24 patients (mean age 47 years) with 16 right- and eight left-sided lesions. Group 2 consisted of 21 patients (mean age 46 years) with 18 right- and three left-sided lesions. Pathological diagnoses were similar between the two groups. Motor stimulation was elicited in 12 patients (50%) in Group 1 and in 21 patients (100%) in Group 2 (p < 0.001). In addition, the mean stimulation amplitude required was significantly higher (13 mA) in patients in whom conscious sedation was used as opposed to general anesthesia (5 mA, p < 0.0001). Electrographic evidence of seizures was seen in 29% of Group 1 cmpared with 10% of Group 2 patients (p > 0.05). Conclusions The use of conscious sedation as an anesthetic technique for motor mapping not only improves the chances of achieving successful stimulation and identification of motor cortex in relationship to the lesion, but it also allows for repetitive monitoring of the patient's motor function during resection of the lesion.

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Combined Utility of Functional MRI, Cortical Mapping, and Frameless Stereotaxy in the Resection of Lesions in Eloquent Areas of Brain in Children

Pediatric Neurosurgery ◽

10.1159/000121167 ◽

1997 ◽

Vol 26 (2) ◽

pp. 68-82 ◽

Cited By ~ 98

Author(s):

Simon R. Stapleton ◽

Elaine Kiriakopoulos ◽

David Mikulis ◽

James M. Drake ◽

Harold J. Hoffman ◽

...

Keyword(s):

Functional Mri ◽

Cortical Mapping ◽

Frameless Stereotaxy ◽

Eloquent Areas

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Preoperative magnetic source imaging for brain tumor surgery: a quantitative comparison with intraoperative sensory and motor mapping

Neurosurgical FOCUS ◽

10.3171/foc.2003.15.1.7 ◽

2003 ◽

Vol 15 (1) ◽

pp. 1-10 ◽

Cited By ~ 26

Author(s):

Hagen Schiffbauer ◽

Mitchel S. Berger ◽

Paul Ferrari ◽

Dirk Freudenstein ◽

Howard A. Rowley ◽

...

Keyword(s):

Brain Tumors ◽

Cortical Mapping ◽

Volume Data ◽

Current Dipole ◽

Source Imaging ◽

Magnetic Source Imaging ◽

Somatosensory Stimulation ◽

Motor Mapping ◽

Ms Imaging ◽

Magnetic Source

Object The aim of this study was to compare quantitatively the methods of preoperative magnetic source (MS) imaging and intraoperative electrophysiological cortical mapping (ECM) in the localization of sensorimotor cortex in patients with intraaxial brain tumors. Methods Preoperative magnetoencephalography (MEG) was performed while patients received painless tactile somatosensory stimulation of the lip, hand, and foot. The early somatosensory evoked field was modeled using a single equivalent current dipole approach to estimate the spatial source of the response. Three-dimensional magnetic resonance image volume data sets with fiducials were coregistered with the MEG recordings to form the MS image. These individualized functional brain maps were integrated into a neuronavigation system. Intraoperative mapping of somatosensory and/or motor cortex was performed and sites were compared. In two subgroups of patients we compared intraoperative somatosensory and motor stimulation sites with MS imaging–based somatosensory localizations. Mediolateral projection of the MS imaging source localizations to the cortical surface reduced systematic intermodality discrepancies. The distance between two corresponding points determined using MS imaging and ECM was 12.5 ± 1.3 mm for somatosensory–somatosensory and 19 ± 1.3 mm for somatosensory–motor comparisons. The observed 6.5 mm increase in site separation was systematically demonstrated in the anteroposterior direction, as expected from actual anatomy. In fact, intraoperative sites at which stimulation evoked the same patient response exhibited a spatial variation of 10.7 ± 0.7 mm. Conclusions Preoperative MS imaging and intraoperative ECM show a favorable degree of quantitative correlation. Thus, MS imaging can be considered a valuable and accurate planning adjunct in the treatment of patients with intraaxial brain tumors.

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28 Localization of Eloquent Cortex and White Matter Tracts Under General Anesthesia

Pediatric Epilepsy Surgery ◽

10.1055/b-0039-171660 ◽

2019 ◽

Keyword(s):

White Matter ◽

General Anesthesia ◽

White Matter Tracts ◽

Eloquent Cortex

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Mapping Alterations of the Functional Structure of the Cerebral Cortex in Obsessive–Compulsive Disorder

Cerebral Cortex ◽

10.1093/cercor/bhz008 ◽

2019 ◽

Vol 29 (11) ◽

pp. 4753-4762 ◽

Cited By ~ 4

Author(s):

Jesus Pujol ◽

Laura Blanco-Hinojo ◽

Dídac Maciá ◽

Pino Alonso ◽

Ben J Harrison ◽

...

Keyword(s):

Cerebral Cortex ◽

Obsessive Compulsive Disorder ◽

Neural Activity ◽

Orbitofrontal Cortex ◽

Inhibitory Neuron ◽

Functional Structure ◽

Neuron Activity ◽

Obsessive Compulsive ◽

Compulsive Disorder ◽

Neurophysiological Studies

AbstractWe mapped alterations of the functional structure of the cerebral cortex using a novel imaging approach in a sample of 160 obsessive–compulsive disorder (OCD) patients. Whole-brain functional connectivity maps were generated using multidistance measures of intracortical neural activity coupling defined within isodistant local areas. OCD patients demonstrated neural activity desynchronization within the orbitofrontal cortex and in primary somatosensory, auditory, visual, gustatory, and olfactory areas. Symptom severity was significantly associated with the degree of functional structure alteration in OCD-relevant brain regions. By means of a novel imaging perspective, we once again identified brain alterations in the orbitofrontal cortex, involving areas purportedly implicated in the pathophysiology of OCD. However, our results also indicated that weaker intracortical activity coupling is also present in each primary sensory area. On the basis of previous neurophysiological studies, such cortical activity desynchronization may best be interpreted as reflecting deficient inhibitory neuron activity and altered sensory filtering.

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