Neural oscillation, network, eloquent cortex and epileptogenic zone revealed by magnetoencephalography and awake craniotomy

Abstract BACKGROUND: Although stereoelectroencephalography (SEEG) has been shown to be a valuable tool for preoperative decision making in focal epilepsy, there are few reports addressing the utility and safety of SEEG methodology applied to children and adolescents. OBJECTIVE: To present the results of our early experience using SEEG in pediatric patients with difficult-to-localize epilepsy who were not considered candidates for subdural grid evaluation. METHODS: Thirty children and adolescents with the diagnosis of medically refractory focal epilepsy (not considered ideal candidates for subdural grids and strip placement) underwent SEEG implantation. Demographics, electrophysiological localization of the hypothetical epileptogenic zone, complications, and seizure outcome after resections were analyzed. RESULTS: Eighteen patients (60%) underwent resections after SEEG implantations. In patients who did not undergo resections (12 patients), reasons included failure to localize the epileptogenic zone (4 patients); multifocal epileptogenic zone (4 patients); epileptogenic zone located in eloquent cortex, preventing resection (3 patients); and improvement in seizures after the implantation (1 patient). In patients who subsequently underwent resections, 10 patients (55.5%) were seizure free (Engel class I) and 5 patients (27.7%) experienced seizure improvement (Engel class II or III) at the end of the follow-up period (mean, 25.9 months; range, 12 to 47 months). The complication rate in SEEG implantations was 3%. CONCLUSION: The SEEG methodology is safe and should be considered in children/adolescents with difficult-to-localize epilepsy. When applied to highly complex and difficult-to-localize pediatric patients, SEEG may provide an additional opportunity for seizure freedom in association with a low morbidity rate.

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Multilobar Epilepsy Surgery in Childhood and Adolescence: Predictors of Long-Term Seizure Freedom

Neurosurgery ◽

10.1093/neuros/nyaa368 ◽

2020 ◽

Vol 88 (1) ◽

pp. 174-182

Author(s):

Evangelos Kogias ◽

Thomas Bast ◽

Susanne Schubert-Bast ◽

Gert Wiegand ◽

Armin Brandt ◽

...

Keyword(s):

Epilepsy Surgery ◽

Seizure Control ◽

Focal Cortical Dysplasia ◽

Benign Tumors ◽

Seizure Freedom ◽

Childhood And Adolescence ◽

Epileptogenic Zone ◽

Seizure Recurrence ◽

Eloquent Cortex

Abstract BACKGROUND Although multilobar resections correspond to one-fifth of pediatric epilepsy surgery, there are little data on long-term seizure control. OBJECTIVE To investigate the long-term seizure outcomes of children and adolescents undergoing multilobar epilepsy surgery and identify their predictors. METHODS In this retrospective study, we considered 69 consecutive patients that underwent multilobar epilepsy surgery at the age of 10.0 ± 5.0 yr (mean ± SD). The magnetic resonance imaging revealed a lesion in all but 2 cases. Resections were temporo-parieto(-occipital) in 30%, temporo-occipital in 41%, parieto-occipital in 16%, and fronto-(temporo)-parietal in 13% cases. Etiologies were determined as focal cortical dysplasia in 67%, perinatal or postnatal ischemic lesions in 23%, and benign tumors in 10% of cases. RESULTS At last follow-up of median 9 yr (range 2.8-14.8), 48% patients were seizure free; 33% were off antiepileptic drugs. 10% of patients, all with dysplastic etiology, required reoperations: 4 of 7 achieved seizure freedom. Seizure recurrence occurred mostly (80%) within the first 6 mo. Among presurgical variables, only an epileptogenic zone far from eloquent cortex independently correlated with significantly higher rates of seizure arrest in multivariate analysis. Among postsurgical variables, the absence of residual lesion and of acute postsurgical seizures was independently associated with significantly higher rates of seizure freedom. CONCLUSION Our study demonstrates that multilobar epilepsy surgery is effective regarding long-term seizure freedom and antiepileptic drug withdrawal in selected pediatric candidates. Epileptogenic zones–and lesions–localized distant from eloquent cortex and, thus, fully resectable predispose for seizure control. Acute postsurgical seizures are critical markers of seizure recurrence that should lead to prompt reevaluation.

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Subdural EEG in Posterior Cortex Epilepsy

Invasive Studies of the Human Epileptic Brain ◽

10.1093/med/9780198714668.003.0026 ◽

2018 ◽

pp. 355-366

Author(s):

Americo C. Sakamoto ◽

Tonicarlo R. Velasco ◽

Jorge Gonzalez Martinez

Keyword(s):

Temporal Lobe Epilepsy ◽

Functional State ◽

Surgical Procedures ◽

Important Predictor ◽

Surgical Strategy ◽

Seizure Outcome ◽

Epileptogenic Zone ◽

Posterior Cortex ◽

Eloquent Cortex ◽

Definition Of

Surgery for extratemporal epilepsy surgery provides seizure control or reduction, but its overall results are less rewarding than those for temporal lobe epilepsy. Strategies for planning extratemporal surgery are more challenging and complex. Completeness of resection of the epileptogenic zone (EZ) is the single most important predictor of postsurgical seizure outcome, and therefore precise spatial delimitation of the EZ is at least as important as its localization. Moreover, careful definition and mapping of the functional state of the cortex bordering the EZ is crucial to ensure more precise and less risky surgical procedures. Invasive studies play a central role in the presurgical evaluation of extratemporal pharmacoresistant epilepsies. This chapter describes the rationale supporting the use of subdural electrodes, their role and limitations in definition of the irritative and ictal onset zones, in functional mapping of the eloquent cortex, and especially in planning of the surgical strategy.

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Awake craniotomy versus surgery under general anesthesia for resection of intrinsic lesions of eloquent cortex—A prospective randomised study

Clinical Neurology and Neurosurgery ◽

10.1016/j.clineuro.2007.01.008 ◽

2007 ◽

Vol 109 (4) ◽

pp. 335-343 ◽

Cited By ~ 91

Author(s):

Deepak Kumar Gupta ◽

P.S. Chandra ◽

B.K. Ojha ◽

B.S. Sharma ◽

A.K. Mahapatra ◽

...

Keyword(s):

General Anesthesia ◽

Awake Craniotomy ◽

Randomised Study ◽

Eloquent Cortex ◽

Prospective Randomised Study

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Development and implementation of a novel child life protocol to enhance psychosocial support for pediatric awake craniotomies: technical note

Neurosurgical FOCUS ◽

10.3171/2019.11.focus19774 ◽

2020 ◽

Vol 48 (2) ◽

pp. E5

Author(s):

Michael M. McDowell ◽

Daniela Ortega Peraza ◽

Taylor J. Abel

Keyword(s):

Prospective Studies ◽

Positive Reinforcement ◽

Psychosocial Support ◽

Patient Experiences ◽

Technical Note ◽

Awake Craniotomy ◽

Child Life ◽

Child Life Specialist ◽

Patient Tolerance ◽

Eloquent Cortex

Awake craniotomies are a crucial tool for identifying eloquent cortex, but significant limitations frequently related to patient tolerance have limited their applicability in pediatric cases. The authors describe a comprehensive, longitudinal protocol developed in collaboration with a certified child life specialist (CCLS) in order to enhance patient experiences and develop resiliency related to the intraoperative portion of cases. This protocol includes preoperative conditioning, intraoperative support, and postoperative positive reinforcement and debriefing. A unique coping plan is developed for each prospective patient. With appropriate support, awake craniotomy may be applicable in a wider array of preadolescent and adolescent patients than has previously been possible. Future prospective studies are needed to validate this approach.

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The Merits of Awake Craniotomy for Glioblastoma in the Left Hemispheric Eloquent Area: One Institution Experience

10.21203/rs.2.15627/v2 ◽

2020 ◽

Author(s):

Ying-Ching Li ◽

Hsiao-Yean Chiu ◽

Ya-Jui Lin ◽

Ko-Ting Chen ◽

Peng-Wei Hsu ◽

...

Keyword(s):

Progression Free Survival ◽

Extent Of Resection ◽

Awake Craniotomy ◽

Treatment Center ◽

Low Grade ◽

Karnofsky Performance Score ◽

Free Survival ◽

Neurological Outcomes ◽

Eloquent Cortex ◽

The Mean

Abstract Background Awake craniotomy (AC) with intraoperative stimulation mapping is the standard treatment for gliomas, especially those on the eloquent cortex. Many studies have reported survival benefits with the use of AC in patients with glioma, however most of these studies have focused on low-grade glioma. The aim of this study was to evaluate the experience of one treatment center over 10 years for resection of left hemispheric eloquent glioblastoma. Methods This retrospective analysis included 48 patients with left hemispheric eloquent glioblastoma who underwent AC and 61 patients who underwent surgery under general anesthesia (GA) between 2008 and 2018. Perioperative risk factors, extent of resection (EOR), preoperative and postoperative Karnofsky Performance Score (KPS), progression-free survival (PFS) and overall survival (OS) were assessed. Results The postoperative KPS was significantly lower in the GA patients compared to the AC patients (p=0.002). The EOR in the GA group was 90.2% compared to 94.9% in the AC group (p=0.003). The mean PFS was 18.9 months in the GA group and 23.2 months in the AC group (p=0.001). The mean OS was 25.5 months in all patients, 23.4 months in the GA group, and 28.1 months in the AC group (p<0.001). In multivariate analysis, the EOR and preoperative KPSindependently predicted better OS. Conclusion The patients with left hemispheric eloquent glioblastoma in this study had better neurological outcomes, maximal tumor removal, and better PFS and OS after AC than surgery under GA. Awake craniotomy should be performed in these patients if the resources are available.

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Awake Craniotomy vs Craniotomy Under General Anesthesia for Eloquent Glioma: Postoperative General Functional Preservation

10.21203/rs.2.15627/v1 ◽

2019 ◽

Author(s):

Ying-Ching Li ◽

Hsiao-Yean Chiu ◽

Ya-Jui Lin ◽

Ko-Ting Chen ◽

Peng-Wei Hsu ◽

...

Keyword(s):

General Anesthesia ◽

Functional Status ◽

Karnofsky Performance Status ◽

Performance Status ◽

Eastern Cooperative Oncology Group ◽

Tumor Resection ◽

Awake Craniotomy ◽

Newly Diagnosed ◽

Eloquent Cortex ◽

Functional Preservation

Abstract Background Awake craniotomy (AC) with intraoperative stimulation mapping is the standard treatment for glioma, especially when present on the eloquent cortex. The purpose of this study was to investigate whether functional preservation after AC compromises patient survival as compared with craniotomy under general anesthesia (GA). Methods The medical records of 339 patients who underwent tumor resection surgery for gliomas from January 2010 to December 2014 were retrospectively reviewed. Among these patients, 62 underwent AC with intraoperative stimulation mapping. The primary outcome was the Eastern cooperative oncology group (ECOG) performance score at 3 months postoperatively. Secondary outcomes were the progression-free survival (PFS) and overall survival (OS). A generalized linear model and the Cox proportional hazard model were used to evaluate potential factors influencing general functional status and progression-free survival.Results The newly-diagnosed disease AC and repeat-surgery groups were comparable in terms of sex, age, pathologic grade, extent of resection (EOR) and preoperative Karnofsky Performance Status (KPS). Among the patients with newly-diagnosed disease, the postoperative ECOG score of the AC group was significantly better than that of the GA group. Pathologic grade and the EOR determined the PFS and OS in both the AC and GA groups.Conclusion AC with intraoperative stimulation mapping is safe and allows maximal removal of lesions around the eloquent cortex. Greater preservation of neurologic function may have resulted in a better postoperative general functional status in the AC group.

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The role of magnetoencephalography in epilepsy surgery

Neurosurgical FOCUS ◽

10.3171/foc/2008/25/9/e16 ◽

2008 ◽

Vol 25 (3) ◽

pp. E16 ◽

Cited By ~ 39

Author(s):

Zulma S. Tovar-Spinoza ◽

Ayako Ochi ◽

James T. Rutka ◽

Cristina Go ◽

Hiroshi Otsubo

Keyword(s):

Mr Imaging ◽

Epilepsy Surgery ◽

Neuropsychological Testing ◽

Source Image ◽

Epileptogenic Zone ◽

Anatomical Localization ◽

Functional Mr Imaging ◽

Eloquent Cortex ◽

Magnetic Source Image ◽

Functional Areas

Epilepsy surgery requires the precise localization of the epileptogenic zone and the anatomical localization of eloquent cortex so that these areas can be preserved during cortical resection. Magnetoencephalography (MEG) is a technique that maps interictal magnetic dipole sources onto MR imaging to produce a magnetic source image. Magneto-encephalographic spike sources can be used to localize the epileptogenic zone and be part of the workup of the patient for epilepsy surgery in conjunction with data derived from an analysis of seizure semiology, scalp video electroencephalography, PET, functional MR imaging, and neuropsychological testing. In addition, magnetoencephalographic spike sources can be linked to neuronavigation platforms for use in the neurosurgical field. Finally, paradigms have been developed so that MEG can be used to identify functional areas of the cerebral cortex including the somatosensory, motor, language, and visual evoked fields. The authors review the basic principles of MEG and the utility of MEG for presurgical planning as well as intra-operative mapping and discuss future applications of MEG technology.

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Stereoelectroencephalography Following Subdural Grid Placement for Difficult to Localize Epilepsy

Neurosurgery ◽

10.1227/neu.0b013e318285b4ae ◽

2013 ◽

Vol 72 (5) ◽

pp. 723-729 ◽

Cited By ~ 47

Author(s):

Sumeet Vadera ◽

Jeffrey Mullin ◽

Juan Bulacio ◽

Imad Najm ◽

William Bingaman ◽

...

Keyword(s):

Perioperative Complications ◽

Temporal Lobectomy ◽

Seizure Freedom ◽

Epileptogenic Zone ◽

Resonance Imaging ◽

Coverage Area ◽

Eloquent Cortex ◽

Seizure Localization ◽

Type Of Surgery

Abstract BACKGROUND: Despite the use of invasive subdural recording, failure to localize or resect the epileptogenic zone (EZ) occurs. Potential causes for this include EZ originating outside of the subdural grid coverage area, involvement of eloquent cortex, or complications requiring removal of electrodes without seizure localization. No study has examined the safety and efficacy of stereoelectroencephalography (SEEG) after subdural grid placement. OBJECTIVE: To determine the efficacy of SEEG in patients who have previously undergone subdural grid placement. METHODS: A prospective analysis was performed on 14 patients who had subdural grid evaluation and underwent subsequent SEEG monitoring. The follow-up period after the SEEG-guided resections ranged from 11 months to 34 months with an average follow-up of 20.1 months. Magnetic resonance imaging findings, EZ localization, outcomes, type of surgery, and perioperative complications were evaluated. RESULTS: Ten patients (71%) underwent a resection after SEEG reimplantation. Of the 4 patients (29%) not undergoing resection, 2 had seizures arising from eloquent cortex, 1 had bitemporal epilepsy, and 1 had a previous temporal lobectomy contralateral to the EZ. An estimate of the EZ was achieved in all patients based on interictal and ictal recordings. In patients undergoing resection, 60% were seizure-free at 11 months. Perioperative complications were minimal and included 1 abscess, which required burr-hole drainage and antibiotics. CONCLUSION: SEEG is a safe and effective method after subdural grid placement is inconclusive, providing an additional opportunity for seizure freedom in this highly challenging group of patients.

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