Magnetoencephalography-guided resection of epileptogenic foci in children

2014 ◽  
Vol 14 (5) ◽  
pp. 532-537 ◽  
Author(s):  
Gregory W. Albert ◽  
George M. Ibrahim ◽  
Hiroshi Otsubo ◽  
Ayako Ochi ◽  
Cristina Y. Go ◽  
...  
Keyword(s):  
Epilepsy Surgery ◽  
Csf Leak ◽  
Pediatric Epilepsy ◽  
Seizure Freedom ◽  
Invasive Monitoring ◽  
Mri Findings ◽  
Resective Surgery ◽  
Depth Electrodes ◽  
Additional Surgery ◽  
Sick Children

Object Resective surgery is increasingly used in the management of pediatric epilepsy. Frequently, invasive monitoring with subdural electrodes is required to adequately map the epileptogenic focus. The risks of invasive monitoring include the need for 2 operations, infection, and CSF leak. The aim of this study was to evaluate the feasibility and outcomes of resective epilepsy surgery guided by magnetoencephalography (MEG) in children who would have otherwise been candidates for electrode implantation. Methods The authors reviewed the records of patients undergoing resective epilepsy surgery at the Hospital for Sick Children between 2001 and 2010. They identified cases in which resections were based on MEG data and no intracranial recordings were performed. Each patient's chart was reviewed for presentation, MRI findings, MEG findings, surgical procedure, pathology, and surgical outcome. Results Sixteen patients qualified for the study. All patients had localized spike clusters on MEG and most had abnormal findings on MRI. Resection was carried out in each case based on the MEG data linked to neuronavigation and supplemented with intraoperative neuromonitoring. Overall, 62.5% of patients were seizure free following surgery, and 20% of patients experienced an improvement in seizures without attaining seizure freedom. In 2 cases, additional surgery was performed subsequently with intracranial monitoring in attempts to obtain seizure control. Conclusions MEG is a viable alternative to invasive monitoring with intracranial electrodes for planning of resective surgery in carefully selected pediatric patients with localization-related epilepsy. Good candidates for this approach include patients who have a well-delineated, localized spike cluster on MEG that is concordant with findings of other preoperative evaluations and patients with prior brain pathologies that make the implantation of subdural and depth electrodes somewhat problematic.

Chronic unlimited recording electrocorticography–guided resective epilepsy surgery: technology-enabled enhanced fidelity in seizure focus localization with improved surgical efficacy

2014 ◽  
Vol 120 (6) ◽  
pp. 1402-1414 ◽  
Author(s):  
Daniel J. DiLorenzo ◽  
Erwin Z. Mangubat ◽  
Marvin A. Rossi ◽  
Richard W. Byrne
Keyword(s):  
Epilepsy Surgery ◽  
Primary Motor Cortex ◽  
Epileptiform Activity ◽  
Seizure Freedom ◽  
Monitoring Technology ◽  
Resective Surgery ◽  
Depth Electrodes ◽  
Small Series ◽  
Number Of Patients ◽  
Ablative Surgery

Object Epilepsy surgery is at the cusp of a transformation due to the convergence of advancements in multiple technologies. Emerging neuromodulatory therapies offer the promise of functionally correcting neural instability and obviating the need for resective or ablative surgery in select cases. Chronic implanted neurological monitoring technology, delivered as part of a neuromodulatory therapeutic device or as a stand-alone monitoring system, offers the potential to monitor patients chronically in their normal ambulatory setting with outpatient medication regimens. This overcomes significant temporal limitations, pharmacological perturbations, and infection risks inherent in the present technology comprising subacute percutaneous inpatient monitoring of presurgical candidates in an epilepsy monitoring unit. Methods As part of the pivotal study for the NeuroPace Responsive Neurostimulation (RNS) System, the authors assessed the efficacy of the RNS System to control seizures in a group of patients with medically refractory epilepsy. Prior to RNS System implantation, these patients were not candidates for further resective surgery because they had temporal lobe epilepsy with bilateral temporal sources, frontal lobe reflex epilepsy with involvement of primary motor cortex, and occipital lobe epilepsy with substantial involvement of eloquent visual cortex. Without interfering with and beyond the scope of the therapeutic aspect of the RNS System study, the authors were able to monitor seizure and epileptiform activity from chronically implanted subdural and depth electrodes in these patients, and, in doing so, they were able to more accurately localize the seizure source. In 5 of these study patients, in whom the RNS System was not effective, the notion of resective surgery was revisited and considered in light of the additional information gleaned from the chronic intracranial recordings obtained from various permutations of electrodes monitoring sources in the frontal, temporal, parietal, and occipital lobes. Results Through long-term analysis of chronic unlimited recording electrocorticography (CURE) from chronically implanted electrodes, the authors were able to further refine seizure source localization and sufficiently increase the expected likelihood of seizure control to the extent that 4 patients who had previously been considered not to be candidates for surgery did undergo resective surgery, and all have achieved seizure freedom. A fifth patient, who had a double-band heterotopia, underwent surgery but did not achieve significant seizure reduction. Conclusions Chronic unlimited recording electrocorticography–guided resective epilepsy surgery employs new monitoring technology in a novel way, which in this small series was felt to improve seizure localization and consequently the potential efficacy of resective surgery. This suggests that the CURE modality could improve outcomes in patients who undergo resective surgery, and it may expand the set of patients in whom resective surgery may be expected to be efficacious and therefore the potential number of patients who may achieve seizure freedom. The authors report 4 cases of patients in which this technique and technology had a direct role in guiding surgery that provided seizure freedom and that suggest this new approach warrants further study to characterize its value in presurgical evaluation. Clinical trial no.: NCT00572195 (ClinicalTrials.gov).

scholarly journals Depth Electrodes in Pediatric Epilepsy Surgery

2013 ◽  
Vol 40 (1) ◽  
pp. 48-55 ◽  
Author(s):  
Janani Kassiri ◽  
Jeff Pugh ◽  
Sharon Carline ◽  
Laura Jurasek ◽  
Thomas Snyder ◽  
...  
Keyword(s):  
Epilepsy Surgery ◽  
Pediatric Epilepsy ◽  
Surgical Removal ◽  
Seizure Freedom ◽  
Sufficient Information ◽  
Epileptogenic Zone ◽  
Depth Electrodes ◽  
Depth Electrode ◽  
Intractable Seizures ◽  
Clinical Scenarios

Abstract:Background:The surgical removal of the epileptogenic zone in medically intractable seizures depends on accurate localization to minimize the neurological sequelae and prevent future seizures. To date, few studies have demonstrated the use of depth electrodes in a pediatric epilepsy population. Here, we report our study of pediatric epilepsy patients at our epilepsy center who were successfully operated for medically intractable seizures following the use of intracranial depth electrodes. In addition, we detail three individuals with distinct clinical scenarios in which depth electrodes were helpful and describe our technical approach to implantation and surgery.Methods:We retrospectively reviewed 18 pediatric epilepsy patients requiring depth electrode studies who presented at the University of Alberta Comprehensive Epilepsy Program between 1999 and 2010 with medically intractable epilepsy. Patients underwent cortical resection following depth electrode placement according to the Comprehensive Epilepsy Program surgical protocols after failure of surface electroencephalogram and magnetic resonance imaging to localize ictal onset zone.Result:The ictal onset zone was successfully identified in all 18 patients. Treatment of all surgical patients resulted in successful seizure freedom (Engel class I) without neurological complications.Conclusion:Intracranial depth electrode use is safe and able to provide sufficient information for the identification of the epileptogenic zone in pediatric epilepsy patients previously not considered for epilepsy surgery.

scholarly journals Blinded study: prospectively defined high frequency oscillations predict seizure outcome in individual patients

2020 ◽  
Author(s):  
V Dimakopoulos ◽  
P Mégevand ◽  
E Boran ◽  
S Momjian ◽  
M Seeck ◽  
...  
Keyword(s):  
Epilepsy Surgery ◽  
High Frequency ◽  
Dwell Time ◽  
Nrem Sleep ◽  
Seizure Outcome ◽  
Seizure Freedom ◽  
University Hospitals ◽  
High Frequency Oscillations ◽  
Depth Electrodes

AbstractBackgroundInterictal high frequency oscillations (HFO) are discussed as biomarkers for epileptogenic brain tissue that should be resected in epilepsy surgery to achieve seizure freedom. The prospective classification of tissue sampled by individual electrode contacts remains a challenge. We have developed an automated, prospective definition of clinically relevant HFO in intracranial EEG (iEEG) from MNI Montreal and tested it in iEEG from Zurich. We here validate the algorithm on iEEG recorded in an independent epilepsy center so that HFO analysis was blinded to seizure outcome.MethodsWe selected consecutive patients from Geneva University Hospitals who underwent resective epilepsy surgery with postsurgical follow-up > 12 months. We analyzed long-term iEEG recordings during non-rapid eye movement (NREM) sleep that we segmented into intervals of 5 min. HFOs were defined in the ripple (80-250 Hz) and the fast ripple (FR, 250-500 Hz) frequency band. Contacts with the highest rate of ripples co-occurring with FR (FRandR) designated the HFO area. If the HFO area was not fully resected and the patient suffered from recurrent seizures (ILAE 2-6), this was classified as a true positive (TP) prediction.ResultsWe included iEEG recordings from 16 patients (median age 32 y, range [18-53]) with stereotactic depth electrodes and/or with subdural electrode grids (median follow-up 27 mo, range [12-55]). The HFO area had high test-retest reliability across intervals (median dwell time 95%). We excluded two patients with dwell time < 50% from further analysis.The HFO area was fully included in the resected volume in 2/4 patients who achieved postoperative seizure freedom (ILAE 1, specificity 50%) and was not fully included in 9/10 patients with recurrent seizures (ILAE > 1, sensitivity 90%), leading to an accuracy of 79%.ConclusionsWe validated the automated procedure to delineate the clinical relevant HFO area in individual patients of an independently recorded dataset and achieved the same good accuracy as in our previous studies.SignificanceThe reproducibility of our results across datasets is promising for a multicienter study testing the clinical application of HFO detection to guide epilepsy surgery.

Pediatric Epilepsy Surgery in Focal and Generalized Epilepsy: Current Trends and Recent Advancements

2021 ◽  
Author(s):  
William B. Harris ◽  
H. Westley Phillips ◽  
Aria Fallah ◽  
Gary W. Mathern
Keyword(s):  
Epilepsy Surgery ◽  
Intractable Epilepsy ◽  
Pediatric Epilepsy ◽  
Seizure Freedom ◽  
Surgical Interventions ◽  
Current Trends ◽  
Pediatric Epilepsy Surgery ◽  
Generalized Epilepsy ◽  
Epileptogenic Foci

AbstractFor a subset of children with medically intractable epilepsy, surgery may provide the best chances of seizure freedom. Whereas the indications for epilepsy surgery are commonly thought to be limited to patients with focal epileptogenic foci, modern imaging and surgical interventions frequently permit successful surgical treatment of generalized epilepsy. Resection continues to be the only potentially curative intervention; however, the advent of various neuromodulation interventions provides an effective palliative strategy for generalized or persistent seizures. Although the risks and benefits vary greatly by type and extent of intervention, the seizure outcomes appear to be uniformly favorable. Advances in both resective and nonresective surgical interventions provide promise for improved seizure freedom, function, and quality of life. This review summarizes the current trends and recent advancements in pediatric epilepsy surgery from diagnostic workup and indications through surgical interventions and postoperative outcomes.

Cognitive Development in Pediatric Epilepsy Surgery

2017 ◽  
Vol 49 (02) ◽  
pp. 093-103 ◽  
Author(s):  
Gitta Reuner ◽  
Georgia Ramantani
Keyword(s):  
Cognitive Development ◽  
Epilepsy Surgery ◽  
Verbal Learning ◽  
Pediatric Epilepsy ◽  
Seizure Freedom ◽  
Effective Treatment Option ◽  
Multicenter Studies ◽  
Assessment Protocol ◽  
Pediatric Epilepsy Surgery ◽  
Developmental Impairment

AbstractEpilepsy surgery is a very effective treatment option for children and adolescents with drug-resistant structural epilepsy, resulting in seizure freedom in the majority of cases. Beyond seizure freedom, the postsurgical stabilization or even improvement of cognitive development constitutes a fundamental objective. This study aims to address key features of cognitive development in the context of pediatric epilepsy surgery. Many surgical candidates present with severe developmental delay and cognitive deficits prior to surgery. Recent studies support that global cognitive development remains stable after surgery. Individual developmental trajectories are determined by the degree of presurgical developmental impairment, age at surgery, seizure freedom, antiepileptic drug tapering, and other case-specific factors. Compared with adults, children may better compensate for temporary postsurgical deficits in circumscribed cognitive functions such as memory. Particularly for left-sided temporal resections, children present a clear advantage in terms of postsurgical recovery with regard to verbal learning compared with adults. In the case of severe presurgical developmental impairment, minimal postsurgical improvements are often not measurable, although they are evident to patients' families and have a large impact on their quality of life. Multicenter studies with a standardized assessment protocol and longer follow-up intervals are urgently called for to provide deeper insights into the cognitive development after epilepsy surgery, to analyze the interaction between different predictors, and to facilitate the selection of appropriate candidates as well as the counseling of families.

Safety of Staged Epilepsy Surgery in Children

Neurosurgery ◽  
2013 ◽  
Vol 74 (2) ◽  
pp. 154-162 ◽  
Author(s):  
Jonathan Roth ◽  
Chad Carlson ◽  
Orrin Devinsky ◽  
David H. Harter ◽  
William S. MacAllister ◽  
...  
Keyword(s):  
Epilepsy Surgery ◽  
Refractory Epilepsy ◽  
Electrode Placement ◽  
Wound Complications ◽  
Neurosurgical Procedures ◽  
Epileptogenic Zone ◽  
Invasive Monitoring ◽  
Depth Electrodes ◽  
Major Complications ◽  
Medically Refractory Epilepsy

Abstract BACKGROUND: Surgical resection of epileptic foci relies on accurate localization of the epileptogenic zone, often achieved by subdural and depth electrodes. Our epilepsy center has treated selected children with poorly localized medically refractory epilepsy with a staged surgical protocol, with at least 1 phase of invasive monitoring for localization and resection of epileptic foci. OBJECTIVE: To evaluate the safety of staged surgical treatments for refractory epilepsy among children. METHODS: Data were retrospectively collected, including surgical details and complications of all patients who underwent invasive monitoring. RESULTS: A total of 161 children underwent 200 admissions including staged procedures (&gt;1 surgery during 1 hospital admission), and 496 total surgeries. Average age at surgery was 7 years (range, 8 months to 16.5 years). A total of 250 surgeries included resections (and invasive monitoring), and 189 involved electrode placement only. The cumulative total number of surgeries per patient ranged from 2 to 10 (average, 3). The average duration of monitoring was 10 days (range, 1–30). There were no deaths. Follow-up ranged from 1 month to 10 years. Major complications included unexpected new permanent mild neurological deficits (2%/admission), central nervous system or bone flap infections (1.5%/admission), intracranial hemorrhage, cerebrospinal fluid leak, and a retained strip (each 0.5%/admission). Minor complications included bone absorption (5%/admission), positive surveillance sub-/epidural cultures in asymptomatic patients (5.5%/admission), noninfectious fever (5%/admission), and wound complications (3%/admission). Thirty complications necessitated additional surgical treatment. CONCLUSION: Staged epilepsy surgery with invasive electrode monitoring is safe in children with poorly localized medically refractory epilepsy. The rate of major complications is low and appears comparable to that associated with other elective neurosurgical procedures.

scholarly journals Presurgical evaluation of pediatric epilepsy patients prior to hemispherotomy: the prognostic value of 18F-FDG PET

2016 ◽  
Vol 18 (6) ◽  
pp. 683-688 ◽  
Author(s):  
Tatjana Traub-Weidinger ◽  
Philip Weidinger ◽  
Gundrun Gröppel ◽  
Georgios Karanikas ◽  
Wolfgang Wadsak ◽  
...  
Keyword(s):  
Clinical Data ◽  
Fdg Pet ◽  
Imaging Techniques ◽  
Pediatric Epilepsy ◽  
Seizure Outcome ◽  
Seizure Freedom ◽  
Presurgical Evaluation ◽  
Mri Findings ◽  
International League

OBJECTIVE The objective of this study was to investigate whether fluorine-18 fluorodeoxyglucose PET (18F-FDG PET) can help to predict seizure outcome after hemispherotomy and therefore may be useful in decision making and patient selection. METHODS Children and adolescents less than 18 years of age who underwent 18F-FDG PET studies during presurgical evaluation prior to hemispherotomy and had follow-up data of at least 12 months after surgery were included. Seizure outcome was classified according to the recommendations of the International League Against Epilepsy. PET data were reevaluated by two specialists in nuclear medicine blinded to clinical data and to MRI. MRI studies were also reinterpreted visually by an experienced neuroradiologist blinded to clinical data and PET findings. RESULTS Thirty-five patients (17 girls) with a median age of 5 years (range 0.4–17.8 years) were evaluable. Of the 35 patients, 91.4% were seizure free after surgery, including 100% of those with unilateral 18F-FDG-PET hypometabolism compared with only 75% of those with bilateral hypometabolism. With respect to MRI, seizure freedom after surgery was observed in 96.4% of the patients with unilateral lesions compared with only 71.4% in those with bilateral MRI lesions. The best seizure outcomes were noted in patients with unilateral findings in both PET and MRI (100% seizure freedom) whereas only 50% of those with bilateral findings in both imaging techniques were seizure free. Furthermore, 100% of the patients with unilateral PET hypometabolism and bilateral MRI findings were also seizure free, but only 87.5% of those with bilateral PET hypometabolism and unilateral MRI findings. CONCLUSIONS According to these results, candidate selection for hemispherotomy can be optimized by the use of 18F-FDG PET as part of a multimodal presurgical evaluation program, especially in patients with inconsistent (bilateral) MRI findings.

A multimodal concept for invasive diagnostics and surgery based on neuronavigated voxel-based morphometric MRI postprocessing data in previously nonlesional epilepsy

2018 ◽  
Vol 128 (4) ◽  
pp. 1178-1186 ◽  
Author(s):  
Daniel Delev ◽  
Carlos M. Quesada ◽  
Alexander Grote ◽  
Jan P. Boström ◽  
Christian Elger ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Diagnostic Yield ◽  
Focal Cortical Dysplasia ◽  
Seizure Outcome ◽  
Epileptogenic Zone ◽  
Mri Findings ◽  
Additional Information ◽  
Resective Surgery ◽  
Depth Electrodes ◽  
Class 1

OBJECTIVEDiagnosis and surgical treatment of refractory and apparent nonlesional focal epilepsy is challenging. Morphometric MRI voxel-based and other postprocessing methods can help to localize the epileptogenic zone and thereby support the planning of further invasive electroencephalography (EEG) diagnostics, and maybe resective epilepsy surgery.METHODSThe authors developed an algorithm to implement regions of interest (ROI), based on postprocessed MRI data, into a neuronavigation tool. This was followed by stereotactic ROI-guided implantation of depth electrodes and ROI-navigated resective surgery. Data on diagnostic yield, histology, and seizure outcome were collected and evaluated.RESULTSFourteen consecutive patients with apparently nonlesional epilepsy were included in this study. Reevaluation of the MR images with the help of MRI postprocessing analysis led to the identification of probable subtle lesions in 11 patients. Additional information obtained by SPECT imaging and MRI reevaluation suggested possible lesions in the remaining 3 patients. The ROI-guided invasive implantation of EEG yielded interictal and ictal activity in 13 patients who were consequently referred to resective surgery. Despite the apparently negative MRI findings, focal cortical dysplasia was found in 64% of the patients (n = 9). At the last available outcome, 8 patients (57%) were completely seizure free (International League Against Epilepsy Class 1).CONCLUSIONSThe results demonstrate the feasibility and usefulness of a robust and straightforward algorithm for implementation of MRI postprocessing-based targets into the neuronavigation system. This approach allowed the stereotactic implantation of a low number of depth electrodes only, which confirmed the seizure-onset hypothesis in 90% of the cases without causing any complications. Furthermore, the neuronavigated ROI-guided lesionectomy helped to perform resective surgery in this rather challenging subgroup of patients with apparent nonlesional epilepsy.

Novel diffusion tractography methodology using Kalman filter prediction to improve preoperative benefit-risk analysis in pediatric epilepsy surgery

2019 ◽  
Vol 24 (3) ◽  
pp. 293-305 ◽  
Author(s):  
Min-Hee Lee ◽  
Nolan B. O’Hara ◽  
Hirotaka Motoi ◽  
Aimee F. Luat ◽  
Csaba Juhász ◽  
...  
Keyword(s):  
Kalman Filter ◽  
Epilepsy Surgery ◽  
Euclidean Distance ◽  
Resection Margin ◽  
Free Probability ◽  
Pediatric Epilepsy ◽  
Seizure Freedom ◽  
Pediatric Epilepsy Surgery ◽  
Map Analysis ◽  
Benefit And Risk

OBJECTIVEIn this study the authors investigated the clinical reliability of diffusion weighted imaging maximum a posteriori probability (DWI-MAP) analysis with Kalman filter prediction in pediatric epilepsy surgery. This approach can yield a suggested resection margin as a dynamic variable based on preoperative DWI-MAP pathways. The authors sought to determine how well the suggested margin would have maximized occurrence of postoperative seizure freedom (benefit) and minimized occurrence of postoperative neurological deficits (risk).METHODSThe study included 77 pediatric patients with drug-resistant focal epilepsy (age 10.0 ± 4.9 years) who underwent resection of their presumed epileptogenic zone. In preoperative DWI tractography from the resected hemisphere, 9 axonal pathways, Ci=1–9, were identified using DWI-MAP as follows: C1–3supporting face, hand, and leg motor areas; C4connecting Broca’s and Wernicke’s areas; C5–8connecting Broca’s, Wernicke’s, parietal, and premotor areas; and C9connecting the occipital lobe and lateral geniculate nucleus. For each Ci, the resection margin, di, was measured by the minimal Euclidean distance between the voxels of Ciand the resection boundary determined by spatially coregistered postoperative MRI. If Ciwas resected, diwas assumed to be negative (calculated as –1 × average Euclidean distance between every voxel inside the resected Civolume, ri). Kalman filter prediction was then used to estimate an optimal resection margin, d*i, to balance benefit and risk by approximating the relationship between diand ri. Finally, the authors defined the preservation zone of Cithat can balance the probability of benefit and risk by expanding the cortical area of Ciup to d*ion the 3D cortical surface.RESULTSIn the whole group (n = 77), nonresection of the preoperative preservation zone (i.e., actual resection margin d*igreater than the Kalman filter–defined d*i) accurately predicted the absence of postoperative motor (d*1–3: 0.93 at seizure-free probability of 0.80), language (d*4–8: 0.91 at seizure-free probability of 0.81), and visual deficits (d*9: 0.90 at seizure-free probability of 0.75), suggesting that the preservation of preoperative Ciwithin d*isupports a balance between postoperative functional deficit and seizure freedom. The subsequent subgroup analyses found that preservation of preoperative Ci=1–4,9within d*i=1–4,9may provide accurate deficit predictions independent of age and seizure frequency, suggesting that the DWI-based surgical margin can be effective for surgical planning even in young children and across a range of epilepsy severity.CONCLUSIONSIntegrating DWI-MAP analysis with Kalman filter prediction may help guide epilepsy surgery by visualizing the margins of the eloquent white matter pathways to be preserved.

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