Surgery for epilepsy

West, Siobhan; Nevitt, Sarah J; Cotton, Jennifer; Gandhi, Sacha E; Weston, Jennifer; Sudan, Ajay; Ramírez, Roberto; Newton, Richard

doi:10.1002/14651858.cd010541.pub3

Cited by 104 publications

(111 citation statements)

References 308 publications

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“…Surgical treatment of drug-resistant temporal lobe epilepsy (TLE) has proven superior to medical management of the disease (1). However, the proportion of seizure-free following TLE surgery remains suboptimal (2,3). In ∼50% of cases in which surgery fails to achieve seizure freedom, patients who continue to experience seizures after surgery are directly associated with an even lower quality of life (4).…”

Section: Introductionmentioning

confidence: 99%

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FDG-PET Profiles of Extratemporal Metabolism as a Predictor of Surgical Failure in Temporal Lobe Epilepsy

Tang

Liao

et al. 2020

Front. Med.

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Objective: Metabolic abnormality in the extratemporal area on fluorine-18-fluorodeoxyglucose positron emission tomography (FDG-PET) is not an uncommon finding in drug-resistant temporal lobe epilepsy (TLE), however the correlation between extratemporal metabolic abnormalities and surgical long-term prognosis has not been fully elucidated. We aim to investigate FDG-PET extratemporal metabolic profiles predictive of failure in surgery for TLE patients.Methods: Eighty-two patients with unilateral TLE (48 female, 34 male; 25.6 ± 10.6 years old; 37 left TLE, 45 right TLE) and 30 healthy age-matched controls were enrolled. Patients were classified either as experiencing seizure-recurrence (SZR, Engel class II through IV) or seizure-free (SZF, Engel class I) at least 1 year after surgery. Regional cerebral metabolism was evaluated by FDG-PET with statistical parametric mapping (SPM12). Abnormal metabolic profiles and patterns on FDG-PET in SZR group were evaluated and compared with those of healthy control and SZF subjects on SPM12. Volume and intensity as well as special brain areas of abnormal metabolism in temporal and extratemporal regions were quantified and visualized.Results: With a median follow-up of 1.5 years, 60% of patients achieved Engel class I (SZF). SZR was associated with left TLE and widespread hypometabolism in FDG-PET visual assessment (both p < 0.05). All patients had hypometabolism in the ipsilateral temporal lobe but SZR was not correlated with volume or intensity of temporal hypometabolism (median, 1,456 vs. 1,040 mm3; p > 0.05). SZR was correlated with extratemporal metabolic abnormalities that differed according to lateralization: in right TLE, SZR exhibited larger volume in extratemporal areas compared to SZF (median, 11,060 vs. 2,112 mm3; p < 0.05). Surgical failure was characterized by Cingulum_Ant_R/L, Frontal_Inf_Orb_R abnormal metabolism in extratemporal regions. In left TLE, SZR presented a larger involvement of extratemporal areas similar to right TLE but with no significant (median, 5,873 vs. 3,464 mm3; p > 0.05), Cingulum_Ant_ R/L, Parietal_Inf_L, Postcentral_L, and Precuneus_R involved metabolic abnormalities were correlated with SZR.Conclusions: Extratemporal metabolic profiles detected by FDG-PET may indicate a prominent cause of TLE surgery failure and should be considered in predictive models for epilepsy surgery. Seizure control after surgery might be improved by investigating extratemporal areas as candidates for resection or neuromodulation.

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Section: Introductionmentioning

confidence: 99%

“…It has proven difficult to identify from existing literature independent biomarker highly predictive of TLE surgery failure. Therefore, understanding the prominent reasons for surgical failure and identifying effective indicators to facilitate early evaluation remain of paramount importance in the context of epilepsy care (3,(5)(6)(7).…”

Section: Introductionmentioning

confidence: 99%

FDG-PET Profiles of Extratemporal Metabolism as a Predictor of Surgical Failure in Temporal Lobe Epilepsy

Tang

Liao

et al. 2020

Front. Med.

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“…In current praxis, the seizure-onset zone (SOZ) is used as the main proxy marker for the EZ. A sustained seizure-free condition is currently, however, obtained in only 50% of carefully selected patients [Krucoff et al, 2017; Mohan et al, 2018; West et al, 2019]. This is likely due to inaccurate localization of the EZ or a network involvement larger than initially expected [Englot, 2018].…”

Section: Introductionmentioning

confidence: 99%

Fast oscillations >40Hz localize the epileptogenic zone: an electrical source imaging study using high-density electroencephalography

Avigdor

Abdallah

Ellenrieder

et al. 2020

Preprint

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CONFLICTS OF INTEREST:None of the authors has any conflict of interested related to the submitted work. P a g e | 3 Avigdor et al. | Fast oscillations localize the epileptogenic zone ABSTRACT (245/250) Fast Oscillations (FO) are a promising biomarker of the epileptogenic zone (EZ) in the intracranial electroencephalogram (EEG). Evidence using scalp EEG remains scarce. This is the first study that assesses if electrical source imaging of FO using 256-channel high-density EEG is feasible and useful for EZ identification. We analyzed high-density EEG recordings of 10 focal drug-resistant epilepsy patients with seizure-free postsurgical outcome (follow-up >2 years). We marked FO candidate events at the time of epileptic spikes and then verified them by screening for an isolated peak in the time-frequency plot. We performed electrical source imaging of FOs >40 Hz and spikes using the coherent Maximum Entropy of the Mean technique. Source localization maps were validated against the surgical cavity as approximation of the EZ. We identified FO events in 5 of the 10 patients. FOs were localizable in all 5 patients. The depth of the epileptic generator was either superficial or intermediate in all 5 patients with FO. The maximum of the FO maps was localized in the surgical cavity. We identified spikes in all 10 patients. Spikes were localized to the surgical cavity in 9 of 10 patients. In summary, FOs recorded with high-density EEG are able to localize the EZ. Our findings suggest that the presence of FOs co-localized with spikes points to a surface-close generator. These results can act as a proof of concept for future examination of FOs localization using scalp 256-channel high-density EEG as a viable marker of the EZ. Key words: high-density electroencephalography, epilepsy, maximum entropy of the mean, electrical source imaging, non-invasive localization P a g e | 4 Avigdor et al. | Fast oscillations localize the epileptogenic zone INTRODUCTION Epilepsy is a chronic condition characterized by recurrent seizures accompanied by negative impact on quality of life [Hinnell et al., 2010]. A significant number of 30% of patients with focal epilepsy are drug-resistant, and these numbers did not change over the past 30 years despite the development of multiple new antiepileptic drugs [Chen et al., 2018]. The therapy of choice for focal drug-resistant epilepsy is epilepsy surgery [Vakharia et al., 2018]. The aim of epilepsy surgery is to remove the epileptogenic zone (EZ) defined as the area of cortex that needs to be removed to achieve seizure freedom [Rosenow and Lüders, 2001]. In current praxis, the seizure-onset zone (SOZ) is used as the main proxy marker for the EZ. A sustained seizure-free condition is currently, however, obtained in only 50% of carefully selected patients [Krucoff et al., 2017; Mohan et al., 2018; West et al., 2019]. This is likely due to inaccurate localization of the EZ or a network involvement larger than initially expected [Englot, 2018]. This underlines the need to develop new markers and localiz...

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“…The two most common medically refractory epilepsy syndromes include temporal lobe epilepsy (TLE) with hippocampal sclerosis as its pathological hallmark [ 3 ] and extra-temporal lobe epilepsy arising developmental malformations, particularly focal cortical dysplasia (FCD) [ 4 ]. Surgical resection of an MRI-identifiable lesion is the first-line treatment option for drug-refractory epilepsy [ 5 ] with success rates that may reach up to 80% [ 6 ]. Notably, complete resection of the lesion is the most reliable predictor for postoperative seizure freedom [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

Contributions of Imaging to Neuromodulatory Treatment of Drug-Refractory Epilepsy

2020

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Epilepsy affects about 1% of the world’s population, and up to 30% of all patients will ultimately not achieve freedom from seizures with anticonvulsive medication alone. While surgical resection of a magnetic resonance imaging (MRI) -identifiable lesion remains the first-line treatment option for drug-refractory epilepsy, surgery cannot be offered to all. Neuromodulatory therapy targeting “seizures” instead of “epilepsy” has emerged as a valuable treatment option for these patients, including invasive procedures such as deep brain stimulation (DBS), responsive neurostimulation (RNS) and peripheral approaches such as vagus nerve stimulation (VNS). The purpose of this review is to provide in-depth information on current concepts and evidence on network-level aspects of drug-refractory epilepsy. We reviewed the current evidence gained from studies utilizing advanced imaging methodology, with a specific focus on their contributions to neuromodulatory therapy.

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Surgery for epilepsy

Abstract: Analysis 2.1. Comparison 2 Comparison of surgical techniques (randomised evidence), Outcome 1 Parahippocampectomy (PHC) or anterior temporal lobectomy (ATL): Proportion free from seizures (Engel Class Scale

Cited by 104 publications

References 308 publications

FDG-PET Profiles of Extratemporal Metabolism as a Predictor of Surgical Failure in Temporal Lobe Epilepsy

FDG-PET Profiles of Extratemporal Metabolism as a Predictor of Surgical Failure in Temporal Lobe Epilepsy

Fast oscillations >40Hz localize the epileptogenic zone: an electrical source imaging study using high-density electroencephalography

Contributions of Imaging to Neuromodulatory Treatment of Drug-Refractory Epilepsy

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