Temporal patterns and mechanisms of epilepsy surgery failure

Najm, Imad; Jehi, Lara; Palmini, André; González-Martínez, Jorge; Paglioli, Eliseu; Bingaman, William

doi:10.1111/epi.12152

Cited by 176 publications

(158 citation statements)

References 89 publications

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“…28,29 The etiology of temporal plus epilepsy may be related to progressive recruitment of tissue within the functional network associated with the epileptic tissue, with seizure activity within the mesial structures acting either as cause or effect in a more diffuse epilepsy syndrome. 3,13,24,26 Noninvasive localization of the epileptogenic zone can usually be accomplished by examining semiology, EEG, imaging, and the chronic effect of seizures on eloquent areas. 27 However, when semiology, MRI, EEG, and neuropsychological tests are contradictory, intracranial recordings are often indicated to determine the epileptogenic zone.…”

Section: Discussionmentioning

confidence: 99%

Temporal lobe epilepsy in patients with nonlesional MRI and normal memory: an SEEG study

Suresh

Sweet

Fastenau

et al. 2015

JNS

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OBJECT Temporal lobe epilepsy (TLE) in the absence of MRI abnormalities and memory deficits is often presumed to have an extramesial or even extratemporal source. In this paper the authors report the results of a comprehensive stereoelectroencephalography (SEEG) analysis in patients with TLE with normal MRI images and memory scores. METHODS Eighteen patients with medically refractory epilepsy who also had unremarkable MR images and normal verbal and visual memory scores on neuropsychological testing were included in the study. All patients had seizure semiology and video electroencephalography (EEG) findings suggestive of TLE. A standardized SEEG investigation was performed for each patient with electrodes implanted into the mesial and lateral temporal lobe, temporal tip, posterior temporal neocortex, orbitomesiobasal frontal lobe, posterior cingulate gyrus, and insula. This information was used to plan subsequent surgical management. RESULTS Interictal SEEG abnormalities were observed in the mesial temporal structures in 17 patients (94%) and in the temporal tip in 6 (33%). Seizure onset was exclusively from mesial structures in 13 (72%), exclusively from lateral temporal cortex and/or temporal tip structures in 2 (11%), and independently from mesial and neocortical foci in 3 (17%). No seizure activity was observed arising from any extratemporal location. All patients underwent surgical intervention targeting the temporal lobe and tailored to the SEEG findings, and all experienced significant improvement in seizure frequency with a postoperative follow-up observation period of at least 1 year. CONCLUSIONS This study demonstrates 3 important findings: 1) normal memory does not preclude mesial temporal seizure onset; 2) onset of seizures exclusively from mesial temporal structures without early neocortical involvement is common, even in the absence of memory deficits; and 3) extratemporal seizure onset is rare when video EEG and semiology are consistent with focal TLE.

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Section: Discussionmentioning

confidence: 99%

Temporal lobe epilepsy in patients with nonlesional MRI and normal memory: an SEEG study

Suresh

Sweet

Fastenau

et al. 2015

JNS

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“…Seizure recurrence is a complex, multifactorial, and dynamic phenomenon. Half of post‐TLE surgery failures first manifest within 6 months of surgery, and half of ETLE surgical failures first manifest within 2–4 months of surgery; the remaining half of all surgical failures represent “late seizure recurrences” first manifesting several months to years after surgery 47. Obvious causes of surgical failure such as inaccurate localization of the epileptogenic zone or incomplete resection of the known epileptogenic cortex are intuitive explanations of ongoing postoperative seizures.…”

Section: Surgical Outcomesmentioning

confidence: 99%

“…Approaches at improving outcomes should expand beyond improving epilepsy localization to understanding the mechanisms of postoperative epileptogenesis 47, 62. Such a paradigm shift in our approach at studying and working to modify surgical outcomes is necessary to avoid the stagnation of seizure‐freedom rates at the 50% range in most types of resective epilepsy surgery.…”

Section: Gaps In Knowledgementioning

confidence: 99%

Not all that glitters is gold: A guide to surgical trials in epilepsy

Jehi

2016

Epilepsia Open

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SummaryEpilepsy surgery is often the only effective treatment in appropriately selected patients with drug‐resistant epilepsy, a disease affecting about 30% of those with epilepsy. We review the evidence supporting the use of epilepsy surgery, with a focus on randomized controlled trials (RCTs). Second, we identify gaps in knowledge about the benefits of epilepsy surgery for certain populations, the challenges of individualizing the choice of surgery, and our lack of understanding of the mechanisms of surgical outcomes. We conducted a search (MEDLINE, Embase, Cochrane, Clinicaltrials.gov) on March 2, 2016, to identify epilepsy surgery RCTs, systematic reviews, or health technology assessments (HTAs). Abstracts were screened to identify resective, palliative (e.g., corpus callosotomy, multiple subpial transection [MST]), ablative (e.g., Laser interstitial thermal therapy [LITT], gamma knife radiosurgery [RS]), and neuromodulation (e.g., cerebellar stimulation [CS], hippocampal stimulation [HS], repetitive transcranial magnetic stimulation [rTMS], responsive neurostimulation [RNS], thalamic stimulation [TS], trigeminal nerve stimulation [TNS], and vagal nerve stimulation [VNS]) RCTs. Study characteristics and outcomes were extracted. Knowledge gaps were identified. Of 1,205 abstracts, 20 RCTs were identified (resective surgery including corpus callosotomy [n = 7], MST [n = 0], RS [n = 1, 3 papers], LITT [n = 0], CS [n = 1], HS [n = 2], RNS [n = 1], rTMS [n = 1], TNS [n = 1], TS [n = 1], and VNS [n = 5]). Most studies targeted patients with temporal lobe epilepsy (TLE) and none examined the effectiveness of resective surgical therapies in patients with extra‐TLE (ETLE) or with specific lesions aside from mesial temporal lobe sclerosis. No pediatric surgical RCTs were identified except for VNS. Few RCTs address the effectiveness of surgery in epilepsy and most are of limited generalizability. Future studies are needed to compare the effectiveness of different surgical strategies, better understand the mechanisms of surgical outcomes, and define the ideal surgical approaches, particularly for patients with high or very low cognitive function, normal imaging, or ETLE.

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“…Epilepsy surgery is a multidisciplinary specialty directed to the identification and localization the epileptic focus 2 , mapping its spatial relationships with functional cortical area(s), and ultimately resecting the epileptic focus to achieve seizure freedom 2 3 6 . The main goal of any resective epileptic surgery is to reduce the number of seizure, preserving the functionality and improving the quality of life 1 .…”

Section: Introductionmentioning

confidence: 99%