Extraoperative Functional Mapping and Staged Resection of Supratentorial Tumors near Eloquent Cortex in Children

Bollo, Robert J.; Carlson, Chad; Schevon, Catherine A.; Wisoff, Jeffrey H.; Devinsky, Orrin; Weiner, Howard L.

doi:10.1159/000218199

Cited by 10 publications

(6 citation statements)

References 62 publications

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“…Our previous study reported that general anesthesia reduced the rate of interictal epileptiform discharges in a majority of patients with focal epilepsy who exhibited frequent interictal spiking during extraoperative recording [52]. Also, not many children with epilepsy can tolerate awake craniotomy for intraoperative functional language mapping [53]. The disadvantages of extraoperative ECoG monitoring include: (i) a requirement for a second craniotomy, (ii) greater financial cost, and (iii) increased risk of complications, including infection [54].…”

Section: Role Of Ecog Monitoringmentioning

confidence: 99%

How to establish causality in epilepsy surgery

Asano

Brown

Juhász

2013

Brain and Development

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Focality in electro-clinical or neuroimaging data often motivates epileptologists to consider epilepsy surgery in patients with medically-uncontrolled seizures, while not all focal findings are causally associated with the generation of epileptic seizures. With the help of Hill's criteria, we have discussed how to establish causality in the context of the presurgical evaluation of epilepsy. The strengths of EEG include the ability to determine the temporal relationship between cerebral activities and clinical events; thus, scalp video-EEG is necessary in the evaluation of the majority of surgical candidates. The presence of associated ictal discharges can confirm the epileptic nature of a particular spell and whether an observed neuroimaging abnormality is causally associated with the epileptic seizure. Conversely, one should be aware that scalp EEG has a limited spatial resolution and sometimes exhibits propagated epileptiform discharges more predominantly than in situ discharges generated at the seizure-onset zone. Intraoperative or extraoperative electrocorticography (ECoG) is utilized when noninvasive presurgical evaluation, including anatomical and functional neuroimaging, fails to determine the margin between the presumed epileptogenic zone and eloquent cortex. Retrospective as well as prospective studies have reported that complete resection of the seizure-onset zone on ECoG was associated with a better seizure outcome, but not all patients became seizure-free following such resective surgery. Some retrospective studies suggested that resection of sites showing high-frequency oscillations (HFOs) at >80 Hz on interictal or ictal ECoG was associated with a better seizure outcome. Others reported that functionally-important areas may generate HFOs of a physiological nature during rest as well as sensorimotor and cognitive tasks. Resection of sites showing task-related augmentation of HFOs has been reported to indeed result in functional loss following surgery. Thus, some but not all sites showing interictal HFOs are causally associated with seizure generation. Furthermore, evidence suggests that some task-related HFOs can be transiently suppressed by the prior occurrence of interictal spikes. The significance of interictal HFOs should be assessed by taking into account the eloquent cortex, seizure-onset zone, and cortical lesions. Video-EEG and ECoG generally provide useful but still limited information to establish causality in presurgical evaluation. A comprehensive assessment of data derived from multiple modalities is ultimately required for successful management.

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Section: Role Of Ecog Monitoringmentioning

confidence: 99%

How to establish causality in epilepsy surgery

Asano

Brown

Juhász

2013

Brain and Development

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“…Invasive monitoring (IM) includes placement of subdural strips, grids, and, in certain cases, depth electrodes. IM directly records EEG activity from suspected brain areas, enabling direct mapping of epileptic networks, as well as functional mapping (Bollo et al., 2009). IM is critical when evaluating patients with multifocal epilepsy (Bauman et al., 2008, Carlson et al, 2011.…”

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confidence: 99%

Epilepsy control following intracranial monitoring without resection in young children

et al. 2012

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Summary Purpose: Intracranial monitoring (IM) is a key diagnostic procedure for select patients with treatment‐resistant epilepsy (TRE). Seizure focus resection may improve seizure control in both lesional and nonlesional TRE. IM itself is not considered to have therapeutic potential. We describe a cohort of patients with improved seizure control following IM without resective surgery. Methods: Over 12.5 years, 161 children underwent 496 surgeries including intracranial monitoring. We retrospectively reviewed the patients’ charts, operative reports, and radiologic scans, under an institutional review board–approved protocol. Key Findings: Seventeen patients underwent only IM, without additional resective surgery, and seven had a dramatic improvement in their epilepsy; six of the seven patients are seizure‐free (Engel class I), and one rarely has seizures (Engel class II). All seven patients had frequent seizures that led to IM: either daily (five patients) or 1–2 per week (two patients). The mean age (± standard deviation, SD) at seizure onset was 1.6 ± 1.3 years (range 0.5–4 years). Etiologies were tuberous sclerosis (3 patients), trauma (1 patient), and unknown (3 patients). Mean age at surgery (± SD) was 4.1 ± 2 years (range 1–7 years), and duration of epilepsy 2.5 ± 1.1 years (range 0.5–4 years). Duration of IM was 11.7 ± 5.6 days (5–19 days). Six patients had bilateral and one unilateral invasive electrodes. At last follow‐up, four patients required fewer antiepileptic drugs (AEDs), one had the same medication but a higher dose, and two patients were taking additional AEDs. Follow‐up was 30.6 ± 9.5 months (range 19–41 months). Significance: Although uncommon, patients with TRE may improve after IM alone. The explanation for this observation remains unclear; however, perioperative medications including steroids, direct cortical manipulation, or other factors may influence the epileptogenic network.

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“…Our center has considerable experience with the use of image guided (navigation and ultrasound) resections aided by neuromonitoring and extra-operative functional mapping [7,2,5] utilizing surface and depth electrodes. This approach serves as an effective alternative in younger children [4] who may be less likely to cooperate with an awake procedure.…”

Section: Discussionmentioning

confidence: 99%