Surgical outcome of cortical dysplasias presenting with chronic intractable epilepsy: A 10-year experience

Malformations caused by abnormalities of cortical development, or cortical dysplasias, were examined in surgical specimens from 108 patients with medically intractable epilepsy to determine the scope of histopathologic changes. The relevance of the clinical findings was also evaluated. Various types and degrees of dysplastic features were observed in various combinations, including architectural abnormalities, an increased number of neurons in the molecular layer and/or cortical layer II, neuronal clustering, an increased number of satellite oligodendrocytes, abnormal gyration, single and/or aggregates of heterotopic neurons in the white matter, and the appearance of cytologically abnormal cells, such as giant or dysmorphic neurons and balloon cells. In the temporal lobe specimens, microdysgenesis (corresponding to mild malformations caused by abnormalities of cortical development and type IA/B focal cortical dysplasias) was more frequently observed than Taylor-type focal cortical dysplasia (type IIA/B), whereas in the frontal lobe specimens, the frequency of occurrence of both types was even. The ages at seizure onset and surgery of patients with the latter type were significantly lower than those of patients with the former. On the other hand, prominent astrocytosis in the cortex and white matter was evident in all cases, and many corpora amylacea and neurofibrillary tangle—like inclusions were observed in a subset of cases. An ultrastructural investigation revealed dilatation of the postsynaptic dendritic spines and shafts in the cortex and features indicating the occurrence in the white matter of demyelination followed by remyelination. Thus, with regard to the epileptogenic lesions, although dysplastic changes constitute the pathogenetic basis, the overlapping subsequent degenerative processes involving synapses, dendrites, and axons might contribute to the development of epileptogenic processes. Astrocytes might also actively participate in the development of the pathogenesis of epilepsy. ( J Child Neurol 2005;20:341—350).

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Focal Cortical Dysplasias

10.1093/med/9780199937837.003.0039 ◽

2017 ◽

Author(s):

Ali Mahta ◽

Peter B. Crino

Keyword(s):

Brain Development ◽

Somatic Mutations ◽

Mammalian Target Of Rapamycin ◽

Intractable Epilepsy ◽

Cell Types ◽

Current Belief ◽

Type Ia ◽

Cortical Dysplasias ◽

Refractory Seizures ◽

Unique Cell

Focal cortical dysplasias (FCDs) are common malformations of cerebral cortical development that are highly associated with medically intractable epilepsy. FCDs have been classified according to neuropathological subtypes (type Ia, Ib, IIA, IIb, and III) based on the severity of cytoarchitectural disruption, and the presence of unique cell types (e.g., balloon cells). Most FCDs can be detected by neuroimaging studies and will require respective epilepsy surgery to cure refractory seizures. The pathogenesis of FCDs remains to be defined, although current belief is that these lesions result from sporadic somatic mutations occurring in brain development. A link to the mammalian target of rapamycin cascade has been defined for some FCD subtypes.

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The Irritative Zone and Seizure Onset Zone in Subdural EEG

Invasive Studies of the Human Epileptic Brain ◽

10.1093/med/9780198714668.003.0008 ◽

2018 ◽

pp. 98-105

Author(s):

Sebastian Bauer ◽

Felix Rosenow

Keyword(s):

Temporal Lobe Epilepsy ◽

Temporal Lobe ◽

Surgical Outcome ◽

Prognostic Value ◽

High Sensitivity ◽

Interictal Spikes ◽

Seizure Onset ◽

Seizure Onset Zone ◽

Cortical Dysplasias ◽

Definition Of

Subdural EEG has a high sensitivity for detecting interictal spikes. The irritative zone is usually more extended than the seizure onset zone. Removal of the entire irritative zone improves outcome in extratemporal as well as neocortical and tumour-related temporal lobe epilepsy, but not in mesial TLE. Quantification of spike features like amplitude, frequency, or latency may help differentiate the localizing and prognostic value of different spike populations. Although EEG patterns are not aetiology, some pathologies such as focal cortical dysplasias are frequently associated with typical EEG patterns, in which case intraoperative electrocorticography should be applied to tailor resections. Presence of a focal seizure onset zone and slow propagation are associated with good surgical outcome. Definition of a sound hypothesis about location of the seizure onset zone from pre-invasive findings is a crucial prerequisite for the success of subdural recordings. Concordance of interictal and ictal recordings is highly predictive of outcomes.

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Callosotomy for intractable epilepsy from bihemispheric cortical dysplasias

Acta Neurochirurgica ◽

10.1007/bf01404852 ◽

1995 ◽

Vol 132 (1-3) ◽

pp. 79-86 ◽

Cited By ~ 14

Author(s):

R. Pallini ◽

S. Aglioti ◽

G. Tassinari ◽

G. Berlucchi ◽

C. Colosimo ◽

...

Keyword(s):

Intractable Epilepsy ◽

Cortical Dysplasias

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Intractable epilepsy and mild brain injury: incidence, pathology and surgical outcome

Brain Injury ◽

10.1080/02699050110102086 ◽

2002 ◽

Vol 16 (6) ◽

pp. 463-467 ◽

Cited By ~ 7

Author(s):

Bahman Jabbari ◽

Olga Prokhorenko ◽

Kaveh Khajavi ◽

Hernando Mena

Keyword(s):

Brain Injury ◽

Surgical Outcome ◽

Intractable Epilepsy ◽

Injury Incidence ◽

Mild Brain Injury

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Focal cortical dysplasias: surgical outcome in 67 patients in relation to histological subtypes and dual pathology

Brain ◽

10.1093/brain/awh277 ◽

2004 ◽

Vol 127 (11) ◽

pp. 2406-2418 ◽

Cited By ~ 143

Author(s):

S. Fauser

Keyword(s):

Surgical Outcome ◽

Histological Subtypes ◽

Dual Pathology ◽

Cortical Dysplasias

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The anatomy of epileptic auras: focal pathology and surgical outcome

Journal of Neurosurgery ◽

10.3171/jns.1995.83.1.0060 ◽

1995 ◽

Vol 83 (1) ◽

pp. 60-66 ◽

Cited By ~ 67

Author(s):

Itzhak Fried ◽

Dennis D. Spencer ◽

Susan S. Spencer

Keyword(s):

Surgical Outcome ◽

Vascular Malformations ◽

Hippocampal Sclerosis ◽

Intractable Epilepsy ◽

Glial Tumors ◽

Content Type ◽

Resective Surgery ◽

Intractable Seizures ◽

Significant Difference ◽

Fine Print

✓ An aura is generally understood to be the beginning of a seizure. Yet, following successful surgery for intractable epilepsy, patients may have persistent auras even though they are otherwise seizure free. Ninety patients with intractable seizures and auras underwent resective surgery. Forty-three patients had hippocampal sclerosis and 47 had temporal or extratemporal lesions such as glial tumors or vascular malformations. The semiology of the auras was found to have value in localization but not lateralization of the pathology. Epigastric auras as well as gustatory and olfactory auras were significantly more frequent in patients with hippocampal sclerosis than in those with temporal or extratemporal lesions. Auras of vertigo or dizziness were most frequent in patients with extratemporal pathology. There was a significant difference between the pathology groups in the efficacy of resection in eliminating the auras. Of the patients with hippocampal sclerosis who were rendered seizure free, 18.9% had persistent auras, whereas only one (2.6%) of the patients with temporal or extratemporal lesions who were rendered seizure free had persistent auras. These findings suggest that for patients with hippocampal sclerosis an anatomical dissociation between seizure and aura may occur, whereas this dissociation is not present in patients with lesions. Patients suspected of having hippocampal sclerosis should be counseled preoperatively as to the significant likelihood of persistent auras even if seizures are successfully abolished.

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