Insular and insulo-opercular epilepsy in childhood: An SEEG study

American Journal of Neuroradiology, 2013

Between 2002 and 2010, a total of 48 patients were seen at our epilepsy clinic with insular/peri-insular cortex epilepsy. Review of their MR imaging scans revealed a neoplastic lesion in 27% of patients, a malformation of cortical development in 21%, a vascular malformation in 19%, and atrophy/gliosis from an acquired insult in 17%. MR imaging results were normal in 4 patients. Other miscellaneous findings included a case of Rasmussen encephalitis, a nonspecific insular millimetric T2 signal abnormality, a neuroepithelial cyst, and hippocampal sclerosis without MR imaging evidence of dual insular pathologic features (despite depth electrode-proven insular seizures). Refractoriness to antiepileptic drug treatment was present in 56% of patients: 100% for patients with malformations of cortical development (1.0; 95% CI, 0.72-1.0), 50.0% (0.5; 95% CI, 0.21-0.78) in the presence of atrophy/gliosis from acquired insults, 39% (0.39; 95% CI, 0.14-0.68) for neoplastic lesions, and 22.2% (0.22; 95% CI, 0.06-0.55) for vascular malformations.

Epilepsia, 2010

Purpose: Different lines of evidence suggest that the insular cortex has many important functional roles. Direct electrical stimulation (ES) of the human insular cortex during surgical procedures for epilepsy, functional imaging techniques, and lesion studies also occasionally induces clinical responses. Methods: In this study, we evaluated 25 patients with drug-refractory focal epilepsy by stereotactically implanting at least one electrode into the insular cortex using an oblique approach (transfrontal or transparietal). One hundred twenty-eight insular sites (each situated between two contiguous contacts within the same electrode) were examined within the gyral substructures. We located each stimulation site by fusing preimplantation threedimensional (3D) magnetic resonance imaging (MRI) images with the postimplantation 3D computed tomography (CT) scans that revealed the electrode contacts.

Epilepsia, 2007

High-resolution imaging techniques can demonstrate anatomic alterations in most patients identified as candidates for surgical treatment of their partial epilepsy. The demonstration of an anatomic lesion is only one step in the presurgical diagnostic procedure, which includes video-EEG and, when necessary, video-stereo-EEG recordings of seizures. A review of the literature shows that the simple removal of the magnetic resonance imaging (MR1)-evident lesion ("lesionectomy") reduces but does not completely suppress seizures in a large percentage of patients, especially those with neuronal migration disorders. This phenomenon could, at least in part, be explained by preliminary data (in 33 patients) showing that less than 20% of seizures correspond to a well-localized, intralesional discharge in about 40% of stereo-EEG-investigated patients with at least one intralesional electrode. The authors illustrate some anatomo-electroclinical examples of intraindividual variability of the ictal symptomatology, raising the problem of the decision about the extent of the surgical removal. Recent histologic and immunohistochemical studies have demonstrated several kinds of structural alterations in the stereo-EEG-defined epileptogenic zone, not always overlapping with the MRI-visible lesion. This aspect can further explain some failures of MRI-guided lesionectomies. That relationships between "lesions" and epileptogenic zones may be variable is also suggested by reports of patients who present with multiple lesions (i.e., cavernous angiomas, Bourneville syndrome) and are cured by removal of only one of them. Key Words: Severe partial epilepsy-Epileptogenic lesions-Stereo-EEG-Intralesional electrical activity-Epilepsy surgery.

JBNC - JORNAL BRASILEIRO DE NEUROCIRURGIA

Insulectomy is an established microsurgical technique for treatment of insular epilepsy refractory to clinical management. The insular origin of epilepsy is unusual. However with depth investigation through hybrid electrodes, it is becoming possible to improve its diagnosis. The authors emphasize the insular functions as well as the anatomical landmarks for surgery. The main complications and physiological basis are discussed.

Pediatric Neurology, 2010

Brain Sciences, 2022

Background: Epilepsy surgery failure is not uncommon, with several explanations having been proposed. In this series, we detail cases of epilepsy surgery failure subsequently attributed to insular involvement. Methods: We retrospectively identified patients investigated at the epilepsy monitoring units of two Canadian tertiary care centers (2004–2020). Included patients were adults who had undergone epilepsy surgeries with recurrence of seizures post-operatively and who were subsequently determined to have an insular epileptogenic focus. Clinical, electrophysiological, neuroimaging, and surgical data were synthesized. Results: We present 14 patients who demonstrated insular epileptic activity post-surgery-failure as detected by intracranial EEG, MEG, or seizure improvement after insular resection. Seven patients had manifestations evoking possible insular involvement prior to their first surgery. Most patients (8/14) had initial surgeries targeting the temporal lobe. Seizure recurre...

Child's Nervous System, 2000

From June 1988 to June 1998, 60 children with extratemporal epilepsies (EE), most of whom were symptomatic, underwent surgery. All patients were studied by means of CT scanning, MRI and scalp EEG. Video-telemetry was used in 40 cases. Intracranial electrodes were placed in 10. Intraoperative ECoG was used in the 35 children who underwent resective procedures and in the 25 in whom disconnection was performed. Surgical procedures were as follows: 24 lesionectomies, 25 disconnecting procedures, 7 polectomies and/or lobectomies, 3 corticectomies and 1 anatomical hemispherectomy. After at least 1 year's follow-up in 48 children, to date 38 are in Engel class I, 7 in class II, 1 in class III and 2 in class IV. That is to say, in 46 of the 48, surgical outcomes ranges from very good to at least worthwhile, as reflected in their classification in Engel class III.

Acta Neurochirurgica, 1994

Twenty patients (13 males, 7 females), who presented with refractory partial epilepsy and a CT and/or MR detected intracranial intra-axial structural lesion were admitted to the University of Gent Epilepsy Monitoring Unit. Mean duration of the epilepsy was 17 years (2-47 years). All patients were enrolled in a comprehensive presurgical protocol including neurological examination, video-scalp-EEG monitoring with prolonged interictal and ictal recording, neuropsychological assessment and positron emission tomography (PET). Intracranial EEG monitoring was performed in 5 patients in whom discrepancies between different tests were found during the non-invasive evaluation. Clinical neurological examination was normal in 16 patients; 4 patients had a mild contralateral hemiparesis. Lesions were mainly located in the temporal lobe (55%). Most patients presented with complex partial seizures (90%). Clinical seizure characteristics correlated well with the lesion location in 55% of patients. Interictal EEG showed focal epileptic activity and focal slowing in respectively 85% and 30% of patients. Interictal EEG lateralization was congruent with the side of the lesion in 17 patients (85%). Interictal EEG localization was congruent with the lobe of the lesion in 13 patients (65%). Ictal EEG lateralized correctly in 14 patients (70%) and localized correctly in 10 patients (50%). Neuropsychological assessment lateralized and localized congruently in respectively 8/17 (47%) and 7/17 (41%) of patients. Interictal PET showed focal interictal hypometabolism, congruent with the lesion, in 13/16 (81%) of patients. Intracranial EEG was congruent with the lesion location in 3 patients but non-congruent in 2 patients. All patients underwent surgical procedures: average follow-up was 14 months (6-24 months). Complete surgical removal of the lesion with free margins resulted in a more than 90% reduction of seizures without postoperative neurological deficit in 12/13 patients.

Epilepsia, 2004

Purpose-To study the relation between the spike frequency during intraoperative electrocorticography (ECoG) under general anesthesia with isoflurane and that during extraoperative ECoG monitoring in children with intractable neocortical epilepsy.

European Journal of Paediatric Neurology, 2009

The second of this 2-part review depicts the specific approach to the common causes of pediatric refractory epilepsy amenable to surgery. These include tumors, malformations due to abnormal cortical development, vascular abnormalities and certain epileptic syndromes.

Neurophysiologie Clinique/Clinical Neurophysiology, 2016

Purpose.-SEEG in children has a low morbidity and leads to a good surgical outcome, in particular in younger patients. We analysed, in detail, the SEEG data of patients that were subsequently cured by surgery. Methods.-We selected the 48 children explored between 2009 and 2013 in our centre and surgically cured after SEEG-based resections with at least one-year follow-up. We retrospectively studied demographic and surgical data and paid particular attention to the data acquired during the invasive recording. Moreover, we compared the children younger than 5 years of age (group 1: 17 children) to those older than 5 years of age at the time of exploration (group 2: 31 patients). Results.-SEEG was well tolerated. Only one patient had slight intracerebral bleeding seen on the post-operative CT-scan without any clinical consequence and which did not prevent the

Hong Kong medical journal = Xianggang yi xue za zhi / Hong Kong Academy of Medicine, 2011

Objective We undertook a collaborative study in a multidisciplinary team to channel refractory epilepsy patients to test a hypothesis about placement of intracranial electroencephalography arrays.

Epilepsia, 2000

Surgery is now an accepted treatment for some medically intractable epilepsies. Presurgical evaluation is particularly important for the localization of the epileptogenic zone, which may necessitate sophisticated imaging techniques and intracranial electroencephalogram (EEG) recordings. If patients are carefully selected, however, successful results can be achieved with noninvasive evaluation methods. Seventy-seven patients were operated on for intractable seizures. All patients underwent EEG, neuropsychological, psychiatric, and magnetic resonance imaging investigations. Ictal EEG-video recording was performed in all nonlesional and in some lesional cases that had discordant data. Selective amygdalo-hippocampectomy was performed on patients with mesial temporal lobe epilepsy (MTLE), an extended or a limited lesionectomy was performed on patients with structural lesions, and a lesionectomy with deafferentation was performed on two patients with West syndrome. Electrocorticography was not used. Tem-

2005

HILDREN with drug-resistant focal epilepsy are undergoing surgery for relief of seizures with increasing frequency. 5,27,47 A considerable number of patients with medically intractable epilepsy experience their first seizures in childhood, 10 and there is increasing evidence that early selection and operation in surgically remediable situations results in a significant impact on brain development, 12,48 reducing the deleterious effects of both long-lasting seizures and antiepileptic medications. 28,45 Furthermore, early surgery takes advantage of the enhanced plasticity of a child's brain, which increases the chances of recovery both from impaired functions secondary to seizures and from possible surgical injury. 7 Successful surgery for epilepsy depends on identification and complete resection of the region of onset and the early spread of the ictal discharge that compose the epileptogenic zone. The definition of this zone is based on the evaluation of clinical, electrophysiological, and anatomical data pertaining to each patient. In the previous decades, increasing experience of dedicated teams and newly developed technologies of brain imaging, especially high-resolution MR imaging, have made it possible to offer surgery to a large number of patients after noninvasive investigations alone. 34 Nevertheless, a low degree of coherence as to localization of the epileptogenic zone, as well as between findings from interictal/ictal EEG procedures, clinical ictal semiology, and brain MR imaging, represents an indication to undertake invasive intracranial EEG monitoring in several patients. 42 Different tools are used to record results of intracranial EEG procedures, depending on a given center's philosophy. The most widely used devices are subdural electrodes arranged in strips or grids according to each patient's needs. 38 They allow an extensive coverage of the cortical surface, but sampling of deep-seated structures is prevented. Intracerebral electrodes are used to record from lesions and

Past surgical series have emphasized the diagnostic complexity of posterior cortex epilepsy (PCE). Available data are sparse, especially in children, and most published series report a high number of surgical failures and post-operative neurological deficits. In this article, we present a paediatric cohort of 62 children who underwent surgery for pharmaco-resistant PCE before the age of 16 years with a mean postoperative follow-up of 6.94 years (range: 2-16). Mean age at epilepsy onset was 3.2 years and 28 children (45%) had onset before 1 year of age. The mean age at surgery was 7.9 years (range: 1-16). Daily seizures were present in 63% of children. MRI was positive in 58 cases (93.5%) and invasive stereo-EEG was judged mandatory in 24/62 (39%) of patients. Surgery was confined to the parietal lobe in 11 children, the occipital lobe in 8, the occipito-parietal region in four, the occipito-temporal region in 18, and involved both the temporal and parietal lobes in the remaining 21. Following surgery, 53 subjects (85.5%) remained seizure-free and among those who underwent a SEEG procedure, 75% achieved seizure freedom. Focal cortical dysplasia was the most frequent histopathological diagnosis (50%), followed by tumoural (24%) and gliotic lesions (14.5%). An older age at epilepsy onset, the presence of a rather restricted epileptogenic area, and a complete resection of the epileptogenic zone were predictive of a favourable surgical outcome. These results demonstrate that a good surgical outcome is possible in children with pharmaco-resistant PCE. Accurate analysis of the chronology of ictal semiology and electrophysiological features, viewed in the context of the complete electroclinical pattern, provides a topographical orientation for PCE and, together with the presence of a lesion detectable on imaging, may improve the rate of surgical success of PCE at paediatric age.