Bruno Maton

Incomplete resection of focal cortical dysplasia is the main predictor of poor postsurgical outcome

Background: Focal cortical dysplasia (FCD) is recognized as the major cause of focal intractable epilepsy in childhood. Various factors influencing postsurgical seizure outcome in pediatric patients with FCD have been reported. Objective: To analyze different variables in relation to seizure outcome in order to identify prognostic factors for selection of pediatric patients with FCD for epilepsy surgery. Methods: A cohort of 149 patients with histologically confirmed mild malformations of cortical development or FCD with at least 2 years of postoperative follow-up was retrospectively studied; 113 subjects had at least 5 years of postoperative follow-up. Twenty-eight clinical, EEG, MRI, neuropsychological, surgical, and histopathologic parameters were evaluated. Results: The only significant predictor of surgical success was completeness of surgical resection, defined as complete removal of the structural MRI lesion (if present) and the cortical region exhibiting prominent ictal and interictal abnormalities on intracranial EEG. Unfavorable surgical outcomes are mostly caused by overlap of dysplastic and eloquent cortical regions. There were nonsignificant trends toward better outcomes in patients with normal intelligence, after hemispherectomy and with FCD type II. Other factors such as age at seizure onset, duration of epilepsy, seizure frequency, associated pathologies including hippocampal sclerosis, extent of EEG and MRI abnormalities, as well as extent and localization of resections did not influence outcome. Twenty-five percent of patients changed Engels class of seizure outcome after the second postoperative year. Conclusions: The ability to define and fully excise the entire region of dysplastic cortex is the most powerful variable influencing outcome in pediatric patients with focal cortical dysplasia.

Different features of histopathological subtypes of pediatric focal cortical dysplasia

Focal cortical dysplasia (FCD) is the most frequent pathological finding in pediatric epilepsy surgery patients. Several histopathological types of FCD are distinguished. The aim of the study was to define distinctive features of FCD subtypes.

Medically intractable epilepsy in Sturge‐Weber syndrome is associated with cortical malformation: Implications for surgical therapy

Purpose:  Anecdotal reports have described cortical malformations in epileptic patients with Sturge‐Weber syndrome (SWS). No data are available regarding the prevalence and significance of this association.

Surgery for medically intractable temporal lobe epilepsy during early life

Purpose: Temporal lobe epilepsy (TLE) in early life is often a catastrophic disorder with pharmacoresistant seizures and secondary neurological deterioration. There is little data available regarding epilepsy surgery performed in infants and young children and no prior study has focused on TLE.

Low‐grade focal cortical dysplasia is associated with prenatal and perinatal brain injury

Purpose:  Prenatal and perinatal adverse events are reported to have a pathogenetic role in focal cortical dysplasia (FCD). However, no data are available regarding the prevalence and significance of this association. A cohort of children with significant prenatal and perinatal brain injury and histologically proven mild malformations of cortical development (mMCD) or FCD was analyzed.

Localizing value of ictal SPECT is comparable to MRI and EEG in children with focal cortical dysplasia

To assess the predictive value of ictal single‐photon emission computed tomography (SPECT) for outcome after excisional epilepsy surgery in a large population of children with focal cortical dysplasia (FCD).

Early seizure onset and dysplastic lesion extent independently disrupt cognitive networks

Objective: To determine the most important factors influencing neuropsychological performance in children with intractable epilepsy due to focal cortical dysplasia and the nature of the interaction among significant variables. Methods: Surgical patients with histologically verified focal cortical dysplasia were retrospectively evaluated to determine the impact of histopathology, extent of lobar involvement, hemispheric laterality, age at onset, and duration of epilepsy on cognitive functioning. A composite neuropsychological variable was obtained by transforming data from 5 major cognitive domains using principal components analysis. Multiple regression was used to examine the unique contributions of predictor variables on composite cognition and Full Scale IQ. Data were qualitatively evaluated for nonstatistical trends. Results: Poor cognitive outcomes were associated with early age at onset of epilepsy (AOE) and widespread dysplastic involvement. Extent of dysplasia and AOE together accounted for 35% of Full Scale IQ variance, and 21% of composite cognitive performance. Each factor contributed independently to cognitive dysfunction. Conclusions: Early AOE disrupts critical periods of development and leads to poor cognitive outcome, but children with multilobar dysplasia are likely to have diminished cognitive skills regardless of AOE. Later AOE is not expected to mitigate deficits because of widespread pathology, nor would a localized lesion be likely to mollify the developmental deficits resulting from early AOE.

Epilepsy surgery in children with gliomatosis cerebri

Summary:  Purpose: Gliomatosis cerebri (GC) is a rare neoplastic disorder that may present as intractable epilepsy during early life. We report our experience regarding the evaluation and the surgical treatment of epilepsy in this population.

Predictive factors of ictal SPECT findings in paediatric patients with focal cortical dysplasia

AimsTo identify variables that influence the extent of ictal single-photon emission computed tomography (SPECT) findings in paediatric patients with focal cortical dysplasia (FCD).MethodsWe visually evaluated 98 ictal SPECT studies from 67 children treated surgically for intractable epilepsy caused by FCD. SPECT findings were classified as “non-localised”, “well-localised”, and “extensive” and compared with parameters of injected seizures (seizure type and duration, injection time, and scalp EEG ictal pattern), presence of structural pathology on MRI, type of surgery performed after SPECT study, and histological findings.ResultsA shorter injection time and duration of injected seizure was associated with more localised SPECT hyperperfusion. SPECT findings were not significantly influenced by type of injected seizure. Widespread ictal scalp EEG patterns were associated with extensive SPECT findings. Larger zones of hyperperfusion were more common in patients with lesional MRI and patients undergoing multilobar resections. SPECT studies demonstrating good localisation were more common in patients with mild malformations of cortical development.ConclusionEarly ictal SPECT radiotracer injection is crucial for successful localisation of the epileptogenic zone. Seizure duration, type of scalp EEG findings, and presence of structural pathology on MRI may influence the extent of ictal SPECT hyperperfusion, which was associated with certain types of epilepsy surgery aswell as histopathological findings.

Ictal SPECT is useful in localizing the epileptogenic zone in infants with cortical dysplasia

AIMS To assess the localizing value of ictal SPECT in very young epilepsy surgery candidates when cerebral haemodynamic responses are known to be immature. METHODS We retrospectively studied 13 infants with intractable focal epilepsy caused by focal cortical dysplasia (FCD). Completeness of resection of the (1) ictal SPECT hyperperfusion zone and (2) cerebral cortex with prominent ictal and interictal abnormalities on intracranial EEG (ECoG or long-term invasive monitoring) and the MRI lesion, when present, were correlated with postoperative seizure outcome. RESULTS All five patients with complete resection of the ictal SPECT hyperperfusion zone were seizure-free compared to only one of eight patients with incomplete or no excision of hyperperfusion zones (p=0.00843). Similar results were noted for the MRI/iEEG-defined epileptogenic region; five of six patients with complete removal were seizure-free, whereas only one of seven incompletely resected patients was seizure-free (p=0.02914). All four patients who underwent complete resection of both regions were seizure-free compared to none of the six with incomplete resection (p=0.01179). CONCLUSION Despite age-related differences in cerebral perfusion, ictal SPECT provides useful localization data in infants with FCD. Complete resection of the hyperperfused regions is a strong predictor of favourable outcome. The added information may alleviate the need for invasive EEG evaluations in some patients.