Different histopathological types of mMCD/FCD have distinct clinical and imaging characteristics. The ability to predict the subtype before surgery could influence surgical planning. Invasive electroencephalographic study should be considered when mMCD/FCD type I is expected based on noninvasive tests.

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.

Summary:Purpose: Children with tuberous sclerosis complex (TSC) benefit from excisional surgery if seizures can be localized to a single tuber. We evaluated the role of noninvasive studies to localize the epileptogenic tuberhegion (ET/R) and the outcome of focal resection.Methods: We identified 21 children with TSC, ages 3 months to 15 years (mean 4.8 years). All had video-(electroencephalogram) EEG and magnetic resonance imaging (MRI) scans, and 18 also had ictal single photon emission-computed tomography (SPECT) studies. An ET/R was localized in 17 patients. Thirteen patients underwent resection guided by intraoperative electrocorticography (n = 7) or subdural monitoring (n = 6).Results: Interictal EEG revealed a principal spike focus (PSF) that corresponded to the ET/R in 14 children. In seven, PSFs occurred in rhythmic runs. PSFs were not observed remote from the ET/R. Focal polymorphic slowing and attenuation occurred in the region of the PSF in 1 I patients. Sixteen patients demonstrated an ictal focus corresponding to the ET/R. Ictal SPECT revealed focal hyperperfusion correlating with the ET/R in 10 patients. Although the MRIs in all children revealed multiple tubers, the E T R corresponded to a large discrete tuber in 8 patients and a calcified tuber in 13 patients. Patchy calcified tubers were also seen elsewhere in six patients. At a mean follow-up of 26 months, 9 of the 13 children who underwent surgery were seizure-free, one had greater than 75% reduction in seizures, two were unchanged, and one was lost to follow-up. New seizures developed in one child from a contralateral tuber.Conclusions: Surgical resection of an ET/R alleviates seizures in most children with TSC and intractable epilepsy. The scalp EEG and MRI help define the ET/R and improve case selection when ictal SPECT is nonlocalizing.

SUMMARYPurpose: Excisional surgery achieves seizure freedom in a large proportion of children with intractable lesional epilepsy, but the outcome for children without a focal lesion on MRI is less clear. We report the outcome of a cohort predominantly of children with nonlesional intractable partial epilepsy undergoing resective surgery. Methods: We studied 102 patients with nonlesional intractable partial epilepsy who underwent excisional surgery. The epileptogenic region was identified by integrating clinical exam and video-EEG data complemented by ictal SPECT (n = 40), PET (n = 10), extraoperative subdural monitoring (n = 80), and electrocorticography (n = 22). All patients had follow-up greater than 2 years, 76 patients had 5-year follow-up, and 43 patients had 10-year follow-up. Results: A total of 66 resections were unilobar; 36 were multilobar. One patient died of causes unrelated to seizures or surgery. At 2-year follow-up, 44 of 101 patients were seizure-free, 15 experienced >90% reduction, 17 had >50% reduction, and 25 were unchanged. At 5-year follow-up, 35 of 76 patients were seizure-free, 12 experienced >90% reduction, 12 had >50% reduction, and 17 were unchanged. At 10-year follow-up, 16 of 43 patients were seizure-free, 13 experienced >90% reduction, 7 had >50% reduction, and 7 were unchanged. A discrete lesion on the MRI scan is arguably one of the most reliable features for defining the epileptogenic region (Engel et al

Summary:Children with malformations of cortical development represent a significant proportion of pediatric epilepsy surgery candidates. From a cohort of 40 children operated on between 1980 and 1992 with malformation of cortical development, 38 were alive and had data 10 years after surgery. Age at surgery ranged from 6 months to 18 years (mean, 9.6 years). Thirty-six had partial seizures, and two had infantile spasms; 20 were nonlesional. Pathologic diagnoses were cortical dysplasia (n = 31) and developmental tumor (n = 7). At 10-year follow-up, 15 (40%) were seizure free, 10 (26%) had >90% seizure reduction, and 13 (34%) were improved or unchanged. Children seizure free at two-year follow-up were likely to remain seizure free. Ten-year seizure freedom was 72% in children with developmental tumors and 32% in the cortical dysplasia group. Complete resection was statistically significant for favorable outcome, and no patient with an incomplete resection was seizure free.

SUMMARYPurpose: 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. Methods: We retrospectively evaluated a surgical series of 200 patients with histologically confirmed mMCD/FCD. Combined historical and radiologic inclusion criteria were used to identify patients with prenatal and perinatal risk factors. Electroclinical, imaging, neuropsychological, surgical, histopathologic, and seizure outcome data were reviewed. Results: Prenatal and perinatal insults including severe prematurity, asphyxia, bleeding, hydrocephalus, and stroke occurred in 12.5% of children with mMCD/FCD (n = 25). Their epilepsy was characterized by early seizure onset, high seizure frequency, and absence of seizure control. Patients with significant prenatal and perinatal risk factors had more abnormal neurologic findings, lower intelligence quotient (IQ) scores, and slower background EEG activity than mMCD/FCD subjects without prenatal or perinatal brain injury. MRI evidence of cortical malformations was identified in 74% of patients. Most patients underwent large multilobar resections or hemispherectomies; 54% were seizure-free 2 years after surgery. Histologically ''milder'' forms of cortical malformations (mMCD and FCD type I) were observed most commonly in our series. Conclusions: Surgically remediable low-grade cortical malformations may occur in children with significant prenatally and perinatally acquired encephalopathies and play an important role in the pathogenesis of their epilepsy. Presurgical detection of dysplastic cortex has important practical consequences for surgical planning.

Functional MR imaging results influenced diagnostic and therapeutic decision making of the seizure team; results indicated language dominance changed, confidence level in identification of critical brain function areas increased, patient and family counseling were altered, and intraoperative mapping and surgical approach were altered.

Object In this study the authors review the outcomes in pediatric patients who presented with seizures and underwent resection of dysembryoplastic neuroepithelial tumors (DNETs). The authors focus on the diagnostic evaluation and surgical techniques that facilitate gross–total tumor resection and subsequent freedom from seizures. Methods Eighteen patients between the ages of 1 month and 13 years who presented with seizures underwent resection of DNETs between January 1992 and December 2004. Preoperative evaluation included magnetic resonance (MR) imaging and interictal scalp electroencephalography (EEG) in all patients, functional MR imaging in eight patients, video monitoring with ictal scalp EEG in 12 patients, interictal single-photon emission computerized tomography (SPECT) scanning in one patient, and ictal SPECT scanning in two patients. Thirteen patients underwent one-stage procedures, whereas five underwent two-stage procedures (implantation of monitoring electrodes followed by tumor resection), either for functional language mapping (three patients) or due to inconclusive preoperative data (two patients). Intraoperative electrocorticography (ECoG) was performed in 17 patients and led to resection of the cerebral cortex beyond the tumor margins in 10 of them. According to operative reports, gross–total tumor resections were achieved in all patients, but one child had minimal residual tumor on postoperative MR images that has remained stable. The only surgical complication was a transient third cranial nerve palsy. Over a median follow-up duration of 1.6 years, all patients are seizure free and without radiographically detected tumor recurrence. Conclusions Dysembryoplastic neuroepithelial tumors are a highly treatable cause of epilepsy in children. Excellent rates of complete tumor resection and seizure control with minimal morbidity can be attained using intraoperative ECoG and two-stage surgical procedures when appropriate.