The Pediatric Epilepsy Surgery Interest Group (PESIG) under the auspice of the ISPN Research Committee: Availability of relevant technology and geographical distribution.

PURPOSE: Epilepsy surgery for pediatric drug-resistant epilepsy has been shown to improve seizure control, enhance patient and family QoL, and reduce mortality. However, diagnostic tools and surgical capacity are less accessible worldwide. The International Society Pediatric Neurosurgery (ISPN) has established a Pediatric Epilepsy Surgery Interest Group (PESIG), aiming to enhance global collaboration in research and educational aspects. The goals of this manuscript are to introduce PESIG and analyze geographical differences of epilepsy surgery and technology availability. METHODS: PESIG was established (2022) following an ISPN executive board decision. Using a standardized form, we surveyed the PESIG members, collecting and analyzing data regarding geographical distribution, and availability of various epilepsy treatment-related technologies. RESULTS: Two hundred eighty-two members registered in PESIG from 70 countries, over 6 continents, were included. We categorized the countries by GDP as follows: low, lower-medium, upper-medium, and high income. The most commonly available technology was vagus nerve stimulation 68%. Stereoelectroencephalography was available for 58%. North America had statistically significant greater availability compared to other continents. Europe had greater availability compared to Africa, Asia, and South (Latin) America. Asia had greater availability compared to Africa. High-income countries had statistically significant greater availability compared to other income groups; there was no significant difference between the other income-level subgroups. CONCLUSION: There is a clear discrepancy between countries and continents regarding access to epilepsy surgery technologies. This strengthens the need for collaboration between neurologists and neurosurgeons from around the world, to enhance medical education and training, as well as to increase technological availability.

Evaluation of the behavioral, histopathological, and immunohistochemical effects resulting from ventriculosubcutaneous shunt obstruction in kaolin-induced hydrocephalus in rats.

PURPOSE: Hydrocephalus is a brain disease prevalent in the pediatric population that presents complex pathophysiology and multiple etiologies. The best treatment is still ventricular shunting. Mechanical obstruction is the most frequent complication, but the resulting pathological effects are still unknown. OBJECTIVE: Evaluation and comparison of clinical, histopathological, and immunohistochemical aspects in the acute phase of experimental hydrocephalus induced by kaolin, after treatment with adapted shunt, and after shunt obstruction and posterior disobstruction. METHODS: Wistar rats aged 7 days were used and divided into 4 groups: control group without kaolin injection (n = 6), untreated hydrocephalic group (n = 5), hydrocephalic group treated with ventriculosubcutaneous shunt (DVSC) (n = 7), and hydrocephalic group treated with shunt, posteriorly obstructed and disobstructed (n = 5). The animals were submitted to memory and spatial learning evaluation through the Morris water maze test. The rats were sacrificed at 28 days of age and histological analysis of the brains was performed with luxol fast blue, in addition to immunohistochemical analysis in order to evaluate reactive astrocytosis, inflammation, neuronal labeling, and apoptotic activity. RESULTS: The group with shunt obstruction had worse performance in memory tests. Reactive astrocytosis was more evident in this group, as was the inflammatory response. CONCLUSIONS: Obstruction of the shunt results in impaired performance of behavioral tests and causes irreversible histopathological changes when compared to findings in the group with treated hydrocephalus, even after unblocking the system. The developed model is feasible and efficient in simulating the clinical context of shunt dysfunction.

Added value of corpus callosotomy following vagus nerve stimulation in children with Lennox-Gastaut syndrome: A multicenter, multinational study.

OBJECTIVE: Lennox-Gastaut syndrome (LGS) is a severe form of epileptic encephalopathy, presenting during the first years of life, and is very resistant to treatment. Once medical therapy has failed, palliative surgeries such as vagus nerve stimulation (VNS) or corpus callosotomy (CC) are considered. Although CC is more effective than VNS as the primary neurosurgical treatment for LGS-associated drop attacks, there are limited data regarding the added value of CC following VNS. This study aimed to assess the effectiveness of CC preceded by VNS. METHODS: This multinational, multicenter retrospective study focuses on LGS children who underwent CC before the age of 18 years, following prior VNS, which failed to achieve satisfactory seizure control. Collected data included epilepsy characteristics, surgical details, epilepsy outcomes, and complications. The primary outcome of this study was a 50% reduction in drop attacks. RESULTS: A total of 127 cases were reviewed (80 males). The median age at epilepsy onset was 6 months (interquartile range [IQR] = 3.12-22.75). The median age at VNS surgery was 7 years (IQR = 4-10), and CC was performed at a median age of 11 years (IQR = 8.76-15). The dominant seizure type was drop attacks (tonic or atonic) in 102 patients. Eighty-six patients underwent a single-stage complete CC, and 41 an anterior callosotomy. Ten patients who did not initially have a complete CC underwent a second surgery for completion of CC due to seizure persistence. Overall, there was at least a 50% reduction in drop attacks and other seizures in 83% and 60%, respectively. Permanent morbidity occurred in 1.5%, with no mortality. SIGNIFICANCE: CC is vital in seizure control in children with LGS in whom VNS has failed. Surgical risks are low. A complete CC has a tendency toward better effectiveness than anterior CC for some seizure types.

Effect of electrical and chemical (activation versus inactivation) stimulation of the infralimbic division of the medial prefrontal cortex in rats with chronic neuropathic pain.

Neuropathic pain (NP) represents a complex disorder with sensory, cognitive, and emotional symptoms. The medial prefrontal cortex (mPFC) takes critical regulatory roles and may change functionally and morphologically during chronic NP. There needs to be a complete understanding of the neurophysiological and psychopharmacological bases of the NP phenomenon. This study aimed to investigate the participation of the infralimbic division (IFL) of the mPFC in chronic NP, as well as the role of the N-methyl-D-aspartic acid receptor (NMDAr) in the elaboration of chronic NP. Male Wistar rats were submitted to the von Frey and acetone tests to assess mechanical and cold allodynia after 21 days of chronic constriction injury (CCI) of the sciatic nerve or Sham-procedure ("false operated"). Electrical neurostimulation of the IFL/mPFC was performed by low-frequency stimuli (20 µA, 100 Hz) applied for 15 s by deep brain stimulation (DBS) device 21 days after CCI. Either cobalt chloride (CoCl2 at 1.0 mM/200 nL), NMDAr agonist (at 0.25, 1.0, and 2.0 nmol/200 nL) or physiological saline (200 nL) was administered into the IFL/mPFC. CoCl2 administration in the IFL cortex did not alter either mechanical or cold allodynia. DBS stimulation of the IFL cortex decreased mechanical allodynia in CCI rats. Chemical stimulation of the IFL cortex by an NMDA agonist (at 2.0 nmol) decreased mechanical allodynia. NMDA at any dose (0.25, 1.0, and 2.0 nmol) reduced the flicking/licking duration in the cold test. These findings suggest that the IFL/mPFC and the NMDAr of the neocortex are involved in attenuating chronic NP in rats.

Clinical and Surgical Approach for Cerebral Cortical Dysplasia.

The present article describes pathophysiological and clinical aspects of congenital malformations of the cerebral tissue (cortex and white matter) that cause epilepsy and very frequently require surgical treatment. A particular emphasis is given to focal cortical dysplasias, the most common pathology among these epilepsy-related malformations. Specific radiological and surgical features are also highlighted, so a thorough overview of cortical dysplasias is provided.

Reduction in anti-seizure medications use in pediatric patients with pharmacoresistant epilepsy submitted to surgical treatment.

PURPOSE: We aimed to analyze the potential for postoperative (PO) medication suspension and reduction, emphasizing passive withdrawal. METHODS: Retrospective study of patients under 18 years old submitted to surgical treatment for pharmacoresistant epilepsy and classified as Engel I during the first year of PO follow-up. Therapeutic management was evaluated through discontinuation or reduction of medications, both in terms of the number of ASM prescribed and in daily maintenance dosages in mg/kg. RESULTS: ASM withdrawal started in the first year PO and occurred in 1.2% of cases, with a significant yearly reduction in the number of ASM during follow-up (p < 0.001). A comparison of the most commonly used ASM in daily mg/kg between the preoperative period (preop) and PO showed a reduction of ASM maintenance dosages during PO. Even though recurrence of seizures was observed 5 years after surgery, 125 patients (85%) were still classified as Engel I, albeit a higher number of ASM per patient was observed. Most patients showed no changes in cognitive and adaptive behavior evaluation between preop and PO, even in those who were able to reduce ASM. CONCLUSION: Significant reduction observed both in the number and daily maintenance dosages of ASM following each year of PO may be an indirect measure of the effectiveness of epilepsy surgery.

Cortical Neurostimulation and N-Methyl-D-Aspartate Glutamatergic Receptor Activation in the Dysgranular Layer of the Posterior Insular Cortex Modulate Chronic Neuropathic Pain.

BACKGROUND AND AIMS: The dysgranula parts of the posterior insular cortex (PIC) stimulation (PICS) has been investigated as a new putative cortical target for nonpharmacologic therapies in patients with chronic and neuropathic pain (NP). This work investigates the neural bases of insula neurostimulation-induced antinociception and glutamatergic neurochemical mechanisms recruited by the PICS in animals with neuropathy. MATERIALS AND METHODS: Male Wistar rats were submitted to the von Frey and acetone tests to assess mechanical and cold allodynia after 21 days of chronic constriction injury (CCI) of the sciatic nerve or Sham procedure ("false operated"). Either the Cascade Blue 3000 MW lysine-fixable dextran (CBD) or the biotinylated dextran amine 3000 MW (BDA) neural tract tracer was microinjected into the PIC. The electrical PICS was performed at a low frequency (20 µA, 100 Hz) for 15 seconds by a deep brain stimulation device. PIC N-methyl-D-aspartate (NMDA) receptors (NMDAR) blockade with the selective antagonist LY235959 (at 2, 4, and 8 nmol/200 nL) followed by PICS was investigated in rats with CCI. RESULTS: PIC sends projections to the caudal pontine reticular nucleus, alpha part of the parvicellular reticular nucleus, dorsomedial tegmental area, and secondary somatosensory cortex (S2). PICS decreased both mechanical and cold allodynia in rats with chronic NP. Blockade of NMDAR in the PIC with LY235959 at 8 nmol attenuated PICS-produced antinociception. CONCLUSION: Neuroanatomic projections from the PIC to pontine reticular nuclei and S2 may contribute to chronic NP signaling. PICS attenuates the chronic NP, and the NMDA glutamatergic system in the PIC may be involved in PICS-induced antinociception in rodents with NP conditions.

Epilepsy surgery in infants up to 3 months of age: Safety, feasibility, and outcomes: A multicenter, multinational study.

OBJECTIVE: Drug-resistant epilepsy (DRE) during the first few months of life is challenging and necessitates aggressive treatment, including surgery. Because the most common causes of DRE in infancy are related to extensive developmental anomalies, surgery often entails extensive tissue resections or disconnection. The literature on "ultra-early" epilepsy surgery is sparse, with limited data concerning efficacy controlling the seizures, and safety. The current study's goal is to review the safety and efficacy of ultra-early epilepsy surgery performed before the age of 3 months. METHODS: To achieve a large sample size and external validity, a multinational, multicenter retrospective study was performed, focusing on epilepsy surgery for infants younger than 3 months of age. Collected data included epilepsy characteristics, surgical details, epilepsy outcome, and complications. RESULTS: Sixty-four patients underwent 69 surgeries before the age of 3 months. The most common pathologies were cortical dysplasia (28), hemimegalencephaly (17), and tubers (5). The most common procedures were hemispheric surgeries (48 procedures). Two cases were intentionally staged, and one was unexpectedly aborted. Nearly all patients received blood products. There were no perioperative deaths and no major unexpected permanent morbidities. Twenty-five percent of patients undergoing hemispheric surgeries developed hydrocephalus. Excellent epilepsy outcome (International League Against Epilepsy [ILAE] grade I) was achieved in 66% of cases over a median follow-up of 41 months (19-104 interquartile range [IQR]). The number of antiseizure medications was significantly reduced (median 2 drugs, 1-3 IQR, p < .0001). Outcome was not significantly associated with the type of surgery (hemispheric or more limited resections). SIGNIFICANCE: Epilepsy surgery during the first few months of life is associated with excellent seizure control, and when performed by highly experienced teams, is not associated with more permanent morbidity than surgery in older infants. Thus surgical treatment should not be postponed to treat DRE in very young infants based on their age.

The intellectual profile of pediatric patients with posterior cortex epilepsy.

BACKGROUND: Cognitive functioning in epileptic syndromes has been widely explored in patients with temporal lobe epilepsy (TLE), but few studies have investigated the neuropsychological profile in posterior cortex epilepsy (PCE). In this study, we investigated the presurgical intellectual profile of children and adolescents with drug-resistant PCE. METHODS: Children and adolescents diagnosed with PCE (n = 25) participated in this study. The data were obtained from medical records, with assessments carried out between the years 2003 and 2019. To compare the intellectual profile, we also included patients diagnosed with frontal (n = 26) and temporal lobe epilepsy (n = 40). The Wechsler Intelligence Scales were used for the assessment of general intelligence. RESULTS: There was an effect of the brain region on the Working Memory Index (p < 0.01), in which patients with TLE had significantly higher scores than groups with FLE (p < 0.01) and PCE (p < 0.05). We also demonstrated that patients with PCE tended to perform worse in the Processing Speed Index than patients with TLE (p = 0.055). The Full-Scale Intelligence Quotient, Verbal Comprehension, and Perceptual Reasoning indexes did not differ among the brain regions. CONCLUSIONS: Children and adolescents with PCE demonstrated significant impairment in working memory and processing speed. The pattern of cognitive dysfunction in PCE was similar to that observed in FLE, which expands the evidence of the involvement of frontoparietal networks on cognitive proficiency.

An Adapted Chronic Constriction Injury of the Sciatic Nerve Produces Sensory, Affective, and Cognitive Impairments: A Peripheral Mononeuropathy Model for the Study of Comorbid Neuropsychiatric Disorders Associated with Neuropathic Pain in Rats.

BACKGROUND: Chronic constriction injury (CCI) is a model of neuropathic pain induced by four loose ligatures around the sciatic nerve. This work aimed to investigate the sensory, affective, cognitive, and motor changes induced by an adaptation of the CCI model by applying a single ligature around the sciatic nerve. METHODS: Mechanical allodynia was measured from day 1 to day 28 postsurgery by the von Frey test. The beam walking test (BWT) was conducted weekly until 28 days after surgery. Anxiety- and depression-like behaviors, and cognitive performance were assessed through the open field (OF), forced swimming (FS), and novel object recognition (NOR) tests, respectively, 21 days after surgery. RESULTS: The two CCI models, both Bennett and Xie's model (four ligatures of the sciatic nerve) and a modification of it (one ligature), induced mechanical allodynia, increased immobility in the FS, and reduced recognition index in the NOR. The exploratory behavior and time spent in the central part of the arena decreased, while the defensive behavior increased in the OF. The animals subjected to the two CCI models showed motor alterations in the BWT; however, autotomy was observed only in the group with four ligatures and not in the group with a single ligature. CONCLUSIONS: Overall these results demonstrate that our adapted CCI model, using a single ligature around the sciatic nerve, induces sensory, affective, cognitive, and motor alterations comparable to the CCI model with four ligatures without generating autotomy. This adaptation to the CCI model may therefore represent an appropriate and more easily performed model for inducing neuropathic pain and study underlying mechanisms and effective treatments.

State of the art in translating experimental myelomeningocele research to the bedside.

Myelomeningocele (MMC), the commonest type of spina bifida (SB), occurs due to abnormal development of the neural tube and manifest as failure of the complete fusion of posterior arches of the spinal column, leading to dysplastic growth of the spinal cord and meninges. It is associated with several degrees of motor and sensory deficits below the level of the lesion, as well as skeletal deformities, bladder and bowel incontinence, and sexual dysfunction. These children might develop varying degrees of neuropsychomotor delay, partly due to the severity of the injuries that affect the nervous system before birth, partly due to the related cerebral malformations (notably hydrocephalus-which may also lead to an increase in intracranial pressure-and Chiari II deformity). Traditionally, MMC was repaired surgically just after birth; however, intrauterine correction of MMC has been shown to have several potential benefits, including better sensorimotor outcomes (since exposure to amniotic fluid and its consequent deleterious effects is shortened) and reduced rates of hydrocephalus, among others. Fetal surgery for myelomeningocele, nevertheless, would not have been made possible without the development of experimental models of this pathological condition. Hence, the aim of the current article is to provide an overview of the animal models of MMC that were used over the years and describe how this knowledge has been translated into the fetal treatment of MMC in humans.

Transcranial ultrasonography as a reliable instrument for the measurement of the cerebral ventricles in rats with experimental hydrocephalus: a pilot study.

PURPOSES: Demonstrate that transcranial ultrasonography (TUS) scanning is viable and useful as a diagnostic method in experimental hydrocephalus, as well as to compare measurements of cerebral and ventricular width obtained from TUS scans of hydrocephalic rats with post-mortem anatomical specimens, aiming for the development of accurate criteria to establish ventricular enlargement and progression of hydrocephalus subsequently. METHODS: Thirty-five male Wistar rats were used. Following hydrocephalus induction, they underwent a transcranial ultrasound scan to measure cerebral and ventricular dimensions, in the fourth and 21 post-induction days. By the end of the experiments, measurements obtained from TUS scans were compared with actual values as seen in the post-mortem specimens of each animal. RESULTS: Ventricular dilation could be clearly visualized in hydrocephalic animals. We performed intraclass correlation coefficient and linear regression analyses that have demonstrated a precise correlation between measurements of TUS scans and post-mortem specimens; we have found a similarity of 0,95 for the cerebral diameter and 0,97 for ventricular width. CONCLUSIONS: Transcranial ultrasonography is a useful and reliable diagnostic tool for experimental hydrocephalus; also, it can be used to assess the progression of ventriculomegaly in animal models of hydrocephalus.

Evaluating H3F3A K27M and G34R/V somatic mutations in a cohort of pediatric brain tumors of different and rare histologies.

PURPOSE: Somatic mutations on H3 histone are currently considered a genetic hallmark for midline pediatric high-grade gliomas (HGGs). Yet, different tumor histologies have been occasionally described to carry these mutations. Since histone modifications can lead to major epigenetic changes with direct impact on prognosis and treatment, we thought to investigate the occurrence of H3F3A K27M and G34R/V mutations in a cohort of pediatric tumors which included HGGs, low-grade gliomas, ependymomas, medulloblastomas, and a series of rare brain tumor lesions of different histologies. METHODS: A total of 82 fresh-frozen pediatric brain tumor samples were evaluated. PCR or RT-PCR followed by Sanger sequencing for the exon 2 of H3F3A (containing both K27 and G34 hotspots) were obtained and aligned to human genome. Loss of trimethylation mark (H3K27me3) in H3F3A/K27M-mutant samples was confirmed by immunohistochemistry. RESULTS: We found H3F3A/K27M mutation in 2 out of 9 cases of HGGs; no H3F3A/K27M mutations were detected in low-grade gliomas (27), ependymomas (n = 10), medulloblastomas (n = 21), or a series of rare pediatric brain tumors which included meningiomas, dysembryoplastic neuroepithelial tumors (DNETs), central nervous system (CNS) germ-cell tumors, choroid plexus tumors, cortical hamartoma, subcortical tubers, and schwannomas (n = 15). H3F3A/G34R/V mutation was not observed in any of the samples. CONCLUSIONS: Our investigation reinforces the low frequency of H3F3A somatic mutations outside the HGG setting. Interestingly, an atypical focal brainstem glioma carrying H3F3A K27M mutation that showed protracted clinical course with late-onset tumor progression was identified.

Drebrin expression patterns in patients with refractory temporal lobe epilepsy and hippocampal sclerosis.

OBJECTIVE: Drebrins are crucial for synaptic function and dendritic spine development, remodeling, and maintenance. In temporal lobe epilepsy (TLE) patients, a significant hippocampal synaptic reorganization occurs, and synaptic reorganization has been associated with hippocampal hyperexcitability. This study aimed to evaluate, in TLE patients, the hippocampal expression of drebrin using immunohistochemistry with DAS2 or M2F6 antibodies that recognize adult (drebrin A) or adult and embryonic (pan-drebrin) isoforms, respectively. METHODS: Hippocampal sections from drug-resistant TLE patients with hippocampal sclerosis (HS; TLE, n = 33), of whom 31 presented with type 1 HS and two with type 2 HS, and autopsy control cases (n = 20) were assayed by immunohistochemistry and evaluated for neuron density, and drebrin A and pan-drebrin expression. Double-labeling immunofluorescences were performed to localize drebrin A-positive spines in dendrites (MAP2), and to evaluate whether drebrin colocalizes with inhibitory (GAD65) and excitatory (VGlut1) presynaptic markers. RESULTS: Compared to controls, TLE patients had increased pan-drebrin in all hippocampal subfields and increased drebrin A-immunopositive area in all hippocampal subfields but CA1. Drebrin-positive spine density followed the same pattern as total drebrin quantification. Confocal microscopy indicated juxtaposition of drebrin-positive spines with VGlut1-positive puncta, but not with GAD65-positive puncta. Drebrin expression in the dentate gyrus of TLE cases was associated negatively with seizure frequency and positively with verbal memory. TLE patients with lower drebrin-immunopositive area in inner molecular layer (IML) than in outer molecular layer (OML) had a lower seizure frequency than those with higher or comparable drebrin-immunopositive area in IML compared with OML. SIGNIFICANCE: Our results suggest that changes in drebrin-positive spines and drebrin expression in the dentate gyrus of TLE patients are associated with lower seizure frequency, more preserved verbal memory, and a better postsurgical outcome.

High-throughput microRNA profile in adult and pediatric primary glioblastomas: the role of miR-10b-5p and miR-630 in the tumor aggressiveness.

Glioblastoma (GBM) is the most common primary malignant neoplasm of the central nervous system and, despite the standard therapy; the patients' prognoses remain dismal. The miRNA expression profiles have been associated with patient prognosis, suggesting that they may be helpful for tumor diagnosis and classification as well as predictive of tumor response to treatment. We described the microRNA expression profile of 29 primary GBM samples (9 pediatric GBMs) and 11 non-neoplastic white matter samples as controls (WM) by microarray analysis and we performed functional in vitro assays on these 2 most differentially expressed miRNAs. Hierarchical clustering analysis showed 3 distinct miRNA profiles, two of them in the GBM samples and a group consisting only of cerebral white matter. When adult and pediatric GBMs were compared to WM, 37 human miRNAs were found to be differentially expressed, with miR-10b-5p being the most overexpressed and miR-630 the most underexpressed. The overexpression of miR-630 was associated with reduced cell proliferation and invasion in the U87 GBM cell line, whereas the inhibition of miR-10b-5p reduced cell proliferation and colony formation in the U251 GBM cell line, suggesting that these miRNAs may act as tumor-suppressive and oncogenic miRNAs, respectively. The present study highlights the distinct epigenetic profiling of adult and pediatric GBMs and underscores the biological importance of mir-10b-5p and miR-630 for the pathobiology of these lethal tumors.

Impact of epilepsy surgery on quality of life and burden of caregivers in children and adolescents.

OBJECTIVE: The objective of this study was to analyze the impact of pediatric epilepsy surgery on the quality of life (QOL), determining whether patients improve, worsen, or maintain their preoperative patterns, as it relates to the burden of caregivers, as well as evaluating potential related factors, from both the children and caregivers perspectives. MATERIAL AND METHODS: This is a retrospective study of children and adolescents who underwent epilepsy surgery and were evaluated through clinical data, videoelectroencephalogram (V-EEG), neuroimaging findings, neuropsychological testing, and aspects of QOL. These assessments were performed prior to surgery and after six months and two years of follow-up. Quality of life was assessed with epilepsy-specialized questionnaires, namely Questionnaire health-related quality of life for children with epilepsy (QVCE-50), Autoquestionnaire Qualité de Vie Enfant Image Scale (AUQUEI), Quality of life in epilepsy inventory for adolescents (QOLEI-AD-48); and burden of caregivers with Burden Interview - ZARIT scale. Postoperative changes in QVCE-50 were quantified using measures of the analysis of variance (ANOVA MR) for comparison of the difference between the three times of the scale and domains. RESULTS: Fifty patients were enrolled. Of these, 27 (54%) were male, with a mean age at surgery of 8.2 years (range: 1-18 years). Thirty-five patients (70%) were Engel I and one was Engel II (2%) at six months of follow-up, whereas 28 (56%) were Engel I and 32 (64%) were Engel I or II at two years of follow-up. Preoperatively, 21 (42%) presented with moderate or severe intellectual disability. Postoperative cognitive evaluations at the two-year follow-up showed 18 (36%) maintained similar deficits. The QVCE-50 showed postoperative improvement in the two-year follow-up period, but not at six months after surgery. Postoperative improvements were associated mainly with better seizure outcome. Autoperception evaluations were limited because of the clinical and cognitive severity of patients. The burden of caregivers was quoted as mild to moderate and remained unchanged postoperatively. CONCLUSIONS: Children and adolescents with surgically treated epilepsy reach a good seizure outcome, stabilize in intellectual and adaptive functions, and have an increase in QOL, from the caregiver's perspective. Nevertheless, their burden remains unchanged. Seizure outcome is the main factor for improvement in the QOL. The upgrading of structured questionnaires and QOL instruments specific to pediatric epilepsy can be helpful to assess patient- and caregiver-reported surgical outcomes, allowing for better planning of therapeutic approaches.

Left hemispherectomy in older children and adolescents: outcome of cognitive abilities.

PURPOSE: Hemispherectomy is an effective treatment option for pharmacoresistant epilepsy. Nevertheless, when high cortical functions are at risk during the presurgical evaluation, especially for older children, and for the left hemisphere, despite good seizure outcome, the anticipated decrease of cognitive functions may prevent a decision to perform surgery. The objective of this study is to report the cognitive outcome, based on verbal and performance intelligence skills, in a series of older children and adolescents who underwent left hemispherectomy, analyzing the risks (residual cognitive deficit) and benefits (seizure reduction) of surgery. METHODS: We retrospectively analyzed pre- and postoperative clinical and neuropsychological data from our patients who underwent left hemispherectomy, aged between 6 and 18 years. RESULTS: We included 15 patients, with a mean follow-up of 3.1 years, 12 patients (80%) were Engel I, and the other three were classified as Engel II, III, and IV. Nine patients were tested by Wechsler Scales of Intelligence; postsurgically all but one kept the same intellectual levels; verbal intelligence quotient (VIQ) remained unchanged in 13 and improved in one, whereas performance intelligence quotient (PIQ) decreased in four patients. Both Total Vineland and communication scores of Vineland Adaptive Behavior Scales were obtained in six patients: in all, scores were classified as deficient adaptive functioning pre- and postoperatively, remaining unchanged. CONCLUSION: The evaluation of the remaining intellectual abilities after left hemispherectomy in older children and adolescents is useful to discuss the risks and benefits of this surgery, enabling better and safer decisions regarding surgical indications and timing.

Risk factors and results of hemispherotomy reoperations in children.

OBJECTIVE: The goal of this study was to perform an analysis of a single-center experience with hemispherotomy reoperations for refractory hemispheric pediatric epilepsy due to persistence of seizures after initial surgery. The authors also identify possible anatomical and neurophysiological reasons for hemispherotomy failure, as well as risk factors and surgical options for this subgroup of patients. METHODS: A review was performed of the medical records in 18 consecutive cases in which candidates for redo hemispherotomy were treated between 2003 and 2018 at the authors' epilepsy surgery center. Fourteen patients underwent reoperation due to seizure recurrence and were studied herein, whereas in 3 the initial surgical procedure was stopped because of uncontrollable bleeding, and the remaining patient refused to undergo a reoperation in spite of seizure recurrence and went on to have a vagus nerve stimulation device placed. RESULTS: Among the 14 patients whose seizures recurred and in whom reoperations were done, the etiology of epilepsy consisted of 7 cases with malformations of cortical development (50%), 5 cases of Rasmussen encephalitis (35.8%), 1 case of porencephaly (7.1%), and 1 case of Sturge-Weber syndrome (7.1%). Eleven patients had radiological evidence of incomplete disconnection. After reoperation, 6 patients were Engel class IA, 1 was Engel II, 5 were Engel III, and 2 were Engel IV, within a mean follow-up of 48.4 months. CONCLUSIONS: Patients with malformations of cortical development have a higher risk of seizure recurrence, and these malformations comprised the main etiology in the reoperation series. Failure of an initial hemispherotomy usually occurs due to incomplete disconnection and needs to be extensively assessed. Outcomes of reoperation are most often favorable, with acceptable complication rates.

Behavioral and Biochemical Features of the Course and Surgical Treatment of Experimental Obstructive Hydrocephalus in Young Rats.

INTRODUCTION: Hydrocephalus is a multifactorial disease, affecting the dynamics of cerebrospinal fluid (CSF) and leading to severe neurological impairment in children; in spite of the recent advances in hydrocephalus research, it has many physiopathological aspects that still remain poorly understood, especially after treatment. OBJECTIVES: To analyze the clinical, radiological, histopathological, and biochemical aspects of kaolin-induced hydrocephalus in an experimental model, both in the acute phase and after shunt treatment, by means of behavioral tests, magnetic resonance imaging (MRI) scans, histopathological studies, and level of inflammatory interleukins in the CSF. METHODS: Seven-day-old Wistar rats were used and subdivided into three subgroups: treated hydrocephalic (n = 24), untreated hydrocephalic (n = 17), and controls (n = 5). The hydrocephalic groups underwent cisternal injection of 15% kaolin for induction of hydrocephalus at 7 days of age. The treated group was submitted to a ventricular-subcutaneous shunt (VSCS) 1 week after induction. All animals were euthanized at 21 days of age. They underwent motor function and memory testing as well as brain MRI scans. Histopathological analysis for glial fibrillary acidic protein and Ki-67 was done, and CSF was collected for measurement of IL-1ß, IL-6, and TNF-α. RESULTS: The average time to reach the water maze platform was highest in the untreated hydrocephalic group. The magnetization transfer rates were 37.21 and 33.76 before and after shunting, respectively. The mean astrocyte counts were 2.45, 1.36, and 90.5 for shunted, untreated, and control animals, respectively. The mean CSF IL-1ß concentrations were 62.3 and 249.6 pg/mL, the average IL-6 levels were 104.2 and 364.7 pg/mL, and the average TNF-α values were 4.9 and 170.5 pg/mL for the treated hydrocephalic group and the untreated group, respectively. CONCLUSIONS: Pups treated with a CSF shunt showed better performance on memory tests. VSCS did not revert demyelination caused by hydrocephalus. Likewise, reactive astrocytosis and cell proliferation over the germinal matrix were not reversed after shunting. Hydrocephalic animals had raised levels of inflammatory interleukins, which returned to normal after treatment.

MicroRNA profile of pediatric pilocytic astrocytomas identifies two tumor-specific signatures when compared to non-neoplastic white matter.

PURPOSES: Pilocytic astrocytoma (PA) is a low-grade neoplasm frequently found in childhood. PA is characterized by slow growth and a relatively good prognosis. Genetic mechanisms such as activation of MAPK, BRAF gene deregulation and neurofibromatosis type 1 (NF1) syndrome have been associated with PA development. Epigenetic signature and miRNA expression profile are providing new insights about different types of tumor, including PAs. METHODS: In the present study we evaluated global miRNA expression in 16 microdissected pediatric PA specimens, three NF1-associated PAs and 11 cerebral white matter (WM) samples by the microarray method. An additional cohort of 20 PAs was used to validate by qRT-PCR the expression of six miRNAs differentially expressed in the microarray data. RESULTS: Unsupervised hierarchical clustering analysis distinguished one cluster with nine PAs, including all NF1 cases and a second group consisting of the WM samples and seven PAs. Among 88 differentially expressed miRNAs between PAs and WM samples, the most underexpressed ones regulate classical pathways of tumorigenesis, while the most overexpressed miRNAs are related to pathways such as focal adhesion, P53 signaling pathway and gliomagenesis. The PAs/NF1 presented a subset of underexpressed miRNAs, which was also associated with known deregulated pathways in cancer such as cell cycle and hippo pathway. CONCLUSIONS: In summary, our data demonstrate that PA harbors at least two distinct miRNA signatures, including a subgroup of patients with NF1/PA lesions.