Surgical treatment of hypothalamic hamartomas.

Hypothalamic hamartomas are aberrant masses, composed of abnormally distributed neurons and glia. Along endocrine and cognitive symptoms, they may cause epileptic seizures, including the specific gelastic and dacrystic seizures. Surgery is the treatment of drug-resistant hamartoma epilepsy, with associated positive results on endocrine, psychiatric, and cognitive symptoms. Recently, alternatives to open microsurgical treatment have been proposed. We review these techniques and compare their efficacy and safety. Open resection or disconnection of the hamartoma, either through pterional, transcallosal, or transventricular approach, leads to good epileptological control, but its high complication rate, up to 30%, limits its indications. The purely cisternal peduncular forms remain the only indication of open, pterional approach, while other strategies have been developed to overcome the neurological, endocrine, behavioral, or cognitive complications. Laser and radiofrequency thermocoagulation-based disconnection through robot-guided stereo-endoscopy has been proposed as an alternative to open microsurgical resection and stereotactic destruction. The goal is to allow safe and complete disconnection of a possibly complex attachment zone, through a single intraparenchymal trajectory which allows multiple laser or radiofrequency probe trajectory inside the ventricle. The efficacy was high, with 78% of favorable outcome, and the overall complication rate was 8%. It was especially effective in patients with isolated gelastic seizures and pure intraventricular hamartomas. Stereotactic radiosurgery has proved as efficacious and safer than open microsurgery, with around 60% of seizure control and a very low complication rate. Multiple stereotactic thermocoagulation showed very interesting results with 71% of seizure freedom and 2% of permanent complications. Stereotactic laser interstitial thermotherapy (LiTT) seems as effective as open microsurgery (from 76 to 81% of seizure freedom) but causes up to 20% of permanent complications. This technique has however been highly improved by targeting only the epileptogenic onset zone in the hamartoma, as shown on preoperative functional MRI, leading to an improvement of epilepsy control by 45% (92% of seizure freedom) with no postoperative morbidity. All these results suggest that the impact of the surgical procedure does not depend on purely technical matters (laser vs radiofrequency thermocoagulation or stereotactic vs robot-guided stereo-endoscopy) but relies on the understanding of the epileptic network, including inside the hamartoma, the aim being to plan an effective disconnection or lesion of the epileptogenic part while sparing the adjacent functional structures.

Optimizing the Detection of Subtle Insular Lesions on MRI When Insular Epilepsy Is Suspected.

Insular epilepsy is underdiagnosed and accounts for a number of failed operations. Identifying insular target lesions on MR imaging can help guide intracranial electroencephalography and improve the outcome of surgery. In this study, we present a novel method of exploring the insular region for subtle lesions on 3D MR imaging by MPR postprocessing of slices in oblique reference planes. Using this method, we retrospectively reviewed presurgical MRIs that were initially considered to have normal findings in 7 pediatric patients with intractable insular epilepsy. Insular epilepsy was confirmed in these patients on stereo-electroencephalography and histopathology. The MPR postprocessing method we describe helped detect subtle insular lesions in all 7 patients.

Outcome of surgery in children with focal cortical dysplasia younger than 5 years explored by stereo-electroencephalography.

PURPOSE: Focal cortical dysplasia (FCD) is the most frequent etiology for drug-resistant epilepsy in young children. Complete removal of the lesion is mandatory to cure the epilepsy. Stereo-EEG (SEEG) is an excellent method to delimitate the zone to be resected in older children and adults. We studied its feasibility in younger children. METHODS: We retrospectively studied 19 children under 5 years of age who underwent SEEG between January 2009 and December 2012 and were subsequently operated on. FCD was diagnosed in all. We reviewed magnetic resonance imaging (MRI), electrophysiological and clinical data, as well as postoperative seizure outcome. We also included fluoro-deoxyglucose positron emission tomography (FDG-PET) studies, which had been systematically performed before invasive recording in 16 of the 19 children. RESULTS: The mean patient's age at the time of SEEG was 38.6 months, and the mean age at seizure onset was 8 months. Three patients had normal MRI. No SEEG-associated complications occurred. We were able to delineate the epileptogenic zone in all children, and electrode stimulation localized the motor area when necessary (12 patients). Hypometabolic areas on FDG-PET included the epileptogenic zone in 13 of the 16 children, with a lobar concordance in 9 (56 %) and the same anatomical extent in 6 (38 %). Twelve children subsequently underwent focal or sublobar resection, six had multilobar resection, and one had hemispherotomy. The etiology was FCD type 2 in 15 and FCD type 1 or type 3 in three children. Eighty-four percent of our population have remained seizure-free at a mean follow-up of 29 months (12-48 months). CONCLUSION: Although children with FCD can successfully undergo resective surgery without invasive EEG, poor seizure semiology at this age inclines to perform SEEG when the dysplastic lesion is ill-defined and/or the electroclinical correlation is unclear. In cases with normal imaging as well as with suspected huge malformations, as was the case in 52 % of our patients, we consider it to be indispensable.

Selective suppression of excessive GluN2C expression rescues early epilepsy in a tuberous sclerosis murine model.

Tuberous sclerosis complex (TSC), caused by dominant mutations in either TSC1 or TSC2 tumour suppressor genes is characterized by the presence of brain malformations, the cortical tubers that are thought to contribute to the generation of pharmacoresistant epilepsy. Here we report that tuberless heterozygote Tsc1(+/-) mice show functional upregulation of cortical GluN2C-containing N-methyl-D-aspartate receptors (NMDARs) in an mTOR-dependent manner and exhibit recurrent, unprovoked seizures during early postnatal life (

Insular and insulo-opercular epilepsy in childhood: an SEEG study.

PURPOSE: In recent years, there have been series analysing the electro-clinical correlations of insular epilepsy in adult populations. In contrast, the ictal semiology in children with insular epilepsy is poorly described. Considering that early and successful surgery may greatly improve the cognitive outcome and quality of life, it is worthwhile to deepen our knowledge of insular epilepsy in children. METHODS: We retrospectively evaluated ten children with drug-resistant focal insular epilepsy who had been consecutively explored with stereoelectroencephalography (SEEG), followed by individually tailored resective surgery that included part of the insula in all cases. A detailed anatomo-electro-clinical analysis of non-invasive EEG and SEEG data was performed. At least one of the electrodes explored the insular cortex. SEEG analysis confirmed that the insular cortex was included in the ictal onset zone. RESULTS: Epilepsy onset was mostly during the first year of life, characterized by subtle seizures as well as spasms and myoclonic seizures. Later on, neurovegetative signs and asymmetric tonic and hypermotor seizures (HMS) dominated the ictal semiology. The epileptogenic zone was frequently wider than insular with frontal and central predominance. In eight patients, the tailored resection included a lesion. In seven patients, an Engel class 1 outcome as well as neuropsychological and behavioural improvement was obtained. CONCLUSIONS: SEEG is feasible and useful in children with drug-resistant insular epilepsy which is often characterized by autonomic symptoms as the initial symptoms and should be suspected in cases with HMS, asymmetric tonic seizures and even asymmetric spasms. Early propagation is mostly frontal and central. Analysis of a larger population is required to refine these findings.

Heterotopia associated with hippocampal sclerosis: an under-recognized cause of early onset epilepsy in children operated on for temporal lobe epilepsy.

PURPOSE: The aim of this study is to report on 52 children operated on for pharmacoresistant temporal lobe epilepsy, with special emphasis on histopathology and correlation with clinical features. METHODS: Charts were retrospectively analyzed. All children underwent comprehensive clinical, electrophysiological and radiological investigations before surgery. Surgical procedures were tailored according to scalp, foramen ovale and eventually depth electrode recordings. Histopathology was compared with clinical variables (χ (2) and Fisher's exact tests). Outcome was evaluated using the Engel scale. RESULTS: Developmental tumor was found in 14 cases, malformation of cortical development (MCD) in 26, isolated hippocampal sclerosis (HS) in 5 and gliosis in 7. Dual pathology (DP) affected 18 patients and the main extrahippocampal lesion consisted of microscopic sub-cortical heterotopias (HS-HT) for 15 patients who shared a particular clinical pattern: a history of febrile seizures (FS) and/or brain injury, early onset of epilepsy without latent period from FS to the first temporal seizure, and a particularly good outcome following surgery. CONCLUSION: In our pediatric temporal lobe surgery series, the prevalence for MCD and for DP was higher than in adult series. Age at seizure onset depends on pathology, and is earlier when involving the neocortex rather than only the hippocampus. We identify the association HS-HT (the most frequent DP in this series), with particular clinical features.

[CT and MR brain imaging following hemispherotomy]. / Imagerie scanner et IRM de l'encéphale après hémisphérotomie.

PURPOSE: The aim of the study was to define the usual and pathological modifications arising in the brain following hemispherotomy for intractable epilepsy in children. METHODS: Preoperative MRI and postoperative imaging scans (CT in the first week, MRI at 3 months and 1 year after surgery) were reviewed in a series of 52 patients, average age 8 years and 7 months, with intractable epilepsy due to dysplasia, Rasmussen's encephalitis, ischemic lesions and/or Sturge-Weber disease. The posterior fossa, brain parenchyma, ventricles and subdural space were also analyzed. RESULTS: Hemispheric scarring was a typical finding on CT and MRI as a consequence of the surgical procedure. Also frequently seen were small subdural effusions, bleeding along the surgical scar on early CT, and chronic subdural effusions with no mass effect on mid-term and late MRI scans. Other features - such as large subdural effusions that required external shunts and hydrocephalus - were rare, but severe, and considered to be postoperative complications. In contrast to the complications associated with other surgical techniques such as hemispherectomy, infection, extensive edema or hemosiderosis were never found in our series. CONCLUSION: Hemispherotomy is a surgical technique performed to treat intractable epilepsy. Our findings will help to identify the typical morphology of postsurgical scars, and to differentiate the usual features and complications seen in the postoperative period on CT and MRI brain scans.

[Surgical disconnection of hypothalamic hamartomas]. / Déconnexion chirurgicale des hamartomes hypothalamiques.

BACKGROUND AND PURPOSE: Surgical resection of hypothalamic hamartomas (HHs) associated with drug-resistant gelastic epilepsy carries a considerable risk of neurological and endocrine morbidity. Alternative surgical routes and techniques have therefore been proposed, especially for broadly attached lesions and for those with a third ventricular location. METHODS: We present an updated series of 43 patients (aged nine months to 34 years), operated on from 1998 through 2005 at our institution. The hamartoma was disconnected using a microsurgical pterional approach of those lesions extending from the hypothalamic floor downward into the interpeduncular cistern. When the HH presented as a paramedian mass, partly or exclusively bulging into the third ventricle, with a rather vertical plane of attachment, we chose a frameless stereotactic endoscopic technique to disconnect the lesion. In several of our patients, both methods were applied subsequently. RESULTS: Surgery-related morbidity was lower with the ventricular endoscopic technique. Twenty-one patients (50%) are seizure-free and two patients (5%) almost seizure-free, while in 17 patients (40%), there was a significant seizure reduction. Two patients (5%) had no postoperative improvement. According to the different topographic features of the HHs, for which we have recently proposed a classification into four subtypes, the intraventricularly located hamartoma had the best prognosis following endoscopic disconnection. Ten of the 12 patients (83%) with this HH location became seizure-free. CONCLUSIONS: Resection of epilepsy-related HHs can be replaced by disconnective procedures. Our results confirm their feasibility and acceptable morbidity, with particularly good seizure outcome in patients with intraventricularly located HHs.

[Electrophysiological investigations in childhood epilepsy surgery]. / Explorations électroencéphalographiques préchirurgicales de l'enfant.

Epilepsy surgery in children is a functional surgery: its goal is to perform the resection of the epileptic brain tissue while sparing the eloquent cortex. Prolonged scalp video-EEGs allow recording of all types of seizures and play a crucial role in localizing the epileptogenic zone. Furthermore, EEG data correlation with clinical and radiological findings provides a guide for the surgical strategy: either resection without further investigations or an invasive recording procedure. In prehemispherotomy evaluation, EEG recordings confirm that limited resections are not indicated and demonstrate that the opposite hemisphere is not involved. If invasive recordings are needed, they consist in foramen ovale electrode insertion, which provides valuable information in mesial temporal lobe epilepsy, stereoelectroencephalography for children older than two years, and subdural grids associated with depth electrodes in infants or when the eloquent areas need to be carefully investigated. Such investigations allow tailoring surgery to each child.

[Long-term outcome after hemispheric disconnection]. / Evaluation à long terme des déconnexions hémisphériques.

Hemispheric disconnection has been largely proposed for patients with severe epilepsy associated with a congenital or acquired hemispheric cerebral pathology. The classical procedure of anatomical hemispherectomy was progressively abandoned by neurosurgeons in order to avoid postoperative complications since then hemispherotomy techniques have been developed. Globally, with hemispheric disconnection, the rate of patients becoming seizure-free has been between 50 and 80%. The factors affecting seizure control have not been completely elucidated, but several authors suggested that differences in etiology as well as the hemispheric disconnection technique used may partially explain this variability. The percentage of seizure-free patients is higher with hemispherotomy techniques and in the group of patients with Rasmussen encephalitis, Sturge-Weber syndrome, and vascular insults. Depending on overall long-term progression, there is an improvement compared to preoperative status even if children exhibit heterogenous abilities. The lowest scores are observed for motor skills but communication and socialization are relatively well-preserved and strongly related to the duration of epilepsy: the longer the duration, the lower the scores were. Neuropsychological outcome following hemispheric disconnection makes it possible to study the development of hemispheric specialization during infancy and to provide information on cognitive recovery. Cerebral reorganization has been proved to exist in motor and language recovery. Ipsilateral corticospinal pathways seem to be involved in the movement of hemiplegic limbs. Everyday language can be supported by both hemispheres, but there is an early hemispheric specialization of the left hemisphere according to metaphonologic abilities.

[Epilepsy surgery during infancy and early childhood in France]. / Chirurgie de l'épilepsie de l'enfant et du nourrisson en France.

BACKGROUND AND PURPOSE: We present the epilepsy surgery activity in infants and children at the Fondation Rothschild Hospital, the main center dedicated to this activity in France. METHOD: A prospective study was conducted from 2003 to 2007 based on three populations: (1) children selected as candidates for surgery, (2) children undergoing presurgical evaluation and (3) children undergoing surgical procedures for epilepsy. RESULTS: Children selected as candidates for surgery: 304 children were referred and discussed by our multidisciplinary staff. They came from Paris and its suburbs (40%), the provinces (43%) or from other countries (14%). Sixty-one percent of them were included in our surgery program and 24% were excluded. Sixty-one percent of them were under 10 years of age. Children undergoing presurgical evaluation: 296 children were recorded: 140 EEG (47%), 46 with foramen ovale electrodes (16%) and 110 with invasive recording techniques (37%). Seventy percent of these children were under 10 years of age. Children undergoing surgical procedures: 316 children underwent surgery; 68% of them were under 10 years of age. The surgical procedures were focal resection (136 children), vertical parasagittal hemispherotomy (77 children), resection and or disconnection for hypothalamic hamartoma (69 children) and 34 had palliative surgery (callosotomy or vagal nerve stimulation). CONCLUSION: Eighty to 100 children undergo surgery each year in our department for drug-resistant partial epilepsy; 70% of them are less than 10 years of age. This activity is part of a network of pediatric neurologists who are deeply involved in treatment of severe epilepsy in children.

[Parasagittal vertical hemispherotomy: surgical procedure]. / Hémisphérotomie verticale parasagittale: technique opératoire.

After the occurrence of long-term complications of hemispherectomy, various methods have been used to reduce them. The aim was to reduce the large dead space left inside the skull. We have developed an original hemispheric disconnection technique that can achieve the same results as anatomic hemispherectomy in epilepsy, with excellent short- and long term-reliability. The detailed technique is described.

Intraspinal primitive neuroectodermal tumour: report of two cases and review of the literature.

Two patients with primary intraspinal primitive neuroectodermal tumour are presented. In a 32-year-old man, the tumour evolved intradurally from a sacral nerve root. Despite repeated surgery and radiochemotherapy, the patient suffered multiple intraspinal tumour relapses and intracranial seedings, and died 29 months after the first diagnosis. In a 17-year-old male adolescent, the tumour was located in the lumbar epidural space, extending into the paraspinal muscles. Following resection and radiochemotherapy, the patient is free from disease 23 months after the initial presentation. The clinical, radiological, histopathological and cytogenetic findings of both patients are presented and the relevant literature is reviewed. Particular attention is given to the histogenetic relationship between peripheral primitive neuroectodermal tumour and Ewing's sarcoma.

Cerebral primitive neuro-ectodermal tumour following treatment of a unilateral retinoblastoma.

Cerebral primitive neuro-ectodermal tumour (PNET) occurring as a second primary malignancy in childhood is exceedingly rare. We present a 7-year-old boy who developed a proven supratentorial PNET five years after enucleation and radio-/chemotherapy for a sporadic, unilateral retinoblastoma with optic nerve invasion. The association with this malignant eye disease as well as the effect of irradiation and multi-agent chemotherapy on second tumour induction are evaluated.

[Extensive brain injury caused by attempted suicide with an airgun and ultrasound controlled removal of the deep intracranial projectile]. / Ausgedehnte Hirnverletzung durch Suizidversuch mit Luftgewehr und ultraschallgestützte Entfernung des tief intrakraniellen Projektils.

A 65-year-old man attempted suicide by shooting himself in the right temple with an air-gun. There was no loss of consciousness. He remained neurologically asymptomatic. On plain x-rays, the pellet was found in the left frontal lobe and CT-scans revealed a vast cerebral injury with a large hematoma in the right frontotemporal region and along the bullet track. The entry wound was opened and the hematoma was evacuated after removal of small bone fragments and limited osteoclastic enlargement of the bullet hole under the view of the microscope. No attempt was made to remove the pellet through the bullet track in order to avoid additional injury to delicate frontal midline structures. A left frontal burr hole was made and a thin silastic tube, as used for ventricular drainage, was placed with its tip at the projectile under ultrasonic guidance. Along the tube, the pellet was removed through a 5 mm cortical incision with the use of the microscope. The postoperative course was uneventful, the patient had no neurological deficit and early postoperative CT-scans showed complete removal of the hematoma and the bullet without additional brain injury.

Severe intracranial injury from a fall in the halo external fixator.

This is a report of a rheumatoid arthritis patient after atlantoaxial stabilization and halo external fixator immobilization who presented with intracranial injury after an accidental fall. Global aphasia and an impaired consciousness resulted from a cerebral hemorrhagic contusion below an impressed bone chip at the left posterior halo-pin site. Cranial penetration of a halo pin has been previously reported; however, brain injury associated with it has not. Since there is a considerable risk of falls in the elderly and in patients with myelopathic gait disturbances, this rare but potentially hazardous complication should be kept in mind during the halo vest fixation.

Hemodynamic and electrophysiological evaluation following extracranial/intracranial bypass surgery.

We examined 50 patients with an extracranial/intracranial bypass using transcranial Doppler blood flow mapping, somatosensory evoked potentials, and computer-assisted EEG analysis. The investigation was supplemented by temporary compression of the extracranial supplying vessel. Transcranial Doppler sonography revealed in addition to 4 patients with nonpatent anastomoses, a bypass-mediated retrograde flow in the ipsilateral middle cerebral artery beyond a depth of 40 mm in the majority of patients. In 9 patients, retrograde flow could be demonstrated in the whole proximal (M1) MCA segment. The precommunicating segment of the anterior cerebral artery (A1) could be reliably insonated in all but 5 patients. Bypass-compression dependent alterations in the SSEP and in EEG analysis were only observed in a small number of patients. Transcranial Doppler sonography, with the aid of the flow mapping system, appears therefore, to be a reliable and repeatedly performable noninvasive technique for the assessment of intracranial hemodynamics following bypass surgery.