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Background Major depressive disorder (MDD) is a system-level disorder affecting multiple functionally integrated cerebral networks. Nevertheless, their temporospatial organization and potential disturbance remain mostly unknown. The present report tested the hypothesis that deficient temporospatial network organization separates MDD and healthy controls (HC), and is linked to symptom severity of the disorder. Methods Eyes-closed resting-state magnetoencephalographic (MEG) recordings were obtained from twenty-two MDD and twenty-two HC subjects. Beamforming source localization and functional connectivity analysis were applied to identify frequency-specific network interactions. Then, a novel virtual cortical resection approach was used to pinpoint putatively critical network controllers, accounting for aberrant cerebral connectivity patterns in MDD. Results We found significantly elevated frontolimbic and frontocentral connectivity mediated by gamma (30–48 Hz) activity in MDD versus HC, and the right amygdala was the key differential network controller accounting for aberrant cerebral connectivity patterns in MDD. Furthermore, this frontolimbic and frontocentral gamma-band hyper-connectivity was positively correlated with depression severity. Limitations The overall sample size was small, and we found significant effects in the deep limbic regions with resting-state MEG, the reliability of which was difficult to corroborate further. Conclusions Overall, these findings support a notion that the right amygdala critically controls the exaggerated gamma-band frontolimbic and frontocentral connectivity in MDD during the resting-state condition, which potentially constitutes pre-established aberrant pathways during task processing and contributes to MDD pathology.

Electrocorticography (ECoG) data can be used to estimate brain-wide connectivity patterns. Yet, the invasiveness of ECoG, incomplete cortical coverage, and variability in electrode placement across individuals make the network analysis of ECoG data challenging. Here, we show that the architecture of whole-brain ECoG networks and the factors that shape it can be studied by analysing whole-brain, interregional and band-limited ECoG networks from a large cohort-in this case, of individuals with medication-resistant epilepsy. Using tools from network science, we characterized the basic organization of ECoG networks, including frequency-specific architecture, segregated modules and the dependence of connection weights on interregional Euclidean distance. We then used linear models to explain variabilities in the connection strengths between pairs of brain regions, and to highlight the joint role, in shaping the brain-wide organization of ECoG networks, of communication along white matter pathways, interregional Euclidean distance and correlated gene expression. Moreover, we extended these models to predict out-of-sample, single-subject data. Our predictive models may have future clinical utility; for example, by anticipating the effect of cortical resection on interregional communication.

Purpose: Hybrid PET/MR is a promising tool in focal drug-resistant epilepsy, however the additional value for the detection of epileptogenic lesions and surgical decision-making remains to be established.Methods: We retrospectively compared 18F-FDG PET/MR images with those obtained by a previous 18F-FDG PET co-registered with MRI (PET+MR) in 25 consecutive patients (16 females, 13-60 year-old) investigated for focal drug-resistant epilepsy. Visual analysis was performed by two readers blinded from imaging modalities, asked to assess the technical characteristics (co-registration, quality of images), confidence in results, location of PET abnormalities and presence of a structural lesion on MRI. The clinical impact on surgical strategy and outcome was assessed independently.Results: The location of epilepsy was temporal in 9 patients and extra-temporal in 16 others. MRI was initially considered negative in 21 of them. PET alone demonstrated metabolic abnormalities in 19 cases (76%), and the co-registration with MRI allowed the detection of 4 additional structural lesions. PET/MR was considered better performing than PET+MR in 56% of patients. The increase in sensitivity was 13% and new structural lesions (mainly focal cortical dysplasias) were detected in 6 patients (24%). Change of surgical decision-making was substantial for 40% of patients, consisting in avoiding invasive monitoring in 6 patients and modifying the planning in 4 others. Seizure-free outcome was obtained in 13/14 patients who underwent a cortical resection.Conclusion: Hybrid PET/MR improves the detection of epileptogenic lesions, allowing to optimize the presurgical work-up and to increase the proportion of successful surgery even in the more complex cases.

OBJECTIVEAlthough epilepsy surgery is an effective treatment option, at least 20%–40% of patients can continue to experience uncontrolled seizures resulting from incomplete resection of the lesion, epileptogenic zone, or secondary epileptogenesis. Reoperation could eliminate or improve seizures. Authors of this study evaluated outcomes following reoperation in a pediatric population.METHODSA retrospective single-center analysis of all patients who had undergone resective epilepsy surgery in the period from 2001 to 2013 was performed. After excluding children who had repeat hemispherotomy, there were 24 children who had undergone a second surgery and 2 children who had undergone a third surgery. All patients underwent MRI and video electroencephalography (VEEG) and 21 underwent magnetoencephalography (MEG) prior to reoperation.RESULTSThe mean age at the first and second surgery was 7.66 (SD 4.11) and 10.67 (SD 4.02) years, respectively. The time between operations ranged from 0.03 to 9 years. At reoperation, 8 patients underwent extended cortical resection; 8, lobectomy; 5, lesionectomy; and 3, functional hemispherotomy. One year after reoperation, 58% of the children were completely seizure free (International League Against Epilepsy [ILAE] Class 1) and 75% had a reduction in seizures (ILAE Classes 1–4). Patients with MEG clustered dipoles were more likely to be seizure free than to have persistent seizures (71% vs 40%, p = 0.08).CONCLUSIONSReoperation in children with recurrent seizures after the first epilepsy surgery could result in favorable seizure outcomes. Those with residual lesion after the first surgery should undergo complete resection of the lesion to improve seizure outcome. In addition to MRI and VEEG, MEG should be considered as part of the reevaluation prior to reoperation.

Children with unilateral resections of ventral occipito-temporal cortex (VOTC) typically do not evince visual perceptual impairments, even when relatively large swathes of VOTC are resected. In search of possible explanations for this behavioral competence, we evaluated white matter microstructure and connectivity in eight pediatric epilepsy patients following unilateral cortical resection and 15 age-matched controls. To uncover both local and broader resection-induced effects, we analyzed tractography data using two complementary approaches. First, the microstructural properties were measured in the inferior longitudinal and the inferior fronto-occipital fasciculi, the major VOTC association tracts. Group differences were only evident in the ipsilesional, and not in the contralesional, hemisphere, and single-subject analyses revealed that these differences were limited to the site of the resection. Second, graph theory was used to characterize the connectivity of the contralesional occipito-temporal regions. There were no changes to the network properties in patients with left VOTC resections nor in patients with resections outside the VOTC, but altered network efficiency was observed in two cases with right VOTC resections. These results suggest that, in many, although perhaps not all, cases of unilateral VOTC resections in childhood, the white matter integrity in the preserved contralesional hemisphere along with residual neural activity might be sufficient for normal visual perception.HighlightsThere is well-circumscribed white matter damage in pediatric epilepsy after surgeryWhite matter pathways are normal distal as well as contralesional to the resectionContralesional network properties differ after left or right hemisphere resectionPreserved cortex and white matter may be sufficient for normal perception

Worldwide experts consider presurgical electrocorticography (ECoG) or intracerebral electrode monitoring a necessary evaluation tool for a selected population of patients with focal epilepsy. The goal of chronic ECoG monitoring at bedside generally includes localizing the seizure onset zone presumably responsible for generation of habitual seizures and localizing the eloquent areas to be preserved for avoiding major functional deficits following cortical resection. Language function directly determines the quality of life in patients following epilepsy surgery; thus, each surgical team makes the best effort to localize the language areas before performing resective surgery.

There is no consensus regarding the ideal treatment for odontogenic myxomas, an odontogenic mesenchymal neoplasm. Various authors have suggested en bloc resection due to a concern regarding inadequate clearance while others have suggested more conservative treatment. We present a case managed by buccal cortical resection and an iliac crest bone graft. The patient had no recurrence for over 7 years.

The main purpose of this retrospective study was to compare the effects of resective surgery (RESgr-26 patients) and vagus nerve stimulation (VNSgr-35 patients) on seizure frequency (2 and 5years after surgery) in patients with nonlesional extratemporal epilepsy (NLexTLE). We analyzed hospital admission costs directly associated with epilepsy (HACE) in both groups at the same follow-up. The decrease in seizure frequency from the preoperative levels, in both VNSgr and RESgr, was statistically significant (p0.001). The seizure frequency reduction did not differ significantly between the follow-up visits for either group (p=0.221 at 2years and 0.218 at 5years). A significantly higher number of Engel I and Engel I+II patients were found in RESgr than in VNSgr at both follow-up visits (p=0.04 and 0.007, respectively). Using McHugh classification, we did not find statistically significant differences between both groups at both follow-up visits. Hospital admission costs directly associated with epilepsy/patient/year in both RESgr and VNSgr dropped significantly at 2- and 5-year follow-up visit and this reduction was not statistically different between RESgr and VNSgr (p=0.232). Both VNS and resective surgery cause comparably significant seizure reduction in NLexTLE. Resective surgery leads to a greater number of patients with excellent postoperative outcome (Engel I+II). The HACE reduction is statistically comparable between both groups.

Twenty-four patients with intractable partial epilepsy underwent surgery between 1969 and 1988. Localization was by non-invasive means using scalp EEG and CT. In 12 cases the focus was temporal and in eight frontal. Craniotomy was undertaken with intraoperative electrocorticography (ECoG). Ten cases had a standard temporal lobectomy, seven a topectomy, four topectomy with tumour excision and one tumour excision alone. Two cases did not have a resection. Pathology revealed a mass lesion in 12 cases, hippocampal sclerosis in two and gliosis in six. Mean length of follow-up was 7.4 years. Fourteen patients (64%) were seizure free, two (9%) almost seizure free, four (18%) had worthwhile improvement and two (9%) no improvement. Of the temporal resections, 9 out of 12 (75%) were seizure free and of the extratemporal resections 5 out of 10 (50%) were seizure free. Removal of a mass lesion carried the most favourable prognosis for seizure outcome: 10 out of 12 (83%) of the cases with mass lesions, but 3 out of 6 (50%) of the cases with gliosis were seizure free. In two of the frontal resections removal of tumour resulted in disappearance of contralateral frontal independent spikes. It is concluded that where sufficient information exists to localize seizure activity by non-invasive means, invasive recording is unnecessary. The utility of intraoperative ECoG is discussed. It may be of limited use in cases of standard resection or when a mass lesion is present, but ECoG can prove useful to delineate the epileptogenic area in cases where there is no mass lesion and the results can still be rewarding.

Medically intractable epilepsy is a clinical condition of concern that arises when a patient with epilepsy suffers seizures, despite a trial of two or more antiepileptic drugs (AEDs) suitable for the type of epilepsy that are prescribed at maximum tolerated doses, does not achieve control of seizures. This diagnosis could be related to cortical dysplasias. We report the case of a 5-year-old girl with a previous normal neurological development and no family history of epilepsy who presented with focal-type seizures at age 4. She started treatment by taking different AEDs for seizure control. She continued having frequent seizures that sometimes progressed to generalized seizures and status epilepticus. After a focal cortical resection performed in the area where interictal spikes were detected, the pathology confirmed a type IIb cortical dysplasia as the cause of the epilepsy. This article discusses cortical dysplasias as a cause of pharmacoresistant epilepsy and its treatment. © 2015 The Authors.

Epilepsy is a chronic disorder characterized by recurrent and unprovoked seizures. The lifetime risk of developing epilepsy is 4%. Approximately 90% of the incident cases in adults have partial epilepsy. The initial response to medication is of prognostic importance. Patients with symptomatic neurologic disease, foreign-tissue lesion, or developmental delay are less likely to be rendered seizure free. The goal of treatment is to render the individual seizure free. Many patients with partial epilepsy will not attain a seizure remission with antiepileptic drug therapy. Epilepsy surgery is an effective and safe alternative form of therapy for selected patients with intractable partial epilepsy. Electronic stimulation is being considered for patients with partial seizures who are not candidates for a focal cortical resection.

The authors end the book by this short but very interesting historic chapter, which demonstrates the serious consequences of the even small cerebral tissue resections.

Resume Nous ne retrouvons pas, chez l’enfant, la grande proportion de chirurgies temporales que l’on note chez l’adulte. Les indications de resection corticale, temporale ou frontale, peuvent etre resumees de la facon suivante : il faut que l’epilepsie provienne d’une region precise et localisee du cerveau, que la pharmaco-resistance soit averee, que le foyer soit extirpable chirurgicalement, et que le handicap soit suffisamment severe. L’hemispherotomie est une technique curative indiquee en cas de pathologie hemispherique, qui peut etre developpementale, acquise, ou encore progressive. La chirurgie palliative est essentiellement representee par la callosotomie, dont la principale indication est celle de crises avec chutes atoniques. La transsection sous-piale multiple, indiquee en cas de localisation du foyer epileptogene en zone eloquente, est relativement peu pratiquee. Les principaux risques lies aux resections corticales sont representes par le deficit moteur controlateral, lie a une lesion per-operatoire du reseau sylvien, ou de l’artere choroidienne anterieure, ou encore des aires motrices elles-memes. Le risque de deterioration neuropsychologique post-operatoire est faible. Le risque de syndrome de dysconnexion apres callosotomie est egalement faible. En conclusion, il se degage de cette revue de la litterature, un fort consensus pour rechercher, des que la pharmaco-resistance est averee, une solution chirurgicale a l’epilepsie de l’enfant.

Resume Les principes d’indication de resection corticale, temporale ou frontale, peuvent etre resumes de la facon suivante : il faut que l’epilepsie provienne d’une region precise et localisee du cerveau, que la pharmaco-resistance soit averee, que le foyer soit extirpable chirurgicalement, et que le handicap soit suffisamment severe. La lobectomie temporale est une technique validee sur le plan scientifique par une etude prospective randomisee. L’hemispherotomie est une technique curative indiquee en cas de pathologie hemispherique, qui peut etre developpementale, acquise, ou encore progressive. Elle est donc rarement utilisee chez l’adulte. La chirurgie palliative est essentiellement representee par la callosotomie, dont la principale indication est celle de crises avec chutes atoniques, et la transsection sous-piale multiple, indiquee en cas de localisation du foyer epileptogene en zone eloquente. Les principaux risques lies aux resections corticales sont representes par le deficit moteur controlateral, lie a une lesion per-operatoire du reseau sylvien, ou de l’artere choroidienne anterieure, ou encore des aires motrices elles-memes. Le risque de deterioration neuropsychologique post-operatoire est faible. Le risque de syndrome de dysconnexion apres callosotomie l’est egalement. En conclusion, la revue de la litterature exposee ici demontre que la chirurgie merite d’etre discutee devant toute epilepsie partielle, des lors que la pharmaco-resistance est averee.

Contains fulltext : 143482.pdf (Publisher’s version ) (Open Access) Research Question Recent discoveries have challenged the traditional view that the thalamus is the primary source driving spike-and-wave discharges (SWDs). At odds, SWDs in genetic absence models have a cortical focal origin in the deep layers of the perioral region of the somatosensory cortex. The present study examines the effect of unilateral and bilateral surgical resection of the assumed focal cortical region on the occurrence of SWDs in anesthetized WAG/Rij rats, a well described and validated genetic absence model. Methods Male WAG/Rij rats were used: 9 in the resected and 6 in the control group. EEG recordings were made before and after craniectomy, after unilateral and after bilateral removal of the focal region. Results SWDs decreased after unilateral cortical resection, while SWDs were no longer noticed after bilateral resection. This was also the case when the resected areas were restricted to layers I-IV with layers V and VI intact. Conclusions These results suggest that SWDs are completely abolished after bilateral removal of the focal region, most likely by interference with an intracortical columnar circuit. The evidence suggests that absence epilepsy is a network type of epilepsy since interference with only the local cortical network abolishes all seizures. 10 p.

The presentation and treatment of a patient with extra-temporal non-lesional partial epilepsy is discussed herein. His clinical semiology was consistent with supplementary motor area seizures; however, MR imaging did not demonstrate a lesion. A region of stable cortical glucose hypermetabolism in the left frontal region was noted with 2-fluoro-2-deoxy-D-glucose (FDG)-PET. This was consistent with the frequent interictal discharges evident over the left fronto-temporal region and the stereotypic high amplitude ictal discharges arising with highest amplitude from the left frontal region. Epileptiform activity evident on an intracranial 64-point subdural recording grid placed over the left dorsolateral frontal cortex confirmed a distribution concordant with FDG-PET findings. The subsequent resection was guided by the PET and EEG findings rather than structural MR imaging, and a limited cortical resection led to an immediate and substantial reduction in seizure frequency.

Background: The observation that resection of structural lesions of the frontal lobe provides an effective treatment of intractable epilepsy has been made by surgeons specializing in this field for over sixty years! However, the excellent results achieved when such resections are coupled with the use of modern diagnostic and operative technologies are not fully appreciated by the modern clinician. Methods: We review the results of resection of large post traumatic frontal lesions in six patients with intractable frontal seizures. No invasive EEG recording was required pre-operatively. Results: The imaging characteristics of the underlying lesions, usually due to depressed skull fractures are illustrated. Surgical treatment rendered five patients seizure free and the sixth had over 85% improvement in seizure frequency. Conclusions: Modern imaging permits ready visualization of the post traumatic lesions with cause intractable seizures. It is important to recognize that resection of these post traumatic scars usually leads to excellent seizure control.

Invasive intracranial monitoring with subdural grids has led to a greater appreciation of cortical function and the discovery of ictal onset either independently or in conjunction with deep structures. With the description of multiple subpial transections the armamentarium for surgical control of intractable seizures has been expanded. Utilizing invasive intracranial monitoring with subdural grids and strips, a large series of patients with intractable complex partial seizures originating in exquisite cortex, and in some cases additionally in deep structures, have undergone surgery. These patients would previously have been judged not to be candidates for surgical control of seizures. We will present 9-month or greater follow-up in an ongoing series of patients undergoing cortical resection and subpial transections in whom there has been a statistical improvement in control or alleviation of their seizure disorder. The report will specifically discuss outcomes as related to exquisite cortex, motor, sensory and language functions, as well as clinical results and EEG.

Despite the use of hemispherectomy in the treatment of medically refractory seizures since the early 1950's, few studies published have documented neuropathologic findings in the resected specimens. This report describes the neuropathologic findings in 38 children who underwent either hemispherectomy or multilobar cortical resection as treatment for medically intractable epilepsy between 1986 and 1990. Examination of the resected specimens revealed a variety of abnormalities which fell into four broad categories. Malformations or hamartomatous lesions were the dominant finding in 15 patients, whereas encephalomalacic lesions were the most prominent abnormality in 16; chronic pathogen-free encephalitits (Rasmussen's encephalitis) was present in 3 and an additional 3 children had Sturge-Weber-Dimitri syndrome. There were no gross or microscopic abnormalities in 1 patient. This report provides the first comprehensive description of the pathologic findings in a series of children with refractory epilepsy of varying types treated by hemispherectomy-multilobar resection.

A retrospective analysis was performed in 30 patients who underwent computer-assisted stereotactic resection of intra-axial mass lesions with intractable partial epilepsy. Mean follow-up was 4.1 years (2-5.5), mean age 21 years (3-45) and mean duration of seizures 8.4 years (1-26). Pathology consisted of vascular malformations in 11, glial neoplasms in 11, cortical dysplasia in 4 and gliosis in 3, and no diagnostic abnormality was found in 2 patients. The location of the lesions in some cases may have precluded a standard craniotomy and cortical resection, e.g. precentral gyrus (5), post-central gyrus (5) and deep-seated left posterior temporal region (4). Operative morbidity involved 3 patients who developed motor or language deficits. Four patients were lost to follow-up. Thirteen patients out of 26 (50%) were class I, 3 (12%) were class II, 4 (15%) were class III and 6 (23%) were class IV. These findings suggest that stereotactic lesion resection in selected cases (e.g. where lesions are located in eloquent brain regions) can be useful in providing a histological diagnosis of the epileptogenic foci and result in a favorable reduction in seizure activity without the need for a standard cortical resection.

The aim of this study was to report the safety and efficacy of tailored cortical resection based on image guided subdural electrode implantations in eight patients with medically refractory epilepsy. The patients were selected for multimodality image guided subdural grid implantation, inpatient invasive electroencephalography video monitoring and surgical resection of epileptogenic foci. All patients had frequent disabling, medically refractory seizures pre-operatively. At a minimum of 10 months post-resection all patients had a worthwhile improvement in seizure frequency, with 7 of the 8 (87.5%) having an excellent outcome (Engel Class I). Short-term complications of grid implantation were: one patient with a post-operative subdural haemorrhage and one patient with a transient fluctuating dysphasia. The only long-term complication was a mild, non-disabling dysarthria following resection near eloquent speech cortex in one patient. We conclude that tailored cortical resection following image-guided insertion of subdural grids is a reliable, safe and highly effective method for the treatment of medically refractory epilepsy in carefully selected patients.

Object The authors undertook this study to review their experience with cortical resections in the rolandic region in children with intractable epilepsy. Methods The authors retrospectively reviewed the medical records obtained in 22 children with intractable epilepsy arising from the rolandic region. All patients underwent preoperative electroencephalography (EEG), MR imaging, prolonged video-EEG recordings, functional MR imaging, magnetoencephalography, and in some instances PET/SPECT studies. In 21 patients invasive subdural grid and depth electrode monitoring was performed. Resection of the epileptogenic zones in the rolandic region was undertaken in all cases. Seizure outcome was graded according to the Engel classification. Functional outcome was determined using validated outcome scores. Results There were 10 girls and 12 boys, whose mean age at seizure onset was 3.2 years. The mean age at surgery was 10 years. Seizure duration prior to surgery was a mean of 7.4 years. Nine patients had preoperative hemiparesis. Neuropsychological testing revealed impairment in some domains in 19 patients in whom evaluation was possible. Magnetic resonance imaging abnormalities were identified in 19 patients. Magnetoencephalography was performed in all patients and showed perirolandic spike clusters on the affected side in 20 patients. The mean duration of invasive monitoring was 4.2 days. The mean number of seizures during the period of invasive monitoring was 17. All patients underwent resection that involved primary motor and/or sensory cortex. The most common pathological entity encountered was cortical dysplasia, in 13 children. Immediately postoperatively, 20 patients had differing degrees of hemiparesis, from mild to severe. The hemiparesis improved in all affected patients by 3–6 months postoperatively. With a mean follow-up of 4.1 years (minimum 2 years), seizure outcome in 14 children (64%) was Engel Class I and seizure outcome in 4 (18%) was Engel Class II. In this series, seizure outcome following perirolandic resection was intimately related to the child's age at the time of surgery. By univariate logistic regression analysis, age at surgery was a statistically significant factor predicting seizure outcome (p < 0.024). Conclusions Resection of rolandic cortex for intractable epilepsy is possible with expected morbidity. Accurate mapping of regions of functional cortex and epileptogenic zones may lead to improved seizure outcome in children with intractable rolandic epilepsy. It is important to counsel patients and families preoperatively to prepare them for possible worsened functional outcome involving motor, sensory and/or language pathways.

We compared scalp ictal EEG in complex partial seizures originating in extratemporal regions with seizures originating in the temporal lobe. All patients were seizure-free for 2 or more years after appropriate cortical resection confirming focus of seizure onset. The electroencephalographer reviewing seizures was blind to patient identity. Extratemporal seizures were shorter, more difficult to lateralize, and had postictal slowing less often. Confident lateralization of seizure onset could not be made in 19% of the seizures, usually because onset was diffuse or artifact obscured the seizure. When lateralization judgments were thought possible, lateralization errors occurred in only 3% of the seizures. Five percent of the seizures had no detectable scalp ictal changes.

We report a 57-year-old female who presented with epilepsia partialis continua and rapidly progressed to refractory complex partial status epilepticus (CPSE) with brain magnetic resonance imaging revealing a focal cortical lesion on T2 sequences corresponding to the seizure focus on ictal electroencephalographic recordings. The patient underwent focal cortical resection of the seizure focus. Though clinical and electrographic seizure activity ceased, the patient remained unresponsive with repeat neuroimaging showing diffuse limbic and brainstem involvement. Serological tests revealed anti-Hu antibodies suggesting a paraneoplastic encephalitis. Chest computed tomography showed a 5-mm pulmonary nodule and resection of the pulmonary nodule confirmed the diagnosis of small cell lung cancer. Plasmapheresis was performed without clinical improvement. Focal resection can be effective in terminating refractory CPSE but evaluation for a paraneoplastic syndrome must be considered early in the diagnosis of epilepsia partialis continua and CPSE as these patients have a poor prognosis.

Object Researchers at The Center for Neural Interfaces at the University of Utah have designed and produced a silicon-based high-density microelectrode array that has been used successfully in mammalian models. The authors investigate the ability to transfer array insertion techniques to humans and examine the acute response of human cortical tissue to array implantation. Methods Six patients who were scheduled to undergo temporal lobectomy surgery were enrolled in an Institutional Review Board–approved protocol. Before the patients underwent lateral temporal cortical resection, one or two high-density microelectrode arrays were implanted in each individual by using a pneumatic insertion device. Cortical tissue was then excised and preserved in formalin. The specimens were sectioned and stained for histological examination. Pneumatic insertion of a microelectrode array into human cortex in the operating room was feasible. There were no clinical complications associated with implantation and no evidence of significant insertion-related hemorrhage. Tissue responses ranged from mild cortical deformity to small focal hemorrhages several millimeters below the electrode tines. Based on initial results, the insertion device was modified. A footplate that mechanically isolates a small area of cortex and a calibrated micromanipulator were added to improve the reproducibility of insertion. Conclusions A high-density microelectrode array designed to function as a direct cortical interface device can be implanted into human cortical tissue without acute clinical complications. Further modifications to the insertion device and array design are ongoing and future work will assess the functional significance of the tissue reactions observed.

Objectives: To estimate frequency and risk factors for acute postoperative seizures (APOS) within the first week after extratemporal cortical resection (ETR) and hemispherectomy (HS) in children and to assess the predictive value of APOS on long-term seizure outcome in this group.Methods: The authors conducted a retrospective analysis of children (Results: Of 132 patients, 34 (26%) had APOS. APOS were more frequent after ETR (26/71) than HS (8/61) (p < 0.01). APOS, irrespective of their timing, number, semiology, or other perioperative complications, were an independent predictor of poor postoperative seizure outcome at 2 years (p < 0.001). The estimated odds of postoperative Engel class I outcome in the APOS vs non-APOS categories was 0.27 (73% less likely) for 0- to 6-month, 0.22 (78% less likely) for 6- to 12-month, and 0.13 (87% less likely) for the 12- to 24-month intervals.Conclusions: Acute postoperative seizures (APOS) occur in 26% children, and the risk is higher after extratemporal cortical resection than hemispherectomy. APOS predict a poor postoperative seizure outcome at 6, 12, and 24 months. This study is useful for counseling families after epilepsy surgery. It also suggests that APOS may not be discounted as “benign” in research studies that evaluate seizure outcomes after epilepsy surgery.

Until recently the diagnosis of gliomatosis cerebri has been made on postmortem examination. This article reviews the use of serial magnetic resonance imaging studies to suggest premorbid diagnosis of this condition. The following is a case report of a 14-year-old female who had a subtotal cortical resection of tumor and several years later developed a progressive dementia. At postmortem examination the diagnosis of gliomatosis cerebri was made. Diffuse progressive white matter changes involving both hemispheres and brainstem, with increased thickness of the corpus callosum and without changes in cortical markings on T2-weighted magnetic resonance images, in this patient were highly suggestive of the diagnosis of gliomatosis cerebri.

We describe our initial results in 50 consecutive patients who had investigation for possible surgical treatment of intractable focal epilepsy. Forty-three were investigated using intracranial epidural or foramen ovale electrodes. Forty-five had cortical resection (43 temporal, one frontal, and one parietal). Thirty-two patients who had resection have been followed up for 6 months to 4 years, and 29 (90%) have had good results. Our findings suggest that epidural recordings are valuable in patients with epilepsy who are being considered for surgical resection. They offer an alternative to depth intracerebral investigations in the majority of patients.

✓ Postcraniotomy residual tumor is often determined by magnetic resonance (MR) imaging. Magnetic resonance changes that occur in the postoperative setting must be defined to ensure both the optimum timing of postoperative image acquisition and the accurate assessment of images for residual tumor. Postoperative changes in nontumor parenchyma have previously been described for computerized tomography but not for MR imaging. In the present study, 11 patients without intracranial neoplastic disease (six females and five males with a median age of 36 years) submitted to MR imaging 17 to 28 hours after undergoing temporal lobectomies for epilepsy. Four of the operations were performed with the patients under general anesthesia and seven under local anesthesia. Postoperative MR images (T1-weighted, T1-weighted gadolinium enhanced, and T2-weighted) were reviewed. Extraaxial fluid, air, or blood was present in all cases. Enhancement of the resection bed parenchyma occurred in seven (64%) of 11 patients. In three of the remaining four patients, assessment of parenchymal enhancement was obscured by extraaxial fluid collections. Dural enhancement occurred adjacent to the resection site in all of the cases and remotely in 73%. Eight (73%) of 11 patients displayed enhancement of the pia-arachnoid of the ipsilateral cerebral convexity, two (18%) of the contralateral convexity, and four (36%) of the pia-arachnoid overlying the cerebellum. Contrary to previous reports, contrast enhancement of nonneoplastic human brain parenchyma can occur postoperatively within 17 hours. Benign parenchymal contrast enhancement is usually linear in appearance; non-neoplastic dural and leptomeningeal enhancement can occur both adjacent to and distant from the surgical site. Extraaxial fluid collections can hinder MR evaluation of the resection bed.

As with every other epilepsy surgery center, evolutionary changes in our Wada test have occurred. This chapter describes our current protocol employed at the Medical College of Georgia. All patients who are candidates for any type of epilepsy surgery (e.g., temporal lobectomy, corpus callosotomy, focal cortical resection) undergo this procedure.

The potential of cortical resection for epilepsy was first demonstrated by Penfield and Jasper 1 at the Montreal Neurologic Institute (Montreal, Quebec) in the 1940s and 1950s. The application of this technique in children was emphasized in the 1960s and 1970s 2-8 ; since then, it has become apparent that early surgery in selected cases may enable children to become seizure free for a normal transition into adulthood. This may prevent some of the difficult psychosocial problems that occur in adults with longstanding epilepsy, including dependency, poor selfesteem, and long-term vocational disability. 9 In addition, if epilepsy surgery enables a child to discontinue antiepileptic medication, years of exposure to these drugs can be avoided. As pediatricians become better acquainted with surgical options, patients are benefiting from earlier referral for surgery. The purpose of this review is to inform children's physicians about the indications for referral

The results of temporal resection for medically intractable epilepsy in 20 children less than age 5 years with at least 2 years follow-up are reported from Miami Children's Hospital, Florida.

The results of hemispherectomy are very satisfactory but depend upon the technique used. Recent reports from a number of centres confirm that 73% of patients are fit free following hemispherectomy. Delayed pressure complications of hemispherectomy are discussed, together with the modified techniques required to cope with such problems.

The principles underlying such surgery are reviewed, together with details of the necessary investigation, and a review of long term results from the literature. Cortical Resection for epilepsy remains a useful treatment for drug resistant epilepsy when a cortical focus can be identified by neurophysiological or radiological means. Such a resection has a reasonable chance of relieving or ameliorating the epilepsy with only a small chance of producing or worsening any neurological deficit.

To determine the relationship between malformations of cortical development and intellectual functioning (IQ), 54 children and adolescents with intractable epilepsy who later underwent cortical resection were studied at the Miami Children’s Hospital, FL.

Summary: Isolated infantile convulsions were noted in 206 patients (13%) of 1,572 patients who underwent cortical resection for medically refractory focal epilepsy at the Montreal Neurological Institute over the period 1928 through 1977. In 59 patients (29% of the 206), the isolated infantile convulsion was associated with an identifiable febrile systemic or neural illness. In 54 patients (26%), there was a definite history of cerebral birth injury in addition to the isolated infantile convulsions. Twenty patients (10%) had some other potential etiological factor for the later development of seizures, such as postnatal head injury, Sturge-Weber syndrome, etc., in addition to the isolated infantile convulsions'. In 95 patients, 6% of the total 1,572 patient series and 41% of those with isolated infantile convulsions, the latter was the sole apparent cause for the later development of recurring seizures. Although this was the case in a small but significant percentage in this series of patients, more frequently, the isolated infantile convulsion represents a manifestation of invasion of the brain by an infectious agent of a systemic or brain disease, or is a harbinger of the later development of a seizure tendency due to some other preexisting etiological factor. RESUME Des convulsions infantiles isolees ont ete retrouvees dans les antecedents de 206 parmi 1,572 patients (13%) ayant subi une cortectomie pour epilepsie focale re-belle au Montreal Neurological Institute de 1928 a 1977. Chez 59 des 206 patients (29%) la ou les convulsions ont ete associees a une maladie infectieuse feabrile, generalisee ou du systeme nerveux. Chez 54 Ďentre eux (26%) il y avait egalement des antecedents de traumatisme obstetrical associe. Chez 20 Ďentre eux (10%), on retrouvait, en plus des convulsions, quelque autre facteur etiologique potentiel, tel qu'un traumatisme crânien post-natal, un syndrome de Sturge-Weber, etc. Chez 95 Ďentre eux (41%), enfin, la ou les convulsions representaient la seule cause ap-parente de Ľepilepsie. Ainsi, pour un pourcentage petit mais significatif de nos 1,572 patients (6%), les convulsions infantiles isolees ont represente la principale cause apparente du developpement ulterieur Ďune epilepsie focale. Mais, plus souvent, ces convulsions ont represente la manifestation Ďune atteinte cerebrate par Ľagent infectieux Ďune maladie generate ou nerveuse, ou bien elles ont represente le phenomene annonciateur du developpement ulterieur Ďune preadisposition epileptique secondaire a un autre facteur etiologique preexistant. RESUMEN De los 1,572 enfermos que entre los anos 1928 a 1977 fueron sometidos a resecciones corticales en el Instituto Naurologico de Montreal, para control de epilepsyias focales refractarias al tratamiento medico, en 206 pacientes (13%) se observaron convulsiones infantiles aisladas. En 59 enfermos (29% de los 206) la convulsion infantil aislada, o convulsiones, se asociaron a un identificado cuadro febril sistemico o a una enfermedad neurologica. En 54 pacientes (26%) se encontro una definitiva historia de dana cerebral obstetrico ademas de la historia de convulsion, o convulsiones infantiles aisladas. En 20 enfermos (10%) se identificaron otros factores potencialmente etiologicos para el desarrollo posterior de los ataques, tales como lesiones cerebrales post-natales, sindrome de Sturge Weber, etc., ademas de la convulsion, o convulsiones infantiles aisladas. En 95 pacientes (6% del total de la serie de 1,572) y en el 41% de aquellos con ataques infantiles aislados, estos ataques fueron la unica causa aparente de las convulsiones recurrentes posteriores. Asi pues, en esta serie de enfermos las convulsiones infantiles aisladas fueron la causa principal, del posterior desarrollo de epilepsyia focal, en un reducido, pero significativo porcentaje. Mas frecuentemente, sin embargo, las convulsiones infantiles aisladas, representan una manifestacion de la invasion cerebral de agentes infecciosos procedentes de procesos sistemicos o de enfermedades cerebrales, o constituyen un precursor del eventual desarrollo de una tendencia convulsiva debida a algun otro factor etiologico preexistente. ZUSAMMENFASSUNG Im Zeitraum von 1928 bis 1977 zeigten 206 (13%) von 1572 Patienten, die im Neurologischen Institut Montreal einer Cortex-Resektion wegen therapieref-raktarer fokaler Epilepsie unterzogen wurden, isolierte infantile Krampfe. Bei 59 (29%) von 206 Patienten traten die isolierten infantilen Krampfe in Verbindung mit einer bestimmbaren fieberhaften systemischen oder neuralen Erkrankung auf. Bei 54 Patienten (26%) war anamnestisch eindeutig eine geburtstraumatische Hirnschadigung zusatzlich zu den isolierten infantilen Krampfen zu erfragen. Bei 20 Patienten (10%) bestan-den zusatzlich zu den isolierten infantilen Krampfen weitere mogliche atiologische Schadigungen, die fur die spatere Entwicklung von Krampfen verant-wortlich zu machen waren, wie ein postnatales Schadeltrauma, Sturge-Weber-Syndrom usw. Bei 95 Patienten (6% der Gesamtzahl von 1572) und bei 41% derjenigen mit isolierten infantilen und anderen Krampfen waren die Krampfe die einzig offenkundige Ursache fur die spautere Entwicklung rezidivierender Anfalle. Damit waren in dieser Serie von Patienten isolierte infantile Krampfe offenkundig der wesentliche Grund fur die spatere Entwicklung einer fokalen Epilepsie nur bei einem kleinen aber sig-nifikanten Prozentsatz von Patienten. Haufiger jedoch zeigt der isolierte infantile Krampf das Eindringen eines infektiosen Agents in das Gehirn im Rahmen einer systemischen oder Hirnerkrankung an, oder er kundigt die spatere Entwicklung einer An-fallsbereitschaft aufgrund irgendeines anderen praexistenten atiologischen Faktors an.

Surgical options for medically uncontrolled seizures include cortical resection corpus callosotomy, hemispherectomy, and stereotaxic lesions. Cortical resection, usually temporal lobectomy, is most widely used and most likely to effect cure in carefully selected patients. The selection criteria, methods of evaluation (including invasive recording techniques), indications, complications, and results of these various procedures are discussed.