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The present study investigates the effectiveness of a deep learning neural network for non-invasively localizing the seizure onset zone (SOZ) using multi-modal MRI data that are clinically acquired from children with drug-resistant epilepsy. A cortical parcellation was applied to localize the SOZ in cortical nodes of the epileptogenic hemisphere. At each node, the laminar surface analysis was followed to sample 1) the relative intensity of gray matter and white matter in multi-modal MRI and 2) the neighboring white matter connectivity using diffusion tractography edge strengths. A cross-validation was employed to train and test all layers of a multi-scale residual neural network (msResNet) that can classify SOZ node in an end-to-end fashion. A prediction probability of a given node belonging to the SOZ class was proposed as a non-invasive MRI marker of seizure onset likelihood. In an independent validation cohort, the proposed MRI marker provided a very large effect size of Cohen's d = 1.21 between SOZ and non-SOZ, and classified SOZ with a balanced accuracy of 0.75 in lesional and 0.67 in non-lesional MRI groups. The subsequent multi-variate logistic regression found the incorporation of the proposed MRI marker into interictal intracranial EEG (iEEG) markers further improves the differentiation between the epileptogenic focus (defined as SOZ resected during surgery) and non-epileptogenic sites (i.e., non-SOZ sites preserved during surgery) up to 15 % in non-lesional MRI group, suggesting that the proposed MRI marker could improve the localization of epileptogenic foci for successful pediatric epilepsy surgery.

The cortex generates high-frequency oscillations (HFO) nested in slow waves during sleep, and these signals are especially elevated in the seizure onset zone. Thus, HFO occurrence rate and Modulation Index (MI), which quantifies the strength of coupling between HFO amplitude and slow-wave phase, represent promising epilepsy biomarkers. However, their diagnostic utility may be suboptimal because the endogenous developmental distributions are unknown. To improve age-appropriate localization of the epileptogenic zone, we hence constructed normative brain atlases demonstrating the developmental changes in MI and HFO rate. Our study investigated extraoperative, intracranial EEG data from 114 patients with focal epilepsy (ages 1.0 to 41.5 years) who achieved International League Against Epilepsy class I outcomes following resective surgery. We analyzed 20-minute slow-wave sleep epochs at 8,251 nonepileptic electrode sites (those outside the seizure onset zone, interictal spike zone, or MRI-visible lesions). Each electrode was transposed onto a standard brain template, and we then calculated its MI and HFO occurrence rate using four different detector toolboxes. Linear and nonlinear regression models determined the developmental slope of MI and HFO rate at each cortical mesh point. Mixed model analysis established the significance of MI and HFO rate developmental changes in each region of interest, while accounting for the independent effects of patient and epilepsy profiles. Finally, we created a dynamic tractography movie visualizing white matter pathways connecting cortical regions showing developmental co-growth in MI. We found that the occipital lobe exhibited enhanced MI compared to other lobes in both children and adults. Increased age, square root of age, and log base 10 of age were independently associated with elevated MI exclusively in the occipital lobe. The cortical regions showing developmental co-growth in MI were connected via the vertical occipital fasciculi and posterior callosal fibers. In contrast, we did not observe any significant association between age measures and HFO rate in the occipital lobe, but rather noted an inverse relationship between age and HFO rate in the temporal, frontal, and parietal lobes. Our study suggests that phase-amplitude coupling between physiologic HFO and delta waves, as rated by MI, is strengthened during development, in the occipital lobe particularly during toddlerhood and preschool. Given that occipital delta-nested HFO are believed to support visual memory consolidation, our observations imply that process may be significantly strengthened during early childhood. The data is publicly available to provide investigators with a crucial reference for MI and HFO-based presurgical evaluation of the epileptogenic zone.

Alpha waves—posterior dominant rhythms at 8–12 Hz reactive to eye opening and closure—are among the most fundamental EEG findings in clinical practice and research since Hans Berger first documented them in the early 20th century. Yet, the exact network dynamics of alpha waves in regard to eye movements remains unknown. High-gamma activity at 70–110 Hz is also reactive to eye movements and a summary measure of local cortical activation supporting sensorimotor or cognitive function. We aimed to build the first-ever brain atlases directly visualizing the network dynamics of eye movement-related alpha and high-gamma modulations, at cortical and white matter levels. We studied 28 patients (age: 5–20 years) who underwent intracranial EEG and electro-oculography recordings. We measured alpha and high-gamma modulations at 2167 electrode sites outside the seizure onset zone, interictal spike-generating areas and MRI-visible structural lesions. Dynamic tractography animated white matter streamlines modulated significantly and simultaneously beyond chance, on a millisecond scale. Before eye-closure onset, significant alpha augmentation occurred at the occipital and frontal cortices. After eye-closure onset, alpha-based functional connectivity was strengthened, while high gamma-based connectivity was weakened extensively in both intra-hemispheric and inter-hemispheric pathways involving the central visual areas. The inferior fronto-occipital fasciculus supported the strengthened alpha co-augmentation-based functional connectivity between occipital and frontal lobe regions, whereas the posterior corpus callosum supported the inter-hemispheric functional connectivity between the occipital lobes. After eye-opening offset, significant high-gamma augmentation and alpha attenuation occurred at occipital, fusiform and inferior parietal cortices. High gamma co-augmentation-based functional connectivity was strengthened, whereas alpha-based connectivity was weakened in the posterior inter-hemispheric and intra-hemispheric white matter pathways involving central and peripheral visual areas. Our results do not support the notion that eye closure-related alpha augmentation uniformly reflects feedforward or feedback rhythms propagating from lower to higher order visual cortex, or vice versa. Rather, proactive and reactive alpha waves involve extensive, distinct white matter networks that include the frontal lobe cortices, along with low- and high-order visual areas. High-gamma co-attenuation coupled to alpha co-augmentation in shared brain circuitry after eye closure supports the notion of an idling role for alpha waves during eye closure. These normative dynamic tractography atlases may improve understanding of the significance of EEG alpha waves in assessing the functional integrity of brain networks in clinical practice; they also may help elucidate the effects of eye movements on task-related brain network measures observed in cognitive neuroscience research.

Alpha waves - posterior-dominant rhythms at 8-12 Hz reactive to eye opening and closure - are among the most fundamental EEG findings in clinical practice and research since Hans Berger first documented them in the early 20th century. Yet, the exact network dynamics of alpha waves in regard to eye movements remains unknown. High-gamma activity at 70-110 Hz is also reactive to eye movements and a summary measure of local cortical activation supporting sensorimotor or cognitive function. We aimed to build the first-ever brain atlases directly visualizing the network dynamics of eye movement-related alpha and high-gamma modulations, at cortical and white matter levels. We studied 28 patients (age: 5-20 years) who underwent intracranial EEG and electrooculography recordings. We measured alpha and high-gamma modulations at 2,170 electrode sites outside the seizure onset zone, interictal spike-generating areas, and MRI-visible structural lesions. Dynamic tractography animated white matter streamlines modulated significantly and simultaneously beyond chance, on a millisecond scale. Before eye closure onset, significant alpha augmentation occurred at the occipital and frontal cortices. After eye closure onset, alpha-based functional connectivity was strengthened, while high gamma-based connectivity was weakened extensively in both intrahemispheric and interhemispheric pathways involving the central visual areas. The inferior fronto-occipital fasciculus supported the strengthened alpha coaugmentation-based functional connectivity between occipital and frontal lobe regions, whereas the posterior corpus callosum supported the interhemispheric functional connectivity between the occipital lobes. After eye opening offset, significant high gamma augmentation and alpha attenuation occurred at occipital, fusiform, and inferior parietal cortices. High gamma coaugmentation-based functional connectivity was strengthened, whereas alpha-based connectivity was weakened in the posterior interhemispheric and intrahemispheric white matter pathways involving central and peripheral visual areas. Proactive and reactive alpha waves involve extensive, distinct white matter networks that include the frontal lobe cortices, along with low- and high-order visual areas. High-gamma co-attenuation coupled to alpha co-augmentation in shared brain circuitry after eye closure supports the notion of an idling role for alpha waves during eye closure. These dynamic tractography atlases may improve understanding of the significance of EEG alpha waves in assessing the functional integrity of brain networks in clinical practice; they also may help elucidate the effects of eye movements on task-related brain network measures observed in cognitive neuroscience research.

Background Brain tumor patients tend to develop postoperative epileptic seizures, which can lead to an unfavorable outcome. Although the incidence of postoperative epileptic seizures and adverse events are improved with the advent of levetiracetam (LEV), postoperative epilepsy occurs at a frequency of 4.6% or higher. In brain tumor patients, the addition of sodium channel blockers (SCBs) to LEV significantly reduces seizures, though confirmed in a non-postoperative study. Thus, the combination of SCBs with LEV might be promising. Objective In this prospective randomized controlled trial we investigated the safety, evaluated by adverse events during one and two weeks after surgery, and the efficacy, evaluated by the incidence of early epilepsy, including non-convulsive status epilepticus (NCSE), of using LEV alone or SCBs added to LEV in patients who underwent craniotomy or biopsy for brain tumors or brain mass lesions. Methods Patients with brain tumors or brain mass lesions undergoing surgical interventions, excluding endoscopic endonasal surgery (EES), with a diagnosis of epilepsy were eligible for this study. Patients are randomized into either Group A or B (B1 or B2) after the informed consents are taken; LEV alone in Group A patients, while LEV and SCBs in Group B patients (GroupB1, intravenous fosphenytoin plus oral lacosamide (LCM) and GroupB2, intravenous LCM plus oral LCM) were administered postoperatively. Fifty-three patients were enrolled during the first two and a half years of the study and four of them were excluded, resulting in the accumulation of 49 patients' data. Results Postoperative epileptic seizures occurred only in three out of 49 patients during the first week (6.1%) and in seven patients within two weeks after surgery (14.3%, including the three patients during the first week). In Group A, epileptic seizures occurred in two out of 26 patients during the first week (7.7%) and in five patients within two weeks (19.2%) after surgery. In Group B, epileptic seizures occurred in one out of 23 patients during the first week (4.3%) and in two patients during the first two weeks (8.7%). Low complication grade of epileptic seizures was observed in Group B rather than in Group A, however, without significant difference (p=0.256). There was no difference in the frequency of adverse effects in each group. Conclusion Although not statistically significant, the incidence of epileptic seizures within one week after surgery was lesser in LEV+SCBs groups than in LEV alone. No hepatic damage or renal function worsening occurred with the addition of LCM, suggesting the safety of LEV+SCBs therapy.

Background Although complications have been associated with head clamp systems, few reports have described head slippage. The present study aimed to determine risk factors for head slippage and speculated that the position of head holder pins might be associated. Patients and Methods We reviewed medical records and compared the positions of the pinned heads of patients on fused preoperative and postoperative computerized tomography (CT) images. We measured the distance between corresponding head pins to determine head slippage. Age, sex, body weight, body mass index, surgical position, surgical duration, craniotomy volume, and the relationship between head pins and the nasion-inion (NI) line were statistically compared between patients with and without head slippage. Results Head slippage in 3 (10%) of 28 patients was significantly associated with the most caudal pin position (p < 0.001) and craniotomy volume (p = 0.036). Receiver operator characteristics curves indicated a cutoff of 4.5 cm from the NI line (sensitivity and specificity, 1.000 and 0.800, respectively). Conclusion Clamped heads can slip during surgical procedures. We found that one head pin should be located within 4.5 cm from the NI line to avoid head slippage.

Background Hemispherotomy, which involves disconnecting hemispherical fibers, is a treatment option for medically intractable epilepsy. As various neurological disorders can cause strabismus, we hypothesized that hemispherotomy can cause post-operative strabismus in patients with medically intractable epilepsy. Methods Nineteen patients underwent the Hirschberg test before and after hemispherical disconnection surgery. Among the 19 patients, 16 patients (six females and 10 males; mean age, 12.2 years; range, 0.17–43 years) who underwent hemispherotomy were included in this study. Results The difference in the angle between the left and right eyes was significantly widened (p = 0.025). Nine (56%) of 16 patients exhibited post-operative chronic strabismus as evaluated with the Hirschberg test. Intermittent strabismus was noticed by family members or caregivers in 10 (63%) of 16 patients. Patients older than 12 years did not show post-operative strabismus as evaluated by the Hirschberg test. Conclusion Hemispherotomy can cause or worsen post-operative strabismus in pediatric patients.

ObjectivePhase-amplitude coupling between high-frequency (≥150 Hz) and delta (3-4 Hz) oscillations - modulation index (MI) - is a promising, objective biomarker of epileptogenicity. We determined whether sevoflurane anesthesia preferentially enhances this metric within the epileptogenic zone.MethodsThis is an observational study of intraoperative electrocorticography data from 621 electrodes chronically implanted into eight patients with drug-resistant, focal epilepsy. All patients were anesthetized with sevoflurane during resective surgery, which subsequently resulted in seizure control. We classified ‘removed’ and ‘retained’ brain sites as epileptogenic and non-epileptogenic, respectively. Mixed model analysis determined which anesthetic stage optimized MI-based classification of epileptogenic sites.ResultsMI increased as a function of anesthetic stage, ranging from baseline (i.e., oxygen alone) to 2 minimum alveolar concentration (MAC) of sevoflurane, preferentially at sites showing higher initial MI values. This phenomenon was accentuated just prior to sevoflurane reaching 2 MAC, at which time, the odds of a site being classified as epileptogenic were enhanced by 86.6 times for every increase of 1 MI.ConclusionsIntraoperative MI best localized the epileptogenic zone immediately before sevoflurane reaching 2 MAC in this small cohort of patients.SignificanceProspective, large cohort studies are warranted to determine whether sevoflurane anesthesia can reduce the need for extraoperative, invasive evaluation.Highlights-We measured the modulation index on intraoperative electrocorticography recording.-Sevoflurane enhanced the modulation index differentially across the epileptogenic and non- epileptogenic sites.-The modulation index best discriminated these two groups of sites before sevoflurane reached 2 minimum alveolar concentration.

OBJECTIVE This study was undertaken to build and validate a novel dynamic tractography-based model for localizing interictal spike sources and visualizing monosynaptic spike propagations through the white matter. METHODS This cross-sectional study investigated 1900 spike events recorded in 19 patients with drug-resistant temporal lobe epilepsy (TLE) who underwent extraoperative intracranial electroencephalography (iEEG) and resective surgery. Twelve patients had mesial TLE (mTLE) without a magnetic resonance imaging-visible mass lesion. The remaining seven had a mass lesion in the temporal lobe neocortex. We identified the leading and lagging sites, defined as those initially and subsequently (but within ≤50 ms) showing spike-related augmentation of broadband iEEG activity. In each patient, we estimated the sources of 100 spike discharges using the latencies at given electrode sites and diffusion-weighted imaging-based streamline length measures. We determined whether the spatial relationship between the estimated spike sources and resection was associated with postoperative seizure outcomes. We generated videos presenting the spatiotemporal change of spike-related fiber activation sites by estimating the propagation velocity using the streamline length and spike latency measures. RESULTS The spike propagation velocity from the source was 1.03 mm/ms on average (95% confidence interval = .91-1.15) across 133 tracts noted in the 19 patients. The estimated spike sources in mTLE patients with International League Against Epilepsy Class 1 outcome were more likely to be in the resected area (83.9% vs. 72.3%, φ = .137, p

Intracranial mature teratomas have good prognoses and are usually treated by total tumor resection. We report a rare case of a germinoma that occurred 11 years after total removal of a pineal mature teratoma. A 5-year-old boy presented with headache and nausea and was diagnosed with a pineal tumor and obstructive hydrocephalus on MRI. He underwent total removal of the lesion, which was pathologically diagnosed as a mature teratoma without any other germ cell tumor components. MR images after 11 years showed a newly developed pineal tumor, which was confirmed as a germinoma after neuroendoscopic biopsy. Chemoradiotherapy resulted in complete remission, without any symptoms. This case demonstrated possible late occurrence of germinoma even after total removal of a mature teratoma had been achieved. A long-term follow-up of 10 years or more should be planned for these patients.

Background Schwannoma originating from the greater superficial petrosal nerve is an extremely rare type of facial nerve schwannoma located in the middle cranial fossa around the midportion of the petrous bone. Here, we provide the first report of greater superficial petrosal nerve schwannoma presenting with contralateral facial palsy and hemiparesis due to compression of the pyramidal tract by associated intradural peritumoral cyst. Case Description A 69-year-old woman presented with a 6-month history of gradually worsening gait unsteadiness. Magnetic resonance imaging demonstrated a well-defined tumor occupying the right middle cranial fossa and extending into the tympanic cavity. Notably, the tumor accompanied a large cyst in the intradural space, resulting in a leftward midline shift. Extradural exploration through thinned periosteal dura mater revealed the tumor within the interdural space. After debulking of most of the tumor in a pull-out, piecemeal fashion, intradural exploration revealed the peritumoral cyst located between the meningeal dura mater and brain parenchyma. Following the disappearance of the mass effect from the tumor, fenestration of the peritumoral cyst, which had been deeper-seated than the tumor, was easily achieved while avoiding excessive retraction of the temporal lobe. Postoperatively, mild left hemiparesis involving the face resolved completely and no new symptoms such as right facial palsy, hearing disturbance, or xerophthalmia developed as postoperative complications. Conclusion The combination of extradural and intradural approaches in the appropriate order is essential for fenestration of an intradural peritumoral cyst along with removal of an interdural tumor.

A prominent view of language acquisition involves learning to ignore irrelevant auditory signals through functional reorganization, enabling more efficient processing of relevant information. Yet, few studies have characterized the neural spatiotemporal dynamics supporting rapid detection and subsequent disregard of irrelevant auditory information, in the developing brain. To address this unknown, the present study modeled the developmental acquisition of cost-efficient neural dynamics for auditory processing, using intracranial electrocorticographic responses measured in individuals receiving standard-of-care treatment for drug-resistant, focal epilepsy. We also provided evidence demonstrating the maturation of an anterior-to-posterior functional division within the superior-temporal gyrus (STG), which is known to exist in the adult STG.We studied 32 patients undergoing extraoperative electrocorticography (age range: eight months to 28 years) and analyzed 2,039 intracranial electrode sites outside the seizure onset zone, interictal spike-generating areas, and MRI lesions. Patients were given forward (normal) speech sounds, backward-played speech sounds, and signal-correlated noises during a task-free condition. We then quantified sound processing-related neural costs at given time windows using high-gamma amplitude at 70-110 Hz and animated the group-level high-gamma dynamics on a spatially normalized three-dimensional brain surface. Finally, we determined if age independently contributed to high-gamma dynamics across brain regions and time windows.Group-level analysis of noise-related neural costs in the STG revealed developmental enhancement of early high-gamma augmentation and diminution of delayed augmentation. Analysis of speech-related high-gamma activity demonstrated an anterior-to-posterior functional parcellation in the STG. The left anterior STG showed sustained augmentation throughout stimulus presentation, whereas the left posterior STG showed transient augmentation after stimulus onset. We found a double dissociation between the locations and developmental changes in speech sound-related high-gamma dynamics. Early left anterior STG high-gamma augmentation (i.e., within 200 ms post-stimulus onset) showed developmental enhancement, whereas delayed left posterior STG high-gamma augmentation declined with development.Our observations support the model that, with age, the human STG refines neural dynamics to rapidly detect and subsequently disregard uninformative acoustic noises. Our study also supports the notion that the anterior-to-posterior functional division within the left STG is gradually strengthened for efficient speech-sound perception after birth.

Our daily activities require frequent switches among competing responses at the millisecond time scale. We determined the spatiotemporal characteristics and functional significance of rapid, large-scale brain network dynamics during task switching.This cross-sectional study investigated patients with drug-resistant focal epilepsy who played a Lumosity cognitive flexibility training game during intracranial electroencephalography (iEEG) recording. According to a given task rule, unpredictably switching across trials, participants had to swipe the screen in the direction the stimulus was pointing or moving. Using this data, we described the spatiotemporal characteristics of iEEG high-gamma augmentation occurring more intensely during switch than repeat trials, unattributable to the effect of task rule (pointing or moving), within-stimulus congruence (the direction of stimulus pointing and moving was same or different in a given trial), or accuracy of an immediately preceding response. Diffusion-weighted imaging (DWI) tractography determined whether distant cortical regions showing enhanced activation during task switch trials were directly connected by white matter tracts. Trial-by-trial iEEG analysis deduced whether the intensity of task switch-related high-gamma augmentation was altered through practice and whether high-gamma amplitude predicted the accuracy of an upcoming response among switch trials.The average number of completed trials during five-minute gameplay was 221.4 per patient (range: 171-285). Task switch trials increased the response times, whereas later trials reduced them. Analysis of iEEG signals sampled from 860 brain sites effectively elucidated the distinct spatiotemporal characteristics of task switch, task rule, and post-error-specific high-gamma modulations. Post-cue, task switch-related high-gamma augmentation was initiated in the right calcarine cortex after 260 ms, right precuneus after 330 ms, right entorhinal after 420 ms, and bilateral anterior middle-frontal gyri after 450 ms. DWI tractography successfully showed the presence of direct white matter tracts connecting the right visual areas to the precuneus and anterior middle-frontal regions but not between the right precuneus and anterior middle-frontal regions. Task-related high-gamma amplitudes in later trials were reduced in the calcarine, entorhinal and anterior middle-frontal regions, but increased in the precuneus. Functionally, enhanced post-cue precuneus high-gamma augmentation improved the accuracy of subsequent responses among switch trials.Our multimodal analysis uncovered two temporally and functionally distinct network dynamics supporting task switching. High-gamma augmentation in the visual-precuneus pathway may reflect the neural process facilitating an attentional shift to a given updated task rule. High-gamma activity in the visual-dorsolateral prefrontal pathway, rapidly reduced through practice, may reflect the cost of executing appropriate stimulus-response translation.

Objective Few studies have examined the localization of seizures presenting with ictal eye deviation (ED) in the absence of other motor symptoms. We aimed to investigate differences in the localization of the ictal onset zone (IOZ) between patients with isolated ED and those with ED plus head turning (HT) during focal seizures. Methods We reviewed intracranial video-EEG data for 931 seizures in 80 patients with focal onset epilepsy in whom the IOZ could be confirmed. The 233 seizures in 49 patients with ED were classified into two semiological groups based on initial ED and the presence/absence of HT: (1) isolated ED (i.e., ED without HT), and (2) ED + HT (i.e., ED with HT). We analyzed the localization and lateralization of IOZs in each semiological group. We performed multivariate logistic regression analysis using a mixed-effects to determine the associations between IOZs and isolated ED/ED + HT. Results A total of 183 IOZs in 24 patients were included in the isolated ED group, while a total of 143 IOZs in 31 patients were included in the ED + HT group. Sixty-eight IOZs of eight patients in the isolated ED group were located in the ipsilateral frontal interhemispheric fissure (F-IHF). Only ipsilateral F-IHF was significantly associated with isolated ED (odds ratio [OR], 2.43; 95% confidence interval [CI], 0.37–4.49; P = 0.021). The contralateral lateral frontal cortex (latF) (P = 0.007) and ipsilateral mesial temporal region (mT) (P = 0.029) were significantly associated with ED + HT. Conclusion The present study is the first to demonstrate that seizures with an F-IHF focus tend to present with initial ipsilateral isolated ED. This finding may aid in identifying the seizure focus in patients with isolated ED prior to resection.

Remote traumatic intracranial haemorrhage (RTIH) may develop after neurosurgery. Recognition of the risk factors for RTIH before surgery might be of great value. The purpose of this study was to verify if the fibrin/fibrinogen degradation product (FDP) value may be a risk factor for RTIH.This was a retrospective study of the data of 56 patients with traumatic intracranial hematomas shown on initial computed tomography (CT) who were treated with craniotomy or decompressive craniectomy and underwent a follow-up CT at a single centre over a period of approximately 10.5 years. We divided the patients into 2 groups: those who developed RTIH (Positive: P-group) and those who did not (Negative: N-group). We compared the 2 groups in terms of not only the laboratory data before surgery, but also patient age, sex, antiplatelet/antithrombotic medications received, cause of injury, and GCS score on arrival.RTIH was observed in 22 patients (P-group, 39.3%). The FDP value was the only significant risk factor identified in this study (FDP levels over 120 µg/mL were determined to be a risk factor for progressive RTIH after neurosurgery. We suggest the FDP level be checked before surgery for traumatic intracranial haemorrhage and follow-up CT be done as soon as possible after the surgery if the serum FDP level is over 120 µg/mL.

Background During neurosurgery, we use a head clamp system for firm head fixation. However, we have encountered slippage using the head clamp system, although this has not been adequately studied. In the present study, to increase the reliability of the analysis using a more homogeneous type of patient data, we conducted a prospective study of patients who had undergone epileptic surgery. We examined the potential risk factors for head slippage and postulated that the location of the pins might be important. Methods We reviewed and compared the positions of the fixed head of the patients on fused preoperative and postoperative computed tomography images. We measured the distance between the corresponding head pins to determine the association with head slippage. We statistically compared the relationship between each head pin and the nasion–inion line. We also assessed age, sex, body weight, body mass index, surgical position, surgical duration, and craniotomy volume as potential risk factors for slippage. Results Head slippage was observed in 3 of 21 patients (14%) in the present prospective study. The most caudal head pin position was not associated with head slippage in the present study. However, the center point between the most caudal point and the most cranial point was significant (P = 0.014). A center point between the most caudal and most cranial pins from the nasion–inion line that was >6.5 cm was more likely to result in slippage. Conclusions We should consider that head clamp slippage could occur intraoperatively.

Background Although complications have been associated with head clamp systems, few reports have described head slippage. The present study aimed to determine risk factors for head slippage and speculated that the position of head holder pins might be associated. Patients and Methods We reviewed medical records and compared the positions of the pinned heads of patients on fused preoperative and postoperative computerized tomography (CT) images. We measured the distance between corresponding head pins to determine head slippage. Age, sex, body weight, body mass index, surgical position, surgical duration, craniotomy volume, and the relationship between head pins and the nasion-inion (NI) line were statistically compared between patients with and without head slippage. Results Head slippage in 3 (10%) of 28 patients was significantly associated with the most caudal pin position (p < 0.001) and craniotomy volume (p = 0.036). Receiver operator characteristics curves indicated a cutoff of 4.5 cm from the NI line (sensitivity and specificity, 1.000 and 0.800, respectively). Conclusion Clamped heads can slip during surgical procedures. We found that one head pin should be located within 4.5 cm from the NI line to avoid head slippage.

CLIPPERS (chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids) is an inflammatory central nervous system disorder that gives rise to brainstem symptoms such as diplopia and articulatory disorders. It shows characteristic "salt-and-pepper" enhancing brainstem lesions on magnetic resonance imaging (MRI) scans. We present an unusual case of CLIPPERS, in which a 29-year-old man initially presented with a seizure. Brain MRI revealed faint open-ring enhancements in the right frontal lobe, and a brain biopsy was performed to make a definitive diagnosis. Immunohistological tests showed perivascular infiltration by primarily CD3- and CD20-positive cells, albeit including a few CD68-positive cells, which confirmed a diagnosis of CLIPPERS. Both the symptoms and the MRI findings were markedly improved by 3 courses of steroid (methylprednisolone) pulse therapy, followed by oral steroid (prednisolone) administration. This case shows that CLIPPERS can present as a phenotype of cortical lesions and seizures as the first signs. A brain biopsy should therefore be actively carried out for differential diagnosis, especially when other, cortically based inflammatory disorders are suspected.

Epilepsy surgery uses both depth electrodes (DEs) and subdural electrodes (SE). DEs have mainly been developed and used in Europe. As we are able to use the DEs safely due to the current advanced level of technology, use of DEs has been increasing rapidly over the last decade. Unlike placement of SEs, which simply requires craniotomy, DE placement generally requires stereotactic techniques such as frame-based stereotactic or robotic arm-based methods. However, such methods are not always available at every epilepsy center. We therefore invented guide pipes for accurate DE placement. With this guide pipe and neuronavigation-based (NB) DE placement system, we are able to place DEs accurately. However, the disadvantages of our original procedure were a relatively large skin incision and the difficulty in anchoring DEs. The purpose of this technical note is to introduce a method to perform NB DE placement with a smaller skin incision and simple anchoring procedure. As we could make the skin incision smaller and achieved easier anchoring of DEs using a titanium plate, we hope this procedure will help facilities to perform DE placement with neuronavigation systems.

Neonatal thalamic hemorrhage is a strong risk factor for developing encephalopathy with continuous spikes and waves during sleep (ECSWS), even when not accompanied by widespread cortical destruction. The efficacy and indication of resective epilepsy surgery in such patients has not yet been reported. A 4-year-old boy was diagnosed with ECSWS based on strong epileptiform activation during sleep and neurocognitive deterioration. He had a history of left thalamic hemorrhage related to a straight sinus thrombosis during the newborn period. He presented with daily absence seizures that were refractory to medical treatment. At age 5, he underwent intracranial electroencephalogram (EEG) recording using depth and subdural strip electrodes placed in the left thalamus and over bilateral cortex, respectively. Interictal and ictal epileptiform discharges were observed in the thalamus, always preceded by discharges in the left or right parietal lobe. Left hemispherotomy successfully normalized the EEG of his unaffected hemisphere and extinguished his seizures. This is the first case report documenting resective epilepsy surgery in a patient with ECSWS due to neonatal thalamic injury without widespread cerebral destruction. Based on intracranial EEG findings, his injured thalamus did not directly generate the EEG abnormalities or absence seizures on its own. Patients with ipsilateral neonatal thalamic injury and even mild lateralized cortical changes may be candidates for resective or disconnective surgery for ECSWS.

Introduction The occurrence rate of posttrauma epilepsy ranges widely from 1% to 30%. Little is known about the underlying epileptogenesis of traumatic brain injury (TBI)-related epilepsy (TRE), because no comparison between TRE and TBI without epilepsy has been performed in terms of neuropathology. Therefore, we postulated that different neuropathological factors may be present between TRE and TBI without epilepsy. The purpose of this study was to clarify differences between TRE and TBI without epilepsy. Methods We studied patients who experienced severe head trauma and underwent brain surgery. The age range of the patients was 9–71 years old. Patients with medically resistant epilepsy were included in the Epilepsy group, and patients without epilepsy were included in the nonepilepsy group. Pathological findings, age, sex, and cause of head trauma were statistically compared between these two groups. Results This study involved 10 patients, nine of whom met the inclusion criteria. Pathological findings for all patients in the Epilepsy group included focal cortical dysplasia (FCD) (p = 0.012). Conclusion The difference between TRE and TBI without epilepsy was underlying FCD in patients with TRE.

Little is known about epilepsy surgery for patients with severe motor and intellectual disorders (SMIDs). We hypothesized that epilepsy surgery could reduce epileptic seizure frequency in these patients. The purpose of this study was to compare pre- and postoperative seizure frequency in patients with SMIDs.A total of 288 surgeries were performed for pediatric patients, including those with SMIDs, from 2009 to 2018. Inclusion criteria were as follows: Oshima classification 1 (intelligence quotient20 and bedridden), ≥2 years old, proven ictal events evaluated by long-term video electroencephalography, and ≥1-year follow-up. Seizure frequency and the number of antiseizure medications (ASMs) were compared between pre- and postepilepsy surgery. Patients' respiratory and feeding conditions were also examined to determine comorbidities.Nineteen patients (5 girls, 14 boys; age: 2 to 12 years) fulfilled the inclusion criteria. One patient underwent focus resection, 2 patients underwent total corpus callosotomy, and 16 patients underwent vagus nerve stimulation therapies. Of 19 patients, 16 (84.2%) had daily seizures, and 3 (15.8%) had weekly seizures before surgery. Epilepsy surgery significantly reduced seizure frequency (p = 0.029). Five patients (26.3%) had status epilepticus (SE) before surgery, which disappeared in all but one after surgery (p = 0.046). The number of ASMs did not change between before and after surgery (p = 0.728).Epilepsy surgery reduced the frequency of epileptic seizures and improved SE even among patients with compromised respiratory function and compromised food intake.

Primary intracranial germinoma is a rare central nervous system tumor that usually arises in the pineal and the supra-sellar region. Here, we report a rare case of primary intracavernous sinus germinoma with an atypical extension pattern, with a comparison to germinomas originating from the cavernous sinus as described in the existing literature. A 12-year-old boy was admitted to our hospital with the chief complaint of the left-side ptosis and double vision. Magnetic resonance imaging showed homogenous enhanced mass lesion in the pineal region together with mass lesions in the lateral ventricle, left cavernous sinus, and temporal lobe, extending into the left masticator space. The enhanced mass in the intracavernous sinus originated from the cavernous sinus. Endoscopic third ventriculostomy and tumor biopsy was done. Pathological diagnosis was pure germinoma. After six courses of chemotherapy followed by radiation therapy, all the lesions decreased in size significantly. Only faint enhancement around the masticator space remained. We report a rare case of a germinoma that developed mainly in the cavernous sinus with additional tumor masses in the pineal region, ventricles, and temporal lobe. Although the lesions shrank significantly on the post-chemoradiation imaging, a long follow-up is necessary not only to check for symptoms, but also monitor imaging findings for possible serial changes in the residual region of the masticator space.

Background Dural arteriovenous fistulae (dAVFs) of the anatomically complex anterior condylar confluence (ACC) are often examined by computed tomography (CT) angiography and conventional angiography before treatment. Contrasted vessels often overlap with skull bones in enhanced CT scan and make it difficult to detect the shunt point of the dAVF. Bone subtraction CT angiography (BSCTA) can overcome this limitation and allow for superior imaging of dAVFs that may help to find an alternative access for catheterization. Case Description An 80-year-old woman suffered from right ear tinnitus, headache, and an audible bruit. Preoperative imaging showed a dAVF of the ACC. It was fed by the bilateral ascending pharyngeal artery, drained to the internal jugular vein (IJV) via the inferior petrosal sinus, and had an intraosseous shunt pouch. We therefore performed transvenous embolization (TVE) via the intercavernous sinus because the angle between the anterior condylar vein and the IJV was too sharp to catheterize vessels through the ipsilateral IJV. Conclusions Understanding the inherently complex and individually unique venous anatomy of the ACC is crucial for treatment of dAVFs. BSCTA is an effective visualization technique for dAVFs of the ACC and allows for precise preoperative vascular structure evaluation. We suggest that in the case of the angle between the ACV and the IJV being too sharp to catheterize vessels through the ipsilateral IJV, TVE via the intercavernous sinus can be efficiently used.

Although Terson's syndrome is a well-known cause of vision loss due to intracerebral aneurysm rupture, optic nerve neuropathy can also occur because of other causes. Here, we report such a case, i.e., a ruptured anterior communicating artery aneurysm accompanied by vision loss and visual field disturbances due to a cause other than Terson's syndrome. A 47-year-old man presented with right superior altitudinal hemianopia. Computed tomography (CT) showed subarachnoid hemorrhage (SAH), and three-dimensional CT angiography revealed an anterior communicating artery aneurysm. Coil embolization was performed. Right visual acuity degenerated to blindness in the acute stage. MRI performed on day 7 post-admission revealed that the aneurysm had swollen and made contact with the right optic disk. On the basis of the patient's clinical course, we believe that the deterioration in his visual acuity could have been due to ischemic optic neuropathy (ION) resulting from SAH, and the subsequent edema and poor blood perfusion may be attributed to spasm. In cases of visual disturbance associated with SAH, as in our case, it is important to perform MRI to evaluate the damage or risk to the optic nerve as soon as possible. (Received December 26, 2016; Accepted June 9, 2017; Published October 1, 2017).

We herein present a case of bilateral chronic subdural hematoma(bilateral CSDH)caused by spontaneous intracranial hypotension(SIH)without orthostatic headache. A 67-year-old male patient with mild head injury suffered from a chronic, non-postural headache. Computed tomography of the brain showed bilateral CSDH. The hematomas were surgically evacuated using a closed drainage method. His headache immediately disappeared, but it recurred after 2 weeks. We further performed hematoma irrigation;however, his neurological status deteriorated with the development of pneumocephalus. Magnetic resonance imaging with gadolinium-DTPA showed diffuse pachymeningeal enhancement. His cerebrospinal fluid pressure was 3cmH

Marfan syndrome can demonstrate tortuous and elongated intracranial arteries. However, these arteries rarely cause neurovascular compression resulting in hemifacial spasm or trigeminal neuralgia. The authors report a 33-year-old woman who was diagnosed as Marfan syndrome, suffered from trigeminal neuralgia. Magnetic resonance (MR) angiography showed tortuous and elongated left vertebral artery (VA). The coronal section of three dimensional (3D) MR cisternography with contrast enhancement showed that the left trigeminal nerve was compressed from underneath by the tortuous and elongated left VA. After successful surgery of microvascular decompression, the patient’s symptom resolved and no recurrence was encountered. Neurosurgeons should not only be aware of hemifacial spasm but also of trigeminal neuralgia caused by elongated vessels in a patient with Marfan syndrome, although it is an extremely rare condition. In addition, offending vessel is not atherosclerotic in younger patients unlike usual cases of trigeminal neuralgia. Thus, microvascular decompression can be easier than usual cases. Care should be taken to prevent arterial dissection during transposition by using some technical tips.