Changes in interhemispheric coherence after total corpus callosotomy: a scalp EEG study in children with non-lesional generalized epilepsy.

PURPOSE: Coherence analysis in electroencephalography (EEG) allows measurement of the degree of consistency of amplitude between pairs of electrodes. Theoretically, disconnective epilepsy surgery should decrease coherence between corresponding areas. The study aimed to evaluate postoperative changes in interhemispheric coherence values after corpus callosotomy (CC). METHODS: Non-lesional, drug-resistant, generalized epilepsy patients who underwent total CC were retrospectively collected. To evaluate coherence, we divided the scalp interictal EEG into "baseline" and "discharge" states after excluding periods with artifacts. Interhemispheric coherence values were obtained between eight pairs of symmetrically opposite scalp electrodes in six different frequency bands. We analyzed both pre- and postoperative EEG sessions and calculated the percentage of difference (POD) in coherence values. RESULTS: We collected 13 patients and analyzed 2496 interhemispheric coherence values. Preoperative coherence values differed significantly between baseline and discharge states (p = 0.0003), but postoperative values did not (p = 0.11). For baseline state, coherence values were decreased after CC and median POD was - 22.3% (p < 0.0001). Delta frequency showed the most decreased POD (-44.3%, p = 0.0009). Median POD was lowest in the Fp1-Fp2 pair of electrodes. For discharge state, coherence values were decreased after CC and median POD was - 24.7% (p < 0.0001). Delta frequency again showed the most decreased POD (-55.9%, p = 0.0016). Median POD was lowest in the F7-F8 pair. CONCLUSION: After total CC, interhemispheric coherence decreased significantly in both baseline and discharge states. The most decreased frequency band was the delta band, which may be used as a representative frequency band in future studies.

[Surgical Treatment of Mesial Temporal Lobe Epilepsy Focusing on Anatomical Understanding].

Surgical treatment is an effective option for medically intractable epilepsy. Amygdalohippocampectomy for mesial temporal lobe epilepsy is a surgically remediable epileptic syndrome. It is a well-established surgery and various approaches to the mesial temporal lobe have been reported. To reduce the complication rate, surgeons should have sufficient knowledge of anatomy in the mesial temporal region. Here, we summarize the surgical treatments for mesial temporal lobe epilepsy, focusing on anatomical understanding. We described in detail the surgical anatomy of amygdalohippocampectomy and various approaches to the mesial temporal region. In addition, we describe hippocampal transection aimed at preserving memory function, which is an alternative surgery in patients without hippocampal sclerosis. An anatomical understanding of the mesial temporal region helps surgeons not only in the field of epilepsy surgery, but also in other fields of neurosurgery, such as brain tumor and vascular surgery.

Vertical Parasagittal Hemispherotomy.

Hemispherotomy is a surgical procedure aimed at the treatment of hemispheric epilepsy. Hemispherotomy disconnects the commissural fibers, projecting fibers, and limbic system while preserving most of the brain parenchyma, unlike conventional hemispherectomy.1 Hemispherotomy is one of most complicated operations currently used in epilepsy surgery and requires a high-level understanding of the intrinsic neuroanatomy. Generally, 2 main techniques are applied in hemispherotomy: lateral hemispherotomy and vertical hemispherotomy.2,3 Vertical hemispherotomy was developed after the lateral technique. Despite a deeper, narrower surgical corridor, vertical hemispherotomy requires a smaller craniotomy and a shorter disconnection line and allows easier disconnection of the insula than the lateral approach.1 In performing vertical hemispherotomy, 2 options are available: the interhemispheric approach4 and the parasagittal approach.3 With the parasagittal approach, the lateral ventricle is opened and entered via superior frontal gyrus. To ease the surgery and minimize the operation time, we apply "partial superior frontal gyrus removal." This procedure is useful to widen a shallower surgical field while skipping the need for interhemispheric dissection. Total callosotomy is then performed via the lateral ventricle. To disconnect limbic system, we used the technique following the falx and tentorial edge as a landmark.5 Here, we present our surgical steps for parasagittal hemispherotomy in a 5-month-old girl diagnosed as hemimegalencephaly (Figures 1-8).

Preoperative interhemispheric coherence as a potential predictive marker for seizure outcome after total corpus callosotomy in nonlesional generalized epilepsy: a scalp EEG study.

OBJECTIVE: Corpus callosotomy (CC) is one of the palliative epilepsy surgical procedures available for nonlesional generalized epilepsy, but it is more invasive than other palliative surgical procedures. The main challenge is proper selection of suitable patients for CC. Coherence analysis is a method for evaluating brain connectivity, but the correlation between preoperative coherence and surgical outcomes has not previously been clarified. The authors aimed to evaluate correlations between preoperative interhemispheric coherence and surgical outcome in patients with nonlesional generalized epilepsy. METHODS: This retrospective study investigated patients with nonlesional generalized epilepsy who underwent total CC. The authors collected data for patients with good seizure outcome (Oguni classification A or B) and bad seizure outcome (Oguni classification D). For coherence analysis, the authors selected a period without interictal discharges. Preoperative interhemispheric coherence values from 8 pairs of symmetrically opposite scalp electrodes were computed across 5 frequency bands. Then, the authors evaluated correlations between coherence and surgical outcomes. RESULTS: Forty patients were included (19 males and 21 females). The mean (range) age at the time of surgery was 5.1 (1-18) years. Seizure outcomes were good in 15 patients and bad in the other 25 patients. Age at onset of epilepsy, duration of epilepsy before surgery, age at time of surgery, and presence of epileptic spasm did not differ significantly between patients with good and bad seizure outcomes (p = 0.36, p = 0.14, p = 0.10, and p = 0.20, respectively). Significant correlations were identified between higher Fp1-Fp2 interhemispheric coherence values in the delta, theta, and alpha frequency bands and bad surgical outcomes (p = 0.0397, p = 0.0322, and p = 0.0476, respectively). The receiver operating characteristic curves of the Fp1-Fp2 coherence values in these frequency bands showed areas under the curve of 67%, 69%, and 67%, respectively. The optimal cutoff values for Fp1-Fp2 interhemispheric coherence to predict surgical outcomes were 55.6 for delta (66.7% sensitivity and 72.0% specificity), 55.9 for theta (60.0% sensitivity and 76.0% specificity), and 50.3 for alpha (53.3% sensitivity and 84.0% specificity). CONCLUSIONS: This is the first study to identify potential predictive factors for surgical outcomes based on preoperative interhemispheric coherence in nonlesional generalized epilepsy. Higher coherence between Fp1-Fp2 in the delta, theta, and alpha frequencies correlated with bad seizure outcome after CC.

Awake Craniotomy in Epilepsy Surgery: A Case Series and Proposal for Three Different Scenarios.

OBJECTIVE: Awake craniotomy (AWC) allows intraoperative evaluation of functions involving the cortical surface and subcortical fibers. In epilepsy surgery, indications for and the role of AWC have not been established because evaluation with intracranial electrodes is considered the gold standard. We report herein our case series of patients who underwent AWC in epilepsy surgery and propose the scenarios for and roles of AWC. METHODS: Patients who underwent AWC in epilepsy surgery at our institutions between 2014 and 2023 were included. Information about age, sex, etiology, location of epileptogenicity, seizure type, use of intracranial electrode placement, surgical complications, neurological deficits, additional surgery, and seizure outcomes was reviewed. Following a diagnostic and treatment flow for epilepsy surgery, we clarified three different scenarios and roles for AWC. RESULTS: Ten patients underwent AWC. Three patients underwent AWC after non-invasive evaluations. Two patients underwent AWC after intracranial evaluation with stereotactic electroencephalography (SEEG). Five patients underwent AWC after intracranial evaluation with subdural grid electrodes (SDG). Among these, two patients were initially evaluated with SEEG and with SDG thereafter. One patient reported slight numbness in the hand, and one patient showed slight cognitive decline. Seizure outcomes according to the Engel outcome scale were class 1A in three patients, IIA in two patients, IIIA in four patients, and IVA in one patient. CONCLUSIONS: AWC can be used for purposes of epilepsy surgery in different situations, either immediately after non-invasive studies or as an additional invasive step after invasive monitoring with either SEEG or SDG. The application of AWC should be individualized according to each patient's specific characteristics.

Characteristics of malignant brain tumor-associated epileptic spasms.

Although epilepsy is the most common comorbidity of brain tumors, epileptic spasms rarely occur. Brain tumors associated with epileptic spasms are mostly low-grade gliomas. To date, few studies in the literature have reported on malignant (Grades 3-4) brain tumors associated with epileptic spasms. Thus, we aimed to investigate the characteristics of malignant brain tumor-associated epileptic spasms. We retrospectively reviewed patients with malignant brain tumors and epileptic spasms in our institution. Data on demographics, tumor histology, magnetic resonance imaging, epileptic spasm characteristics, electroencephalography, and treatment responsiveness were also collected. Six patients were included. In all cases, the brain tumors occurred in infancy in the supratentorial region and epileptic spasm onset occurred after the completion of brain tumor treatment. Anti-seizure medication did not control epileptic spasms; two patients were seizure-free after epileptic surgery. Although all patients had developmental delays caused by malignant brain tumors and their treatment, developmental regression proceeded after epileptic spasm onset. Two patients who achieved seizure-free status showed improved developmental outcomes after cessation of epileptic spasms. This is the first report of the characteristics of malignant brain tumor-associated epileptic spasms. Our report highlights a difficulties of seizure control and possibillity of efficacy of epileptic surgery in this condition. In malignant brain tumor-associated epileptic spasms, it is important to proceed with presurgical evaluation from an early stage, bearing in mind that epileptic spasms may become drug-resistant.

Location-based selection of the surgical approach to preserve the hippocampus in lesion-associated temporal lobe epilepsy.

BACKGROUND AND OBJECTIVES: Surgical resections for lesions associated with intractable temporal lobe epilepsy (TLE) offers good seizure outcomes.However, the necessity of hippocampectomy in addition to lesionectomy is controversial, especially when the hippocampus is not involved by the lesion. Lesionectomy alone, preserving the hippocampus by an appropriate surgical approach, might offer good seizure outcomes while maintaining neurocognitive function. In the present study, the aims were to examine the surgical strategy for lesions associated with TLE and to present how to select surgical approaches to preserve the hippocampus. METHODS: A total of 22 consecutive lesion-associated TLE patients who underwent lesionectomy alone were retrospectively reviewed. The surgical approach, transsylvian, transorbital, subtemporal, supracerebellar transtentorial, or transcortical approach, was selected based on the location of the lesion. Postoperative seizure outcomes were classified by the Engel classification. Neurocognitive outcomes were assessed before and after surgery if possible. The pathology, the extent of resection, and lesion recurrence were reviewed. RESULTS: The transsylvian approach was selected in six patients, the transorbital approach in one patient, the subtemporal approach in three patients, the supracerebellar transtentorial approach in five patients, and the transcortical approach in seven patients. Eighteen of 22 (81.8 %) patients achieved Engel's class I or II good seizure outcomes. No patients had neurocognitive deterioration after surgery. Twelve patients had various types of brain tumors, and ten patients had non-tumorous lesions. Gross total resection was achieved in 21 patients. All patients had no recurrence. CONCLUSION: For patients with lesion-associated TLE, lesionectomy alone by the appropriate surgical approach offers satisfactory seizure outcomes while preserving hippocampus.

Limited dorsal myeloschisis associated with intramedullary infantile hemangioma in the conus medullaris: illustrative case.

BACKGROUND: Limited dorsal myeloschisis (LDM) and intramedullary infantile hemangioma rarely coexist in the spinal cord. OBSERVATIONS: The authors describe the case of a 3-month-old girl who, despite lacking neurological symptoms or signs, had a cigarette burn-like mark at the lumbosacral area and skin dimpling in the gluteal area. Magnetic resonance imaging showed a low-set conus due to a thickened filum and an abnormal subcutaneous stalk connected to the conus medullaris. In combination with the skin lesions, these findings strongly implied nonsaccular-type LDM. An intramedullary mass in the conus medullaris was also shown on magnetic resonance imaging and was homogenously enhanced with isointensity on T1- and T2-weighted images. We prophylactically untethered the spinal cord and partially removed the intramedullary mass, which had no clear borders, for a safe surgical dissection. Histologically, the intramedullary mass was an infantile hemangioma, and the subcutaneous stalk was a lesion associated with LDM. The patient remained neurologically intact after surgery, and then 2 years later, there was spontaneous regression of the residual tumor. LESSONS: Although rare, nonsaccular type LDM may appear concurrently with intramedullary infantile hemangioma at the conus medullaris. The authors present a possible mechanism behind this concurrent presentation in the same area.

Use of an Endoscope Reduces the Size of Craniotomy Without Increasing Operative Time Compared With Conventional Microscopic Corpus Callosotomy.

BACKGROUND AND OBJECTIVES: Corpus callosotomy (CC) is an epilepsy surgery that disconnects the commissural fibers at the corpus callosum, a structure that often plays a key role in propagating seizure activity. CC is particularly beneficial in patients with drop attacks. Less invasive endoscopic surgeries have recently been introduced to some fields of neurosurgery but have not yet become common in epilepsy surgery. Endoscopic surgeries offer better visualization and require a smaller corridor than conventional microscopic surgeries. Here, we presented a case series comparing endoscopic CC with microscopic CC. METHODS: This 2-center retrospective study involved patients who underwent all types of CC (anterior, total, or posterior CC [pCC]) between January 2014 and May 2022. We excluded patients who underwent additional craniotomy for electrocorticography rather than CC, prior craniotomy, or CC without craniotomy. The primary outcomes were comparing size of craniotomy, operative time, and surgical complications between endoscopic CC and microscopic CC. RESULTS: We included 14 CCs in 11 patients in the endoscopic group and 58 CCs in 55 patients in the microscopic group. No significant difference in age was seen between groups. Craniotomies were significantly smaller in the endoscopic group for anterior (13.36 ± 1.31 cm 2 vs 27.55 ± 3.78 cm 2 ; P = .001), total (14.07 ± 2.54 cm 2 vs 26.63 ± 6.97 cm 2 ; P = .001), and pCC (9.44 ± 1.18 cm 2 vs 30.23 ± 10.76 cm 2 ; P = .002). Moreover, no significant differences in operative time (anterior CC [261 ± 53.11 min vs 298.73 ± 81.08 min, P = .226], total CC [339.5 ± 48.2 min vs 321.39 ± 65.98 min, P = .452], pCC [198 ± 24.73 min vs 242.5 ± 59.12 min, P = .240]), or complication rate were seen. CONCLUSION: Endoscopic CC is a promising technique requiring a smaller craniotomy than microscopic CC, without significantly increasing operative time or complication rate compared with microscopic CC.

Comparing late-onset epileptic spasm outcomes after corpus callosotomy and subsequent disconnection surgery between post-encephalitis/encephalopathy and non-encephalitis/encephalopathy.

OBJECTIVE: We aimed to analyze the efficiency of corpus callosotomy (CC) and subsequent disconnection surgeries in patients with late-onset epileptic spasms (LOES) by comparing post-encephalitis/encephalopathy (PE) and non-encephalitis/encephalopathy (NE). We hypothesized these surgeries can control potential focal onset epileptic spasms (ES) in the NE group but not in the PE group. METHODS: We retrospectively included 23 patients (12 with PE and 11 with NE) who initially underwent CC and subsequent disconnection surgeries (five NE). We compared the clinical courses, seizure types, MRI, video-EEG, epilepsy surgery, and seizure outcomes between the two groups. RESULTS: The median age of LOES onset in the PE group was 2.8 (range 1.0-10.1 years) and 2.9 years (range 1.1-12.6) in the NE group. Bilateral MRI abnormalities were observed in both groups (PE, n = 12; NE, n = 3; P < 0.05). The PE group presented ES alone (n = 2), ES + focal seizures (FS) (n = 3), ES + generalized seizures (GS) (n = 3), and ES + FS + GS (n = 4) in addition to stimulus-induced startle seizures (SS) (n = 8) (mean 3.1 seizure types/patient). The NE group presented ES alone (n = 1), ES + FS (n = 2), and ES + FS + GS (n = 8) (mean 2.7 seizure types/patient). In the PE group, CC stopped ES (n = 1) and SS (n = 1) and achieved <50% SS (n = 3). In the NE group, CC achieved immediate ES-free status (n = 2) and < 50% ES (n = 1), and additional disconnection surgeries subsided all seizure types (n = 3) based on lateralized interictal/ictal EEG findings. LOES was significantly remitted by surgery in the NE group (6/11 [55%]) compared with the PE group (1/12 [8%]) (P < 0.05). SIGNIFICANCE: LOES is a drug-resistant, focal/generalized/unknown onset ES. Lateralization of ES in NE could be achieved after CC and eliminated by further disconnection surgeries because of potential focal onset ES. LOES in PE had little benefit from CC for generalized onset ES. However, CC might reduce SS in patients in the PE group with multiple seizure types.

Primary Experiences with Robot-assisted Navigation-based Frameless Stereo-electroencephalography: Higher Accuracy than Neuronavigation-guided Manual Adjustment.

The use of robot-assisted frameless stereotactic electroencephalography (SEEG) is becoming more common. Among available robotic arms, Stealth Autoguide (SA) (Medtronic, Minneapolis, MN, USA) functions as an optional instrument of the neuronavigation system. The aims of this study were to present our primary experiences with SEEG using SA and to compare the accuracy of implantation between SA and navigation-guided manual adjustment (MA). Seventeen electrodes from two patients who underwent SEEG with SA and 18 electrodes from four patients with MA were retrospectively reviewed. We measured the distance between the planned location and the actual location at entry (De) and the target (Dt) in each electrode. The length of the trajectory did not show a strong correlation with Dt in SA (Pearson's correlation coefficient [r] = 0.099, p = 0.706) or MA (r = 0.233, p = 0.351). De and Dt in SA were shorter than those in MA (1.99 ± 0.90 vs 4.29 ± 1.92 mm, p = 0.0002; 3.59 ± 2.22 vs 5.12 ± 1.40 mm, p = 0.0065, respectively). SA offered higher accuracy than MA both at entry and target. Surgical times per electrode were 38.9 and 32 min in the two patients with SA and ranged from 51.6 to 88.5 min in the four patients with MA. During the implantation period of 10.3 ± 3.6 days, no patients experienced any complications.

Disconnection surgery to cure or palliate medically intractable epileptic spasms: a retrospective study.

OBJECTIVE: Surgery is a treatment option for medically intractable epileptic spasms (ESs). However, outcomes of ES after surgery are not well understood, especially when surgeries aimed at seizure palliation are included. The purpose of the present study was to 1) investigate the proportion of favorable postoperative ES outcomes, 2) explore the preoperative factors related to favorable postoperative ES outcomes, and 3) examine the timing of ES recurrence after disconnection surgeries, including both curative and palliative indications. METHODS: This retrospective study included patients who underwent disconnection surgery for medically intractable ES at the authors' institution between May 2015 and April 2021. Patients with suggested focal-onset ES based on preoperative evaluations initially underwent lobar disconnection. Patients with suggested generalized or unknown-onset ES underwent corpus callosotomy (CC). If evaluations after initial CC showed focalized or lateralized change, they were considered secondarily revealed focal-onset ES, and lobar disconnection was performed. ES outcomes were evaluated using the International League Against Epilepsy classification. ES outcomes were divided into classes 1-4 as favorable outcomes and classes 5 and 6 as unfavorable outcomes. The relationship between the favorable postoperative ES outcomes and the following preoperative factors was analyzed: sex, age at onset (< or > 1 year), duration between seizure onset and initial surgery (< or > 2 years), type of seizure at onset (ES or others), presence of other types of seizures, substrate, hypsarrhythmia, and MRI abnormalities. The period between the last surgery and ES recurrence was also analyzed. RESULTS: A total of 41 patients were included, of whom 75.6% achieved favorable ES outcomes. A longer seizure duration between seizure onset and initial surgery, presence of hypsarrhythmia, and positive MRI findings led to poorer postoperative ES outcomes (p = 0.0028, p = 0.0041, and p = 0.0241, respectively). A total of 60.9% of patients had ES recurrence during the follow-up period, and their ES recurred within 13 months after the last surgery. CONCLUSIONS: Disconnection surgery is an effective treatment option for medically intractable ES, even when the preoperative evaluation suggests a generalized or unknown onset.

Robust information routing by dorsal subiculum neurons.

The dorsal hippocampus conveys various information associated with spatial navigation; however, how the information is distributed to multiple downstream areas remains unknown. We investigated this by identifying axonal projections using optogenetics during large-scale recordings from the rat subiculum, the major hippocampal output structure. Subicular neurons demonstrated a noise-resistant representation of place, speed, and trajectory, which was as accurate as or even more accurate than that of hippocampal CA1 neurons. Speed- and trajectory-dependent firings were most prominent in neurons projecting to the retrosplenial cortex and nucleus accumbens, respectively. Place-related firing was uniformly observed in neurons targeting the retrosplenial cortex, nucleus accumbens, anteroventral thalamus, and medial mammillary body. Theta oscillations and sharp-wave/ripples tightly controlled the firing of projection neurons in a target region-specific manner. In conclusion, the dorsal subiculum robustly routes diverse navigation-associated information to downstream areas.

Monosynaptic connection from the subiculum to medial mammillary nucleus neurons projecting to the anterior thalamus and Gudden's ventral tegmental nucleus.

As a major hippocampal output structure, the subiculum projects to diverse cortical and subcortical areas, and its projection to the medial mammillary nucleus (MM) has been implicated in memory. Major efferent targets of the MM are the anteroventral and anteromedial thalamic nuclei and Gudden's ventral tegmental nucleus. These projections may play a key role in distributing subicular information. However, it remains unknown whether neurons in the MM that receive monosynaptic input from the subiculum project to these target regions. We addressed this issue with anterograde transsynaptic tracing mediated using adeno-associated virus serotype 1 (AAV1). Injection of AAV1-Cre and a Cre-dependent AAV encoding enhanced yellow fluorescent protein (EYFP) into the rat dorsal subiculum and MM, respectively, labeled the soma of the MM and axons in the anteroventral / anteromedial thalamic nuclei and Gudden's ventral tegmental nucleus with EYFP. The EYFP-positive neurons in the MM were immunoreactive for glutamate and leu-enkephalin and received perisomatic GABAergic inputs. These results revealed monosynaptic projections from the subiculum to MM neurons projecting to the anteroventral / anteromedial thalamic nuclei and Gudden's ventral tegmental nucleus. This monosynaptic connection may support a fast and robust signal flow through the hippocampal-mammillothalamic and hippocampal-mammillotegmental pathways.

Surgical Aspects of Corpus Callosotomy.

Corpus callosotomy (CC) is one of the options in epilepsy surgeries to palliate patient seizures, and is typically applied for drop attacks. The mechanisms of seizure palliation involve disrupting the propagation of epileptic activity to the contralateral side of the brain. This review article focuses on the surgical aspects of CC. As a variations of CC, anterior two-thirds, posterior one-third, and total callosotomy are described with intraoperative photographs. As less-invasive surgical variations, recent progress in endoscopic CC, and CC without craniotomy, is described. CC remains acceptable under the low prevalence of complications, and surgeons should make the maximum effort to minimize the complication rate.

Anatomic Understanding of Subtotal Hemispherotomy Using Cadaveric Brain, 3-Dimensional Simulation Models, and Intraoperative Photographs.

BACKGROUND: When the epileptogenic foci skip the motor area, the epilepsy can be cured by surgery while preserving the motor function. This surgery has been reported as subtotal hemispherectomy. The disconnective variant of this surgery, subtotal hemispherotomy, is described. OBJECTIVE: To demonstrate each step clearly, a cadaveric brain, 3-dimensional reconstruction and simulation model, and intraoperative photographs were used. METHODS: A formalin-fixed cadaveric brain was dissected to show each step of this surgery. For the 3-dimensional model, several brain structures were reconstructed from preoperative images, and the surgery was simulated. Intraoperative photographs and postoperative magnetic resonance images were taken from the representative cases. RESULTS: Temporo-parieto-occipital disconnection is performed to disconnect these lobes and the insula, limbic system, and splenium of the corpus callosum. The postcentral sulcus is the anterior border of the disconnection. Next, prefrontal disconnection is performed to disconnect the frontal lobe and the insula, frontal lobe and basal ganglia, and the anterior part of the corpus callosum. The precentral sulcus is the posterior border of the disconnection. Finally, corpus callosotomy of the central part is performed. After these steps, subtotal hemispherotomy, with preservation of the pre- and postcentral gyrus, is achieved. The 3-dimensional model clearly shows the anatomic relationships between deep brain structures. In the representative cases, postoperative motor deterioration was transient or none, and seizure-free status was achieved after surgery. CONCLUSION: Subtotal hemispherotomy is generally difficult because of the complicated anatomy and narrow and deep surgical corridors. Combined use of these methods facilitates a clearer understanding of this surgery.

Oligodendrocytes Up-regulate the Invasive Activity of Glioblastoma Cells via the Angiopoietin-2 Signaling Pathway.

BACKGROUND/AIM: Glioblastoma (GBM) is one of the most lethal solid cancers due to its highly invasive nature. The malignant potential of GBM cells might be partially regulated by surrounding normal cells, such as oligodendrocytes or fibroblasts. The aim of this study was to examine the interaction between stromal cells and GBM cells. MATERIALS AND METHODS: Two GBM cell lines were used. The effect of stromal cells, oligodendrocytes or fibroblasts, on the invasive ability of GBM cells was examined by wound-healing assay and invasion assay. RESULTS: Oligodendrocytes, in contrast to fibroblasts, significantly increased the migration and invasive ability of GBM cells. Angiopoietin-2 levels were high in the conditioned medium obtained from oligodendrocytes. Angiopoietin-2 significantly increased the motility of GBM, and the motility-stimulating activity of the oligodendrocytes-derived conditioned medium was significantly decreased by anti-angiopoietin-2-neutralizing antibody. CONCLUSION: Glioma stromal cells, oligodendrocytes, might up-regulate the invasiveness of GBM cells via angiopoietin-2 signaling.

Adult-Onset Mixed Germ Cell Tumor Composed Mainly of Yolk Sac Tumor Around the Pineal Gland: A Case Report and Review of the Literature.

BACKGROUND: Mixed germ cell tumors (MGCTs) usually occur in children. In the present report, we discuss an extremely rare case of adult-onset MGCT composed mainly of yolk sac tumor (YST) around the pineal gland. CASE DESCRIPTION: A 54-year-old Japanese man presented with disturbance of consciousness, Parinaud's syndrome, and gait disturbance. Magnetic resonance imaging revealed a pineal mass lesion, and subtotal resection of the tumor was achieved. The histologic diagnosis was MGCT, consisting mainly of YST. Although he underwent 5 courses of chemotherapy and craniospinal irradiation after surgery, tumor dissemination could not be controlled, and he died 10 months postoperatively. CONCLUSION: The present case highlights the need for clinicians to include YST in the differential diagnosis of acute progressive lesions around the pineal region, even in adult patients.

Anatomic Understanding of Posterior Quadrant Disconnection from Cadaveric Brain, 3D Reconstruction and Simulation Model, and Intraoperative Photographs.

BACKGROUND: Posterior quadrant disconnection is a surgery for refractory unilateral temporoparieto-occipital epilepsy to limit propagation of epileptic discharges. As incomplete disconnection can lead to residual seizures, detailed procedures are presented using a cadaveric brain, three-dimensional (3D) reconstruction and simulation models, and intraoperative photographs. METHODS: A formalin-fixed adult cadaveric brain was dissected to show each step in posterior quadrant disconnection. Using 3D preoperative planning software, we reconstructed 3D models of operative views from computed tomography and magnetic resonance imaging. Intraoperative photographs were taken from the case of a 7-year-old girl with temporoparieto-occipital epilepsy. RESULTS: Frontotemporoparietal craniotomy was performed. The Sylvian fissure was widely dissected, and the insular cortex was exposed. The temporal stem was disconnected along the inferior peri-insular sulcus. The disconnection was extended from the limen insulae to the atrium of the lateral ventricle. The fibers between the head of the hippocampus and the amygdala were disconnected. The parietal lobe was disconnected along the postcentral sulcus, and the disconnection was connected to the atrium of the lateral ventricle. At the medial surface of the parietal lobe, the disconnection was continued to the corpus callosum. The splenium of the corpus callosum was disconnected via the medial wall of the lateral ventricle. The fornix was divided in the atrium of the lateral ventricle. After these steps, disconnection of the unilateral tempoparieto-occipital lobe was achieved while preserving the arteries and veins. CONCLUSIONS: Inclusion of views from cadaveric brain, 3D reconstruction and simulation models, and intraoperative photographs facilitates a clearer anatomic understanding of posterior quadrant disconnection.