Neural Sources of Vagus Nerve Stimulation-Induced Slow Cortical Potentials.

OBJECTIVES: This study investigated neuronal sources of slow cortical potentials (SCPs) evoked during vagus nerve stimulation (VNS) in patients with epilepsy who underwent routine electroencephalography (EEG) after implantation of the device. MATERIALS AND METHODS: We analyzed routine clinical EEG from 24 patients. There were 5 to 26 trains of VNS during EEG. To extract SCPs from the EEG, a high-frequency filter of 0.2 Hz was applied. These EEG epochs were averaged and used for source analyses. The averaged waveforms for each patient and their grand average were subjected to multidipole analysis. Patients with at least 50% seizure frequency reduction were considered responders. Findings from EEG analysis dipole were compared with VNS responses. RESULTS: VNS-induced focal SCPs whose dipoles were estimated to be located in several cortical areas including the medial prefrontal cortex, postcentral gyrus, and insula, with a significantly higher frequency in patients with a good VNS response than in those with a poor response. CONCLUSIONS: This study suggested that some VNS-induced SCPs originating from the so-called vagus afferent network are related to the suppression of epileptic seizures.

Clinical outcomes of brain metastases from hepatocellular carcinoma: a multicenter retrospective study and a literature review.

INTRODUCTION: The introduction of systemic chemotherapy for advanced hepatocellular carcinoma in recent years has led to the prediction that cases of brain metastases from hepatocellular carcinoma will increase. However, because brain metastases from hepatocellular carcinoma are relatively rare, the characteristics of this pathology are poorly understood. METHODS: We carried out a multicenter retrospective study to verify the characteristics of brain metastases from hepatocellular carcinoma in Japan. RESULTS: A total of 38 patients were enrolled and patient characteristics were poor general condition in many patients due to the progression of primary cancers. Stereotactic radiosurgery/stereotactic radiotherapy alone was the most common treatment (39.5%), with best supportive care provided for 10.5%. Median survival was 6 months, the neurological death rate was 28%, and the rate of brain hemorrhage was high (39.5%). Overall survival was analyzed for correlations with age, etiology of chronic liver disease, albumin-bilirubin (ALBI) grade, RPA classification, control of the primary tumor, number of brain metastases, brain hemorrhage, surgical resection, and radiotherapy. In multivariate analysis, ALBI grade, number of brain metastases and brain hemorrhage showed statistically significant correlation. CONCLUSIONS: A multivariate analysis extracted three items-ALBI grade, number of brain metastases, and brain hemorrhage-as prognostic factors for survival of brain metastases from hepatocellular carcinoma.

C1 transverse process-hyoid bone line for preoperative evaluation of the accessible internal carotid artery on carotid endarterectomy: technical note.

BACKGROUND: The preoperative imaging diagnosis of the distal portion of the internal carotid artery (ICA) is extremely important for carotid endarterectomy (CEA). Herein the authors defined a line from the C1 transverse process to the hyoid bone (C1-H line) and evaluated whether the line can be used to predict an accessible ICA in CEA. METHODS: A cross point between the C1-H line and distal ICA was analyzed using three-dimensional computerized tomographic angiography (3D-CTA) in 20 patients. The C1-H line was compared to the line drawn from the mastoid process to the mandible (M-M line). Intraoperative exposure of the distal ICA was evaluated using both lines. Furthermore, the distance of each line from the C2 vertebra was measured to identify the distance difference of each line in relation to the cervical posture. RESULTS: A distal ICA exposed at a cross point of the C1-H line corresponded well with the intraoperative findings. The cross point between the C1-H line and distal ICA was positioned at an average of 7.0 ± 0.7 mm cranially in comparison to the M-M line. The C1-H line showed smaller distance differences at different cervical positions than the M-M line. The C1-H line moved an average of 2.8 ± 2.5 mm from a cervical neutral position to an extensional one in the perpendicular direction. CONCLUSION: The C1-H line measured by 3D-CTA is a simple and useful indicator of the distal ICA exposure in the preoperative diagnosis for CEA.

The chicken egg and skull model of endoscopic endonasal transsphenoidal surgery improves trainee drilling skills.

BACKGROUND: We verified the effectiveness of training in endoscopic endonasal transsphenoidal surgery (eETSS) techniques using chicken eggs and a skull model. METHODS: We verified the area of eggshell removed by drilling when five residents and four experts used the chicken eggs and a skull model. RESULTS: When residents performed drilling on 10 eggs, a mean (± standard deviation [SD]) area of 31.2 ± 17.5 mm2 was removed from the first egg, and 104.8 ± 3.3 mm2 from the tenth and final egg, representing an increase in area and a decrease in SD. The experts performed the same drilling operation on a single egg, and removed a mean area of 257± 31.7 mm2. These results demonstrated that skills improved as a result of this training, and suggested that this method was also capable of overcoming the initial individual differences in the amount of force applied and ability. An obvious difference between residents and experts was seen in the area removed (p = 0.00011); however, this was attributed to differences in endoscopic manipulation, rather than drilling skill. CONCLUSION: Our findings suggest that this training method could be adequate for acquiring eETSS techniques. Although experts showed superior endoscopic manipulation, residents may also be able to acquire adequate endoscopic skills through further training, and our training method appears to offer an effective means of improving eETSS techniques.

Spontaneous closure of a dural arteriovenous fistula immediately after cerebral angiography using a gadolinium contrast agent.

Gadolinium (Gd) contrast agents have been used instead of iodinated contrast agents in patients in whom iodine is contraindicated, but cerebral angiography of a dural arteriovenous fistula (dAVF) using a Gd contrast agent has not previously been reported. We recently performed cerebral angiography using a Gd contrast agent in a patient with an anterior condylar confluence dAVF who was allergic to iodine. To our surprise, there was spontaneous closure of the dAVF immediately after angiography. We now report what we believe is the first such case report.

Training in endoscopic endonasal transsphenoidal surgery using a skull model and eggs.

BACKGROUND: Recently, endoscopic pituitary surgery is increasingly being used in pituitary surgery. Compared to conventional microscopic pituitary surgery, outcomes have been non-inferior, so endoscopic pituitary surgery has become an established surgical technique. However, this is a highly specialized surgery and sophisticated surgical techniques are required. We report our development of a training model for endoscopic endonasal transsphenoidal surgery. METHODS: Our training model is constructed using a skull model and eggs. The sella turcica of the skull model is hollowed out and an egg is placed. The bottom of the egg simulates the sella turcica floor and the egg contents simulate a tumor. Training is conducted using this model in an actual operating room with actual surgical instruments. RESULTS: This model is highly realistic and is within acceptable limits as a surgical simulation. Since practice can be repeated, this model is effective for familiarization with endoscopic imaging and to increase technical skills such as drilling and curetting. In addition, variations in eggs, ranging from raw eggs to boiled eggs, can be used to simulate various tumors for training. CONCLUSIONS: This training model using a skull model and eggs is useful to improve surgical techniques in endoscopic endonasal transsphenoidal surgery.

Reorganization of sensorimotor function after functional hemispherectomy studied using near-infrared spectroscopy.

Hemimegalencephaly is a rare congenital disease that occurs with intractable epilepsy and is a childhood developmental disorder. A functional hemispherectomy is indicated for the treatment of hemimegalencephaly with intractable epilepsy. We present a case of hemimegalencephaly in a 6-month-old male. After hemispherectomy, his seizures disappeared completely and postoperative neurological examination showed right hemiplegia. His right arm and limb function were recovered gradually by rehabilitation with passive movement. We investigated cortical activation using near-infrared spectroscopy (NIRS). Serial NIRS showed right cortical activation by passive movement of his right arm. We suggest that NIRS showed the ipsilateral reorganization process as an effect of neurorehabilitation for disconnection of the brain.

[A Case of Primary Central Nervous System Lymphomatoid Granulomatosis that was Completely Ameliorated by Corticosteroid Treatment].

Lymphomatoid granulomatosis (LYG) is an angiocentric, angiodestructive lymphoreticular proliferative disease that usually affects the lungs but it has been speculated to also effect the central nervous system (CNS). However, unique primary LYG of the CNS has rarely been reported in the literature. Herein, we describe a clinical case of a 37-year-old female patient with grade 1 primary CNS-LYG having a good prognosis owing to corticosteroid treatment. The aforesaid patient, presented with a headache and left leg weakness with no evidence of a systemic disease. MRI revealed multiple small enhancing nodules in the right hemisphere with diffuse high-intensity lesions on T2/ FLAIR image. A brain biopsy showed lymphohistiocytic cells with blood vessels infiltrated with CD3+ and CD20+. The Epstein-Barr virus encoded small RNA-ISH test was negative. Based on the above findings, grade 1 primary CNS-LYG was diagnosed. Following the administration of oral corticosteroids, a systemic high-dose corticosteroid therapy was administrated. Complete remission was achieved and maintained for 24 months following treatment. Grade 1 primary CNS-LYG is a rare disease that is not apparently associated with the Epstein-Barr virus (EBV) and possibly yields much better prognosis than the frequently EBV-positive systemic LYG with CNS localization. (Received November 5, 2019; Accepted November 20, 2019; Published February 1, 2020).

The Japan Neurosurgical Database: Overview and Results of the First-year Survey.

The Japan Neurosurgical Database (JND) is a prospective observational study registry established in 2017 by the Japan Neurosurgical Society (JNS) to visualize real-world clinical practice, promote science, and improve the quality of care and neurosurgery board certification in Japan. We summarize JND's aims and methods, and describes the 2018 survey results. The JND registered in-hospital patients' clinical data mainly from JNS training institutions in 2018. Caseload, patient demographics, and in-hospital outcomes of the overall cohort and a neurosurgical subgroup were examined according to major classifications of main diagnosis. Neurosurgical caseload per neurosurgeon in training in core hospitals in 2018 was calculated as an indicator of neurosurgical training. Of 523,283 cases (male 55.3%) registered from 1360 participating institutions, the neurosurgical subgroup comprised of 33.9%. Among the major classifications, cerebrovascular diseases comprised the largest proportion overall and in the neurosurgical subgroup (53.1%, 41.0%, respectively), followed by neurotrauma (19.1%, 25.5%), and brain tumor (10.4%, 12.8%). Functional neurosurgery (6.4%, 3.7%), spinal and peripheral nerve disorders (5.1%, 10.1%), hydrocephalus/developmental anomalies (2.9%, 5.3%), and encephalitis/infection/inflammatory and miscellaneous diseases (2.9%, 1.6%) comprised smaller proportions. Most patients were aged 70-79 years in the overall cohort and neurosurgical subgroup (27.8%, 29.4%). Neurotrauma and cerebrovascular diseases in the neurosurgical subgroup comprised a higher and lower proportion, respectively, than in the overall cohort in elderly patients (e.g. 80 years, 46.9% vs. 33.5%, 26.8% vs. 54.4%). The 2018 median neurosurgical caseload per neurosurgeon in training was 80.7 (25-75th percentile 51.5-117.5). These initial results from 2018 reveal unique aspects of neurosurgical practice in Japan.

Neural decoding using gyral and intrasulcal electrocorticograms.

Electrocorticography of the primary motor cortex (M1) is a promising tool for controlling a brain-computer interface (BCI). Electrocorticograms (ECoG) of the human M1 within the central sulcus (intrasulcal ECoG) have been rarely examined. In order to evaluate the usefulness of intrasulcal ECoG for BCI, we examined patients with subdural electrodes placed temporarily inside the central sulcus and over the sensorimotor cortex (gyral ECoG). Five patients were asked to perform or imagine two or three classes of simple upper limb movements. Univariate statistical analysis of the results revealed that the intrasulcal ECoG on M1 showed significant variability across movement classes. A support vector machine was used for classification of single-trial ECoG signals to infer movement class (neural decoding). The movement classes were predicted with 80-90% accuracy (chance level: 33% or 50%). To reveal the relative importance of anatomical areas for neural decoding, the decoding performance was compared between gyral and intrasulcal ECoGs. The intrasulcal ECoG on the motor bank showed higher performance than the equally-sized gyral ECoG or the intrasulcal ECoG on the sensory bank. Analysis using a short time window revealed that movement class could be decoded even before movement onset. These results suggest the usefulness of intrasulcal ECoG on M1 to infer upper limb movements and present a promising application for a practical BCI system.

Serial volumetric assessment of the natural history and growth pattern of incidentally discovered meningiomas.

OBJECT: Due to advances in neuroimaging and the increasing use of imaging to screen for brain disease ("brain checkups"), meningiomas are now often detected as an incidental finding. The natural history of these asymptomatic meningiomas remains unclear, however. In this study, the authors investigated the natural history and growth pattern of incidentally detected meningiomas using serial volumetric assessment and regression analysis. METHODS: In 70 patients with incidentally discovered meningiomas who underwent follow-up for longer than 1 year, tumor volumes were calculated volumetrically at each follow-up visit, and tumor growth was determined. In patients with tumor growth, regression analysis was performed to determine the pattern of growth. RESULTS: Forty-four tumors exhibited growth and 26 did not. In a regression analysis, 16 of the tumors that grew followed an exponential growth pattern and 15 exhibited linear growth patterns. The presence of calcification was the only imaging characteristic that significantly distinguished the group with tumor growth from that without, although no radiological characteristics significantly distinguished the exponential growth group from the linear growth group. Two patients with obvious tumor growth underwent surgical removal and the pathological specimens extracted showed a high proliferative potential. CONCLUSIONS: The authors found that incidentally discovered meningiomas did not always follow an exponential growth pattern but often exhibited more complex patterns of growth. Serial monitoring of tumor volumes and regression analysis may reveal the growth pattern of incidental meningiomas and provide information useful for determining treatment strategy.

[Microvascular decompression of trigeminal neuralgia caused by vascular compression which penetrated the trigeminal nerve: a case report].

A rare case of trigeminal neuralgia, caused by a branch of the superior cerebral artery running through the trigeminal nerve, was successfully treated by microvascular decompression. The nerve gap at the arterial penetration point was widened by the dissection of the epineurium to obtain sufficient mobilization of the artery and decompression of the nerve. This technique would be useful for securing neurovascular decompression, as well as for avoiding postoperative hypesthesia owing to the neurotomy described in previous reports. Preparing for such a rare case is important as preoperative magnetic resonance imaging (MRI) often fails to disclose precise diagnoses.

[Treatment of leptomeningeal carcinomatosis from gastric cancer].

Leptomeningeal carcinomatosis is a serious complication leading to a fatal outcome in patients with gastric cancer. We tried to treat leptomeningeal carcinomatosis from gastric cancer with intrathecal chemotherapy using methotrexate (MTX)and cytosine arabinoside(Ara-C). We described and discussed the therapeutic strategy. Six patients with leptomeningeal carcinomatosis from gastric cancer were admitted in our institution from March 2004 to July 2007. Three of 6 patients were accepted for intrathecal chemotherapy. They received intraventricular injections of MTX(5 mg)and Ara-C(20 mg)through the Ommaya reservoir. The other 3 patients who rejected the therapy were conservatively treated with betamethasone, carbamazepine and glyceol. Two of the intrathecal chemotherapy group received whole-brain radiotherapy after the initial intrathecal chemotherapy. The mean survival time was 122.3 days(median survival time 35.0 days). The survival of the intrathecal chemotherapy group was from 39 to 367 days, whereas the survival of the conservative treatment group was from 10 to 31 days. The intrathecal chemotherapy improved not only survival but also clinical symptoms dramatically. Intrathecal chemotherapy is thus recommended for leptomeningeal carcinomatosis from gastric cancer.

Significance of Elevated HMGB1 Expression in Pituitary Apoplexy.

BACKGROUND/AIM: High-mobility group box 1 (HMGB1) is a nuclear DNA-binding protein that exerts a range of proinflammatory actions when it is secreted extracellularly. We hypothesized that HMGB1 released from damaged cells in pituitary apoplexy would exacerbate the neurological symptoms due to acute inflammation. PATIENTS AND METHODS: All the patients included in this study suffered from non-functioning pituitary adenoma. Four patients with apoplexy and three patients without apoplexy were included in this study. They underwent endonasal transsphenoidal endoscopic surgery to resect the tumors. We conducted enzyme-linked immunosorbent assay (ELISA) to measure HMGB1 in the surgical specimens. RESULTS: Patients with apoplexy expressed HMGB1 at significantly higher levels than those in the non-apoplexy group (p=0.0478). CONCLUSION: HMGB1 may be involved in subacute inflammation of pituitary apoplexy. Further work is needed to elucidate the detailed biological significance of HMGB1 in this disease.

A case of unilateral vertebral artery dissection progressing in a short time period to bilateral vertebral artery dissection.

BACKGROUND: Vertebral artery dissection (VAD) is an important cause of stroke in young and middle- aged people. Bilateral occurrence of VAD is generally considered rare, but the number of reports of bilateral VAD has been increasing in recent years. In this paper, we report a case of de novo VAD on the contralateral side presenting with subarachnoid hemorrhage in the acute stage of cerebral infarction due to unilateral VAD. CASE DESCRIPTION: A 52-year-old man developed sudden-onset left occipital headache, dizziness, dysphagia, and right-sided hemiparesthesia and was admitted to our hospital. Head magnetic resonance imaging on admission showed a left lateral medullary infarction due to the left VAD. At this point, the right vertebral artery was normal. However, on day 9 after onset, he suddenly presented with subarachnoid hemorrhage due to the right VAD. Emergency endovascular treatment was performed for the dissecting aneurysm of the right vertebral artery. The patient's condition improved gradually after the procedure, and he was discharged with a modified Rankin Scale score of 1. CONCLUSION: Bilateral occurrence of VAD may be more common than previously believed. Even in cases of unilateral VAD, we need to pay attention to the occurrence of de novo VAD on the contralateral side.

A case of leptomeningeal metastases of human epidermal growth factor receptor 2-positive breast cancer that responded well to lapatinib plus capecitabine.

BACKGROUND: Leptomeningeal metastases (LM) pose the most difficult form of cancer metastasis to treat and portend a poor prognosis. Standard treatment has yet to be established, and intrathecal chemotherapy and whole- brain radiotherapy are administered on an empirical basis. CASE DESCRIPTION: We report on a 46-year-old woman with LM from human epidermal growth factor receptor 2 (HER2)-positive breast cancer. She was suffering from intractable headaches, severe nausea and vomiting, and cerebellar ataxia. Contrast-enhanced magnetic resonance imaging (MRI) revealed diffuse enhancement of the meninges, mainly in the posterior cranial fossa, and compression of the cerebellum by the profoundly thickened meninges. The first step in the treatment was decompression of the posterior cranial fossa to relieve intracranial hypertension. After surgery, her symptoms immediately improved. The second step was treatment with lapatinib at 1250 mg and capecitabine 1200 mg, which dramatically improved her symptoms and disappeared diffuse abnormal signal enhancement on MRI. CONCLUSION: We treated a patient with LM from primary HER2-positive breast cancer who responded well to lapatinib plus capecitabine.

Intravascular Lymphoma Presenting as a Cavernous Sinus Tumor.

Intravascular lymphoma (IVL) is a malignant lymphoma that lacks the expression of cell surface adhesion molecules so that cells fluidly migrate within the blood vessels. The patient in the present study had restricted eye movement caused by IVL, mimicking a cavernous sinus tumor. Because the cavernous sinus lumen is divided into multiple compartments by trabeculae and venous channels, IVL tumor cells were trapped in these compartments, thus forming a mass, which subsequently extended into the contralateral cavernous sinus via the anterior and posterior intercavernous sinuses. This is a rare case of IVL forming a mass inside the cavernous sinus.

Ipsilateral motor-related hyperactivity in patients with cerebral occlusive vascular disease.

BACKGROUND AND PURPOSE: Cerebral occlusive vascular disease is an established risk factor for ischemic stroke; however, little is known about its effects on brain function in patients without stroke. To detect possible functional alterations, we used magnetoencephalography and evaluated cerebral cortical activity during hand motor tasks in a group of such patients. Method- Event-related desynchronization (ERD) during hand-grasping and self-paced finger-tapping tasks was examined in 38 right-hand-dominant patients with occlusive disease of the internal carotid or middle cerebral artery caused by diverse pathologies (atherosclerosis, 28; others, 10) and in 8 control subjects. All patients had no apparent motor impairments. The spatial distribution and the intensity (t value) of ERD in the beta band were analyzed with synthetic aperture magnetometry. According to the laterality index calculated from the ratios of peak t values on ipsilateral vs contralateral (with respect to the hand movement) hemispheres, the distribution of ERD was classified into 3 patterns: contralateral, bilateral, and ipsilateral. RESULTS: Abnormal ipsilateral dominant distribution of beta ERD was observed significantly more often during contralesional hand grasping in patients with atherosclerotic vascular lesion. It was accompanied by significantly higher t values on the ipsilateral hemisphere, without a decrease in those on the contralateral side. The age, the rating scores of periventricular hyperintensity, and ventricular size were all significantly higher in patients who showed the ipsilateral-dominant pattern. CONCLUSIONS: Abnormal ipsilateral hyperactivity may indicate the presence of subclinical functional alterations related to atherosclerotic occlusive vascular disease.

MRI-based correction for partial-volume effect improves detectability of intractable epileptogenic foci on 123I-iomazenil brain SPECT images.

UNLABELLED: (123)I-Iomazenil brain SPECT has been used for the detection of epileptogenic foci, especially when surgical intervention is considered. Although epileptogenic foci exhibit a decrease in (123)I-iomazenil accumulation, normal cerebral cortices often exhibit similar findings because of thin cortical ribbons, gray matter atrophy, or pathologic brain structures. In the present study, we created (123)I-iomazenil SPECT images corrected for gray matter volume using MRI and tested whether the detectability of the epileptogenic foci improved. METHODS: Seven patients (1 male patient and 6 female patients; mean age +/- SD, 34 +/- 17 y) with intractable epilepsy were surgically treated by resecting the cerebral cortex after surface electroencephalography. Histopathologic examination of the resected specimens and a good outcome after surgery indicated that the resected lesions were epileptogenic foci. These patients underwent (123)I-iomazenil SPECT and 3-dimensional T1-weighted MRI examinations before their operations. Each SPECT image was coregistered to the corresponding MR image, and its partial-volume effect (PVE) was corrected on a voxel-by-voxel basis with a smoothed gray matter distribution image. Four nuclear medicine physicians visually evaluated the (123)I-iomazenil SPECT images with and without the PVE correction. The SPECT count ratio of the suspected focus to the contralateral cerebral cortex was evaluated as an asymmetry index (%) based on the volume of interest. RESULTS: The sensitivity, specificity, and accuracy of focus detection by visual assessment were higher after PVE correction (88%, 99%, and 98%, respectively) than before correction (50%, 92%, and 87%, respectively). The mean asymmetry index for the surgically resected lesions was significantly higher on the PVE-corrected SPECT images (22%) than on the PVE-uncorrected ones (16%) (P = 0.006). CONCLUSION: MRI-based PVE correction for (123)I-iomazenil brain SPECT improves the sensitivity and specificity of the detection of cortical epileptogenic foci in patients with intractable epilepsy.

[Effectiveness of intraoperative fluorescence for diagnosis of malignant lymphoma].

Primary central nervous system lymphoma is generally treated with radiochemotherapy, but surgical treatment can be used in combination with biopsy. We used fluorescein Na to provide intraoperative fluorescence during biopsy to improve the safety and accuracy of surgical treatment. After dural incision, fluorescein Na was administered intravenously at 20 mg/kg, which is double the usual dose, and appeared in the tumor after 10 to 15 minutes. Yellow-stained tissue was collected during stereotactic biopsy. Strongly fluorescent tumor cells were observed under the microscope; these cells would have otherwise been difficult to distinguish from normal brain tissue. Sufficient fluorescence was observed endoscopically, and we conclude that use of fluorescein Na is effective in diagnosis and surgery for malignant lymphoma.