Endoscopic and exoscopic surgery for brain tumors.

Nerves and blood vessels must be protected during brain tumor surgery, which has traditionally relied on microscopes. In the 2000s, endoscopes and related equipment were developed for neurosurgery. In this review, we aim to outline the role of endoscopes in brain tumor surgery and discuss the emerging use of exoscopes. The primary use of endoscopes in brain tumor surgery is in endoscopic endonasal surgery for pituitary tumors. By using the space within the sphenoid sinus, surgeons can insert an endoscope and instruments such as forceps or scissors through the nose to access and remove the tumor. Compared to microscopes, endoscopes can get closer to tumors, nerves, and blood vessels. They enable wide-angle observation of the skull base, making them valuable for skull base tumors as well as pituitary tumors. Endoscopes are also used in cases where a brain tumor is associated with hydrocephalus, allowing surgeons to correct obstructive hydrocephalus and perform tumor biopsies simultaneously. Exoscopy, a newer technique introduced in recent years, involves surgeons wearing special glasses and removing the tumor while viewing a three-dimensional monitor. This approach reduces surgeon fatigue and allows for more natural positioning during lengthy brain tumor surgeries. Future brain tumor surgeries will likely involve robotic surgery, which is already used for other organs. This is expected to make brain tumor removal safer and more accurate.

Therapeutic potential of pentamidine for glioma-initiating cells and glioma cells through multimodal antitumor effects.

Glioma-initiating cells, which comprise a heterogeneous population of glioblastomas, contribute to resistance against aggressive chemoradiotherapy. Using drug reposition, we investigated a therapeutic drug for glioma-initiating cells. Drug screening was undertaken to select candidate agents that inhibit proliferation of two different glioma-initiating cells lines. The alteration of proliferation and stemness of the two glioma-initiating cell lines, and proliferation, migration, cell cycle, and survival of these two differentiated glioma-initiating cell lines and three different glioblastoma cell lines treated with the candidate agent were evaluated. We also used a xenograft glioma mouse model to evaluate anticancer effects of treated glioma cell lines. Among the 1301 agents, pentamidine-an antibiotic for Pneumocystis jirovecii-emerged as a successful antiglioma agent. Pentamidine treatment suppressed proliferation and stemness in glioma-initiating cell lines. Proliferation and migration were inhibited in all differentiated glioma-initiating cells and glioblastoma cell lines, with cell cycle arrest and caspase-dependent apoptosis induction. The in vivo study reproduced the same findings as the in vitro studies. Pentamidine showed a stronger antiproliferative effect on glioma-initiating cells than on differentiated cells. Western blot analysis revealed pentamidine inhibited phosphorylation of signal transducer and activator of transcription 3 in all cell lines, whereas Akt expression was suppressed in glioma-initiating cells but not in differentiated lines. In the present study, we identified pentamidine as a potential therapeutic drug for glioma. Pentamidine could be promising for the treatment of glioblastomas by targeting both glioma-initiating cells and differentiated cells through its multifaceted antiglioma effects.

Glioblastomas at the white matter of temporo-parietal junction cause a poor postoperative independence level.

INTRODUCTION: Right cerebral hemispheric glioblastomas (GBMs) often decrease the Karnofsky performance status (KPS) score postoperatively, despite the patient having sufficient patient function while performing daily living. This study aimed to evaluate the factors that could cause poor KPS scores during the postoperative chronic phase in patients with right cerebral hemispheric GBMs. METHODS: Data of 47 patients with newly diagnosed right cerebral hemispheric GBMs were analyzed. All patients were assessed preoperatively and 3 months postoperatively to determine KPS and brain function. To determine tumor location related to the postoperative KPS scores, we used voxel-based lesion symptom mapping (VLSM). The patients were divided into two groups (involvement and non-involvement groups) based on whether their lesion involved a significant region identified by VLSM. We then compared functional factors and prognosis between the groups using the chi-squared and log-rank tests, respectively. RESULTS: The KPS score significantly decreased after surgery compared to that preoperatively measured (p = 0.023). VLSM revealed that tumors in the white matter of temporo-parietal junction (WM-TPJ) caused a significant decline in the KPS score at three months postoperatively. The patients in the involvement group had a higher probability of impaired attention, visuospatial cognition, emotion recognition, and visual field than did those in the non-involvement group. In addition, tumor in the WM-TPJ were associated with shorter progression-free survival and overall survival (p = 0.039 and 0.023, respectively). CONCLUSIONS: GBMs involving the right WM-TPJ are more likely to result in poor postoperative KPS scores and prognoses. Impairments of several kinds of brain functions caused by tumor invasion to the WM-TPJ may be associated with lower KPS scores.

Recovery of Visual Field After Awake Stimulation Mapping of the Optic Pathway in Glioma Patients.

Brain mapping during awake craniotomy for gliomas can help preserve neurological functions, including maintenance of central and peripheral vision. However, the consecutive changes in the visual field remain unknown. We retrospectively assessed 14 patients who underwent awake craniotomy for gliomas infiltrating into the optic radiation. Cortico-subcortical direct electrical stimulation (DES) was intraoperatively applied until transient visual symptoms were elicited and recorded. The visual fields were examined consecutively in the preoperative period and postoperative subacute and chronic periods. To evaluate the anatomo-functional validity of the recordings, all DES-elicited points were overlaid onto a three-dimensional template that included the optic radiation, using voxel-based morphometry (VBM) mapping. All patients experienced visual symptoms that were classified as phosphenes, blurred vision, or hallucinations during DES, and surgical resection was limited to within the functional boundaries. In VBM, almost all the subcortical positive mapping points overlapped with the surface of the optic radiation, and the distribution of sites that induced visual phenomena in the upper or lower visual fields could be differentiated in the anatomical space. We observed no postoperative visual deficit in four patients (29%), time-dependent improvements in five out of eight patients that presented transient quadrantanopia or partial visual defect (36% out of 57%), and permanent hemianopsia (14%) in two patients with occipital lesions. Intraoperative DES that identifies and preserves optic radiation in awake craniotomy for gliomas is a reliable and effective technique to reduce risk of permanent deficits, but has a low success rate in patients with occipital involvement.

Quality of life following awake surgery depends on ability of executive function, verbal fluency, and movement.

INTRODUCTION: The outcome of awake surgery has been evaluated based on functional factors, return to work, and oncological aspects, and there have been no reports directly examining QOL. This study aimed to investigate the outcome of QOL following awake surgery and to determine the functional factors influencing QOL. METHODS: Seventy patients with WHO grade II/III gliomas were included. For the assessment of QOL, we used the SF-36 and calculated summary and sub-component scores. Three summary component scores, including physical (PCS), mental (MCS), and role/social summary (RCS) component scores, were computed based on sub-component scores. Additionally, various assessments of neurological/neuropsychological function were performed. We performed univariate and multiple regression analyses to investigate the functional factors influencing the SF-36. RESULTS: PCS and MCS were maintained, but only RCS was low to 42.0 ± 16.1. We then focused on the RCS and its sub-components: general health (GH), role physical (RP), social functioning (SF), and role emotional (RE). Multiple regression analysis showed following significant correlations between the sub-component scores and brain functions: GH to executive function and movement (p = 0.0033 and 0.032), RP to verbal fluency and movement (p = 0.0057 and 0.0010), and RE to verbal fluency (p = 0.020). Furthermore, when the sub-component scores were compared between groups with and without functional deficits related to GH, RP, and RE, each score was significantly lower in the groups with functional deficits (p = 0.012, 0.014, and 0.0049, respectively). CONCLUSIONS: In patients who underwent awake surgery, a subset of patients had low QOL because of poor RCS. Functional factors influencing QOL included executive function, verbal fluency, and movement.

Intraoperative rupture of intracerebral aneurysm immediately after meningioma resection: a case report.

BACKGROUND: Meningiomas and unruptured cerebral aneurysms (UCAs) rarely coexist. However, the treatment strategy remains to be fully elucidated. This report is a first report that UCA related to the tumor feeder intraoperatively ruptured when the meningioma was resected. CASE PRESENTATION: Herein, we present a case of meningioma coexisting with contralateral UCA related to a tumor feeder. Immediately after the meningioma was resected, intraoperative acute brain swelling due to rupture of the contralateral aneurysm appeared. The swollen brain protruding into the epidural space was resected, following contralateral ruptured aneurysm was performed by endovascular surgery. Intensive neurological treatment was administered and the patient gradually recovered. CONCLUSION: This report highlights the possibility of intraoperative UCA rupture related to the tumor feeder when the meningioma is resected.

A Fiber Dissection Study of the Anterior Commissure: Correlations with Diffusion Spectrum Imaging Tractography and Clinical Relevance in Gliomas.

The anterior commissure, which connects bilateral temporal lobes and olfactive areas, remains elusive in many aspects of its structure and functional role. To comparatively describe anatomical details of the anterior commissure using cadaveric fiber dissection (FD) and diffusion spectrum imaging (DSI) thus refining our knowledge of the tract and exploring its clinical relevance in glioma migration. Twelve normal postmortem hemispheres were treated with Klingler's method and subjected to FD with medial, inferior, and lateral approaches. The FD findings were correlated with DSI tractography results. To illustrate the clinical relevance, two patients with recurrent temporal high-grade glioma are described. Our FD and DSI tractography of the anterior commissure disclosed a new anatomical paradigm. The FD confirmed that the anterior limb (absent sometimes and variable) and the lateral/temporal extension include the rostral portion and caudal portion, respectively, of the anterior commissure fibers. The shape of the lateral/temporal extension predominantly resembles an 'H'. The DSI tractography findings corresponded to these FD results. According to the FD, the Virchow-Robin space is continuous with the subarachnoid space and very close to the anterior commissure. The two clinical cases presented severe disturbances of consciousness and behavior despite good local tumor control. Subsequent magnetic resonance images showed new lesions infiltrating the contralateral temporal lobes. FD combined with DSI provided anatomical details facilitating a better understanding of the anterior commissure. Glioma migration routes to the contralateral temporal lobe included the anterior commissure, Virchow-Robin space, and subarachnoid space and were clinically relevant.

Non-occlusive mesenteric ischemia during bevacizumab treatment for glioblastoma: a case report.

Glioblastoma is one of the most aggressive brain tumors in adults. The standard treatment is radiotherapy and chemotherapy based on the Stupp regimen after maximal safe resection. One effective chemotherapeutic drug is bevacizumab, which can prolong progression-free survival in glioblastoma patients but not overall survival. Adverse events of bevacizumab include hypertension, proteinuria, delayed wound healing, bleeding of the nose and gums, and thromboembolism resulting in gastrointestinal perforation. Herein, we describe an autopsy case of a patient with glioblastoma who died from non-occlusive mesenteric ischemia that was presumably caused by bevacizumab.

Awake surgery for right frontal lobe glioma can preserve visuospatial cognition and spatial working memory.

PURPOSE: Awake surgery is the standard treatment to preserve motor and language functions. This longitudinal study aimed to evaluate the resection rate and preservation of neurocognitive functions in patients with right frontal lobe glioma who underwent awake surgery. METHODS: Thirty-three patients (mean age, 48.0 years) with right frontal lobe glioma who underwent awake surgery at our hospital between 2013 and 2019 were included. Fourteen, thirteen, and six cases had WHO classification grades of II, III, and IV, respectively. We evaluated visuospatial cognition (VSC) and spatial working memory (SWM) before and three months after surgery. Relevant brain areas for VSC and SWM were intraoperatively mapped, whenever the task was successfully accomplished. Therefore, patients were divided into an intraoperative evaluation group and a non-evaluation group for each function, and the resection rate and functional outcomes were compared. RESULTS: The removal rate in the evaluation group for VSC and SWM were similar to that in the non-evaluation group. Chronic impairment rate of VSC was significantly lower in the evaluation than in the non-evaluation group (5.6% vs. 33.3%, p = 0.034). No patient showed postoperative SWM impairment in the evaluation group as opposed to the non-evaluation group (16.7%, p = 0.049). The probability of resection of the deeper posterior part of the middle frontal gyrus, the relevant area of VSC, was higher in the non-evaluation group than in the evaluation group. CONCLUSIONS: We statistically verified that awake surgery for right frontal lobe glioma results in successful preservation of VSC and SWM with satisfying resection rates.

Disconnection of posterior part of the frontal aslant tract causes acute phase motor functional deficit.

The frontal aslant tract (FAT) mainly connects the supplementary motor area (SMA) and inferior frontal gyrus. The left FAT is involved in language-related functions, while the functional role of the right FAT is not fully understood. The aim of this study was to investigate the function of the right FAT by dividing it into three segments according to the anatomical structure. A total of 34 right frontal gliomas who had undergone surgery were studied. Participants were assessed for the acute and chronic phases of several neuropsychological and motor functions. FAT was reconstructed into the anterior, middle, and posterior segments according to the cortical connections as the medial prefrontal cortex, pre-SMA, and SMA proper, respectively. The relationships between the damaged severity of each FAT segment and behavioral scores were analyzed. A significant relationship was observed only in the acute phase motor function and posterior segment of the FAT. The middle segment was involved in motor function, but it did not have a sufficient significance level compared to the posterior segment. Our study revealed that the right FAT can be divided into three segments and that its posterior segment is related to acute phase motor function.

Pyramid-Shape Crossings and Intercrossing Fibers Are Key Elements for Construction of the Neural Network in the Superficial White Matter of the Human Cerebrum.

Structural analysis of the superficial white matter is prerequisite for the understanding of highly integrated functions of the human cerebral cortex. However, the principal components, U-fibers, have been regarded as simple wires to connect adjacent gyri (inter-gyral U-fibers) but have never been thought as indispensable elements of anatomical structures to construct the cortical network. Here, we reported such novel structures made of U-fibers. Seven human cerebral hemispheres were treated with Klingler's method and subjected to fiber dissection (FD). Additionally, tractography using diffusion spectrum imaging (DSI) was performed. Our FD and DSI tractography succeeded disclosing a new type of U-fibers that was hidden in and ran along the white matter ridge of a gyral convolution (intra-gyral U-fibers). They were distinct from inter-gyral U-fibers which paved sulcal floors. Both intra- and inter-gyral U-fibers converged from various directions into junctional areas of white matter ridges, organizing novel anatomical structures, "pyramid-shape crossings". U-fibers to form pyramid-shape crossings also render routes for communication between crossings. There were 97 (mean, range 73-148) pyramid-shape crossings per lateral cortical surface. They are key structures to construct the neural network for intricate communications throughout the entire cerebrum. They can be new anatomical landmarks, too, for the segmentation of the cerebral cortex.

[Brain Functional Networks and Awake Craniotomy for Gliomas].

The sophisticated functional networks of the human brain are integral to life, controlling domains such as language understanding and production and social cognition, which are important for inter-personal communication. Glioma, a primary brain tumor, infiltrates into the brain tissue, forcing the normal brain to reorganize the neural networks(brain plasticity)to resist the invasion. Awake craniotomy for gliomas enables reliable intraoperative identification and preservation of not only the innate normal brain functional areas but also the brain functional networks that have adapted and changed in response to the tumor-invasive environment. Recent advances in neurosurgical techniques and anesthetics have enabled the performance of intraoperative mapping of various brain functions, while maintaining the patient at a high level of awake condition. Attempts have also been made to preserve not only the language functions in the left cerebral hemisphere but also the higher brain functions represented by the right frontal lobe. Herein, we introduce the neural networks of the brain that glioma surgeons need to be aware of, and further describe the indications, methods, and usefulness of awake craniotomy for preserving these networks. In addition, we will discuss topics expected to become the standard in the near future.

RBPJ contributes to the malignancy of glioblastoma and induction of proneural-mesenchymal transition via IL-6-STAT3 pathway.

Notch signaling plays a pivotal role in many cancers, including glioblastoma (GBM). Recombination signal binding protein for immunoglobulin kappa J region (RBPJ) is a key transcription factor of the Notch signaling pathway. Here, we interrogated the function of RBPJ in GBM. Firstly, RBPJ expression of GBM samples was examined. Then, we knocked down RBPJ expression in 2 GBM cell lines (U251 and T98) and 4 glioblastoma (GBM) stem-like cell lines derived from surgical samples of GBM (KGS01, KGS07, KGS10 and KGS15) to investigate the effect on cell proliferation, invasion, stemness, and tumor formation ability. Expression of possible downstream targets of RBPJ was also assessed. RBPJ was overexpressed in the GBM samples, downregulation of RBPJ reduced cell proliferation and the invasion ability of U251 and T98 cells and cell proliferation ability and stemness of glioblastoma stem-like cells (GSC) lines. These were accompanied by reduced IL-6 expression, reduced activation of STAT3, and inhibited proneural-mesenchymal transition (PMT). Tumor formation and PMT were also impaired by RBPJ knockdown in vivo. In conclusion, RBPJ promotes cell proliferation, invasion, stemness, and tumor initiation ability in GBM cells through enhanced activation of IL-6-STAT3 pathway and PMT, inhibition of RBPJ may constitute a prospective treatment for GBM.

Gelsolin inhibits malignant phenotype of glioblastoma and is regulated by miR-654-5p and miR-450b-5p.

We have previously shown that gelsolin (GSN) levels are significantly lower in the blood of patients with glioblastoma (GBM) than in healthy controls. Here, we analyzed the function of GSN in GBM and examined its clinical significance. Furthermore, microRNAs involved in GSN expression were also identified. The expression of GSN was determined using western blot analysis and found to be significantly lower in GBM samples than normal ones. Gelsolin was mainly localized in normal astrocytes, shown using immunohistochemistry and immunofluorescence. Higher expression of GSN was correlated with more prolonged progression-free survival and overall survival. Gelsolin knockdown using siRNA and shRNA markedly accelerated cell proliferation and invasion in GBM in vitro and in vivo. The inactive form of glycogen synthase kinase-3ß was dephosphorylated by GSN knockdown. In GBM tissues, the expression of GSN and microRNA (miR)-654-5p and miR-450b-5p showed an inverse correlation. The miR-654-5p and miR-450b-5p inhibitors enhanced GSN expression, resulting in reduced proliferation and invasion. In conclusion, GSN, which inhibits cell proliferation and invasion, is suppressed by miR-654-5p and miR-450b-5p in GBM, suggesting that these miRNAs can be targets for treating GBM.

Awake surgery for glioblastoma can preserve independence level, but is dependent on age and the preoperative condition.

PURPOSE: Lately, awake surgery has been frequently adapted for glioblastoma (GBM). However, even with awake surgery, the expected long-term independence levels may not be achieved. We studied the characteristics of independence levels in GBM patients, and investigated the usefulness and parameter thresholds of awake surgery from the standpoint of functional outcomes. METHODS: Totally, 60 GBM patients (awake group, n = 30; general anesthesia group, n = 30) who underwent tumor resection surgery were included. We collected preoperative and 1- and 3-month postoperative Karnofsky Performance Status (KPS) scores, and analyzed causes of low KPS scores from the aspect of function, brain region, and clinical factors. Then, we focused on the operative method, and investigated the usefulness of awake surgery. Finally, we explored the parameter standards of awake surgery in GBM considering independence levels. RESULTS: Postoperative KPS were significantly lower than preoperative scores. Responsible lesions for low KPS scores were deep part of the left superior temporal gyrus and the right posterior temporal gyri that may be causes of aphasia and neuropsychological dysfunctions, respectively. Additionally, operative methods influenced on low independence level; long-term KPS scores in the awake group were significantly higher than those in the general anesthesia group, but they depended on age and preoperative KPS scores. Receiver operating characteristic curve analysis showed preoperative KPS = 90 and age = 62 years as the cutoff values for preservation of long-term KPS scores in awake group. CONCLUSION: Awake surgery for GBM is useful for preserving long-term independence levels, but outcomes differ depending on age and preoperative KPS scores.

Case of metastatic glioblastoma with primitive neuronal component to the lung.

Glioblastoma (GBM) with primitive neuronal component (GBM-PNC) is a rare GBM subtype recently categorized by the World Health Organization in the revised classification system of 2016. Extracranial metastases originating from GBM-PNC are rare and metastasis to solid organs has never been reported. Herein, we present the first case of metastasis of GBM-PNC to the lung. A 49-year-old man presenting with headache was diagnosed with multiple tumors adhering to the dura matter in the right temporal lobe. Despite surgery and chemoradiotherapy, 2 months after the initial therapy, the patient presented with CSF dissemination and lung metastases. The patient succumbed to the disease 12 months after the first surgery. We discuss the possibility that GBM-PNC may constitute a subtype of glioma with particularly poor prognosis, tending to dissemination and metastasis. Our results suggest that a complementary regular inspection of the whole body via CT may be recommended for the follow-up of patients with GBM- PNC.

[Stereotactic Biopsy in the Lateral Position Using a Neuronavigation System].

BACKGROUND: Stereotactic brain biopsy using a navigation system is minimally invasive because it can be performed under local anesthesia. However, there are problems due to the localization and accessibility of the tumor and instability of the airway under sedation. This study aimed to examine the differences in safety and surgical time between the supine and lateral position. METHODS: This study included 25 cases which underwent navigation-guided brain biopsies from May 2015 to March 2018 in the Kanazawa University Hospital. We compared tumor localization, operation time, standby time, intraoperative difficulties, and final diagnosis acquisition rates between the supine and lateral positions. Puncture sites were then examined by visualizing all biopsy trajectories simultaneously on a three-dimensional cerebral template. RESULTS: Biopsies of the tumor in all cerebrum lobes were possible in the lateral position. There were no significant differences in operating time or standby time between the supine and lateral positions. One case in the spine position required sedation by an anesthesiologist due to body movement, but there were no difficulties in any cases of lateral positioning. The final diagnosis acquisition rate was 100% in all cases. In the lateral position, stable breathing was maintained because the head and the trunk axes remined in the same line. CONCLUSION: Stereotactic brain biopsy in the lateral position can be safer and more useful than in the supine position under local anesthesia.

Characterization of Heme-DNA Complexes Composed of Some Chemically Modified Hemes and Parallel G-Quadruplex DNAs.

Heme {Fe(II)- or Fe(III)-protoporphyrin IX complex [heme(Fe(2+)) or heme(Fe(3+)), respectively]} binds selectively to the 3'-terminal G-quartet of a parallel G-quadruplex DNA formed from a single repeat sequence of the human telomere, d(TTAGGG), through a π-π stacking interaction between the porphyrin moiety of the heme and the G-quartet. The binding affinities of some chemically modified hemes(Fe(3+)) for DNA and the structures of complexes between the modified hemes(Fe(2+)) and DNA, with carbon monoxide (CO) coordinated to the heme Fe atom on the side of the heme opposite the G6 G-quartet, have been characterized to elucidate the interaction between the heme and G-quartet in the complexes through analysis of the effects of the heme modification on the structural properties of the complex. The study revealed that the binding affinities and structures of the complexes were barely affected by the heme modification performed in the study. Such plasticity in the binding of heme to the G-quartet is useful for the versatile design of the complex through heme chemical modification and DNA sequence alteration. Furthermore, exchangeable proton signals exhibiting two-proton intensity were observed at approximately -3.5 ppm in the (1)H nuclear magnetic resonance (NMR) spectra of the CO adducts of the complexes. Through analysis of the NMR results, together with theoretical consideration, we concluded that the heme(Fe(2+)) axial ligand trans to CO in the complex is a water molecule (H2O). Identification of the Fe-bound H2O accommodated between the heme and G-quartet planes in the complex provides new insights into the structure-function relationship of the complex.

Detection of the development of late-onset idiopathic aqueductal stenosis (LIAS) by chronological magnetic resonance imaging: a case report.

Late-onset idiopathic aqueductal stenosis (LIAS) has been recognized as one of the clinical entities of adulthood hydrocephalus for decades, although there have been no radiological reports that show normal ventricular systems before the development of LIAS. We present here an adolescent case of LIAS with a previously normal ventricular system on magnetic resonance imaging (MRI). A 17-year-old boy had been suffering from chronic headaches and mild intellectual disability (MID) since he became a teenager, and this had prevented him from leading an ordinary school life. MRIs on admission showed triventriculomegaly from the aqueductal stenosis that had not been detected on previous MRIs, at least until the age of 6. An endoscopic third ventriculostomy was successfully performed, which improved both the headache and the MID. The developmental mechanism of LIAS remains unclear, although the membranous ependymal-like tissue observed in the aqueduct suggested the preceding existence of an inflammatory process around this region. To the best of our knowledge, this case was noteworthy because the development of LIAS was clearly demonstrated on MRI for the first time.