The major shortcoming of image-guided navigation systems is the use of presurgically acquired image data, which does not account for intra-operative changes such as brain shift, tissue deformation and tissue removal occurring during the surgical procedure. Intra-operative ultrasound (iUS) is becoming widely used in neurosurgery but they lack orientation and panoramic view. In this article, we describe our procedure for US-based real-time neuro-navigation during surgery. We used fusion imaging between preoperative magnetic resonance imaging (MRI) and iUS for brain lesion removal in 67 patients so far. Surgical planning is based on preoperative MRI only. iUS images obtained during surgery are fused with the preoperative MRI. Surgery is performed under intra-operative US control. Relying on US imaging, it is possible to recalibrate navigated MRI imaging, adjusting distortion due to brain shift and tissue resection, continuously updating the two modalities. Ultrasound imaging provides excellent visualization of targets, their margins and surrounding structures. The use of navigated MRI is helpful in better understanding cerebral ultrasound images, providing orientation and panoramic view. Intraoperative US-guided neuro-navigation adjustments are very accurate and helpful in the event of brain shift. The use of this integrated system allows for a true real-time feedback during surgery.
Intraoperative ultrasound (ioUS) has become increasingly widespread in brain tumor surgery but it is not yet a standard procedure in spinal surgery. We analyzed intraoperative ultrasonographic findings of different spinal tumors and their influence on the surgical strategy.
Contrast-enhanced ultrasound (CEUS) is a dynamic and continuous modality that offers a real-time, direct view of vascularization patterns and tissue resistance for many organs. Thanks to newer ultrasound contrast agents, CEUS has become a well-established, live-imaging technique in many contexts, but it has never been used extensively for brain imaging. The use of intraoperative CEUS (iCEUS) imaging in neurosurgery is limited.
Contrast enhanced ultrasound (CEUS) is a dynamic and continuous modality providing real-time view of vascularization and flow distribution patterns of different organs and tumors. Nevertheless its intraoperative use for brain tumors visualization has been performed few times, and a thorough characterization of cerebral glioma had never been performed before.
Prospective follow-up studies of large cohorts of patients with glioblastoma (GBM) are needed to assess the effectiveness of conventional treatments in clinical practice. We report GBM survival data from the Brain Cancer Register of the Fondazione Istituto Neurologico Carlo Besta (INCB) in Milan, Italy, which collected longitudinal data for all consecutive patients with GBM from 1997 to 2010.
Venous thromboembolism (VTE) events are frequent in neurooncological patients in perioperative period thus increasing mortality and morbidity. The role of prophylaxis has not yet been established with certainty, and in various neurosurgery and intensive care units the practice is inconsistent. A better definition of the risk/cost/benefit ratio of the various methods, both mechanical (intermittent pneumatic compression-IPC, graduated compression stockings-GCS) and pharmacological (unfractionated heparin-UFH or low molecular weight heparin-LMWH), is warranted. We aim to define the optimal prophylactic treatment in the perioperative period in neurooncological patients. A systematic review of the literature was performed in Medline, Embase and Cochrane Library. Thirteen randomized controlled trials (RCTs) were identified, in which physical methods (IPC or GCS) and/or drugs (UFH or LMWHs) were evaluated in perioperative prophylaxis of neurological patients, mostly with brain cancer not treated with anticoagulants for other diseases. The analysis was conducted on a total of 1,932 randomized patients of whom 1,558 had brain tumours. Overall data show a trend of reduction of VTE in patients treated with mechanical methods (IPC or GCS) that should be initiated preoperatively and continued until discharge or longer in case of persistence of risk factors. The addition of enoxaparin starting the day after surgery, significantly reduces clinically manifest VTE, despite an increase in major bleeding events. Further studies are needed to delineate the types of patients with an increase of VTE risk and risk/benefits ratio of physical and pharmacological treatments in the perioperative period.
Posterior fossa surgery traditionally implies permanent bone removal. Although suboccipital craniectomy offers an excellent exposure, it could lead to complications. Thus, some authors proposed craniotomy as a valuable alternative to craniectomy. In the present study we compare postoperative complications after craniotomy or craniectomy for posterior fossa surgery.
Locoregional chemotherapy with carmustine wafers, positioned at surgery and followed by radiation therapy, has been shown to prolong survival in patients with newly diagnosed glioblastoma, as has concomitant radiochemotherapy with temozolomide. A combination of carmustine wafers with the Stupp treatment regimen has only been investigated in retrospective studies.
Glioblastoma multiforme (GBM) is the most common primary malignant adult brain tumor and is associated with poor survival. Recently, stem-like cell populations have been identified in numerous malignancies including GBM. To identify genes whose expression is changed with differentiation, we compared transcript profiles from a GBM oncosphere line before and after differentiation. Bioinformatic analysis of the gene expression profiles identified podocalyxin-like protein (PODXL), a protein highly expressed in human embryonic stem cells, as a potential marker of undifferentiated GBM stem-like cells. The loss of PODXL expression upon differentiation of GBM stem-like cell lines was confirmed by quantitative real-time PCR and flow cytometry. Analytical flow cytometry of numerous GBM oncosphere lines demonstrated PODXL expression in all lines examined. Knockdown studies and flow cytometric cell sorting experiments demonstrated that PODXL is involved in GBM stem-like cell proliferation and oncosphere formation. Compared to PODXL-negative cells, PODXL-positive cells had increased expression of the progenitor/stem cell markers Musashi1, SOX2, and BMI1. Finally, PODXL expression directly correlated with increasing glioma grade and was a marker for poor outcome in patients with GBM. In summary, we have demonstrated that PODXL is expressed in GBM stem-like cells and is involved in cell proliferation and oncosphere formation. Moreover, high PODXL expression correlates with increasing glioma grade and decreased overall survival in patients with GBM.
Despite improvements in brain surgery and radiotherapy, patients with brain metastases (BM) from breast cancer still have a poor prognosis. The aim of the present study is to evaluate the outcome of a multimodal therapeutic strategy in an unselected cohort of patients.
Although CD90 has been identified as a marker for various kinds of stem cells including liver cancer stem cells (CSCs) that are responsible for tumorigenesis, the potential role of CD90 as a marker for CSCs in gliomas has not been characterized. To address the issue, we investigated the expression of CD90 in tissue microarrays containing 15 glioblastoma multiformes (GBMs), 19 WHO grade III astrocytomas, 13 WHO grade II astrocytomas, 3 WHO grade I astrocytomas and 8 normal brain tissues. Immunohistochemical analysis showed that CD90 was expressed at a medium to high level in all tested high-grade gliomas (grade III and GBM) whereas it was barely detectable in low-grade gliomas (grade I and grade II) and normal brains. Double immunofluorescence staining for CD90 and CD133 in GBM tissues revealed that CD133(+) CSCs are a subpopulation of CD90(+) cells in GBMs in vivo. Flow cytometry analysis of the expression of CD90 and CD133 in GBM-derived stem-like neurospheres further confirmed the conclusion in vitro. The expression levels of both CD90 and CD133 were reduced along with the loss of stem cells after differentiation. Furthermore, the limiting dilution assay demonstrated that the sphere formation ability was comparable between the CD90(+)/CD133(+) and the CD90(+)/CD133(-) populations of GBM neurospheres, which is much higher than that of the CD90(-)/CD133(-) population. We also performed double staining for CD90 and a vascular endothelial cell marker CD31 in tissue microarrays which revealed that the CD90(+) cells were clustered around the tumor vasculatures in high-grade glioma tissues. These findings suggest that CD90 is not only a potential prognostic marker for high-grade gliomas but also a marker for CSCs within gliomas, and it resides within endothelial niche and may also play a critical role in the generation of tumor vasculatures via differentiation into endothelial cells.
Lesions in the ventrolateral region of the dominant frontal lobe have been historically associated with aphasia. Recent imaging results suggest that frontal language regions extend beyond classically defined Brocas area to include the ventral precentral gyrus (VPCG) and the arcuate fasciculus (AF). Frontal gliomas offer a unique opportunity to identify structures that are essential for speech production. The aim of this prospective study was to investigate the correlation between language deficits and lesion location in patients with gliomas.
One important function of endothelial cells in glioblastoma multiforme (GBM) is to create a niche that helps promote self-renewal of cancer stem-like cells (CSLC). However, the underlying molecular mechanism for this endothelial function is not known. Since activation of NOTCH signaling has been found to be required for propagation of GBM CSLCs, we hypothesized that the GBM endothelium may provide the source of NOTCH ligands. Here, we report a corroboration of this concept with a demonstration that NOTCH ligands are expressed in endothelial cells adjacent to NESTIN and NOTCH receptor-positive cancer cells in primary GBMs. Coculturing human brain microvascular endothelial cells (hBMEC) or NOTCH ligand with GBM neurospheres promoted GBM cell growth and increased CSLC self-renewal. Notably, RNAi-mediated knockdown of NOTCH ligands in hBMECs abrogated their ability to induce CSLC self-renewal and GBM tumor growth, both in vitro and in vivo. Thus, our findings establish that NOTCH activation in GBM CSLCs is driven by juxtacrine signaling between tumor cells and their surrounding endothelial cells in the tumor microenvironment, suggesting that targeting both CSLCs and their niche may provide a novel strategy to deplete CSLCs and improve GBM treatment.
Cancer stem cells are responsible for tumor formation through self-renewal and differentiation into multiple cell types and thus represent a new therapeutic target for tumors. Glycoproteins play a critical role in determining the fates of stem cells such as self-renewal, proliferation, and differentiation. Here we applied a multilectin affinity chromatography and quantitative glycoproteomics approach to analyze alterations of glycoproteins relevant to the differentiation of a glioblastoma-derived stem cell line HSR-GBM1. Three lectins including concanavalin A (Con A), wheat germ agglutinin (WGA), and peanut agglutinin (PNA) were used to capture glycoproteins, followed by LC-MS/MS analysis. A total of 73 and 79 high-confidence (FDR < 0.01) glycoproteins were identified from the undifferentiated and differentiated cells, respectively. Label-free quantitation resulted in the discovery of 18 differentially expressed glycoproteins, wherein 9 proteins are localized in the lysosome. All of these lysosomal glycoproteins were up-regulated after differentiation, where their principal function was hydrolysis of glycosyl residues. Protein-protein interaction and functional analyses revealed the active involvement of lysosomes during the process of glioblastoma stem cell differentiation. This work provides glycoprotein markers to characterize differentiation status of glioblastoma stem cells that may be useful in stem-cell therapy of glioblastoma.
Despite progress in the treatment of glioblastoma, more than 95% of patients suffering from this disease still die within 2 years. Recent findings support the belief that cancer stem-like cells are responsible for tumor formation and ongoing growth. Here a method combining lectin microarray and LC-MS/MS was used to discover the cell surface glycoprotein markers of a glioblastoma-derived stem-like cell line. Lectin microarray analysis of cell surface glycans showed that two galactose-specific lectins Trichosanthes kirilowii agglutinin (TKA) and Peanut agglutinin (PNA) could distinguish the stem-like glioblastoma neurosphere culture from a traditional adherent glioblastoma cell line. Agarose-bound TKA and PNA were used to capture the glycoproteins from the two cell cultures, which were analyzed by LC-MS/MS. The glycoproteins were quantified by spectral counting, resulting in the identification of 12 and 11 potential glycoprotein markers from the TKA and PNA captured fractions respectively. Almost all of these proteins were membrane proteins. Differential expression was verified by Western blotting analysis of 6 interesting proteins, including the up-regulated Receptor-type tyrosine-protein phosphatase zeta, Tenascin-C, Chondroitin sulfate proteoglycan NG2, Podocalyxin-like protein 1 and CD90, and the down-regulated CD44. An improved understanding of these proteins may be important for earlier diagnosis and better therapeutic targeting of glioblastoma.
Brain metastases occur in about 25% of patients who die of cancer. The most common sources of brain metastases in adults are lung, breast, kidney, colorectal cancer and melanoma. The chemokine/receptor system CXCL12/CXCR4 plays a key role in multiple biological functions; among these, homing of neoplastic cells from the primary site to the target and metastasis progression. Recently, an alternative CXCL12 receptor CXCR7 has been discovered. The aim of our study was to investigate the expression of CXCL12 and its receptors CXCR4 and CXCR7 by immunohistochemistry in 56 patients with metastatic brain disease from different non-CNS primary tumors and evaluate their prognostic relevance as well as that of other patient/treatment-related features on patient survival. CXCL12 showed an expression in tumor cells and in tumor vessels; CXCR7 was expressed by tumor and endothelial cells (both within the tumor and in the adjacent brain tissue), while CXCR4 showed a positivity in all samples with a nuclear pattern. Among the investigated immunohistochemical parameters, only CXCL12 expression in tumor endothelial cells showed a statistically significant correlation with shorter survival (p = 0.04 log-rank), perhaps identifying more aggressive tumors. Thus, this is the first study evaluating at the same time the expression of CXCL12 and its two receptors in a cohort of brain metastases.
Neurospheres derived from glioblastoma (GBM) and other solid malignancies contain neoplastic stem-like cells that efficiently propagate tumor growth and resist cytotoxic therapeutics. The primary objective of this study was to use histone-modifying agents to elucidate mechanisms by which the phenotype and tumor-promoting capacity of GBM-derived neoplastic stem-like cells are regulated. Using established GBM-derived neurosphere lines and low passage primary GBM-derived neurospheres, we show that histone deacetylase (HDAC) inhibitors inhibit growth, induce differentiation, and induce apoptosis of neoplastic neurosphere cells. A specific gene product induced by HDAC inhibition, Delta/Notch-like epidermal growth factor-related receptor (DNER), inhibited the growth of GBM-derived neurospheres, induced their differentiation in vivo and in vitro, and inhibited their engraftment and growth as tumor xenografts. The differentiating and tumor suppressive effects of DNER, a noncanonical Notch ligand, contrast with the previously established tumor-promoting effects of canonical Notch signaling in brain cancer stem-like cells. Our findings are the first to implicate noncanonical Notch signaling in the regulation of neoplastic stem-like cells and suggest novel neoplastic stem cell targeting treatment strategies for GBM and potentially other solid malignancies.
With the advent of the cancer stem cell hypothesis, the field of cancer research has experienced a revolution in how we think of and approach cancer. The discovery of "brain tumor stem cells" has offered an explanation for several long-standing conundrums on why brain tumors behave the way they do to treatment. Despite the great amount of research that has been done in order to understand the molecular aspects of malignant gliomas, the prognosis of brain tumors remains dismal. The slow progress in extending the survival of patients with malignant CNS neoplasms is very likely due to poor understanding of the cell of origin in these tumors. This review article discusses the progress in our understanding of brain tumor stem cells as the cell of origin in brain cancers. We review the different proposed mechanisms of how brain tumor stem cells may originate, the intracellular pathways disrupted in the pathogenesis of BTSCs, the molecular markers used to identify BTSCs, the molecular mechanisms of cancer initiation and progression, and finally the clinical implications of this research.
The prognosis of patients with glioblastoma is very poor with a mean survival of 10-12 months. Currently available treatment options are multimodal, which include surgery, radiotherapy, and chemotherapy. However, these have been shown to improve survival only marginally in glioblastoma multiforme (GBM) patients. Methylated methylguanine methyltransferase (MGMT) promoter is correlated with improved progression-free and overall survival in patients treated with alkylating agents. Strategies to overcome MGMT-mediated chemoresistance are being actively investigated.
Preoperative brain mapping is vital to improve the outcome of patients with tumors located in eloquent areas. While functional magnetic resonance imaging (fMRI) remains the most commonly used preoperative mapping technique, navigated transcranial magnetic stimulation (nTMS) has recently been proposed as a new preoperative method for the clinical and surgical management of such patients. This study aims at evaluating the impact of nTMS as a routine examination and its ultimate contribution to patient outcome. We performed a preliminary prospective study on eight patients harboring a cerebral lesion in eloquent motor areas. Each patient underwent preoperative cortical brain mapping via both fMRI and nTMS; then, we assessed the reliability of both methods by comparing them with intraoperative mapping by direct cortical stimulation (DCS). This study suggests that nTMS was more accurate than fMRI in detecting the true cortical motor area when compared with DCS data, with a mean of deviation ± confidence interval (CI) of 8.47 ± 4.6 mm between nTMS and DCS and of 12.9 ± 5.7 mm between fMRI and DCS (p < 0.05). The results indicated that within the limits of our statistical sample, nTMS was found to be a useful, reliable, and non-invasive option for preoperative planning as well as for the identification of the motor strip; in addition, it usually has short processing times and is very well tolerated by patients, thereby increasing their compliance and possibly improving surgical outcome.
In human glioblastomas (hGBMs), tumor-propagating cells with stem-like characteristics (TPCs) represent a key therapeutic target. We found that the EphA2 receptor tyrosine kinase is overexpressed in hGBM TPCs. Cytofluorimetric sorting into EphA2(High) and EphA2(Low) populations demonstrated that EphA2 expression correlates with the size and tumor-propagating ability of the TPC pool in hGBMs. Both ephrinA1-Fc, which caused EphA2 downregulation in TPCs, and siRNA-mediated knockdown of EPHA2 expression suppressed TPCs self-renewal ex vivo and intracranial tumorigenicity, pointing to EphA2 downregulation as a causal event in the loss of TPCs tumorigenicity. Infusion of ephrinA1-Fc into intracranial xenografts elicited strong tumor-suppressing effects, suggestive of therapeutic applications.
Incident reporting systems are universally recognized as important tools for quality improvement in all complex adaptive systems, including the operating room. Nevertheless, introducing a safety culture among neurosurgeons is a slow process, and few studies are available in the literature regarding the implementation of an incident reporting system within a neurosurgical department. The authors describe the institution of an aviation model of incident reporting and investigation in neurosurgery, focusing on the method they have used and presenting some preliminary results.
High-grade gliomas are highly vascularized tumors, in which the amount of new blood vessels is closely related with the degree of malignancy. The role of endothelial progenitor cells (EPCs) in the neoangiogenesis of gliomas and the effects of post-surgical therapies (i.e., radiotherapy (RT) and chemotherapy) have not yet been fully elucidated. The aim of the present study was to evaluate the effect of surgery and post-surgical treatment on the levels of circulating EPCs in glioma patients and their correlation with vascular endothelial growth factor (VEGF). In this study, we assessed by flow cytometry the number of EPCs in the peripheral blood of 78 high-grade glioma patients (both untreated and treated with RT and chemotherapy) and 34 age- and sex-matched healthy controls. EPCs were markedly decreased in all treated glioma patients as compared to untreated ones. VEGF levels were significantly higher in patients as compared to controls, and surgery, but not chemotherapy, significantly decreased VEGF concentrations. We found no relationship between VEGF plasma levels and EPCs. In conclusion, the reliability of EPCs as a biomarker for monitoring angiogenesis in glioma patients needs further studies of correlations of this parameter with other markers of tumor-related vasculature.
Tumours close to cerebral cortices involved in motor and language functions represent a major challenge for neurosurgeons. Intraoperative neurophysiologic monitoring is useful to gain insight into the anatomy of and the relationship between pathological and normal tissues. In this study we report on the experience of electrocortical stimulation in the surgery of tumours adjacent to the motor cortex in 50 patients under general anaesthesia (26 under propofol, 24 under sevoflurane), and on EMG responses from contralateral muscles. In 18 patients stimulation evoked seizures, which were controlled only with antiepileptic drugs (36%). No difference was found in the incidence of intra-operative seizures between the patients with (10 out of 27) or without (8 out of 23) pre-operative epilepsy (p = 0.8685). The majority of the patients (13 out of 18) with intraoperative seizures were under sevoflurane (p = 0.01) and there was a statistically significant difference in the mean electrical intensity used between the two groups, sevoflurane and propofol, respectively 5.3 ± 1.3 mA and 3.6 ± 2 mA (p = 0.03). Regarding pre-operative anti-epileptic drugs, the use of levitiracetam was associated with a high incidence of intraoperative seizure (5 out of 6 patients). 4 patients developed new, unwanted, permanent neurological deficits, of which 2 had intraoperative seizures controlled only with antiepileptic drugs. Electrocortical stimulation is a powerful tool to understand the functional organization of patients eloquent areas. Intraoperative epileptic seizures may represent an unwanted complication preventing further stimulation and possibly worsening neurological results. The choice of anaesthetics according to the patients characteristics, pre-op symptoms and medical therapy is pivotal.
Spinal cord herniation is a rare entity that has been recognized and described with increasing frequency in the past few years. It is characterized by herniation of the spinal cord through an anterior dural defect. In their study of 12 cases, the authors attempt to develop management and treatment guidelines for patients suffering from this condition.
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