'The Reports of My Death Are Greatly Exaggerated'-Evaluating the Effect of Necrosis on MGMT Promoter Methylation Testing in High-Grade Glioma.

(1) Background: MGMT (O-6-methylguanine-DNA methyltransferase) promoter methylation remains an important predictive biomarker in high-grade gliomas (HGGs). The influence of necrosis on the fidelity of MGMT promoter (MGMTp) hypermethylation testing is currently unknown. Therefore, our study aims to evaluate the effect of varying degrees of necrosis on MGMTp status, as determined by pyrosequencing, in a series of primary and recurrent HGGs; (2) Methods: Within each case, the most viable blocks (assigned as 'true' MGMTp status) and the most necrotic block were determined by histopathology review. MGMTp status was determined by pyrosequencing. Comparisons of MGMTp status were made between the most viable and most necrotic blocks. (3) Results: 163 samples from 64 patients with HGGs were analyzed. MGMTp status was maintained in 84.6% of primary and 78.3% of recurrent HGGs between the most viable and necrotic blocks. A threshold of ≥60% tumor cellularity was established at which MGMTp status was unaltered, irrespective of the degree of necrosis. (4) Conclusions: MGMTp methylation status, as determined by pyrosequencing, does not appear to be influenced by necrosis in the majority of cases at a cellularity of at least 60%. Further investigation into the role of intratumoral heterogeneity on MGMTp status will increase our understanding of this predictive marker.

Anterior To Psoas lumbar and lumbosacral combined with posterior reconstruction in Adult Spinal Deformity: A bicentric European study.

Introduction: Lateral lumbar fusion via the trans-psoas approach is popular in adult deformity reconstruction. To overcome its limitations (neurological damage to the plexus and lack of applicability to the lumbosacral junction), a modified anterior-to-psoas (ATP) approach has been described and used. Research question: To investigate the results of ATP lumbar and lumbosacral fusion, in a cohort of adult patients treated with combined anteroposterior approaches for adult spinal deformity (ASD). Materials and methods: ASD patients surgically treated at two tertiary spinal centres were followed up. Forty patients were treated with combined ATP and posterior surgery: 11 with open lumbar lateral interbody-fusions (lumbotomy LLIF) and 29 with lesser invasive oblique lateral interbody-fusions (OLIF). Preoperative demographics, aetiology, clinical characteristics, and spinopelvic parameters were comparable between the two cohorts. Results: At a minimum 2-year follow-up, both cohorts showed significant improvements in patient reported outcome measures (PROMs), i.e. Visual Analogue Scale and Core Outcome Measures Index, as well as radiological parameters, with no significant differences based on the type of surgical approach. No significant differences were found in major (P â€‹= â€‹0.457) and minor (P â€‹= â€‹0.071) complications between the two cohorts. Discusson and conclusion: Anterolateral lumbar interbody fusions, whether performed via a direct or oblique approach, proved to be safe and effective adjuvants to posterior surgery in patients with ASD. No significant complication differences were noted between techniques. In addition, the anterior-to-psoas approaches limited the risks of post-operative pseudoarthrosis by providing solid anterior support to lumbar and lumbosacral segments, demonstrating a positive impact on PROMS.

Cellular Invasion Assay for the Real-Time Tracking of Individual Cells in Spheroid or Tumor-like Mimics.

Cellular invasion is the gateway to metastasis, with cells moving from a primary tumor into neighboring regions of healthy tissue. Invasion assays provide a tractable experimental platform to quantitatively assess cellular movement in the presence of potential chemokines or inhibitors. Many such assays involve cellular movement from high cell densities to cell-free regions. To improve the physiological relevance of such assays, we developed an assay format to track cellular movement throughout a uniform density of cells. This assay format imparts diffusion-dominated environments along the channel, resulting in oxygen and nutrient gradients found in spheroids or poorly vascularized tumors. By incorporating oxygen- and pH-sensing films, we quantified spatial and temporal changes in the extracellular environment while simultaneously tracking the movement of a subset of cells engineered to express fluorescent proteins constitutively. Our results show the successful invasion into neighboring tissues likely arises from a small population with a highly invasive phenotype. These highly invasive cells continued to move throughout the 48 h experiment, suggesting they have stem-like or persister properties. Surprisingly, the distance these persister cells invaded was unaffected by the density of cells in the channel or the presence or absence of an oxygen gradient. While these datasets cannot determine if the invasive cells are inherent to the population or if diffusion-dominated environments promote them, they highlight the need for further study.

Implications of Concurrent IDH1 and IDH2 Mutations on Survival in Glioma-A Case Report and Systematic Review.

Both IDH1 (isocitrate dehydrogenase 1) and IDH2 (isocitrate dehydrogenase 2) mutations play a vital role in the development of gliomas through disruption of normal cellular metabolic processes. Here we describe a case of a patient with an IDH-mutant astrocytoma, in which both IDH1 and IDH2 mutations were detected within the same tumour. The patient remains disease-free, nine and a half years after her initial diagnosis. Interrogation of cancer genomic databases and a systematic review was undertaken, demonstrating the rarity of the co-occurrence of IDH1 and IDH2 mutations in a variety of cancer types, and in glioma specifically. Due to the favourable outcome observed in this patient, the potential effect of concurrent IDH1 and IDH2 mutations on survival was also investigated.

An Open-Source AI Framework for the Analysis of Single Cells in Whole-Slide Images with a Note on CD276 in Glioblastoma.

Routine examination of entire histological slides at cellular resolution poses a significant if not insurmountable challenge to human observers. However, high-resolution data such as the cellular distribution of proteins in tissues, e.g., those obtained following immunochemical staining, are highly desirable. Our present study extends the applicability of the PathoFusion framework to the cellular level. We illustrate our approach using the detection of CD276 immunoreactive cells in glioblastoma as an example. Following automatic identification by means of PathoFusion's bifocal convolutional neural network (BCNN) model, individual cells are automatically profiled and counted. Only discriminable cells selected through data filtering and thresholding were segmented for cell-level analysis. Subsequently, we converted the detection signals into the corresponding heatmaps visualizing the distribution of the detected cells in entire whole-slide images of adjacent H&E-stained sections using the Discrete Wavelet Transform (DWT). Our results demonstrate that PathoFusion is capable of autonomously detecting and counting individual immunochemically labelled cells with a high prediction performance of 0.992 AUC and 97.7% accuracy. The data can be used for whole-slide cross-modality analyses, e.g., relationships between immunochemical signals and anaplastic histological features. PathoFusion has the potential to be applied to additional problems that seek to correlate heterogeneous data streams and to serve as a clinically applicable, weakly supervised system for histological image analyses in (neuro)pathology.

Paradoxical Association Between Relative Cerebral Blood Volume Dynamics Following Chemoradiation and Increased Progression-Free Survival in Newly Diagnosed IDH Wild-Type MGMT Promoter Methylated Glioblastoma With Measurable Disease.

Background and Purpose: While relative cerebral blood volume (rCBV) may be diagnostic and prognostic for survival in glioblastoma (GBM), changes in rCBV during chemoradiation in the subset of newly diagnosed GBM with subtotal resection and the impact of MGMT promoter methylation status on survival have not been explored. This study aimed to investigate the association between rCBV response, MGMT methylation status, and progression-free (PFS) and overall survival (OS) in newly diagnosed GBM with measurable enhancing lesions. Methods: 1,153 newly diagnosed IDH wild-type GBM patients were screened and 53 patients (4.6%) had measurable post-surgical tumor (>1mL). rCBV was measured before and after patients underwent chemoradiation. Patients with a decrease in rCBV >10% were considered rCBV Responders, while patients with an increase or a decrease in rCBV <10% were considered rCBV Non-Responders. The association between change in enhancing tumor volume, change in rCBV, MGMT promotor methylation status, and PFS or OS were explored. Results: A decrease in tumor volume following chemoradiation trended towards longer OS (p=0.12; median OS=26.8 vs. 16.3 months). Paradoxically, rCBV Non-Responders had a significantly improved PFS compared to Responders (p=0.047; median PFS=9.6 vs. 7.2 months). MGMT methylated rCBV Non-Responders exhibited a significantly longer PFS compared to MGMT unmethylated rCBV Non-Responders (p<0.001; median PFS=0.5 vs. 7.1 months), and MGMT methylated rCBV Non-Responders trended towards longer PFS compared to methylated rCBV Responders (p=0.089; median PFS=20.5 vs. 13.8 months). Conclusions: This preliminary report demonstrates that in newly diagnosed IDH wild-type GBM with measurable enhancing disease after surgery (5% of patients), an enigmatic non-response in rCBV was associated with longer PFS, particularly in MGMT methylated patients.

Association between Delay to Radical Prostatectomy and Clinically Meaningful Outcomes among Patients with Intermediate and High-Risk Localized Prostate Cancer.

PURPOSE: There are limited data regarding the effect of treatment delays on important long-term outcomes among men with intermediate/high-risk prostate cancer (PC). MATERIALS AND METHODS: We identified 3,962 men with intermediate/high-risk disease from the SEARCH cohort treated with radical prostatectomy (RP) from 1988 to 2018. Cox proportional hazard models assessed the association between time from biopsy to RP (up to 1 year) and time to castration-resistant PC (CRPC), metastasis and all-cause mortality. Interaction terms were used to test for effect modification by risk group. RESULTS: Of the 3,962 men, 167 developed CRPC, 248 developed metastases and 884 died after a median followup of 85 months. Longer delays between biopsy and RP were associated with a decreased risk of CRPC (adjusted HR=0.88, 95% CI: 0.80-0.98, p=0.02), independent of D'Amico risk group (interaction p >0.05). In men with intermediate and high-risk disease, we found no statistically significant association between length of time to RP and risk of developing metastases (p=0.5 and 0.9, respectively) or all-cause mortality (p=0.1 and 0.1, respectively). CONCLUSIONS: Among men with intermediate and high-risk PC, we found no statistically significant increased risk of adverse long-term outcomes, including CRPC, metastasis and death, for men who had treatment delays up to 1 year following PC diagnosis.

PathoFusion: An Open-Source AI Framework for Recognition of Pathomorphological Features and Mapping of Immunohistochemical Data.

We have developed a platform, termed PathoFusion, which is an integrated system for marking, training, and recognition of pathological features in whole-slide tissue sections. The platform uses a bifocal convolutional neural network (BCNN) which is designed to simultaneously capture both index and contextual feature information from shorter and longer image tiles, respectively. This is analogous to how a microscopist in pathology works, identifying a cancerous morphological feature in the tissue context using first a narrow and then a wider focus, hence bifocal. Adjacent tissue sections obtained from glioblastoma cases were processed for hematoxylin and eosin (H&E) and immunohistochemical (CD276) staining. Image tiles cropped from the digitized images based on markings made by a consultant neuropathologist were used to train the BCNN. PathoFusion demonstrated its ability to recognize malignant neuropathological features autonomously and map immunohistochemical data simultaneously. Our experiments show that PathoFusion achieved areas under the curve (AUCs) of 0.985 ± 0.011 and 0.988 ± 0.001 in patch-level recognition of six typical pathomorphological features and detection of associated immunoreactivity, respectively. On this basis, the system further correlated CD276 immunoreactivity to abnormal tumor vasculature. Corresponding feature distributions and overlaps were visualized by heatmaps, permitting high-resolution qualitative as well as quantitative morphological analyses for entire histological slides. Recognition of more user-defined pathomorphological features can be added to the system and included in future tissue analyses. Integration of PathoFusion with the day-to-day service workflow of a (neuro)pathology department is a goal. The software code for PathoFusion is made publicly available.

Vertebral body cemented stents combined with posterior stabilization in the surgical treatment of metastatic spinal cord compression of the thoracolumbar spine.

BACKGROUND: Extensile interventions to provide anterior spinal column support in metastatic spinal cord compression (MSCC) surgery incur added morbidity in this surgically frail group of patients. We present our preliminary results of posterior spinal decompression and stabilization coupled with vertebral body cemented stents for anterior column support in MSCC. METHODS: Fourteen patients underwent posterior spinal decompression and pedicle screw construct along with vertebral body stenting (VBS) technique for reconstruction and augmentation of the vertebral body. The primary in all except one was solid organ malignancy and 10 patients (71%) were treatment naïve. The mean revised Tokuhashi score was 10.7 ± 2.7 and the mean spinal instability neoplastic score was 9.6 ± 1.9. All vertebral body lesions were purely lytic and were associated with a cortical defect in the posterior wall. RESULTS: A mean 5.3 ± 2.7 ml low-viscosity polymethyl methacrylate bone cement was injected within the stent at each compression level. No cement extrusion posteriorly was noted in any case from intraoperative fluoroscopy or postoperative radiographs. Five patients died at a mean 6.8 months (range 1-15 months), while the remaining patients have a mean survival of 18 months. Neither further revision surgical intervention nor any neurological deterioration was noted in any patient, who all continued to be ambulatory. The mean postoperative Core Outcome Measures Index score for 11 patients was 4.03 (standard deviation 3.11, 95% confidence interval (1.93-6.12). CONCLUSION: In lytic vertebral body lesions with posterior wall erosions, cemented VBS technique adds to the surgical armamentarium in MSCC surgery showing promising early results without added complications.

A Comprehensive Proteomic SWATH-MS Workflow for Profiling Blood Extracellular Vesicles: A New Avenue for Glioma Tumour Surveillance.

Improving outcomes for diffuse glioma patients requires methods that can accurately and sensitively monitor tumour activity and treatment response. Extracellular vesicles (EV) are membranous nanoparticles that can traverse the blood-brain-barrier, carrying oncogenic molecules into the circulation. Measuring clinically relevant glioma biomarkers cargoed in circulating EVs could revolutionise how glioma patients are managed. Despite their suitability for biomarker discovery, the co-isolation of highly abundant complex blood proteins has hindered comprehensive proteomic studies of circulating-EVs. Plasma-EVs isolated from pre-operative glioma grade II-IV patients (n = 41) and controls (n = 11) were sequenced by Sequential window acquisition of all theoretical fragment ion spectra mass spectrometry (SWATH-MS) and data extraction was performed by aligning against a custom 8662-protein library. Overall, 4054 proteins were measured in plasma-EVs. Differentially expressed proteins and putative circulating-EV markers were identified (adj. p-value < 0.05), including those reported in previous in-vitro and ex-vivo glioma-EV studies. Principal component analysis showed that plasma-EV protein profiles clustered according to glioma histological-subtype and grade, and plasma-EVs resampled from patients with recurrent tumour progression grouped with more aggressive glioma samples. The extensive plasma-EV proteome profiles achieved here highlight the potential for SWATH-MS to define circulating-EV biomarkers for objective blood-based measurements of glioma activity that could serve as ideal surrogate endpoints to assess tumour progression and allow more dynamic, patient-centred treatment protocols.

Deep Sequencing of Small RNAs from Neurosurgical Extracellular Vesicles Substantiates miR-486-3p as a Circulating Biomarker that Distinguishes Glioblastoma from Lower-Grade Astrocytoma Patients.

Extracellular vesicles (EVs) play key roles in glioblastoma (GBM; astrocytoma grade IV) biology and are novel sources of biomarkers. EVs released from GBM tumors can cross the blood-brain-barrier into the periphery carrying GBM molecules, including small non-coding RNA (sncRNA). Biomarkers cargoed in circulating EVs have shown great promise for assessing the molecular state of brain tumors in situ. Neurosurgical aspirate fluids captured during tumor resections are a rich source of GBM-EVs isolated directly from tumor microenvironments. Using density gradient ultracentrifugation, EVs were purified from cavitron ultrasonic surgical aspirate (CUSA) washings from GBM (n = 12) and astrocytoma II-III (GII-III, n = 5) surgeries. The sncRNA contents of surgically captured EVs were profiled using the Illumina® NextSeqTM 500 NGS System. Differential expression analysis identified 27 miRNA and 10 piRNA species in GBM relative to GII-III CUSA-EVs. Resolved CUSA-EV sncRNAs could discriminate serum-EV sncRNA profiles from GBM and GII-III patients and healthy controls and 14 miRNAs (including miR-486-3p and miR-106b-3p) and cancer-associated piRNAs (piR_016658, _016659, _020829 and _204090) were also significantly expressed in serum-EVs. Circulating EV markers that correlate with histological, neuroradiographic and clinical parameters will provide objective measures of tumor activity and improve the accuracy of GBM tumor surveillance.

High-Throughput Label-Free Isolation of Heterogeneous Circulating Tumor Cells and CTC Clusters from Non-Small-Cell Lung Cancer Patients.

(1) Background: Circulating tumor cell (CTC) clusters are emerging as clinically significant harbingers of metastases in solid organ cancers. Prior to engaging these CTC clusters in animal models of metastases, it is imperative for technology to identify them with high sensitivity. These clusters often present heterogeneous surface markers and current methods for isolation of clusters may fall short. (2) Methods: We applied an inertial microfluidic Labyrinth device for high-throughput, biomarker-independent, size-based isolation of CTCs/CTC clusters from patients with metastatic non-small-cell lung cancer (NSCLC). (3) Results: Using Labyrinth, CTCs (PanCK+/DAPI+/CD45-) were isolated from patients (n = 25). Heterogeneous CTC populations, including CTCs expressing epithelial (EpCAM), mesenchymal (Vimentin) or both markers were detected. CTCs were isolated from 100% of patients (417 ± 1023 CTCs/mL). EpCAM- CTCs were significantly greater than EpCAM+ CTCs. Cell clusters of ≥2 CTCs were observed in 96% of patients-of which, 75% were EpCAM-. CTCs revealed identical genetic aberrations as the primary tumor for RET, ROS1, and ALK genes using fluorescence in situ hybridization (FISH) analysis. (4) Conclusions: The Labyrinth device recovered heterogeneous CTCs in 100% and CTC clusters in 96% of patients with metastatic NSCLC. The majority of recovered CTCs/clusters were EpCAM-, suggesting that these would have been missed using traditional antibody-based capture methods.

Comparison of clinical outcomes in anterior cervical discectomy versus foraminotomy for brachialgia.

AIM: The choice between anterior cervical discectomy & fusion (ACD) or posterior cervical foraminotomy (PCF) for the treatment of cervical brachialgia is controversial. This study aimes to compare clinical outcomes between these two operative inteventions for brachialgia. METHODS: Retrospective review of prospectively collected data was performed. Patients receiving a primary ACD or PCF to treat brachialgia, in a single tertiary neurosurgical unit were included. Surgical details, and patient reported outcomes (COMI-Neck questionnaire) were extracted from a prospectively maintained spinal procedure database. Minimum clinically important difference (MCID) was defined as a change in COMI score of -2 at 12 months. The student t-test, Chi-square test, and linear regression were used to compare groups. RESULTS: Between June 2011 ad February 2016 there were 634 ACD procedures (Median age 49; 321 Male), and 54 PCF procedures (Median age 50; 37 Male) perfomed for brachialgia. Age, ASA and pre-operative COMI were similar between the groups (p > .05). Complete outcome data was recorded at twelve months in 312 ACD and 36 PCF patients. Both ACD and PCF were associated with an improvement in COMI at 3 and 12 months (all p < .01). Mean change in COMI at 3 months was -2.38 for ACD, versus -2.31 for PCF (p = .88); at twelve months it was -2.94 for ACD, versus -2.67 for PCF (p = .55). MCID was seen in 59% of ACD cases, versus 58% of PCF cases at twelve months (p = .91). CONCLUSION: There was no significant difference between outcomes in the ACD and PCF groups. This is supportive of published literature. The proposed multicenter RCTs may inform further.

Extracellular Vesicles from Neurosurgical Aspirates Identifies Chaperonin Containing TCP1 Subunit 6A as a Potential Glioblastoma Biomarker with Prognostic Significance.

Glioblastoma, WHO-grade IV glioma, carries a dismal prognosis owing to its infiltrative growth and limited treatment options. Glioblastoma-derived extracellular vesicles (EVs; 30-1000 nm membranous particles) influence the microenvironment to mediate tumor aggressiveness and carry oncogenic cargo across the blood-brain barrier into the circulation. As such, EVs are biomarker reservoirs with enormous potential for assessing glioblastoma tumors in situ. Neurosurgical aspirates are rich sources of EVs, isolated directly from glioma microenvironments. EV proteomes enriched from glioblastoma (n = 15) and glioma grade II-III (n = 7) aspirates are compared and 298 differentially-abundant proteins (p-value < 0.00496) are identified using quantitative LC-MS/MS. Along with previously reported glioblastoma-associated biomarkers, levels of all eight subunits of the key molecular chaperone, T-complex protein 1 Ring complex (TRiC), are higher in glioblastoma-EVs, including CCT2, CCT3, CCT5, CCT6A, CCT7, and TCP1 (p < 0.00496). Analogous increases in TRiC transcript levels and DNA copy numbers are detected in silico; CCT6A has the greatest induction of expression and amplification in glioblastoma and shows a negative association with survival (p = 0.006). CCT6A is co-localized with EGFR at 7p11.2, with a strong tendency for co-amplification (p < 0.001). Immunohistochemistry corroborates the CCT6A proteomics measurements and indicated a potential link between EGFR and CCT6A tissue expression. Putative EV-biomarkers described here should be further assessed in peripheral blood.

Deep sequencing of circulating exosomal microRNA allows non-invasive glioblastoma diagnosis.

Exosomes are nano-sized extracellular vesicles released by many cells that contain molecules characteristic of their cell of origin, including microRNA. Exosomes released by glioblastoma cross the blood-brain barrier into the peripheral circulation and carry molecular cargo distinct to that of "free-circulating" miRNA. In this pilot study, serum exosomal microRNAs were isolated from glioblastoma (n = 12) patients and analyzed using unbiased deep sequencing. Results were compared to sera from age- and gender-matched healthy controls and to grade II-III (n = 10) glioma patients. Significant differentially expressed microRNAs were identified, and the predictive power of individual and subsets of microRNAs were tested using univariate and multivariate analyses. Additional sera from glioblastoma patients (n = 4) and independent sets of healthy (n = 9) and non-glioma (n = 10) controls were used to further test the specificity and predictive power of this unique exosomal microRNA signature. Twenty-six microRNAs were differentially expressed in serum exosomes from glioblastoma patients relative to healthy controls. Random forest modeling and data partitioning selected seven miRNAs (miR-182-5p, miR-328-3p, miR-339-5p, miR-340-5p, miR-485-3p, miR-486-5p, and miR-543) as the most stable for classifying glioblastoma. Strikingly, within this model, six iterations of these miRNA classifiers could distinguish glioblastoma patients from controls with perfect accuracy. The seven miRNA panel was able to correctly classify all specimens in validation cohorts (n = 23). Also identified were 23 dysregulated miRNAs in IDHMUT gliomas, a partially overlapping yet distinct signature of lower-grade glioma. Serum exosomal miRNA signatures can accurately diagnose glioblastoma preoperatively. miRNA signatures identified are distinct from previously reported "free-circulating" miRNA studies in GBM patients and appear to be superior.

Regulator of G protein signaling 20 enhances cancer cell aggregation, migration, invasion and adhesion.

Several RGS (regulator of G protein signaling) proteins are known to be upregulated in a variety of tumors but their roles in modulating tumorigenesis remain undefined. Since the expression of RGS20 is elevated in metastatic melanoma and breast tumors, we examined the effects of RGS20 overexpression and knockdown on the cell mobility and adhesive properties of different human cancer cell lines, including cervical cancer HeLa, breast adenocarcinoma MDA-MB-231, and non-small cell lung carcinoma H1299 and A549 cells. Expression of RGS20 enhanced cell aggregation, migration, invasion and adhesion as determined by hanging drop aggregation, wound healing, transwell chamber migration and invasion assays. Conversely, shRNA-mediated knockdown of endogenous RGS20 impaired these responses. In addition, RGS20 elevated the expression of vimentin (a mesenchymal cell marker) but down-regulated the expression of E-cadherin, two indicators commonly associated with metastasis. These results suggest that the expression of RGS20 may promote metastasis of tumor cells.

Surgical disconnection of the cortical venous reflux for high-grade intracranial dural arteriovenous fistulas.

OBJECTIVES: To assess the clinical outcome, complications, and angiographic outcomes after surgical disconnection of intracranial dural arteriovenous fistulas (DAVFs). METHODS: Analysis of prospectively collected data, including clinical presentation, preoperative angiographic findings, postoperative complications, clinical, and angiographic outcomes. RESULTS: Between January 2002 and January 2012, 25 patients underwent surgery for DAVFs. The anatomical locations included tentorial (8), ethmoidal (8), foramen magnum (5), middle fossa (2), torcular (1), and parafalcine (1). All had cortical venous reflux (CVR) and all were treated with craniotomy and disconnection of CVR. Two patients required repeat surgery for residual CVR. One patient had a postoperative seizure. There were no other complications. All patients had complete disconnection of CVR confirmed by digital subtraction angiography. None of the patients have had hemorrhage or recurrence of CVR on follow-up. CONCLUSIONS: Surgical disconnection of CVR for high-grade intracranial DAVFs is highly effective and can be performed with very low complication rates. Where embolization cannot be performed safely, surgical disconnection (rather than stereotactic radiosurgery) is the treatment of choice for high grade DAVFs.