SARS-CoV2 evokes structural brain changes resulting in declined executive function

BACKGROUND

Several research has underlined the multi-system character of COVID-19. Though effects on the Central Nervous System are mainly discussed as disease-specific affections due to the virus' neurotropism, no comprehensive disease model of COVID-19 exists on a neurofunctional base by now. We aimed to investigate neuroplastic grey- and white matter changes related to COVID-19 and to link these changes to neurocognitive testings leading towards a multi-dimensional disease model.

METHODS

Groups of acutely ill COVID-19 patients (n = 16), recovered COVID-19 patients (n = 21) and healthy controls (n = 13) were prospectively included into this study. MR-imaging included T1-weighted sequences for analysis of grey matter using voxel-based morphometry and diffusion-weighted sequences to investigate white matter tracts using probabilistic tractography. Comprehensive neurocognitive testing for verbal and non-verbal domains was performed.

RESULTS

Alterations strongly focused on grey matter of the frontal-basal ganglia-thalamus network and temporal areas, as well as fiber tracts connecting these areas. In acute COVID-19 patients, a decline of grey matter volume was found with an accompanying diminution of white matter tracts. A decline in executive function and especially verbal fluency was found in acute patients, partially persisting in recovered.

CONCLUSION

Changes in gray matter volume and white matter tracts included mainly areas involved in networks of executive control and language. Deeper understanding of these alterations is necessary especially with respect to long-term impairments, often referred to as 'Post-COVID'.

Both coiling and clipping induce the time-dependent release of endogenous neuropeptide Y into serum

Background

The vaso- and psychoactive endogenous Neuropeptide Y (NPY) has repeatedly been shown to be excessively released after subarachnoid hemorrhage and in numerous psychiatric disorders. NPY is stored in sympathetic perivascular nerve fibers around the major cerebral arteries. This prospective study was designed to analyze the impact of microsurgical and endovascular manipulation of the cerebral vasculature versus cranio- and durotomy alone on the serum levels of NPY.

Methods

58 patients (drop-out n = 3; m:f = 26:29; mean age 52.0 ± 14.1 years) were prospectively enrolled. The vascular group underwent repair for unruptured intracranial aneurysms (UIA) of the anterior circulation [endovascular aneurysm occlusion (EV) n = 13; microsurgical clipping (MS) n = 17]; in the non-vascular group, 14 patients received microsurgical resection of a small-sized convexity meningioma (CM), and 11 patients with surgically treated degenerative lumbar spine disease (LD) served as control. Plasma was drawn (1) before treatment (t0), (2) periprocedurally (t1), (3) 6 h postprocedurally (t2), (4) 72 h postprocedurally (t3), and (5) at the 6-week follow-up (FU; t4) to determine the NPY levels via competitive enzyme immunoassay in duplicate serum samples. We statistically evaluated differences between groups by calculating one-way ANOVA and for changes along the time points using repeated measure ANOVA.

Results

Except for time point t0, the serum concentrations of NPY ranged significantly higher in the vascular than in the non-vascular group (p < 0.001), with a slight decrease in both vascular subgroups 6 h postprocedurally, followed by a gradual increase above baseline levels until FU. At t3, the EV subgroup showed significantly higher NPY levels (mean ± standard deviation) than the MS subgroup (0.569 ± 0.198 ng/mL vs. 0.415 ± 0.192 ng/mL, p = 0.0217). The highest NPY concentrations were measured in the EV subgroup at t1, t3, and t4, reaching a climax at FU (0.551 ± 0.304 ng/mL).

Conclusion

Our study reveals a first insight into the short-term dynamics of the serum levels of endogenous NPY in neurosurgical and endovascular procedures, respectively: Direct manipulation within but also next to the major cerebral arteries induces an excessive release of NPY into the serum. Our findings raise the interesting question of the potential capacity of NPY in modulating the psycho-behavioral outcome of neurovascular patients.

CXCR2-Blocking Has Context-Sensitive Effects on Rat Glioblastoma Cell Line Outgrowth (S635) in an Organotypic Rat Brain Slice Culture Depending on Microglia-Depletion (PLX5622) and Dexamethasone Treatment

In glioblastoma (GBM), the interplay of different immune cell subtypes, cytokines, and/or drugs shows high context-dependencies. Interrelations between the routinely applied dexamethasone (Dex) and microglia remain elusive. Here, we exploited rat organotypic brain slice co-cultures (OBSC) to examine the effects on a rat GBM cell line (S635) outgrowth resulting from the presence of Dex and pretreatment with the colony-stimulating factor receptor 1 (CSF1-R) inhibitor PLX5622: in native OBSC (without PLX5622-pretreatment), a diminished S635 spheroid outgrowth was observable, whereas Dex-treatment enhanced outgrowth in this condition compared to PLX5622-pretreated OBSC. Screening the supernatants of our model with a proteome profiler, we found that CXCL2 was differentially secreted in a Dex- and PLX5622-dependent fashion. To analyze causal interrelations, we interrupted the CXCL2/CXCR2-axis: in the native OBSC condition, CXCR2-blocking resulted in increased outgrowth, in combination with Dex, we found potentiated outgrowth. No effect was found in the PLX5622-pretreated. Our method allowed us to study the influence of three different factors-dexamethasone, PLX5622, and CXCL2-in a well-controlled, simplified, and straight-forward mechanistic manner, and at the same time in a more realistic ex vivo scenario compared to in vitro studies. In our model, we showed a GBM outgrowth enhancing synergism between CXCR2-blocking and Dex-treatment in the native condition, which was levelled by PLX5622-pretreatment.

Does the distance to the cancer center affect psycho-oncological care and emergency visits of patients with IDH wild-type gliomas? A retrospective study

Background

Malignant isocitrate dehydrogenase wild-type (IDHwt) gliomas impose a high symptomatic and psychological burden. Wide distances from patients' homes to cancer centers may affect the delivery of psycho-oncological care. Here, we investigated, in a large brain tumor center with a rural outreach, the initiation of psycho-oncological care depending on spatial distance and impact of psycho-oncological care on emergency visits.

Methods

Electronic patient charts, the regional tumor registry, and interviews with the primary care physicians were used to investigate clinical data, psycho-oncological care, and emergency unit visits. Interrelations with socio-demographic, clinical, and treatment aspects were investigated using univariable and multivariable binary logistic regression analysis and the Pearson's Chi-square test.

Results

Of 491, 229 adult patients of this retrospective cohort fulfilled the inclusion criteria for analysis. During the last three months of their lives, 48.9% received at least one psycho-oncological consultation, and 37.1% visited the emergency unit at least once. The distance from the cancer center did neither affect the initiation of psycho-oncological care nor the rate of emergency unit visits. Receiving psycho-oncological care did not correlate with the frequency of emergency unit visits in the last three months of life.

Conclusion

We conclude that the distance of IDHwt glioma patients' homes from their cancer center, even in a rural area, does not significantly influence the rate of psycho-oncological care.

Factors influencing the reliability of intraoperative testing in deep brain stimulation for Parkinson's disease

BACKGROUND

Several meta-analyses comparing the outcome of awake versus asleep deep brain stimulation procedures could not reveal significant differences concerning the postoperative improvement of motor symptoms. Only rarely information on the procedural details is provided for awake operations and how often somnolence and disorientation occurred, which might hamper the reliability of intraoperative clinical testing. The aim of our study was to investigate possible influencing factors on the occurrence of somnolence and disorientation in awake DBS procedures.

METHODS

We retrospectively analyzed 122 patients with Parkinson's disease having received implantation of a DBS system at our centre. Correlation analyses were performed for the duration of disease prior to surgery, number of microelectrode trajectories, AC-PC-coordinates of the planned target, UPDRS-scores, intraoperative application of sedative drugs, duration of the surgical procedure, perioperative application of apomorphine, and the preoperative L-DOPA equivalence dosage with the occurrence of intraoperative somnolence and disorientation.

RESULTS

Patients with intraoperative somnolence were significantly older (p=0.039). Increased duration of the DBS procedure (p=0.020), delayed start of the surgery (p=0.049), higher number of MER trajectories (p=0.041), and the patients' % UPDRS improvement (p=0.046) also correlated with the incidence of intraoperative somnolence. We identified the main contributing factor to intraoperative somnolence as the use of sedative drugs applied during skin incision and burr hole trepanation (p=0.019). Perioperatively applied apomorphine could reduce the occurrence of somnolent phases during the operation (p=0.026).

CONCLUSION

Several influencing factors were found to seemingly increase the risk of intraoperative somnolence and disorientation, while the use of sedative drugs seems to be the main contributing factor. We argue that awake DBS procedures should omit the use of sedatives for best clinical outcome. When reporting on awake DBS surgery these factors should be considered and adjusted for, to permit reliable interpretation and comparison of DBS study results.

Brain metastasis resection: the impact of fluorescence guidance (MetResect study)

OBJECTIVE

Maximal resection of brain metastases (BMs) improves both progression-free survival and overall survival (OS). Fluorescein sodium (FL) in combination with the YELLOW 560-nm filter is a safe and feasible method for visualizing residual tumor tissue during BM resection. The authors of this study aimed to show that use of FL would positively influence the volumetric extent of resection (EOR) and thus the survival outcome in patients undergoing BM resection.

METHODS

Analyzing their institution's prospective brain tumor registry, the authors identified 539 consecutive patients with BMs (247 women, mean age 62.8 years) by using preoperative high-quality MR images for volumetric analysis. BMs were resected under white light (WL) in 293 patients (54.4%; WL group) and under FL guidance in 246 patients (45.6%; FL group). Sex, age, presurgical Karnofsky Performance Status (KPS), recursive partitioning analysis class, and adjuvant treatment modalities were well balanced between the two groups. Volumetric analysis was performed in a blinded fashion by quantifying pre- and postoperative tumor volume based on gadolinium-enhanced T1-weighted sequences.

RESULTS

In the FL group, the postoperative tumor volume was significantly smaller (p = 0.01), and hence the quantitative EOR was significantly larger (p = 0.024) and OS was significantly longer (p = 0.0001) (log-rank testing). Multivariate Cox regression modeling showed that age, presurgical KPS, metastasis status, and FL-guided resection are independent prognostic factors for survival.

CONCLUSIONS

Compared with WL resection, FL-guided BM resection increased resection quality, significantly improved EOR, and prolonged OS.

Radiomics for the non-invasive prediction of PD-L1 expression in patients with brain metastases secondary to non-small cell lung cancer

BACKGROUND

The expression level of the programmed cell death ligand 1 (PD-L1) appears to be a predictor for response to immunotherapy using checkpoint inhibitors in patients with non-small cell lung cancer (NSCLC). As differences in terms of PD-L1 expression levels in the extracranial primary tumor and the brain metastases may occur, a reliable method for the non-invasive assessment of the intracranial PD-L1 expression is, therefore of clinical value. Here, we evaluated the potential of radiomics for a non-invasive prediction of PD-L1 expression in patients with brain metastases secondary to NSCLC.

PATIENTS AND METHODS

Fifty-three NSCLC patients with brain metastases from two academic neuro-oncological centers (group 1, n = 36 patients; group 2, n = 17 patients) underwent tumor resection with a subsequent immunohistochemical evaluation of the PD-L1 expression. Brain metastases were manually segmented on preoperative T1-weighted contrast-enhanced MRI. Group 1 was used for model training and validation, group 2 for model testing. After image pre-processing and radiomics feature extraction, a test-retest analysis was performed to identify robust features prior to feature selection. The radiomics model was trained and validated using random stratified cross-validation. Finally, the best-performing radiomics model was applied to the test data. Diagnostic performance was evaluated using receiver operating characteristic (ROC) analyses.

RESULTS

An intracranial PD-L1 expression (i.e., staining of at least 1% or more of tumor cells) was present in 18 of 36 patients (50%) in group 1, and 7 of 17 patients (41%) in group 2. Univariate analysis identified the contrast-enhancing tumor volume as a significant predictor for PD-L1 expression (area under the ROC curve (AUC), 0.77). A random forest classifier using a four-parameter radiomics signature, including tumor volume, yielded an AUC of 0.83 ± 0.18 in the training data (group 1), and an AUC of 0.84 in the external test data (group 2).

CONCLUSION

The developed radiomics classifiers allows for a non-invasive assessment of the intracranial PD-L1 expression in patients with brain metastases secondary to NSCLC with high accuracy.

Analysis of Functional Neuroplastic Changes in the Cortical Language System in Relation to Different Growth Patterns of Glioblastoma

The interpretation of fMRI data in glioblastoma (GB) is challenging as these tumors exhibit specific hemodynamic processes which, together with malignancy, tumor volume and proximity to eloquent cortex areas, may lead to misinterpretations of fMRI signals. The aim of this study was to investigate if different radiologically defined GB tumor growth patterns may also influence the fMRI signal, activation pattern and functional connectivity differently. Sixty-four patients with left-hemispheric glioblastoma were included and stratified according to their radiologically defined tumor growth pattern into groups with a uniform (U-TGP) or diffuse tumor growth pattern (D-TGP). Task-based fMRI data were analyzed using SPM12 with the marsbar, LI and CONN toolboxes. The percent signal change and the laterality index were analyzed, as well as functional connectivity between 23 selected ROIs. Comparisons of both patient groups showed only minor non-significant differences, indicating that the tumor growth pattern is not a relevant influencing factor for fMRI signal. In addition to these results, signal reductions were found in areas that were not affected by the tumor underlining that a GB is not a localized but rather a systemic disease affecting the entire brain.

Spinal meningiomas

Spinal meningiomas (SM) are lesions with a mostly favorable oncological and surgical prognosis and a low incidence of tumor recurrence. SM account for approximately 1.2-12.7% of all meningiomas and 25% of all spinal cord tumors. Typically, SM are located in the intradural extramedullary space. SM grow slowly and spread laterally into the subarachnoid space, stretching and sometimes incorporating the surrounding arachnoid but rarely the pia. Standard treatment is surgery with the primary aims of achieving complete tumor resection as well as improving and recovering neurologic function. Radiotherapy may be considered in case of tumor recurrence, for challenging surgical cases, and for patients with higher-grade lesions (World Health Organization grade 2 or 3); however, radiotherapy is mostly used as an adjuvant therapy for SM. New molecular and genetic profiling increases the understanding of SM and may uncover additional treatment options.

Corticosteroid-Dependent Leukocytosis Masks the Predictive Potential of White Blood Cells for Delayed Cerebral Ischemia and Ventriculoperitoneal Shunt Dependency in Aneurysmatic Subarachnoid Hemorrhage

A multitude of pathological and inflammatory processes determine the clinical course after aneurysmal subarachnoid hemorrhage (aSAH). However, our understanding of predictive factors and therapeutic consequences is limited. We evaluated the predictive value of clinically relevant factors readily available in the ICU setting, such as white blood cell (WBC) count and CRP, for two of the leading comorbidities, delayed cerebral ischemia (DCI) and ventriculoperitoneal (VP) shunt dependency in aSAH patients with and without corticosteroid treatment. We conducted a retrospective analysis of 484 aSAH patients admitted to our institution over an eight-year period. Relevant clinical factors affecting the risk of DCI and VP shunt dependency were identified and included in a multivariate logistic regression model. Overall, 233/484 (48.1%) patients were treated with corticosteroids. Intriguingly, predictive factors associated with the occurrence of DCI differed significantly depending on the corticosteroid treatment status (dexamethasone group: Hunt and Hess grade (p = 0.002), endovascular treatment (p = 0.016); no-dexamethasone group: acute hydrocephalus (p = 0.018), peripheral leukocyte count 7 days post SAH (WBC at day 7) (p = 0.009)). Similar disparities were found for VP shunt dependency (dexamethasone group: acute hydrocephalus (p = 0.002); no-dexamethasone group: WBC d7 (p = 0.036), CRP peak within 72 h (p = 0.015)). Our study shows that corticosteroid-induced leukocytosis negates the predictive prognostic potential of systemic inflammatory markers for DCI and VP shunt dependency, which has previously been neglected and should be accounted for in future studies.

Fluorescein-guided resection of newly diagnosed high-grade glioma: Impact on extent of resection and outcome

Introduction

Maximal resection of high-grade glioma (HGG) improves progression-free survival (PFS) and overall survival (OS). Fluorescein sodium (FL) in combination with the YELLOW 560 ​nm filter (Carl Zeiss Meditec, Germany) is a safe and feasible method of visualizing residual tumor tissue during brain tumor resection.

Research question

We hypothesized that use of FL positively influenced the volumetric extent of resection (EOR), PFS, and OS in patients undergoing resection of a newly diagnosed HGG.

Materials and method

Using a prospective HGG registry, we identified 347 patients (median age 62.4 years; 141 women) with preoperative high-quality magnetic resonance images for volumetric analysis. Resection was performed under white light in n ​= ​151 (43.5%, white-light group) and under FL-guidance in n ​= ​196 (56.5%, FL group). Sex, age, presurgical Karnofsky Performance Index (KPI), O6-Methylguanin-DNA-Methyltransferase-Gene (MGMT) status, and adjuvant treatment modalities were well balanced between the groups. Volumetric analysis was performed by quantifying pre- and postoperative tumor volume based on gadolinium-enhanced T1 sequences in a blinded fashion.

Results

In the FL group, postoperative tumor volume was significantly smaller (p ​= ​0.003); accordingly, quantitative EOR was significantly larger (p ​= ​0.003). Significantly more complete resections were achieved in the FL group than in the white-light group (p ​= ​0.003). The FL group showed significantly longer PFS (p ​= ​0.020) and OS (p ​= ​0.015, log rank testing). Multivariate Cox regression modelling showed age, presurgical KPI, MGMT status, and FL-guided resection to be independent prognostic factors for survival.

Discussion and conclusion

Compared to white-light resection, FL-guided resection of newly diagnosed HGG significantly improved EOR and prolonged OS.

Insufficient Closing Forces of Yasargil Titanium Clips in Two Small Aneurysms Detected with Intraoperative Indocyanine Green Videoangiography

Background and Study Aims Aneurysm clips must have adequate closing forces because residual blood flow in clipped aneurysms may result in aneurysm recurrence. Such flow can be intraoperatively detected by visual inspection, microvascular Doppler sonography, indocyanine green videoangiography (ICG-V), angiography, and puncture.

Patients We present two patients with ruptured very small middle cerebral artery aneurysms (3 and 2.9 mm). The necks of both aneurysms were microsurgically clipped with Yasargil aneurysm clips without any complications.

Results In both aneurysms, visual inspection suggested complete occlusion, but ICG-V showed persistent residual blood flow between the middle parts of the clip blades.

The first patient was treated with a 5.4-mm FT744T clip (closing force of 1.47 N). After the ICG-V finding, a second 3.9-mm FT714T clip (closing force of 1.08 N) was placed on the tips of the already implanted clip to increase the closing forces. Subsequent ICG-V did not show any further residual blood flow. In the second patient, the aneurysm was clipped with an 8.0-mm FE764K clip (closing force of 1.77 N). Intraoperative ICG-V showed persistent residual blood flow within the aneurysmal dome despite complete closure of the clip. The clip was repositioned closer to the parent vessel. Consecutive ICG-V did not show any residual blood flow.

Conclusion Visually undetected incomplete aneurysm occlusion can be revealed with ICG-V. In very small aneurysms, standard closing forces of clips may not be sufficient and complete closure of the clip branches should be intraoperatively validated with ICG-V.

The endogenous neuropeptide calcitonin gene-related peptide after spontaneous subarachnoid hemorrhage–A potential psychoactive prognostic serum biomarker of pain-associated neuropsychological symptoms

Background

The pronociceptive neuromediator calcitonin gene-related peptide (CGRP) is associated with pain transmission and modulation. After spontaneous subarachnoid hemorrhage (sSAH), the vasodilatory CGRP is excessively released into cerebrospinal fluid (CSF) and serum and modulates psycho-behavioral function. In CSF, the hypersecretion of CGRP subacutely after good-grade sSAH was significantly correlated with an impaired health-related quality of life (hrQoL). Now, we prospectively analyzed the treatment-specific differences in the secretion of endogenous CGRP into serum after good-grade sSAH and its impact on hrQoL.

Methods

Twenty-six consecutive patients (f:m = 13:8; mean age 50.6 years) with good-grade sSAH were enrolled (drop out n = 5): n = 9 underwent endovascular aneurysm occlusion, n = 6 microsurgery, and n = 6 patients with perimesencephalic SAH received standardized intensive medical care. Plasma was drawn daily from day 1 to 10, at 3 weeks, and at the 6-month follow-up (FU). CGRP levels were determined with competitive enzyme immunoassay in duplicate serum samples. All patients underwent neuropsychological self-report assessment after the onset of sSAH (t₁: day 11–35) and at the FU (t₂).

Results

During the first 10 days, the mean CGRP levels in serum (0.470 ± 0.10 ng/ml) were significantly lower than the previously analyzed mean CGRP values in CSF (0.662 ± 0.173; p = 0.0001). The mean serum CGRP levels within the first 10 days did not differ significantly from the values at 3 weeks (p = 0.304). At 6 months, the mean serum CGRP value (0.429 ± 0.121 ng/ml) was significantly lower compared to 3 weeks (p = 0.010) and compared to the first 10 days (p = 0.026). Higher mean serum CGRP levels at 3 weeks (p = 0.001) and at 6 months (p = 0.005) correlated with a significantly poorer performance in the item pain, and, at 3 weeks, with a higher symptom burden regarding somatoform syndrome (p = 0.001) at t₂.

Conclusion

Our study reveals the first insight into the serum levels of endogenous CGRP in good-grade sSAH patients with regard to hrQoL. In serum, upregulated CGRP levels at 3 weeks and 6 months seem to be associated with a poorer mid-term hrQoL in terms of pain. In migraineurs, CGRP receptor antagonists have proven clinical efficacy. Our findings corroborate the potential capacity of CGRP in pain processing.

Declining Numbers of Neurosurgical Emergencies at a German University Medical Center during the Coronavirus Lockdown

BACKGROUND

 The coronavirus pandemic due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is posing unprecedented challenges to health care systems around the globe. Consequently, various lockdown scenarios have been politically imposed to get control over the spread of this disease. We examined the impact of the lockdown situation on the number of neurosurgical emergency patients admitted to our tertiary care center with a catchment area of ∼2.2 million inhabitants in the south of Germany to ensure adequate neurosurgical emergency care during a pandemic lockdown.

METHODS

 All emergency admissions (with consecutive inpatient treatment) to the Department of Neurosurgery at the University Medical Center Regensburg, Germany, between March 1 and May 8 (69 days) of the years 2018, 2019, and 2020 were retrospectively identified and reviewed for this study. Demographic data, diagnoses, urgency of surgery, and duration of the journey to the emergency room were examined.

RESULTS

 Between March 1 and May 8, 2020, 59 emergency patients were neurosurgically treated at our department. Compared with 2018 and 2019, emergency admissions in 2020 had thus declined by 37.2 and 27.1%, respectively. Regarding the year 2020, we found a significant drop from 1.71 and 1.52 emergency patients per day in January and February 2020, respectively, to 0.86 during lockdown (p < 0.001). The decline especially concerned nontraumatic spinal cases and also patients with other neurosurgical diagnoses such as intracranial hemorrhage. Evaluation of the overall disease severity of admitted patients by means of the urgency of surgery showed no difference between the baseline years and the lockdown period.

CONCLUSION

 Our findings are in line with other observational studies of neurosurgical, neurologic, and cardiologic centers in Europe that have described a drop in emergency cases. The reasons for this drop that seems to affect various medical fields and countries across Europe are still unidentified. Morbidity and mortality rates are still unknown, and efforts should be made to facilitate neurosurgical emergency care during a pandemic lockdown.

BRMP-02. Feasibility and evaluation of a novel language paradigm for intraoperative language testing

INTRODUCTION

Mapping language during direct cortical stimulation (DCS) in the stetting of awake craniotomy might be challenging without using more than one language paradigm. Applying several language tasks leads to increasing surgery times and to patient’s exhaustion. Additionally, a single language trial must be performed in less than 4 seconds to avoid DCS-induced seizures. Therefore, we aimed to design a single language paradigm which pictures highly relevant language functions and simultaneously restrains the assessment time of single language trials up to 4 seconds.

METHOD

The intraoperative language task comprised a combination of picture naming and verb generation. During DCS patients should generate correct sentences according to the language stimulus by not exceeding 4 seconds. To assess the intraoperative feasibility of the language task we included 30 healthy subjects in a pilot study to measure subjects’ speed of performing a single language task trial and to evaluate the language paradigm according to its language sensitivity by using the paradigm as a task for functional MRI. Intraoperatively, 21 patients with brain tumors in language associated brain areas were included. Patients received neuropsychological testing before and after surgery.

RESULTS

The pilot study showed in healthy subjects that by applying the novel paradigm during fMRI there is activation in a left accentuated network of inferior frontal and parietal regions and the superior and middle temporal gyrus (p&lt;.05, FEW). It was feasible to conduct a single language trial of the novel paradigm in a time frame of 4s (performance speed 2.53 s; SD=.32s). Intraoperatively, tumor patients showed DCS-associated language errors while conducting the language task. Postoperatively, mild language but no other neuropsychological deteriorations compared to presurgical assessment were observed (p&lt;.05).

CONCLUSION

We present a novel language paradigm which safely pictures and monitors highly relevant language functions and consequently can minimize postoperative language deficits.

NIMG-01. INTEROBSERVER VARIABILITY OF THE REVISED IMAGING SCORECARD FOR LEPTOMENINGEAL METASTASIS: A JOINT EORTC BRAIN TUMOR GROUP AND RANO EFFORT

BACKGROUND

Validation of the 2016 LANO MRI scorecard for leptomeningeal metastasis failed for multiple reasons. The objective of this joint EORTC Brain Tumor Group and RANO effort was to validate the feasibility of the revised MRI scorecard for assessing response in leptomeningeal metastasis.

METHODS

Coded paired cerebrospinal MRI of 20 patients with leptomeningeal metastases from solid cancers at baseline and follow-up after treatment and instructions for assessment were provided via the EORTC imaging platform. The kappa coefficient (K) was used to evaluate inter-observer pairwise agreement. Statistical analyses were performed using SAS V9.4 software (Cary, NC). The sponsor of the study was the University Hospital Zurich (2018-00192).

RESULTS

Thirty-five raters participated, including 9 neuroradiologists, 17 neurologists, 4 radiation oncologists, 3 neurosurgeons and 2 medical oncologists. Among leptomeningeal metastases-related items at baseline, the best median concordance was noted for hydrocephalus (K=0.63), and the worst median for spinal linear enhancing disease (K=0.46). The median concordance for overall response was moderate (K=0.44). Notably, the interobserver agreement for the presence of parenchymal brain metastases at baseline was minimal (K=0.29). Significant differences were observed when considering the specialty of the raters. Only 394 of 700 ratings (56%) were fully completed. Among 394 fully completed ratings, perfect concordance was noted in 293 ratings (74%) when comparing the overall response according to the guidelines provided in the scorecard and the overall response provided by the raters. The main discordances were noted for partial response according to the rater versus stable disease according to the guidelines (n=44), followed by progression according to the raters versus stable disease according to the guidelines (n=23).

CONCLUSION

Electronic case report forms with "blocking solutions" are probably required to enforce completeness and quality of scoring. These results confirm the necessity of central review and the need for training of MRI assessment in clinical trials.

Brain multimodality monitoring in patients suffering from acute aneurysmal subarachnoid hemorrhage: clinical value and complications

Brain multimodality monitoring measuring brain tissue oxygen pressure, cerebral blood flow, and cerebral near-infrared spectroscopy may help optimize the neurocritical care of patients with aneurysmal subarachnoid hemorrhage and delayed cerebral ischemia. We retrospectively looked for complications associated with the placement of the probes and checked the reliability of the different tools used for multimodality monitoring. In addition, we screened for therapeutic measures derived in cases of pathological values in multimodality monitoring in 26 patients with acute aneurysmal subarachnoid hemorrhage. Computed tomography scans showed minor hemorrhage along with the probes in 12 patients (46.2%). Missing transmission of values was observed in 34.1% of the intended time of measurement for cerebral blood flow probes and 15.5% and 16.2%, respectively, for the two kinds of probes measuring brain tissue oxygen pressure. We identified 744 cumulative alarming values transmitted from multimodality monitoring. The most frequent intervention was modifying minute ventilation (29%). Less frequent interventions were escalating the norepinephrine dosage (19.9%), elevating cerebral perfusion pressure (14.9%) or inspiratory fraction of inspired oxygen (7.5%), transfusing red blood cell concentrates (1.2%), initiating further diagnostics (2.3%) and neurosurgical interventions (1.9%). As well, 355 cases of pathological values had no therapeutic consequence. The reliability of the measuring tools for multimodality monitoring regarding a continuous transmission of values must be improved, particularly for cerebral blood flow monitoring. The overall high rate of missing therapeutic responses to pathological values derived from multimodality monitoring in patients with aneurysmal subarachnoid hemorrhage underlines the need for structured tiered algorithms. In addition, such algorithms are the basic requirement for prospective multicenter studies, which are urgently needed to evaluate the role of multimodality monitoring in treating these patients.

Massively calcified aneurysm of the anterior communicating artery: an unsuccessful clipping attempt followed by successful pCONus2-assisted coil occlusion

We report the unique case of a 67-year-old female patient with an incidentally discovered massively calcified aneurysm of the anterior communicating artery. After interdisciplinary discussion, we decided to attempt clipping the aneurysm because interventional therapy did not seem feasible and anchoring a stent would also have been difficult because of the morphology of the aneurysm. The clipping attempt was unsuccessful because of the aneurysm’s massive calcification with strong adherence to the sphenoid planum. The aneurysm was then successfully occluded using pCONus 2-assisted coiling. We illustrate this and consecutive procedures, and we reviewed the literature on aneurysm calcification.

Endoscopic Assistance in the Deep and Narrow Spaces of the Brain-Microscopic Tumor Surgery Supported by the New Micro-Inspection Tool QEVO® (Technical Note)

Introduction: To evaluate the feasibility and efficacy of the innovative micro-inspection tool QEVO® (Carl Zeiss Meditec, Oberkochen, Germany) as an endoscopic adjunct to microscopes for better visualization of the surgical field in complex deep-seated intracranial tumors in infants and adults.

Materials and Methods: We retrospectively assessed the surgical videos of 25 consecutive patients with 26 complex intracranial lesions (time frame 2018–2020). Lesions were classified according to their anatomical area: 1 = sellar region (n = 6), 2 = intra-ventricular (except IV.ventricle, n = 9), 3 = IV.ventricle and rhomboid fossa (n = 4), and 4 = cerebellopontine angle (CPA) and foramen magnum (n = 7). Indications to use the QEVO® tool were divided into five “QEVO® categories”: A = target localization, B = tailoring of the approach, C = looking beyond the lesion, D = resection control, and E = inspection of remote areas.

Results: Overall, the most frequent indications for using the QEVO® tool were categories D (n = 19), C (n = 17), and E (n = 16). QEVO® categories B (n = 8) and A (n = 5) were mainly applied to intra-ventricular procedures (anatomical area 2).

Discussion: The new micro-inspection tool QEVO® is a powerful endoscopic device to support the comprehensive visualization of complex intracranial lesions and thus instantly increases intraoperative morphological understanding. However, its use is restricted to the specific properties of the respective anatomical area.

A Novel Language Paradigm for Intraoperative Language Mapping: Feasibility and Evaluation

(1) Background-Mapping language using direct cortical stimulation (DCS) during an awake craniotomy is difficult without using more than one language paradigm that particularly follows the demand of DCS by not exceeding the assessment time of 4 s to prevent intraoperative complications. We designed an intraoperative language paradigm by combining classical picture naming and verb generation, which safely engaged highly relevant language functions. (2) Methods-An evaluation study investigated whether a single trial of the language task could be performed in less than 4 s in 30 healthy subjects and whether the suggested language paradigm sufficiently pictured the cortical language network using functional magnetic resonance imaging (fMRI) in 12 healthy subjects. In a feasibility study, 24 brain tumor patients conducted the language task during an awake craniotomy. The patients' neuropsychological outcomes were monitored before and after surgery. (3) Results-The fMRI results in healthy subjects showed activations in a language-associated network around the (left) sylvian fissure. Single language trials could be performed within 4 s. Intraoperatively, all tumor patients showed DCS-induced language errors while conducting the novel language task. Postoperatively, mild neuropsychological impairments appeared compared to the presurgical assessment. (4) Conclusions-These data support the use of a novel language paradigm that safely monitors highly relevant language functions intraoperatively, which can consequently minimize negative postoperative neuropsychological outcomes.

Intraoperative imaging of brain tumors with fluorescein: confocal laser endomicroscopy in neurosurgery. Clinical and user experience

OBJECTIVE

Confocal laser endomicroscopy (CLE) is an established tool in basic research for tissue imaging at the level of microstructures. Miniaturization and refinement of the technology have made this modality available for operative imaging with a handheld device. Sufficient image contrast is provided by the preoperative application of fluorescein sodium. The authors report their first experiences in a clinical case series using the new confocal laser endomicroscope.

METHODS

Handling, operative workflow, and visualization of the CLE were critically evaluated in 12 cases of different CNS tumors. Three different imaging positions in relation to the tumor were chosen: the tumor border (I), tumor center (II), and perilesional zone (III). Respective diagnostic sampling with H & E staining and matching intraoperative neuronavigation and microscope images are provided.

RESULTS

CLE was found to be beneficial in terms of high-quality visualization of fine structures and for displaying hidden anatomical details. The handling of the device was good, and the workflow was easy.

CONCLUSIONS

Handling ergonomics and image acquisition are intuitive. The endomicroscope allows excellent additional visualization of microstructures in the surgical field with a minimally invasive technique and could improve safety and clinical outcomes. The new confocal laser endomicroscope is an advanced tool with the potential to change intracranial tumor surgery. Imaging of these microstructures is novel, and research with comparative validation with traditional neuropathological assessments is needed.

Application of the Endoscopic Micro-Inspection Tool QEVO® in the Surgical Treatment of Anterior Circulation Aneurysms-A Technical Note and Case Series

Introduction: The application of neuro-endoscopes in cerebral aneurysm surgery may help to avoid unintended aneurysm remnants and the accidental clipping of perforating arteries and aid the detection of blood collecting in the subdural spaces. Here, we present our experience with the novel endoscopic micro-inspection tool QEVO® (Carl Zeiss Meditec, Germany) in aneurysm surgery.

Materials and Equipment: In all patients the surgical microscope KINEVO® (Carl Zeiss Meditec, Germany) and the Microinspection tool QEVO® were applied.

Methods: The case series comprises 22 unruptured cerebral aneurysms of the anterior circulation. All aneurysms were treated surgically. All patients routinely underwent computed tomography and digital subtraction angiography within 10 days after surgery.

Results: No aneurysm remnants, cerebral ischemic deficits, or subdural hematomas were detected.

Discussion: In this technical note, we discuss the benefits and limitations of the QEVO® tool and illustrate the major paradigms by means of intraoperative photographs.

CBIO-09. INTRATUMORAL HETEROGENEITY OF DIELECTRIC PROPERTIES IN GLIOBLASTOMA

INTRODUCTION

Recently, tumor treating fields (TTFields) were established for the treatment of newly diagnosed glioblastoma (GBM). One of the most crucial parameters defining the treatment efficacy of TTFields is the electric field intensity, which depends on the dielectric properties of the tumor tissue. In this study we determined the dielectric properties of GBM by analyzing resected tissue following a fast acquisition protocol. To account for the intratumoral heterogeneity, different regions of the tumor were analyzed separately.

METHODS

A cohort of 38 patients with newly diagnosed GBM were analyzed. Tissue probes were acquired from the vital tumor area and perinecrotic compartment. The tissue was measured immediately to avoid artifacts. A fragment was dissected from each tissue sample and was placed into a cylindrical cell with a known diameter. The impedance was recorded at frequencies 20Hz-1MHz using a software specifically developed for this study, which controls the LCR meter. The measured impedance was translated into dielectric properties of the sample (conductivity and relative permittivity) based on the parallel plate model, the recorded complex impedance and the geometry of the samples. Each tissue probe was fixed, and stained with H&E to visualize cellularity, luxol fast blue to analyze the myelinated fiber content and against factor VIII related antigen to assess tumor vascularity.

RESULTS

We found significant differences between the conductivity and permittivity of tissue samples from each individual tumor (mean conductivity [S/m]: 0.302; range: 0.607 – 0.100; mean permittivity [Farad/m]: 3519.8; range: 11182.5 – 135.7). Consistently, the perinecrotic areas displayed lower conductivity values compared to the solid tumor compartments. Histological analysis revealed significantly higher cellularity and lower myelinated fiber content in tissue samples with high conductivity and permittivity.

CONCLUSION

The dielectric properties of GBM show a high intratumoral heterogeneity which correlate to the extent of cellularity and myelin fiber content within the tissue.

Features of tumor texture influence surgery and outcome in intracranial meningioma

Background

Texture-related factors such as consistency, vascularity, and adherence vary considerably in meningioma and are thought to be linked with surgical resectability and morbidity. However, data analyzing the true impact of meningioma texture on the surgical management is sparse.

Methods

Patients with intracranial meningioma treated between 08/2014 and 04/2018 at our institution were prospectively collected for demographics, clinical presentation, histology, and surgical treatment with related morbidity and extend of resection. Tumor characteristics were reported by the surgeon using a standardized questionnaire including items such as tumor consistency, homogeneity, vascularization, and adherence to surrounding neurovascular structure and analyzed for their impact surgical outcome parameters using univariate and logistic regression analyses.

Results

Tumor texture-related parameters of 300 patients (72.3% female) with meningioma were analyzed. Meningioma localizations were grouped into 3 different cohorts namely convexity, skull base, and posterior. Postoperative occurrence of a neurological deficit (transient 23.0%; permanent 6.1%) was associated with the duration of surgery (P = .001), size of tumor (P = .046), tumor vascularization (P = .015), and adherence to neurovascular structures (P = .002). Coherently, the duration of surgery (mean 230.99 ± 101.33 min) was associated with size of tumor (P < .0001), vascularization (P < .0001), and adherence (P < .0001). Similar associations were recapitulated in subgroup analyses of different tumor localizations. Noteworthy, tumor rigidity had no significant impact on time of surgery and neurological outcome.

Conclusions

Our analysis demonstrates that tumor texture has an impact on the surgical management of meningioma and provides data that tumor vascularization and adherence are significant factors influencing surgical outcome whereas the influence of tumor consistency has less impact than previously thought.

Diagnostic reliability of the Berlin classification for complex MCA aneurysms-usability in a series of only giant aneurysms

Background and objective

The main challenge of bypass surgery of complex MCA aneurysms is not the selection of the bypass type but the initial decision-making of how to exclude the affected vessel segment from circulation. To this end, we have previously proposed a classification for complex MCA aneurysms based on the preoperative angiography. The current study aimed to validate this new classification and assess its diagnostic reliability using the giant aneurysm registry as an independent data set.

Methods

We reviewed the pretreatment neuroimaging of 51 patients with giant (> 2.5 cm) MCA aneurysms from 18 centers, prospectively entered into the international giant aneurysm registry. We classified the aneurysms according to our previously proposed Berlin classification for complex MCA aneurysms. To test for interrater diagnostic reliability, the data set was reviewed by four independent observers.

Results

We were able to classify all 51 aneurysms according to the Berlin classification for complex MCA aneurysms. Eight percent of the aneurysm were classified as type 1a, 14% as type 1b, 14% as type 2a, 24% as type 2b, 33% as type 2c, and 8% as type 3. The interrater reliability was moderate with Fleiss’s Kappa of 0.419.

Conclusion

The recently published Berlin classification for complex MCA aneurysms showed diagnostic reliability, independent of the observer when applied to the MCA aneurysms of the international giant aneurysm registry.

Imaging and diagnostic advances for intracranial meningiomas

The archetypal imaging characteristics of meningiomas are among the most stereotypic of all central nervous system (CNS) tumors. In the era of plain film and ventriculography, imaging was only performed if a mass was suspected, and their results were more suggestive than definitive. Following more than a century of technological development, we can now rely on imaging to non-invasively diagnose meningioma with great confidence and precisely delineate the locations of these tumors relative to their surrounding structures to inform treatment planning. Asymptomatic meningiomas may be identified and their growth monitored over time; moreover, imaging routinely serves as an essential tool to survey tumor burden at various stages during the course of treatment, thereby providing guidance on their effectiveness or the need for further intervention. Modern radiological techniques are expanding the power of imaging from tumor detection and monitoring to include extraction of biologic information from advanced analysis of radiological parameters. These contemporary approaches have led to promising attempts to predict tumor grade and, in turn, contribute prognostic data. In this supplement article, we review important current and future aspects of imaging in the diagnosis and management of meningioma, including conventional and advanced imaging techniques using CT, MRI, and nuclear medicine.

Lighting Up the Tumor-Fluorescein-Guided Resection of Gangliogliomas

(1) Background: Gangliogliomas comprise a small number of brain tumors. They usually present as World Health Organization (WHO) grade I, and they delineate on gadolinium-enhanced MRI; the surgical goal is wide radical resection, and the course thereafter is usually benign. Fluorescein sodium (FL) tends to accumulate in areas with altered blood–brain barrier (BBB). Thus far, the results provided by prospective and retrospective studies show that the utilization of this fluorophore may be associated with better visualization and improvement of resection for several tumors of the central nervous system. In this study, we retrospectively studied the effect of fluorescein sodium on visualization and resection of gangliogliomas. (2) Methods: Surgical databases in three neurosurgical departments (Regensburg University Hospital; Besta Institute, Milano, Italy; and Liv Hospital, Istanbul, Turkey), with approval by the local ethics committee, were retrospectively reviewed to find gangliogliomas surgically removed by a fluorescein-guided technique by the aid of a dedicated filter on the surgical microscope from April 2014 to February 2020. Eighteen patients (13 women, 5 men; mean age 22.9 years, range 3 to 78 years) underwent surgical treatment for gangliogliomas during 19 operations. Fluorescein was intravenously injected (5 mg/kg) after general anesthesia induction. Tumors were removed using a microsurgical technique with the YELLOW 560 Filter (YE560) (KINEVO/PENTERO 900, Carl Zeiss Meditec, Oberkochen, Germany). (3) Results: No side effects related to fluorescein occurred. In all tumors, contrast enhancement on preoperative MRI correlated with bright yellow fluorescence during the surgical procedure (17 gangliogliomas WHO grade I, 1 ganglioglioma WHO grade II). Fluorescein was considered helpful by the operating surgeon in distinguishing tumors from viable tissue in all cases (100%). Biopsy was intended in two operations, and subtotal resection was intended in one operation. In all other operations considered preoperatively eligible, gross total resection (GTR) was achieved in 12 out of 16 (75%) instances. (4) Conclusions: The use of FL and YE560 is a readily available method for safe fluorescence-guided tumor resection, possibly visualizing tumor margins intraoperatively similar to contrast enhancement in T1-weighted MRI. Our data suggested a positive effect of fluorescein-guided surgery on intraoperative visualization and extent of resection during resection of gangliogliomas.

Meningioma infiltrating into porous polymethylmethacrylate cranioplasty-report of a unique case

Implantation of a cranioplasty after osteoclastic craniotomy or craniectomy is one of the most common neurosurgical procedures, and polymethylmethacrylate (PMMA) is one of the most frequently applied materials for cranioplasty. This report describes the unique case of a patient with recurrent transitional meningioma WHO I that infiltrated the PMMA cranioplasty 7 years after primary surgery. We propose to restrict the use of porous PMMA as cranioplasty after the removal of convexity meningioma.

Exome sequencing in 38 patients with intracranial aneurysms and subarachnoid hemorrhage

Objective

Genetic risk factors for unruptured intracranial aneurysms (UIA) and aneurysmal subarachnoid hemorrhage (aSAH) are poorly understood. We aimed to verify recently reported risk genes and to identify novel sequence variants involved in the etiology of UIA/aSAH.

Methods

We performed exome sequencing (ES) in 35 unrelated individuals and 3 family members, each with a history of UIA and/or aSAH. We searched for sequence variants with minor allele frequency (MAF) ≤ 5% in the reported risk genes ADAMTS15, ANGPTL6, ARHGEF17, LOXL2, PCNT, RNF213, THSD1 and TMEM132B. To identify novel putative risk genes we looked for unknown (MAF = 0) variants shared by the three relatives.

Results

We identified 20 variants with MAF ≤ 5% in 18 individuals: 9 variants in PCNT (9 patients), 4 in RNF213 (3 patients), 3 in THSD1 (6 patients), 2 in ANGPTL6 (3 patients), 1 in ADAMTS15 (1 patient) and 1 in TMEM132B (1 patient). In the affected family, prioritization of shared sequence variants yielded five novel putative risk genes. Based on predicted pathogenicity of identified variants, population genetics data and a high functional relevance for vascular biology, EDIL3 was selected as top candidate and screened in additional 37 individuals with UIA and/or aSAH: a further very rare EDIL3 sequence variant in two unrelated sporadic patients was identified.

Conclusions

Our data support a role of sequence variants in PCNT, RNF213 and THSD1 as susceptibility factors for cerebrovascular disease. The documented function in vascular wall integrity, the crucial localization of affected amino acids and gene/variant association tests suggest EDIL3 as a further valid candidate disease gene for UIA/aSAH.

Electronic supplementary material

The online version of this article (10.1007/s00415-020-09865-6) contains supplementary material, which is available to authorized users.

The burden of headache following aneurysmal subarachnoid hemorrhage: a prospective single-center cross-sectional analysis

Background

Aneurysmal subarachnoid hemorrhage (SAH) as a serious type of stroke is frequently accompanied by a so-called initial thunderclap headache. However, the occurrence of burdensome long-term headache following SAH has never been studied in detail so far. The aim of this study was to determine the prevalence and characteristics of long-term burdensome headache in good-grade SAH patients as well as its relation to health-related quality of life (HR-QOL).

Methods

All SAH cases treated between January 2014 and December 2016 with preserved consciousness at hospital discharge were prospectively interviewed regarding burdensome headache in 2018. Study participants were subsequently scrutinized by means of a standardized postal survey comprising validated pain and HR-QOL questionnaires. A retrospective chart review provided data on the initial treatment.

Results

A total of 93 out of 145 eligible SAH patients participated in the study (62 females). A total of 41% (38/93) of subjects indicated burdensome headache at follow-up (mean 32.6 ± 9.3 months). Comparison between patients with (HA+) and without long-term headache (HA-) revealed significantly younger mean age (47.9 ± 11.8 vs. 55.6 ± 10.3 years; p < .01) as well as more favorable neurological conditions (WFNS I/II: 95% vs. 75%; p = .03) in HA+ cases. The mean average headache of the HA+ group was 3.7 ± 2.3 (10-point numeric rating scale), and the mean maximum headache intensity was 5.7 ± 2.9. Pain and HR-QOL scores demonstrated profound alterations in HA+ compared to HA- patients.

Conclusions

Our results suggest that a considerable proportion of SAH patients suffers from burdensome headache even years after the hemorrhage. Moreover, long-term headache is associated with reduced HR-QOL in these cases.

Electronic supplementary material

The online version of this article (10.1007/s00701-020-04235-7) contains supplementary material, which is available to authorized users.

Local Intracerebral Immunomodulation Using Interleukin-Expressing Mesenchymal Stem Cells in Glioblastoma

PURPOSE

Mesenchymal stem cells (MSCs) show an inherent brain tumor tropism that can be exploited for targeted delivery of therapeutic genes to invasive glioma. We assessed whether a motile MSC-based local immunomodulation is able to overcome the immunosuppressive glioblastoma microenvironment and to induce an antitumor immune response.

EXPERIMENTAL DESIGN

We genetically modified MSCs to coexpress high levels of IL12 and IL7 (MSC^IL7/12, Apceth-301). Therapeutic efficacy was assessed in two immunocompetent orthotopic C57BL/6 glioma models using GL261 and CT2A. Immunomodulatory effects were assessed by multicolor flow cytometry to profile immune activation and exhaustion of tumor-infiltrating immune cells. Diversity of the tumor-specific immune response as analyzed using T-cell receptor sequencing.

RESULTS

Intratumoral administration of MSC^IL7/12 induced significant tumor growth inhibition and remission of established intracranial tumors, as demonstrated by MR imaging. Notably, up to 50% of treated mice survived long-term. Rechallenging of survivors confirmed long-lasting tumor immunity. Local treatment with MSC^IL7/12 was well tolerated and led to a significant inversion of the CD4⁺/CD8⁺ T-cell ratio with an intricate, predominantly CD8⁺ effector T-cell-mediated antitumor response. T-cell receptor sequencing demonstrated an increased diversity of TILs in MSC^IL7/12-treated mice, indicating a broader tumor-specific immune response with subsequent oligoclonal specification during generation of long-term immunity.

CONCLUSIONS

Local MSC-based immunomodulation is able to efficiently alter the immunosuppressive microenvironment in glioblastoma. The long-lasting therapeutic effects warrant a rapid clinical translation of this concept and have led to planning of a phase I/II study of apceth-301 in recurrent glioblastoma.

Giant intracranial aneurysms: natural history and 1-year case fatality after endovascular or surgical treatment

OBJECTIVE

Clinical evidence on giant intracranial aneurysms (GIAs), intracranial aneurysms with a diameter of at least 25 mm, is limited. The authors aimed to investigate the natural history, case fatality, and treatment outcomes of ruptured and unruptured GIAs.

METHODS

In this international observational registry study, patients with a ruptured or unruptured GIA received conservative management (CM), surgical management (SM), or endovascular management (EM). The authors investigated rupture rates and case fatality.

RESULTS

The retrospective cohort comprised 219 patients with GIAs (21.9% ruptured GIAs and 78.1% unruptured GIAs) whose index hospitalization occurred between January 2006 and November 2016. The index hospitalization in the prospective cohort (362 patients with GIAs [17.1% ruptured and 82.9% unruptured]) occurred between December 2008 and February 2017. In the retrospective cohort, the risk ratio for death at a mean follow-up of 4.8 years (SD 2.2 years) after CM, compared with EM and SM, was 1.63 (95% CI 1.23-2.16) in ruptured GIAs and 3.96 (95% CI 2.57-6.11) in unruptured GIAs. In the prospective cohort, the 1-year case fatality in ruptured GIAs/unruptured GIAs was 100%/22.0% during CM, 36.0%/3.0% after SM, and 39.0%/12.0% after EM. Corresponding 1-year rupture rates in unruptured GIAs were 25.0% during CM, 1.2% after SM, and 2.5% after EM. In unruptured GIAs, the HR for death within the 1st year in patients with posterior circulation GIAs was 6.7 (95% CI 1.5-30.4, p < 0.01), with patients with a GIA at the supraclinoid internal carotid artery as reference. Different sizes of unruptured GIAs were not associated with 1-year case fatality.

CONCLUSIONS

Rupture rates for unruptured GIAs were high, and the natural history and treatment outcomes for ruptured GIAs were poor. Patients undergoing SM or EM showed lower case fatality and rupture rates than those undergoing CM. This difference in outcome may in part be influenced by patients in the CM group having been found poor candidates for SM or EM.Clinical trial registration no.: NCT02066493 (clinicaltrials.gov).

MNGI-02. FEATURES OF TUMOR TEXTURE INFLUENCE SURGERY AND OUTCOME IN INTRACRANIAL MENINGIOMA

OBJECTIVE

Texture-related factors such as consistency, vascularity and adherence vary considerably in meningioma and are thought to be linked with surgical resectability and morbidity. However, data analyzing the true impact of meningioma texture on the surgical management is sparse.

METHODS

Patients with intracranial meningioma treated between 08/2014-04/2018 were prospectively collected for demographics and surgical treatment with related morbidity and extend of resection (EOR). Tumor characteristics were reported by the surgeon using a standardized questionnaire including items such as tumor rigidity, homogeneity, vascularization and adherence to surrounding neurovascular structure and analyzed for their impact on EOR and neurological outcome using multivariate regression analyses.

RESULTS

296 patients (214 female (72.3%) with intracranial meningiomas were included with a mean age of 60.4 years. 23% of patients had a transient and 6.1% permanent neurological deficits and three patients (1.1%) died. The occurrence of a neurological deficit was associated with duration of surgery (p = 0.013) and tumor adherence to neurovascular structures (p = 0.014). Similar associations were observed in subgroup analyses of different tumor localizations (e.g. convexity and skull base). With regard to EOR, the tumor adherence (p < 0.001) and recurrent surgery (p = 0.001) were found as independent predictors for subtotal resection. Noteworthy, the tumor rigidity had no significant impact on the morbidity or EOR.

CONCLUSION

Our analysis supports the notion that tumor texture has an impact on the surgical management of meningioma and provides sound data that tumor adherence is a significant factor influencing neurological outcome and EOR. In contrast, the influence of tumor rigidity has less impact than previously thought. Preoperative prediction of tumor texture is therefore required for optimized risk assessment.

Postoperative Nausea and Vomiting Following Craniotomy: Risk Factors and Complications in Context of Perioperative High-dose Dexamethasone Application

Introduction Postoperative nausea and vomiting (PONV) is common in patients after craniotomy and may lead to severe postoperative complications. The aim of this study was to identify risk factors and postoperative complications associated with PONV in the context of perioperative high-dose dexamethasone administration.

Patients and Methods In this prospective single-center study, all patients planned for elective craniotomy for supra- and infratentorial lesions were eligible to be included. Any PONV in a 24-hour period after craniotomy was recorded and analyzed with regard to time to postoperative complications and the administration of perioperatively administered high-dose dexamethasone.

Results The overall PONV rate of 421 patients during a 9-month period was 18.1% (76 patients). Multivariate analysis revealed a significant association of PONV with female sex, infratentorial localization, age, and history of PONV. There was no association between PONV and postoperative complications such as intracranial hemorrhage, cerebrospinal fluid (CSF) leaks, or pneumonia. Perioperative administration of high-dose dexamethasone for prophylactic prevention of edema was the only significant risk factor for postoperative complications (odds ratio [OR]: 3.34; confidence interval [CI], 1.39–8.05; p < 0.01) with a highly significant association with the occurrence of CSF leaks (OR: 6.85; CI, 1.62–29.05; p < 0.01).

Conclusion The low PONV rate of 18.1% in this study may be the result of the frequent perioperative administration of high-dose dexamethasone for the prevention of edema. Our data indicate that perioperative high-dose dexamethasone is significantly associated with CSF leaks and can therefore not be recommended on a regular basis.

Imaging flow cytometry facilitates multiparametric characterization of extracellular vesicles in malignant brain tumours

Cells release heterogeneous nano-sized vesicles either as exosomes, being derived from endosomal compartments, or through budding from the plasma membrane as so-called microvesicles, commonly referred to as extracellular vesicles (EVs). EVs are known for their important roles in mammalian physiology and disease pathogenesis and provide a potential biomarker source in cancer patients. EVs are generally often analysed in bulk using Western blotting or by bead-based flow-cytometry or, with limited parameters, through nanoparticle tracking analysis. Due to their small size, single EV analysis is technically highly challenging. Here we demonstrate imaging flow cytometry (IFCM) to be a robust, multiparametric technique that allows analysis of single EVs and the discrimination of distinct EV subpopulations. We used IFCM to analyse the tetraspanin (CD9, CD63, CD81) surface profiles on EVs from human and murine cell cultures as well as plasma samples. The presence of EV subpopulations with specific tetraspanin profiles suggests that EV-mediated cellular responses are tightly regulated and dependent on cell environment. We further demonstrate that EVs with double positive tetraspanin expression (CD63+/CD81+) are enriched in cancer cell lines and patient plasma samples. In addition, we used IFCM to detect tumour-specific GFP-labelled EVs in the blood of mice bearing syngeneic intracerebral gliomas, indicating that this technique allows unprecedented disease modelling. In summary, our study highlights the heterogeneous and adaptable nature of EVs according to their marker profile and demonstrates that IFCM facilitates multiparametric phenotyping of EVs not only in vitro but also in patient plasma at a single EV level, with the potential for future functional studies and clinically relevant applications. Abbreviation: EDTA = ethylenediamine tetraacetic acid.

Somatosensory evoked potentials in patients with high-grade aneurysmal subarachnoid hemorrhage

OBJECTIVE The aim of this prospective study was to investigate the value of somatosensory evoked potentials (SEPs) in predicting outcome in patients with high-grade aneurysmal subarachnoid hemorrhage (SAH). METHODS Between January 2013 and January 2015, 48 patients with high-grade SAH (Hunt and Hess Grade III, IV, or V) who were admitted within 3 days after hemorrhage were enrolled in the study. Right and left median and tibial nerve SEPs were recorded on Day 3 after hemorrhage and recorded again 2 weeks later. Glasgow Outcome Scale (GOS) scores were determined 6 months after hemorrhage and dichotomized as poor (Scores 1-3) or good (Scores 4-5). Results of SEP measurements were dichotomized (present or missing cortical responses or normal or prolonged latencies) for each nerve and side. These variables were summed and tested using logistic regression and a receiver operating characteristic curve to assess the value of SEPs in predicting long-term outcome. RESULTS At the 6-month follow-up visit, 29 (60.4%) patients had a good outcome, and 19 (39.6%) had a poor outcome. The first SEP measurement did not correlate with clinical outcome (area under the curve [AUC] 0.69, p = 0.52). At the second measurement of median nerve SEPs, all patients with a good outcome had cortical responses present bilaterally, and none of them had bilateral prolonged latencies (p = 0.014 and 0.003, respectively). In tibial nerve SEPs, 7.7% of the patients with a good GOS score had one or more missing cortical responses, and bilateral prolonged latencies were found in 23% (p = 0.001 and 0.034, respectively). The second measurement correlated with the outcome regarding each of the median and tibial nerve SEPs and the combination of both (AUC 0.75 [p = 0.010], 0.793 [p = 0.003], and 0.81 [p = 0.001], respectively). CONCLUSIONS Early SEP measurement after SAH did not correlate with clinical outcome, but measurement of median and tibial nerve SEPs 2 weeks after a hemorrhage did predict long-term outcome in patients with high-grade SAH.

Maternal Aneurysmal Subarachnoid Hemorrhage During Pregnancy as an Interdisciplinary Task

Maternal aneurysmal subarachnoid hemorrhage (aSAH) during pregnancy presents a challenge regarding treatment and management. Due to the limited number of cases there are no treatment guidelines available. Thus, treatment is usually done on a case-by-case basis. Here we report on four cases of aSAH during pregnancy, describing the different management strategies and suggesting a possible treatment algorithm. Patients treated between 2003 and 2013 in our center were included in this retrospective study. Clinical data focused on time management concerning gestation week (GW), microsurgical or endovascular treatment, and outcome of the patients and the fetuses. Results were compared to the present literature on this issue. Mean age was 30.8 years, initial Hunt & Hess (H&H) grade ranged from III to V. All patients suffered from aSAH during the 3rd trimester of pregnancy. In the four cases, two emergency Caesarean sections (CS) were performed. Two aneurysms were occluded by microsurgical clipping and one was treated endovascularly. One patient died before definitive treatment of the aneurysm could be achieved, whereas fetal mortality was 0%. The mean follow-up was 83 months. aSAH during pregnancy needs individualized interdisciplinary management. Efforts must focus on the mother so that a delay in the best available treatment for the pregnant patient is avoided. Therefore treatment modality should be primarily determined by the aneurysm itself. However, timing in terms of delivery of the fetus and aneurysm treatment is a crucial point.

Real-world experience of treatment decision-making in carotid stenosis in a neurovascular board

OBJECTIVE

To describe our experience with consensus-based decision-making for treatment of internal carotid artery (ICA) stenosis by neurologists, interventional neuroradiologists, vascular surgeons, and neurosurgeons in a multidisciplinary neurovascular board and to study adherence to treatment recommendations in the context of uncertainty with respect to the best treatment option.

METHODS

We established a multidisciplinary neurovascular board meeting twice a week with structured documentation of consensus decisions. Over a time period of 53 months, 614 cases with ICA stenosis were discussed, with 285 (46%) symptomatic and 279 (45%) asymptomatic cases.

RESULTS

Recommendation for symptomatic ICA stenosis was revascularization in 76%, medical management alone in 8%, and further diagnostics in 16%. For asymptomatic ICA stenosis, recommendation was randomization in a clinical trial in 29%, revascularization in 27%, medical management alone in 23%, and further diagnostics in 22%. Treatment recommendations were followed in 94% of symptomatic ICA stenosis and 69% of asymptomatic ICA stenosis. Patients in whom carotid artery stenting was recommended for revascularization were younger and showed a higher rate of severe (≥70%) ICA stenosis.

CONCLUSIONS

Interdisciplinary board decisions are a helpful and transparent tool to assure adherence to guideline recommendations, and to provide consensus-based individualized treatment strategies in clinical practice in the absence of unequivocal evidence.

Surgical management of pituitary metastases

BACKGROUND

Pituitary metastases are rare and commonly described in case reports or small case series. Due to its rarity this entity is not subject to standardized treatment guidelines, there is debate about typical initial symptoms that may lead to finding the correct diagnosis and information about the clinical course is also sparse.

METHODS

We have conducted a retrospective analysis of patients with pituitary metastases who were surgically treated via a transsphenoidal procedure at our institution between 2006 and 2014. Underlying primary disease, clinical and surgical course as well as adjuvant radiotherapy and follow-up data are presented.

RESULTS

14 patients met the inclusion criteria (8 female, 6 male). Mean age was 61.5 years. Most patients became symptomatic with visual symptoms--both visual deterioration and/or diplopia (n = 13)--and anterior lobe insufficiency (n = 8). Surprisingly diabetes insipidus was only seen in three patients. All patients underwent transsphenoidal surgery initially, four patients had to undergo surgery for residual tumor or recurrence, two of them via a transcranial route. Breast cancer was the most common entity (n = 6), followed by prostate cancer (n = 3), nsclc (n = 2) and melanoma, thyroid cancer and renal cancer in one case each. Postoperative MRI showed gross total resection in four cases and residual disease in eight cases (subtotal resection, partial resection and biopsy), two patients files were incomplete regarding MRI-results. All patients underwent adjuvant radiotherapy. Survival after the initial diagnosis of cancer was 36 and 16 months after diagnosis of pituitary metastases.

CONCLUSION

Our results indicate that transsphenoidal surgery is a safe method to resect pituitary metastases and that the extend of resection does not have an influence on survival time. Our results also indicate that diabetes insipidus may not be the most common initial symptom of pituitary metastases and lack thereof should not lead to making a wrong diagnosis and delaying appropriate therapy.

A novel threshold criterion in transcranial motor evoked potentials during surgery for gliomas close to the motor pathway

OBJECTIVE Warning criteria for monitoring of motor evoked potentials (MEP) after direct cortical stimulation during surgery for supratentorial tumors have been well described. However, little is known about the value of MEP after transcranial electrical stimulation (TES) in predicting postoperative motor deficit when monitoring threshold level. The authors aimed to evaluate the feasibility and value of this method in glioma surgery by using a new approach for interpreting changes in threshold level involving contra- and ipsilateral MEP. METHODS Between November 2013 and December 2014, 93 patients underwent TES-MEP monitoring during resection of gliomas located close to central motor pathways but not involving the primary motor cortex. The MEP were elicited by transcranial repetitive anodal train stimulation. Bilateral MEP were continuously evaluated to assess percentage increase of threshold level (minimum voltage needed to evoke a stable motor response from each of the muscles being monitored) from the baseline set before dural opening. An increase in threshold level on the contralateral side (facial, arm, or leg muscles contralateral to the affected hemisphere) of more than 20% beyond the percentage increase on the ipsilateral side (facial, arm, or leg muscles ipsilateral to the affected hemisphere) was considered a significant alteration. Recorded alterations were subsequently correlated with postoperative neurological deterioration and MRI findings. RESULTS TES-MEP could be elicited in all patients, including those with recurrent glioma (31 patients) and preoperative paresis (20 patients). Five of 73 patients without preoperative paresis showed a significant increase in threshold level, and all of them developed new paresis postoperatively (transient in 4 patients and permanent in 1 patient). Eight of 20 patients with preoperative paresis showed a significant increase in threshold level, and all of them developed postoperative neurological deterioration (transient in 4 patients and permanent in 4 patients). In 80 patients no significant change in threshold level was detected, and none of them showed postoperative neurological deterioration. The specificity and sensitivity in this series were estimated at 100%. Postoperative MRI revealed gross-total tumor resection in 56 of 82 patients (68%) in whom complete tumor resection was attainable; territorial ischemia was detected in 4 patients. CONCLUSIONS The novel threshold criterion has made TES-MEP a useful method for predicting postoperative motor deficit in patients who undergo glioma surgery, and has been feasible in patients with preoperative paresis as well as in patients with recurrent glioma. Including contra- and ipsilateral changes in threshold level has led to a high sensitivity and specificity.

The simplified acute physiology score II to predict hospital mortality in aneurysmal subarachnoid hemorrhage

BACKGROUND

Early prediction of increased morbidity and mortality in aneurysmal subarachnoid hemorrhage (aSAH) remains crucial to improving patient management. Most prediction models lack external validation and focus on disease-specific items without considering physiological parameters and the past medical history. The aim was to assess the validity of the established Simplified Acute Physiology Score II (SAPS-II) in an aSAH cohort for the prediction of hospital mortality and to identify additional physiological and clinical predictors.

METHODS

The predictive value of SAPS-II for hospital mortality was assessed in a retrospective analysis of 263 consecutive patients with aSAH. Additional physiological and clinical parameters including the past medical history were analyzed by forward selection multivariate analysis to identify independent predictors of hospital mortality and to improve the prediction model.

RESULTS

The SAPS-II predicted hospital mortality with an area under the curve (AUC) of 0.834 with an odds ratio (OR) of 1.097 [95 % confidence interval 1.067-1.128) for each additional point. Forward selection multivariate analysis identified the Glasgow Coma Scale score (P < 0.001), history of chronic headache (P = 0.01) and medication with anticoagulants (P = 0.04) as independent predictors of hospital mortality. Adding these parameters to the SAPS-II, the AUC increased to 0.86.

CONCLUSION

This study validates the predictive accuracy of SAPS-II for hospital mortality in aSAH patients. Additional parameters from the past medical history increase its predictive power. From a practical viewpoint, SAPS-II alone already represents a sufficient and powerful score to predict hospital mortality at an early time point and may help to improve patient management.

Intramedullary spinal cavernoma: clinical presentation, microsurgical approach, and long-term outcome in a cohort of 48 patients

OBJECT Intramedullary spinal cavernoma (ISC) is a rare entity and accounts for approximately 5%-12% of all spinal vascular pathologies. The purpose of the present study was to examine the influence of clinical presentation, localization, and different surgical approaches on long-term outcome in patients treated for ISC. METHODS The authors performed a retrospective single-center study of 48 cases of ISC treated microsurgically over the past 28 years. Analyzed factors included preoperative clinical history, microsurgical strategies, neurological outcome (American Spinal Injury Association [ASIA] grade, Epstein and Cooper grade), and the occurrence of postoperative spinal ataxia. Univariate analysis was performed to identify factors influencing long-term outcome. RESULTS Preoperatively, 18.8% of all patients experienced a slow, progressive decline in neurological function and 33.3% suffered repetitive episodes of acute neurological deterioration over a time frame of months to years. Moreover, 16.7% noted the sudden onset of a severe neurological deficit, whereas 25% experienced the sudden onset of symptoms with a subsequent gradually progressive decline in neurological function. On long-term follow-up after treatment (mean ± SD, 79.3 ± 35.2 months), 70.8% of patients showed no change in neurological function, 6.3% suffered from a decline, and 22.9% improved neurologically. Thoracolumbar localization (p = 0.043), low preoperative Epstein and Cooper grade for the lower extremities (p < 0.001), and a low preoperative ASIA grade (p < 0.001) were identified as factors associated with an unfavorable outcome (ASIA Grade A-C). The rate of spinal ataxia related to surgical approach was 16.7%. CONCLUSION Postoperative neurological function in ISC patients is determined by the preoperative neurological status. On long-term follow-up after microsurgical treatment, 93.7% of patients presented with a stable or improved condition (ASIA grade); thus, definite microsurgical treatment should be considered as long as patients present with only mild symptoms after the diagnosis of symptomatic ISC.

Intraoperative Micro-Doppler in Cerebral Arteriovenous Malformations

INTRODUCTION

Intraoperative micro-Doppler (IOMD), intraoperative digital substraction angiography (DSA), and microscope-integrated indocyanine green angiography are methods that guide neurosurgical resection of arteriovenous malformations (AVMs) in the brain and minimize the trauma of healthy tissue. In this study we emphasize the use of IOMD in AVM surgery, analyzing the advantages and the limitations of this method. Patients and

METHODS

A total of 32 patients were diagnosed with an AVM. Supplying arteries and draining veins were analyzed regarding hemodynamic profiles, flow velocities, pulsatility index (PI), and resistance index (RI). Venous drainages were accompanied by arterial blood flow disturbances that showed typical characteristics in all cases. We set an angle of 60 degrees between the examined vessel and the probe to achieve a more reliable and comparable measurement. Postoperative DSA was performed in all patients.

RESULTS

Supplying arterial blood vessels of AVMs could be identified by their characteristic blood flow profiles with PI < 0.7 and RI < 0.55. Drainage veins in all 32 cases showed normalized venous flow patterns without arterial flow turbulences at the end of the surgical procedure. Postoperative DSA revealed a residual AVM in one patient.

CONCLUSIONS

IOMD constitutes a safe, accurate, and low-cost imaging modality for evaluating blood flow velocities and for optimal stepwise AVM elimination without unnecessary sacrifice of veins. PI and RI are reliable parameters in diagnosing cerebrovascular malformations, but systolic and diastolic flow velocities may vary to a greater extent. This phenomenon has never been elucidated previously and therefore needs to be emphasized when using this technique intraoperatively.

Changes in volume of giant intracranial aneurysms treated by surgical strategies other than direct clipping

BACKGROUND

Giant intracranial aneurysms (GIA) are often not eligible for direct clip occlusion. Surgical alternatives include partial clip occlusion or the placement of a cerebrovascular bypass or the combination of both. These alternative indirect strategies are expected to lead to a decrease in GIA volume over time rather than instantaneously. To examine whether this is the case, we analyzed follow-up imaging results 1 year after surgery.

METHODS

We retrospectively screened the prospective GIA Registry's imaging database for anterior circulation GIA treated by surgical strategies other than direct clipping. We measured pre- and 1-year post-treatment GIA volume, lateral ventricle volume (LVV), and mid-line shift (MLS) in 19 cases.

RESULTS

After a mean follow-up of 466 days (standard deviation ±171) GIA volumes decreased from 9.6 cm(3) (interquartile range (IQR) 6.1-14.1) to 4.3 cm(3) (IQR 2.9-5.7; p < 0.01). Ipsilateral LVV increased from 8.6 cm(3) (IQR 6.4-24.9) to 16.0 cm(3) (IQR 9.1-27.2; p < 0.01) while contralateral LVV increased from 10.3 cm(3) (IQR 7.3-20.1) to 11.7 cm(3) (IQR 8.2-19.4; p = 0.02). MLS changed from 0.1 mm (IQR -1.9 to 2.0) to -0.9 mm (IQR -1.8 to 0.4; p = 0.03). The decrease in GIA volume correlated with the increase in ipsilateral LVV (rs = 0.60; p = 0.01) but not with the changes in MLS (rs = 0.41; p = 0.08).

CONCLUSIONS

In our patient cohort, surgical strategies other that direct clipping for the treatment of anterior circulation GIA lead to a significant decrease in GIA volume over time. The resulting decrease in mass effect was more sensitively monitored by the measurement of changes in ipsilateral LVV than changes in MLS.

CLINICAL TRIAL REGISTRATION-URL

http://www.clinicaltrials.gov . Unique identifier: NCT02066493.