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Stagnant blood flow and organizing thrombus are intralesional components of patients with cerebral cavernous malformations (CCM). Stasis and inflammation are mechanisms of growth, lesional instability and acute hemorrhages with or w/o symptoms. We evaluate the association of pre-diagnostic aspirin and/or statin use with acute hemorrhages at diagnosis. Patients with a CCM diagnosis were identified and categorized according to their medications on admission into four groups (no therapy, statin, aspirin, combined). The primary outcome was an acute hemorrhage (with or w/o symptoms) at diagnosis reported in a standardized manner from the T2 weighted magnetic resonance image. A multivariate generalized linear mixed models (GLMM) was utilized to conduct per-lesion analysis. We identified 446 patients with 635 lesions. An acute hemorrhage at diagnosis was observed in 31% of the patients. There were 328 patients without statin or aspirin therapy, 34% of whom presented with acute hemorrhage. Of patients on aspirin therapy at diagnosis, 25% presented with hemorrhage. Of patients on statin therapy, 26% had a hemorrhage at diagnosis. Combined therapy in 44 patients demonstrated a lower proportion of patients with acute hemorrhages (7 patients, 16% incidence). A GLMM showed that patients in the combined therapy group to have significantly lower odds of having an acute hemorrhage at diagnosis compared to the reference group of no therapy (OR 0.24; 95% CI 0.09–0.59; P = 0.002). Patients with a CCM receiving therapy with both aspirin and statins were less likely to present at diagnosis with acute hemorrhage.

New York City has become the global epicenter of the coronavirus 2019 (COVID-19) pandemic. Despite a massive shift in health care resources, cerebrovascular disease continues to be a substantial burden. We review the first 10 patients undergoing thrombectomy following a series of governmental and institutional policy changes diverting resources to the care of critically ill patients with COVID-19. Ten patients with emergent large-vessel occlusion underwent thrombectomy between March 23 and April 1, 2020. Five patients tested positive for the COVID-19 virus. Successful reperfusion was achieved in 9 of 10 patients, at a median time of 37 minutes from vascular access. The postprocedural NIHSS score improved by an average of 7.7 points. Of the 5 patients positive for COVID-19, none have experienced a critical respiratory illness. We report the early incidence of COVID-19 positivity in patients with emergent large-vessel occlusion and demonstrate that thrombectomy continues to be an efficacious option, as well as safe for health care providers.

In an attempt to make a step forward towards predictive fire modelling, the application of turbulence modelling approaches, calculating the sub-grid scale viscosity, kinetic energy, turbulent Prandtl and Schmidt numbers based on a dynamic procedure, has been tested on a wide range of pool fire scenarios (i.e., MaCFP workshop test cases). Through the use of Large Eddy Simulations, it is investigated whether the applied modelling approaches can accurately predict the pool fire dynamics on different grid sizes and result in improved predictions compared to models using constant parameters. Additionally, it is evaluated whether the theoretical constants related to turbulence modelling, derived from isotropic decaying turbulence scenarios, are justified in turbulent buoyant flows.

BACKGROUND AND PURPOSE: The Neuroform Atlas is a new microstent to assist coil embolization of intracranial aneurysms that recently gained FDA approval. We present a postmarket multicenter analysis of the Neuroform Atlas stent. MATERIALS AND METHODS: On the basis of retrospective chart review from 11 academic centers, we analyzed patients treated with the Neuroform Atlas after FDA exemption from January 2018 to June 2019. Clinical and radiologic parameters included patient demographics, aneurysm characteristics, stent parameters, complications, and outcomes at discharge and last follow-up. RESULTS: Overall, 128 aneurysms in 128 patients (median age, 62 years) were treated with 138 stents. Risk factors included smoking (59.4%), multiple aneurysms (27.3%), and family history of aneurysms (16.4%). Most patients were treated electively (93.7%), and 8 (6.3%) underwent treatment within 2 weeks of subarachnoid hemorrhage. Previous aneurysm treatment failure was present in 21% of cases. Wide-neck aneurysms (80.5%), small aneurysm size (

OBJECTIVEThe Pipeline embolization device (PED) is a routine choice for the endovascular treatment of select intracranial aneurysms. Its success is based on the high rates of aneurysm occlusion, followed by near-zero recanalization probability once occlusion has occurred. Therefore, identification of patient factors predictive of incomplete occlusion on the last angiographic follow-up is critical to its success.METHODSA multicenter retrospective cohort analysis was conducted on consecutive patients treated with a PED for unruptured aneurysms in 3 academic institutions in the US. Patients with angiographic follow-up were selected to identify the factors associated with incomplete occlusion.RESULTSAmong all 3 participating institutions a total of 523 PED placement procedures were identified. There were 284 procedures for 316 aneurysms, which had radiographic follow-up and were included in this analysis (median age 58 years; female-to-male ratio 4.2:1). Complete occlusion (100% occlusion) was noted in 76.6% of aneurysms, whereas incomplete occlusion (≤ 99% occlusion) at last follow-up was identified in 23.4%. After accounting for factor collinearity and confounding, multivariable analysis identified older age (> 70 years; OR 4.46, 95% CI 2.30–8.65, p < 0.001); higher maximal diameter (≥ 15 mm; OR 3.29, 95% CI 1.43–7.55, p = 0.005); and fusiform morphology (OR 2.89, 95% CI 1.06–7.85, p = 0.038) to be independently associated with higher rates of incomplete occlusion at last follow-up. Thromboembolic complications were noted in 1.4% and hemorrhagic complications were found in 0.7% of procedures.CONCLUSIONSIncomplete aneurysm occlusion following placement of a PED was independently associated with age > 70 years, aneurysm diameter ≥ 15 mm, and fusiform morphology. Such predictive factors can be used to guide individualized treatment selection and counseling in patients undergoing cerebrovascular neurosurgery.

Objective Frame-based stereotactic biopsy (FSB) remains the “gold standard” for obtaining diagnostic samples of intracranial lesions to guide therapy. Nevertheless, diagnostic yield is highly variable. This study aims to provide an analysis of diagnostic yield, surgical complications, and factors associated with obtaining nondiagnostic samples in a contemporary FSB series. Methods A retrospective cohort study was conducted of all adult patients with imaging-documented lesions undergoing FSB at our institution between 2013 and 2018. Diagnostic accuracy, lesion characteristics associated with nondiagnostic biopsy, and surgical complications were evaluated. A biopsy was considered nondiagnostic if all frozen samples and the final pathology yielded normal brain tissue or nonspecific reactive tissue unless the “reactive” pathology was consistent with radiation injury from prior therapy. Results Our search identified 198 FSB patients. Mean (standard deviation) age was 62 ± 17 years, and 44.2% were female. Median procedure time was 32 minutes. A definitive histologic diagnosis was established in 187 cases (94.4% diagnostic yield). Mean lesion diameter was 31.9 ± 16.8 mm. Multivariable logistic regression revealed only lesion diameter to be significantly associated with diagnostic result (odds ratio for nondiagnostic result: 0.94 per mm diameter decrease, 95% confidence interval 0.87–0.99, P = 0.028). On univariable analysis, diagnosis of central nervous system lymphoma appeared to increase the risk of a nondiagnostic biopsy (P = 0.025), but this association disappeared when controlling for lesion size and steroid administration before biopsy. Eight patients (4.0%) developed postoperative hemorrhagic complications, 3 of whom required reoperation, and another expired. Conclusions This study demonstrates that diagnostic yield from contemporary FSB is high and depends predominantly on lesion size.

Adjacent segment disease (ASD) is a long-term complication of lumbar spinal fusion. This study aims to evaluate demographic and operative factors that influence development of ASD after fusion for lumbar degenerative pathologies.A retrospective cohort study was performed on patients undergoing instrumented lumbar fusion for degenerative disorders (spondylolisthesis, stenosis, or intervertebral disk degeneration) with a minimum follow-up of 6 months.Our inclusion criteria were met by 568 patients; 29.4% of patients had developed surgical ASD. Median follow-up was 2.8 years. Multivariate logistic regression analysis showed that decompression of segments outside the fusion construct had higher ASD (odds ratio = 2.6; P 0.001), and those undergoing fusion for spondylolisthesis had lower ASD (odds ratio = 0.47; P = 0.003).Results of our study show that the most important surgical factor contributing to ASD is decompression beyond fused levels. Hence caution should be exercised when decompressing spinal segments outside the fusion construct. Conversely, spondylolisthesis patients had the lowest ASD rates in our cohort.

Both unfractionated heparin (UH) and low-molecular-weight heparin (LMWH) are routinely used prophylactically after traumatic brain injury (TBI) to prevent deep vein thrombosis (DVT). Their comparative risk for development or worsening of intracranial hemorrhage necessitating cranial decompression is unclear. Furthermore, the absence of a specific antidote for LMWH may lead to UH being used more often for high-risk patients. This study aims to compare the incidence of delayed cranial decompression occurring after initiation of prophylactic UH versus LMWH using the National Trauma Data Bank.Cranial decompression procedures included craniotomy and craniectomy. Multiple imputation was used for missing data. Propensity score matching was used to account for selection bias between UH and LMWH. The 1:1 matched groups were compared using logistic regression for the primary outcome of postprophylaxis cranial decompression.A total of 218,594 patients with TBI were included, with 61,998 (28.3%) receiving UH and 156,596 (71.7%) receiving LMWH as DVT prophylaxis. The UH group had higher patient age, body mass index, comorbidity rates, Injury Severity Score, and worse motor Glasgow Coma Scale score. After the UH and LMWH groups were matched for these factors, logistic regression showed lower rates of postprophylaxis cranial decompression for the LMWH group (odds ratio, 0.13; 95% confidence interval, 0.11-0.16; P0.001).Despite the absence of a specific antidote, LMWH was associated with lower rates of need for post-DVT-prophylaxis in craniotomy/craniectomy. This finding questions the notion of UH being safer for patients with TBI because it can be readily reversed. Randomized studies are needed to elucidate causality.

Stage 3 acute kidney injury (AKI) has been observed to develop after serious traumatic brain injury (TBI) and is associated with worse outcomes, though its incidence is not consistently established. This study aims to report the incidence of stage 3 AKI in serious isolated TBI in a large, national trauma database and explore associated predictive factors.This was a retrospective cohort study using 2015-2018 data from the American College of Surgeons Trauma Quality Improvement Program, a national database of trauma patients. Adult trauma patients admitted to the hospital with isolated serious TBI were included. Variables relating to demographics, comorbidities, vitals, hospital presentation, and course of stay were assessed. Imputed multivariable logistic regression assessed factors predictive of stage 3 AKI development.A total of 342,675 patients with isolated serious TBI were included, 1585 (0.5%) of whom developed stage 3 AKI. Variables associated with stage 3 AKI in multivariable analysis were older age, male sex, Black race, higher body mass index, history of hypertension, diabetes, peripheral artery disease, chronic kidney disease, higher injury severity score, higher heart rate on arrival, lower oxygen saturation and motor Glasgow Coma Scale, admission to the intensive care unit or operating room, development of catheter-associated urinary tract infections or acute respiratory distress syndrome, longer intensive care unit stay, and ventilation duration.Stage 3 AKI occurred in 0.5% of serious TBI cases. Complications of acute respiratory distress syndrome and catheter-associated urinary tract infections are more likely to co-occur with stage 3 AKI in patients with serious TBI.

Background: Aneurysmal persistence after flow diversion (FD) occurs in 5% to 25% of aneurysms, which may necessitate retreatment. There are limited data on safety/efficacy of repeat FD—a frequently utilized strategy in such cases. Methods: A series of consecutive patients undergoing FD retreatment from 15 centers were reviewed (2011–2019), with inclusion criteria of repeat FD for the same aneurysm at least 6 months after initial treatment, with minimum of 6 months post-retreatment imaging. The primary outcome was aneurysmal occlusion, and secondary outcome was safety. A multivariable logistic regression model was constructed to identify predictors of incomplete occlusion (90%–99% and Results: Ninety-five patients (median age, 57 years; 81% women) harboring 95 aneurysms underwent 198 treatment procedures. Majority of aneurysms were unruptured (87.4%), saccular (74.7%), and located in the internal carotid artery (79%; median size, 9 mm). Median elapsed time between the first and second treatment was 12.2 months. Last available follow-up was at median 12.8 months after retreatment, and median 30.6 months after the initial treatment, showing complete occlusion in 46.2% and near-complete occlusion (90%–99%) in 20.4% of aneurysms. There was no difference in ischemic complications following initial treatment and retreatment (4.2% versus 4.2%; P >0.99). On multivariable regression, fusiform morphology had higher nonocclusion odds after retreatment (odds ratio [OR], 7.2 [95% CI, 1.97–20.8]). Family history of aneurysms was associated with lower odds of nonocclusion (OR, 0.18 [95% CI, 0.04–0.78]). Likewise, positive smoking history was associated with lower odds of nonocclusion (OR, 0.29 [95% CI, 0.1–0.86]). History of hypertension trended toward incomplete occlusion (OR, 3.10 [95% CI, 0.98–6.3]), similar to incorporated branch into aneurysms (OR, 2.78 [95% CI, 0.98–6.8]). Conclusions: Repeat FD for persistent aneurysms carries a reasonable success/safety profile. Satisfactory occlusion (100% and 90%–99% occlusion) was encountered in two-thirds of patients, with similar complications between the initial and subsequent retreatments. Fusiform morphology was the strongest predictor of retreatment failure.

Levonorgestrel-releasing intrauterine devices (LIUDs) are thought to release this progestin locally in the uterus to limit side effects. Authors here present a case of treatment-refractory hydrocephalus and pseudomeningocele (PMC), both of which fully resolved after LIUD removal.A 35-year-old woman with an implanted LIUD developed symptomatic PMC and hydrocephalus after suboccipital craniectomy for Chiari malformation type I. Over the next 8 months, she underwent ventriculoperitoneal shunt placement and two attempts at needle decompression of the fluid collection, which did not relieve her symptoms or the PMC, except for a few days at a time. Subsequently, she had her LIUD removed. Three weeks after removal of the LIUD, her symptoms as well as the fluid collection resolved completely without any further intervention. Thus, the increased intracranial pressure and associated persistence of the PMC may be partially attributed to the LIUD.This case indicates that a persistent problem (PMC and intracranial hypertension) that may be associated with the LIUD rapidly resolves after its removal. Implication of LIUDs as the cause of intracranial hypertension is still a matter of controversy. Further studies are needed to evaluate any potential causal relationship between LIUDs and intracranial hypertension, and physicians are advised to consider this scenario in their differential diagnosis.

Introduction:Controversy exists in antiepileptic drug (AED) prophylaxis prescribing in patients with aneurysmal subarachnoid hemorrhage (SAH). We undertook the Use of Antiepileptic Drugs in Aneurysmal Subarachnoid Hemorrhage (ALIBI) study to identify factors associated with prescribing practices.Methods:A retrospective chart review of all consecutive patients requiring Level 1 care with aneurysmal SAH admitted between 2012 and 2014 to the intensive care unit at Toronto Western Hospital, Ontario, Canada, was conducted. Data were collected on clinical and imaging characteristics. Primary and secondary outcomes were AED prophylaxis and clinical seizure activity during hospitalization. Data were compared using chi-square or Mann–Whitney U-tests. Those variables found to be significant, or trending toward significance, on univariate analysis were fitted to multivariate regression.Results:Sixty-eight patients were included. Mean age was 62 ± 12.2, and 42.6% of patients were male. Of these, 21 patients (30.9%) received AED prophylactically, while 18 (26.5%) had reported seizures at some point during hospitalization. Female gender and presence of midline shift (MLS) were significantly associated or approached significance with AED prophylaxis in univariate analysis (p = 0.036 and p = 0.062, respectively). In multivariate analysis, only MLS was an independent predictor (odds ratio 5.09, p = 0.04).Conclusion:The presence of MLS was an independent predictor of seizure activity in patients with aneurysmal SAH. AED prophylaxis prescribing patterns seemed arbitrary and was not informed by identifiable clinical factors or true risk factors for seizure. A current lack of evidence guiding AED prescribing practice highlights the need for larger studies in this patient population.

Large eddy simulations of flame extinction with N2 as extinguishing agent are performed focusing on combustion modelling with infinitely fast chemistry. EDM and EDC combustion models, an enthalpy-based flame extinction model based on a locally variable critical flame temperature and WSGGM for radiation are employed in order to predict flame extinction in a turbulent CH4 line burner. The numerical predictions of mean thermocouple temperatures, combustion efficiencies and radiative fractions with different grid sizes are compared to the experiments by White et al. (2015). Overall, the results from the numerical simulations agree well qualitatively and, to some extent, quantitatively with the experimental data when small grid sizes are employed. The examined centerline and radial profiles at two axial locations of the mean temperatures are reasonably well predicted. The decrease in the combustion efficiencies as the extinction limit is approached is reproduced by the numerical simulations. The decreasing trend in the radiative fractions as the oxidizer stream is diluted with N2 is also captured by the simulations using a WSGGM model for radiation. Nevertheless, the influence of the combustion model is shown to be substantial towards predicting flame extinction due to differences in the predicted flame temperatures. Equally important is the influence of the simple re-ignition model based on a constant re-ignition temperature.

Large eddy simulations of water spray-hot air jet plume interactions, as obtained with FireFOAM 2.2.x, are presented. Three hot air jet plumes, with thermal powers of 1.6, 2.1 and 2.6 kW, are examined, interacting with a water spray with discharge rate of 0.084 lpm. A systematic comparison between simulations and experiments involving only the hot air jet plumes, the water spray alone and the combination of the two has been performed in order to evaluate the predictive capabilities of FireFOAM. Overall, the code is capable of predicting well the mean values of the hot air jet plumes but deviations are evident for the rms values. Discrepancies in the predictions of the volume fluxes in the near-field for the water spray alone case are observed if the experimentally reported injection angle is used. Improvements are observed if the injection angle is modified based on the experimentally reported data in the near-field. The interactions between the hot air jet plumes and water sprays, are characterized by the location of the interaction region. The interaction boundary moves up from the base of the plume by increasing the convective heat release rates. The simulation results follow the experimental trend but deviate up to 26% due to the differences in the predicted hot air jet plumes and spray characteristics.

Focusing on advancing predictive fire modeling, large eddy simulations using improved approaches related to thermophysical, turbulence, combustion and radiation modeling are presented. More specifically, the consideration of a non-unity Lewis number, the use of the Hirschfelder-Curtiss diffusion model, the inclusion of differential diffusion and Soret effects, the application of the dynamic Smagorinsky model with a variable turbulent Prandtl number, an eddy dissipation concept model for combustion and the weighted-sum-of-gray-gases model for radiation have been included in a modified version of fireFoam 2.2.x. A comprehensive comparison between the predictions of the modified code against the standard version of fireFoam and experimental data of a medium-scale 22.6 kW methanol pool fire is presented. Evaporation modeling is not yet included.

Progress in fire safety science strongly relies on the use of Computational Fluid Dynamics (CFD) to simulate a wide range of scenarios, involving complex geometries, multiple length/time scales and multi-physics (e.g., turbulence, combustion, heat transfer, soot generation, solid pyrolysis, flame spread and liquid evaporation), that could not be studied easily with analytical solutions and zone models. It has been recently well recognised in the fire community that there is need for better modelling of the physics in the near-wall region of boundary layer combustion. Within this context, heat transfer modelling is an important aspect since the fuel gasification rate for solid pyrolysis and liquid evaporation is determined by a heat feedback mechanism that depends on both convection and radiation. The paper focuses on convection and reviews the most commonly used approaches for modelling convective heat transfer with CFD using Large Eddy Simulations (LES) in the context of fire-driven flows. The considered test cases include pool fires and turbulent wall fires. The main assumptions, advantages and disadvantages of each modelling approach are outlined. Finally, a selection of numerical results from the application of the different approaches in pool fire and flame spread cases, is presented in order to demonstrate the impact that convective heat transfer modelling can have in such scenarios.

Focusing on convective heat transfer modelling upward flame spread scenarios, different methods for calculating the convective heat fluxes are explored. These approaches involve: 1) calculating convective heat transfer based on the stagnant film theory; 2) using a simplified approach based on the stagnant film theory; 3) using Nusselt correlations for natural convection; and 4) modelling convection based on the effective (i.e., laminar plus sgs) thermal diffusivity. Large eddy simulations (LES) of a series of Single Burning Item (SBI) experiments with Medium Density Fiberboard (MDF) and plywood walls are performed. Even though discrepancies are observed, the approach which considered the sgs effects performs overall better and is able to predict both the initial flame growth period and the decay phase with reasonable accuracy (i.e., deviations in the peak HRR of approximately 5 % and 34 % for the MDF and plywood tests cases, respectively). The predicted total heat fluxes are, in most cases, in fairly good agreement with the experiments (i.e., deviations of up to 15 % and 20 % for the MDF and plywood tests cases, respectively). The predictions with the other methods are far less satisfactory. Overall, it is demonstrated that accurate convective heat transfer modelling can be important in flame spread scenarios.

Background The ISAT (International Subarachnoid Aneurysm Trial) has generated a paradigm shift towards endovascular treatment for intracranial aneurysms but remains unclear if this has led to a true reduction in the risk for aneurysmal subarachnoid hemorrhage (aSAH). We sought to study the association between the treatment burden of unruptured and ruptured aneurysms in the post‐ISAT era. Methods and Results Admissions data from the National Inpatient Sample (2004–2014) were extracted, including patients with a primary diagnosis of aSAH or unruptured intracranial aneurysms treated by clipping or coiling. Within each year, this combined group was randomly matched to non‐aneurysmal control group, based on age, sex, and Elixhauser comorbidity index. Multinomial regression was performed to calculate the relative risk ratio of undergoing treatment for either ruptured or unruptured aneurysms in comparison with the reference control group, adjusted for time. After adjusting for National Inpatient Sample sampling effects, 243 754 patients with aneurysm were identified, 174 580 (71.6%) were women; mean age, 55.4±13.2 years. A total of 121 882 (50.01%) patients were treated for unruptured aneurysms, 79 627 (65.3%) endovascularly and 42 256 (34.7%) surgically. A total of 121 872 (49.99%) patients underwent procedures for aSAH, 68 921 (56.6%) endovascular, and 52 951 (43.5%) surgically. Multinomial regression revealed a significant year‐to‐year decrease in aSAH procedures compared with the control group of non‐aneurysmal hospitalizations (relative risk ratio, 0.963 per year; P P =0.35). Conclusions With each passing year, there is a significant decrease in relative risk ratio of undergoing treatment for aSAH, concomitant with a stable annual risk of undergoing treatment for unruptured intracranial aneurysms.

The role of an early CTA approach in neurologically stable patients with nontraumatic SAH has not been assessed. This study explored the use of CTA in clinically stable SAH patients to pre-emptively identify cerebral vasospasm, to evaluate whether this approach is associated with improved clinical outcomes.We conducted a retrospective chart review of SAH patients presenting between July 2007 and December 2016 in a single academic center. Patients were divided into two groups: (1) Early CTA (stable patients who underwent a CTA between days 5-8 post-SAH), and (2) Standard Protocol. The co-primary outcomes were a composite of the mRS at discharge and last clinical follow-up (good = 0-2; poor = 3-6). A multivariable binary logistic regression was conducted to compare both groups against outcomes, controlling for potential confounders.A total of 415 patients were included, 103 (24.8%) with early CTA, and 312 (75.2%) undergoing the standard protocol; the mean age was 57 years and 248 (59.8%) patients were female. Patients in the early CTA group had a higher modified Fisher grade (3-4) (87.4% vs 63.1%; p 0.02). The multivariable analysis showed that early CTA was independently associated with lower poor outcomes at discharge (OR = 0.21, 95% CI 0.07-0.61, p = 0.004). Plus, vasospasm detection was associated with an increased risk of poor outcomes (OR = 4.77, 95% CI 1.41 - 16.10, p = 0.01). Early CTA was not associated with outcomes at clinical follow-up.The early CTA surveillance approach was associated with better functional outcomes at discharge when compared to the current imaging standard practice.

Background: The COVID-19 pandemic presented unique challenges for endoscopic skull base surgery (ESBS) given the elevated viral load in the nasopharynx and aerosolization of particles inherent to the endoscopic endonasal approach (EEA). Furthermore, reports and anecdotes shared within the skull base surgeon community suggesting potential elevated risk of COVID-19 transmission during ESBS led to an abundance of precaution and scrutiny regarding endonasal procedures during the pandemic. The Mount Sinai Hospital is a busy ESBS center located in New York City, the United States COVID-19 pandemic epicenter. We report a case series describing the early experience of resuming ESBS during the COVID-19 pandemic, including systems for case selection, surgical precautions and modifications, and patient outcomes. Methods: All consecutive ESBS cases and deferred surgical cases were identified prospectively within the first three-week period after resumption of urgent scheduled surgery. Data regarding indications, pre-surgical screening, operative results, and postoperative course were collected retrospectively. All data are presented using descriptive statistics. Results: With the study time frame, 14 patients underwent ESBS. Four patients had surgery deferred. The mean age was 57. The most common pathology was pituitary tumor, in 57% of patients. Visual symptoms precipitated the urgency in 36% of cases. All patients underwent COVID-19 screening with a minimum of one SARSCoV-2 reverse transcriptase polymerase chain reaction (RT-PCR) nasal swab within 48 hours preceding surgery. All patients tested negative. There were no intraoperative complications. Median length of stay was two days. A total of 14% of patients experienced postoperative complications. Mean follow-up was 100.9 days. Conclusions: Due to its relatively low morbidity and potential short length of stay, ESBS is adaptable to unique pandemic challenges such as bed scarcity and exposure minimization. As endoscopic centers return to normal operations during the COVID-19 era, standard testing, case selection algorithms, and systematic surgical precautions and modifications can enable a safe resumption of ESBS.

The COVID-19 pandemic has forced neurosurgeons to adapt in the face of an unforeseen crisis, including reevaluating an important aspect of neurosurgical practice: surgical infection control and prevention. Before COVID-19, surgical site infections (SSI) remained a costly and burdensome issue within neurosurgery and the medical field at-large. Furthermore, as options for linking payment to quality of care and mandatory reporting of SSI expands, cranial and spine surgery can expect to face increased oversight and pressure in efforts to reduce SSI. The risk of COVID-19 transmission to both patients and healthcare workers has inspired rigorous attention to inspection control practices. Therefore, at our institution we have applied the momentum gained introducing new infection control practices and procedures to prevent of COVID-19 transmission to the adoption of a surgical infection control bundle. We describe our implementation spanning screening and selection of patients for surgery, intraoperative precautions, postoperative care, and systems for monitoring and feedback.

Focusing on convective heat transfer modelling of pool fires, different approaches for calculating the convective heat fluxes at the pool surface have been employed, namely to resolve them; model them based on Nusselt correlations for forced or natural convection; model them based on the stagnant film theory. Large eddy simulations of medium-scale, 30 cm in diameter, alcohol pool fires (methanol, ethanol and acetone) are conducted and compared against experimental convective and radiative heat flux measurements. Overall, the best approach is the one based on the stagnant film theory which is only slightly grid sensitive, and provides satisfactory predictions for all the different fuels tested. The predictions using the other approaches are highly grid dependent, due to a fuel rich region formed just above the pool surface when the grid size is refined, which greatly influence the calculation of the convective heat fluxes using the first grid cell values.

Background The severe acute respiratory syndrome coronavirus 2 pandemic has created challenges to neurosurgical patient care. Despite editorials evaluating neurosurgery responses to 2019 novel coronavirus disease (COVID-19), data reporting effects of COVID-19 on neurosurgical case volume, census, and resident illness are lacking. The aim of this study was to present a real-world analysis of neurosurgical volumes, resident deployment, and unique challenges encountered during the severe acute respiratory syndrome coronavirus 2 outbreak peak in New York City. Methods Daily census and case volume data were prospectively collected throughout the severe acute respiratory syndrome coronavirus 2 outbreak in spring 2020. Neurosurgical census was compared against COVID-19 system-wide data. Neurosurgical cases during the crisis were analyzed and compared with 7-week periods from 2019 and early 2020. Resident deployment and illness were reviewed. Results From March 16, 2020, to May 5, 2020, residents participated in 72 operations and 69 endovascular procedures compared with 448 operations and 253 endovascular procedures from January 2020 to February 2020 and 530 operations and 340 endovascular procedures from March 2019 to May 2019. There was a 59% reduction in neurosurgical census during the outbreak (median 24 patients, 2.75 average total cases daily). COVID-19 neurosurgical admissions peaked in concert with the system-wide pandemic. Three residents demonstrated COVID-19 symptoms (no hospitalizations occurred) for a total 24 workdays lost (median 7 workdays). Conclusions These data provide real-world guidance on neurosurgical infrastructure needs during a COVID-19 outbreak. While redeployment to support the COVID-19 response was required, a significant need remained to continue to provide critical neurosurgical service.

Background Aneurysmal persistence after flow-diversion (FD) occurs in 5–25% of aneurysms which might necessitate further treatment. A frequently used retreatment paradigm utilizes the deployment of another flow-diverting device (FDD) in a telescoping fashion within the existing device. There are no current data evaluating this strategy. Methods A retrospective review of patients undergoing FD retreatment from 15 centers was performed, with inclusion criteria being repeat FD occurring for the same aneurysm at least 6 months after initial treatment, with minimum of 6 months of imaging follow-up after retreatment. Primary outcome was aneurysmal occlusion, and secondary outcomes were safety and complications. A multivariable logistic regression model was constructed to identify predictors of persistence/occlusion after retreatment. Comparative Kaplan-Meier curves were developed to assess the effect of early (6–12 months since initial treatment) vs late retreatment (>12 months since initial treatment) on the cumulative incidence of aneurysm occlusion over time. Results Ninety-five patients (median age 57, 81% females) harboring 95 aneurysms underwent 198 treatment procedures. In our cohort, 87.4% of aneurysms were unruptured; 74.7% were saccular and 79% were located in the internal carotid artery (median maximal diameter 9-mm), with 87 patients treated twice and 8 patients treated thrice. Median elapsed-time between first and second treatment was 12.2 months. Last available follow-up was performed at median of 12.8 months after retreatment, and median of 30.6 months after initial treatment, showing complete occlusion in 46.2%, and near-complete occlusion (90–99%) in 20.4% of aneurysms. No difference in ischemic complications following initial treatment and retreatment (4.2% vs 4.2; p>0.99). On multivariable logistic regression, fusiform morphology was associated with higher odds of non-occlusion after retreatment (OR 7.2; p=0.003), with history of hypertension and incorporated branch into aneurysms trending toward incomplete occlusion (p=0.055 and p=0.054; respectively). Family history of aneurysms and positive smoking history were associated with higher odds of complete occlusion (p=0.019 and p=0.026; respectively). Kaplan-Meier curves comparative estimators showed no significant difference in time-to-occlusion between the two groups (log rank test, p=0.48). Conclusion Repeat flow diversion for persistent aneurysms is safe and effective. Fusiform morphology is the strongest predictor of aneurysmal persistence after repeat flow diversion. Disclosures M. Salem: None. A. Sweid: None. A. Kuhn: None. A. Dmytriw: None. S. Gomez-Paz: None. G. Maragkos: None. M. Waqas: None. C. Parra-Farinas: None. A. Salehani: None. N. Adeeb: None. P. Brouwer: None. G. Pickett: None. M. Ghuman: None. V. Yang: None. A. Weill: None. C. Cognard: None. L. Renieri: None. P. Kan: None. N. Limbucci: None. V. Mendes Pereira: None. M. Harrigan: None. A. Puri: None. E. Levy: None. J. Moore: None. C. Ogilvy: None. T. Marotta: None. P. Jabbour: None. A. Thomas: None.

Background The International Subarachnoid Aneurysm Trial has generated a paradigm shift towards endovascular procedures for treating intracranial aneurysms, but it remains unclear if this has led to a true reduction in the risk for aneurysmal subarachnoid hemorrhage (aSAH). Our study aims to simultaneously quantify the annual intervention rates for ruptured and unruptured cerebral aneurysms, in order to evaluate any association between the treatment burden of unruptured and ruptured aneurysms after the endovascular treatment era. Methods Admissions data from the National Inpatient Sample (NIS; 2004–2014) were extracted. Patients with a primary diagnosis of subarachnoid hemorrhage or unruptured aneurysms treated by either clipping or coiling were included. Within each year, this combined group was randomly matched to a non-aneurysmal control group, based on age, sex and Elixhauser comorbidity index. Multinomial logistic regression was performed to calculate the relative risk ratio (RRR) of undergoing treatment for either ruptured or unruptured aneurysms in comparison to the reference control group, adjusted for time. Results After adjusting for the NIS sampling effects, 243,7754 aneurysm patients were identified, 174,580 (71.6%) of whom were female. The mean (SD) age was 55.4±13.2 years. A total of 121,882 (50.01%) patients were treated for unruptured aneurysms, 79,627 (65.3%) endovascularly and 42,256 (34.7%) surgically. A total of 121,872 (49.99%) patients underwent procedures for aSAH, 68,921 (56.6%) endovascular and 52,951 (43.5%) surgical. Multinomial logistic regression revealed a significant year-to-year decrease in aSAH procedures compared to the control group of non-aneurysmal hospitalizations (RRR 0.963 per year, 95% CI 0.944–0.982, P Conclusion With each passing year, there is a significant decrease in RRR of undergoing treatment for aSAH, concomitant with a stable annual risk of undergoing treatment for UIA. Disclosures M. Salem: None. G. Maragkos: None. S. Gomez-Paz: None. L. Ascanio: None. L. Ngo: None. C. Ogilvy: None. A. Thomas: None. J. Moore: None.

Primary CNS lymphomas (PCNSLs) are aggressive diffuse large B-cell lymphomas (DLBCLs) limited to the CNS that generally have a poor prognosis. Classification of DLBCL into germinal center B-cell (GCB) and activated B-cell (non-GCB) subtypes has prognostic value in systemic DLBCL, with GCB-type having a better prognosis. The aim of this study was to determine whether GCB versus non-GCB classification in PCNSLs has similar prognostic value. We analyzed clinical, radiological and histologic data from 24 patients with biopsy confirmed DLBCL of the CNS with classification into GCB versus non-GCB subtypes. We found that after a median follow-up of 15 months, only 39% of patients with non-GCB-type PCNS DLBCL were alive, whereas all patients with GCB-type were alive. Non-GCB-type had a median survival of 11 months, whereas all GCB-type patients were alive after a median follow-up of 22 months. As previously reported, we also found that patients younger than 70 years had longer survival (median 29 months) compared to older patients (median 8.8 months). There was no statistically significant difference between the ages, gender, focality, size or location of lesions, or treatment of non-GCB and GCB-type patients. Our findings suggest that classifying PCNSLs into GCB versus non-GCB subtype using the Hans algorithm may help stratify patients into two groups with different prognosis.

BACKGROUND The association of blood pressure variation with poor outcomes in aneurysmal subarachnoid hemorrhage (aSAH) is unknown. OBJECTIVE To evaluate the association of systolic blood pressure (SBP) variation and clinical outcomes in aSAH. METHODS We conducted a retrospective chart review of all aSAH patients treated at an academic institution between 2007 and 2016. Patient demographics, aSAH characteristics, and blood pressure observations for the first 24 h of admission in 4-h intervals were obtained. SBP variability metrics assessed were mean, standard deviation, maximum, minimum, peak, trough, coefficient of variation, and successive variation. The primary outcome was a composite of the modified Rankin scale as good (0-2) or poor (3-6) at last follow-up. Comparisons between outcome groups were performed. Logistic regression models for each significant SBP metric controlling for potential confounders were constructed. RESULTS The study population was 202 patients. The mean age was 57 yr; 66% were female. The median follow-up time was 18 mo; 57 (29%) patients had a poor outcome. Patients with poor outcomes had higher standard deviation (17.1 vs 14.7 mmHg, P = .01), peak (23.5 vs 20.0 mmHg, P = .02), trough (22.6 vs 19.2 mmHg, P

Andexanet alfa, a novel anticoagulation reversal agent for factor Xa inhibitors, was recently approved. Traumatic intracranial hemorrhage presents a prime target for this drug. The Novel Antidote to the Anticoagulation Effects of Factor Xa Inhibitors study established the efficacy of andexanet alfa in reversing factor Xa inhibitors. However, the association between anticoagulation reversal and traumatic intracranial hemorrhage progression is not well understood. The objective of this study was to determine progression rates of patients with traumatic intracranial hemorrhage on factor Xa inhibitors prior to hospitalization who were managed without the use of andexanet alfa.A retrospective cohort study was performed between 2016 and 2019 at a single institution. An institutional traumatic brain injury (TBI) registry was queried. Patients with recorded use of apixaban or rivaroxaban18 hours before injury were included. The primary study outcome was35% increase in hemorrhage volume or thickness on repeated head computed tomography (CT) scans.We identified 25 patients meeting the inclusion criteria. Two patients were excluded because of a lack of necessary CT data. Twelve patients (52%) were receiving apixaban, and 11 were (48%) on rivaroxaban. On admission CT scan, 14 patients had subdural hematoma, 6 had traumatic intraparenchymal hemorrhage, and 3 had subarachnoid hemorrhage. Anticoagulation reversal was attempted in 17 patients (74%), primarily using 4-factor prothrombin complex concentrate. Twenty patients (87%) were adjudicated as having excellent or good hemostasis on repeat imaging.Our results indicate that patients on factor Xa inhibitors with complicated mild TBI have a similar intracranial hemorrhage progression rate to patients who are not anticoagulated or anticoagulated with a reversible agent. The hemostatic outcomes in our cohort were similar to those reported after andexanet alfa administration.

Objective Headache is the presenting symptom of unruptured intracranial aneurysm (UIA) in more than one-third of cases. Some patients may expect their headache to remit after aneurysm treatment. This study aims to identify factors influencing headache outcomes following endovascular treatment of UIA. Methods This prospective observational study was conducted in patients with UIAs treated with flow diversion. Subjects reported their headache intensity with a visual analog scale (VAS) and completed 3 surveys before treatment: Migraine Disability Assessment (MIDAS), Headache Impact Test (HIT-6), and Patient Health Questionnaire-2 (PHQ-2). Follow-up was at 1 month, 3 months, and 6 months after treatment. Analysis was performed using generalized mixed-effects models. Results We identified 38 patients, 29 of whom reported headaches at baseline (76.3%). Mean patient age was 55.3 ± 12.4 years, and 79% of the cohort was female. Mean aneurysm diameter was 6.8 ± 5.3 mm, and treatment modality was Pipeline embolization in all cases. At the last follow-up, 5 aneurysms (15.1%) were incompletely occluded. The mean VAS scores for patients with headache at baseline were 4.36 ± 0.59 at baseline, 4.08 ± 0.60 at 1 month, 3.04 ± 0.62 at 3 months, and 2.76 ± 0.57 at 6 months. Controlling for occlusion status, medication, and depression, significant improvement was seen at the 3- and 6-month follow-ups. Similar patterns were observed with MIDAS and HIT-6. Conclusions In the present study, endovascular UIA treatment led to significantly decreased headache intensity in patients with headache at baseline, after a short delay. Our data shed light on postintervention headache patterns and can help inform patient discussions and treatment expectations.

In the current dynamic health environment, increasing number of procedures are being completed by advanced practitioners (nurse practitioners and physician assistants). This is the first study to assess the clinical outcomes and safety of external ventricular drain (EVD) placements by specially trained advanced practitioners. Compare the safety and outcomes of EVD placement by advanced practitioners in patients with subarachnoid hemorrhage (SAH). A cohort comparison study was performed from an aneurysmal SAH database selecting patients treated with EVD from a single major academic institution in the USA between June 2007 and June 2017. Safety, accuracy, and complications of EVD placement were compared between advanced practitioners and neurosurgical physicians (attending neurosurgeon and subspecialty clinical fellow). Statistical analysis was performed using the Mann–Whitney test for continuous variables and χ2 test for categorical variables, with p values set at

Stroke in pregnant women has a mortality rate of 1.4 deaths per 100,000 deliveries. Vascular malformations are the most common cause of hemorrhagic stroke in this population; preeclampsia and other risk factors have been identified. However, nearly a quarter of strokes have an undeterminable cause. Spontaneous intracranial hemorrhage (ICH) is less frequent but results in significant morbidity. The main objective of this study is to review the literature on pregnant patients who had a spontaneous ICH. A systematic review of the literature was conducted on PubMed and the Cochrane library from January 1992 to September 2016 following the PRISMA guidelines. Studies reporting pregnant patients with spontaneous intraparenchymal hemorrhage (IPH), subarachnoid hemorrhage (SAH), and subdural hemorrhage (SDH) were selected and included if patients had non-structural ICH during pregnancy or up to 6 weeks postpartum confirmed by imaging. Twenty studies were included, and 43 patients identified. Twenty-two patients (51.3%) presented with IPH, 15 patients (34.8%) with SAH, and five patients (11.6%) with SDH. The most common neurosurgical management was clinical in 76.7% of patients, and cesarean section was the most common obstetrical management in 28% of patients. The most common maternal outcome was death (48.8%), and fetal outcomes were evenly distributed among term delivery, preterm delivery, and fetal or neonatal death. Spontaneous ICH carries a high maternal mortality with IPH being the most common type, most frequently presenting in the third trimester. Diagnosis and management do not differ for the parturient compared to the non-pregnant woman.

Computational Fluid Dynamics (CFD) results are discussed for momentum driven planar jet flows, resembling configurations in use for air curtain in the context of smoke control in building fire. The CFD package Fire Dynamics Simulator (FDS) is used. Special focus is given to the impact of grid resolution, synthetic turbulent inflow boundary condition and sub-grid scale eddy viscosity models. The computational results are compared with summarized literature data. Investigation of different set-ups of inlet boundary conditions, including the inlet duct length, velocity profile and method of generation of turbulence at the level of the inflow, reveals that the inlet boundary condition is the most influential factor governing the flow downstream. The FDS results successfully reproduce the planar jet flows, both in terms of mean variables and second-order statistics. ‘Reference’ results have been obtained with a fully developed turbulent flow emerging from a long inlet duct. By reducing the inlet duct length and applying the Synthetic Eddy Method (SEM) at the inflow boundary condition, the ‘reference’ results have been reproduced with a reduction in the computing times of approximately 20%. However, care must be taken when choosing the parameters of SEM, in particular the number of eddies and their length scale. The impact of turbulent viscosity model is noticeable, but not of primary importance for the flow at hand, provided that a sufficiently fine computational mesh is used.

The paper reports a comprehensive set of large-eddy simulations (LES) of a turbulent hot air jet impinging onto a ceiling. The hot air source is a 72-mm diameter circular nozzle with an exit temperature maintained at 205 °C. Three exit velocities have been tested: 3.3, 4.2 and 5.3 m/s, corresponding to Reynolds numbers of respectively 6800, 8600 and 10900 and Froude numbers of respectively 3.9, 5.0 and 6.3. The horizontal aluminium ceiling plate of 1.22 m × 1.22 m has been placed at a distance of 590 mm above the hot air nozzle. This configuration has been examined experimentally by Zhou [Proceedings of the Combustion Institute, 2015] to characterize gas phase conditions prior to experiments which aim at studying the interaction between hot air jets and water sprays. This paper constitutes the first part of a numerical study that aims at assessing the current modelling capabilities of the two-phase flow configuration examined by Zhou [Proceedings of the Combustion Institute, 2015]. The results show that the centerline mean vertical velocity profiles of the vertical jet are predicted with maximum deviations of less than 6% from the experimental data at the condition of an appropriate set-up of the inflow conditions (i.e., geometry of the inlet and turbulence inflow boundary conditions). Furthermore, the best results were obtained with the dynamic Smagorinsky model for the turbulent viscosity. The modified Deardorff results are nevertheless very good given the substantial decrease in computational time (in comparison to the dynamic Smagorinsky model). A good prediction of the vertical jet allowed relatively good predictions of the ceiling jet maximum velocity, boundary layer thickness and Gaussian momentum width with maximum deviations of respectively 20%, 1 mm and 18%. The numerical modelling of the gas phase described in this paper can thus be relied upon in the two-phase simulations described in the companion paper [Part II: Two-phase flow simulations].