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A systematic review and meta-analysis of the peri-operative outcomes of carotid endarterectomy (CEA) on dual antiplatelet therapy (DAPT) vs. aspirin monotherapy was carried out, to determine optimal peri-operative management with these antiplatelet agents.The Web of Science, Pubmed, and Embase databases were searched from inception to July 2021. The corresponding authors of excluded articles were contacted to obtain additional data for possible inclusion.The main outcomes included ischaemic complications (stroke, transient ischaemic attack [TIA], and transcranial Doppler [TCD] measured micro-emboli), haemorrhagic complications (haemorrhagic stroke, neck haematoma, and re-operation for bleeding), and composite outcomes. Pooled estimates using odds ratios (ORs) were combined using a random or fixed effects model based on the results of the chi square test and calculation of IIn total, 47 411 patients were included in 11 studies, with 14 345 (30.2%) receiving DAPT and 33 066 (69.7%) receiving aspirin only. There was no significant difference in the rates of peri-operative stroke (OR 0.87, 95% confidence interval [CI] 0.72 - 1.05) and TIA (OR 0.78, 95% CI 0.52 - 1.17) despite a significant reduction in TCD measured micro-emboli (OR 0.19, 95% CI 0.10 - 0.35) in the DAPT compared with the aspirin monotherapy group. Subgroup analysis did not reveal any significant difference in ischaemic stroke risk between patients with asymptomatic and symptomatic carotid artery stenosis. DAPT was associated with an increased risk of neck haematoma (OR 2.79, 95% CI 1.87 - 4.18) and re-operation for bleeding (OR 1.98, 95% CI 1.77 - 2.23) vs. aspirin. Haemorrhagic stroke was an under reported outcome in the literature.This meta-analysis found that CEA while on DAPT increased the risk of haemorrhagic complications, with similar rates of ischaemic complications, vs. aspirin monotherapy. This suggests that the risks of performing CEA on DAPT outweigh the benefits, even in patients with symptomatic carotid stenosis. The overall quality of studies was low, and improved reporting of CEA outcomes in the literature is necessary.

OBJECTIVE Torcular dural sinus malformations (tDSMs) are rare pediatric cerebrovascular malformations characterized by giant venous lakes localized to the midline confluence of sinuses. Historical clinical outcomes of patients with these lesions were poor, though better prognoses have been reported in the more recent literature. Long-term outcomes in children with tDSMs are uncertain and require further characterization. The goal of this study was to review a cohort of tDSM patients with an emphasis on long-term outcomes and to describe the treatment strategy. METHODS This study is a single-center retrospective review of a prospectively maintained data bank including patients referred to and cared for at The Hospital for Sick Children for tDSM from January 1996 to March 2019. Each patient’s clinical, radiological, and demographic information, as well as their mother’s demographic information, was collected for review. RESULTS Ten patients with tDSM, with a mean follow-up of 58 months, were included in the study. Diagnoses were made antenatally in 8 patients, and among those cases, 4 families opted for either elective termination (n = 1) or no further care following delivery (n = 3). Of the 6 patients treated, 5 had a favorable long-term neurological outcome, and follow-up imaging demonstrated a decrease or stability in the size of the tDSM over time. Staged embolization was performed in 3 patients, and anticoagulation was utilized in 5 treated patients. CONCLUSIONS The authors add to a growing body of literature indicating that clinical outcomes in tDSM may not be as poor as initially perceived. Greater awareness of the lesion’s natural history and pathophysiology, advancing endovascular techniques, and individualized anticoagulation regimens may lead to continued improvement in outcomes.

There is an increasing number of trauma patients presenting on pre-injury antiplatelet (AP) agents attributable to an aging population and expanding cardio- or cerebrovascular indications for antithrombotic therapy. The effects of different AP regimens on outcomes after traumatic brain injury (TBI) have yet to be elucidated, despite the implications on patient/family counseling and the potential need for better reversal strategies. The goal of this systematic review and meta-analysis was to assess the impact of different pre-injury AP regimens on outcomes after TBI. In accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the OVID Medline, Embase, BIOSIS, Scopus, and Cochrane databases were searched from inception to February 2022 using a combination of terms pertaining to TBI and use of AP agents. Baseline demographics and study characteristics as well as outcome data pertaining to intracerebral hematoma (ICH) progression, need for neurosurgical intervention, hospital length of stay, mortality, and functional outcome were extracted. Pooled odds ratios (ORs) and mean differences comparing groups were calculated using random-effects models. Thirteen observational studies, totaling 1244 patients receiving single AP therapy with acetylsalicylic acid or clopidogrel, 413 patients on dual AP therapy, and 3027 non-AP users were included. No randomized controlled trials were identified. There were significant associations between dual AP use and ICH progression (OR, 2.81; 95% confidence interval [CI], 1.19-6.61; I 2, 85%; p = 0.02) and need for neurosurgical intervention post-TBI (OR, 1.61; 95% CI, 1.15-2.28; I 2, 15%; p = 0.006) compared to non-users, but not between single AP therapy and non-users. There were no associations between AP use and hospital length of stay or mortality after trauma. Pre-injury dual AP use, but not single AP use, is associated with higher rates of ICH progression and neurosurgical intervention post-TBI. However, the overall quality of studies was low, and this association should be further investigated in larger studies.

The Woven EndoBridge (WEB) can be used to treat wide-necked aneurysms without antiplatelet medications, suggesting it may have advantages in the setting of aneurysmal subarachnoid hemorrhage (aSAH). The goal was assessment of safety and efficacy of WEB in aSAH given the delayed nature of aneurysmal thrombosis. An international retrospective analysis of patients with aSAH treated with WEB was conducted at 7 tertiary centers from 2016 to 2020. Outcomes included rates of rebleeding, retreatment, complications, and complete occlusion. Furthermore, a systematic review and meta-analysis was conducted from 2011 to 2020 assessing the same outcomes. All pooled event rates were calculated using a random effect model. Consecutive patients with aSAH harbored 25 aneurysms that were treated with 29 WEB devices. The mean age was 53 years, and 65% were female. Zero experienced rebleeding, 2 were retreated, 2 experienced complications, 16 were completely occluded at 3 months, and 21 were completed occluded at 9–12 months. Meta-analysis of 309 WEB treatments for aSAH from 7 case series revealed 2.5% (95% CI 1–5%) had rebleeding, 9% (95% CI 4–17%) were retreated, 17% (95% CI 10–30%) had complications, and 61% (95% CI 51–71%) were completely occluded at 3–6 months. WEB embolization in the setting of aSAH provides similar protection against rebleeding with comparable retreatment rates to traditional approaches. However, there is a higher rate of incomplete radiographic occlusion and operative complications compared to WEB embolization of unruptured aneurysms. Long-term prospective studies are needed to fully delineate the role of WEB embolization in aSAH.

Herein, we demonstrate a method of intravascular catheter-based extrusion of hydrogels with in situ photomodulation to dynamically adjust the hydrogel properties utilizing a custom catheter setup. A novel UV-integrated microcatheter (luminal diameter 0.9 mm) was assembled and a suite of low-viscosity, shear thinning hydrogel precursors were formulated for delivery. We show that by modulating the precursor flow rate (up to 0.2 ml/min) as well as the UV power (0–37.5 mW), we can extrude hydrogels with viscosities dynamically varying from

BACKGROUND AND PURPOSE: Imaging of the cerebral venous sinuses has evolved Substantially during the past 2 decades, and most recently intravascular sinus imaging with sonography has shed light on the pathophysiology of sinus thrombosis and intracranial hypertension. Optical coherence tomography is the highest resolution intravascular imaging technique available but has not been previously used in cerebral sinus imaging. The purpose of this study was to develop a preclinical animal model of endovascular optical coherence tomography cerebral venous sinus imaging and compare optical coherence tomography findings with histology. MATERIALS AND METHODS: Four consecutive Yorkshire swine were selected. The superior sagittal sinus was first catheterized with a microwire, and the optical coherence tomography catheter was delivered via a monorail technique into the sinus. Luminal blood was cleared with a single arterial injection. After structural and Doppler optical coherence tomography imaging, a craniotomy was performed and the sinus and adjacent dura/veins were resected. Bland-Altman analysis was performed to compare optical coherence tomography and histology. RESULTS: Technically successful optical coherence tomography images were obtained in 3 of 4 swine. The luminal environment and visualization of dural arteries and draining cortical veins were characterized. The average maximum diameters of the sinus, dural arteries, and cortical veins were 3.14 mm, 135 µm, and 260 µm, respectively. Bland-Altman analysis demonstrated good agreement between histology and optical coherence tomography images. CONCLUSIONS: Endovascular optical coherence tomography imaging was feasible in this preclinical animal study. Adoption of this imaging technique in the human cerebral venous sinus could aid in the diagnosis, treatment, and understanding of the pathophysiology of various diseases of the sinus. Human safety and feasibility studies are needed.

OBJECTIVEAlthough the majority of patients with cerebral venous sinus thrombosis (CVST) will improve with anticoagulation therapy, a portion of patients will either present in a comatose state or continue to deteriorate clinically despite early anticoagulation. In these cases, along with treating the underlying thrombophilia, timely thrombolysis may be beneficial. Repurposed arterial thrombectomy devices may not perform as expected in the cerebral venous sinus, and there are currently no preclinical endovascular thrombectomy (EVT) models for CVST. Contrary to arterial stroke research, preclinical models utilized to test various endovascular techniques and devices are lacking. The purpose of this research was to develop a reliable preclinical animal model for the testing of endovascular strategies to treat CVST.METHODSFive consecutive male Yorkshire swine weighing 45 kg were utilized. Thrombosis of the superior sagittal sinus was induced with a bovine thrombin injection via a microcatheter under distal balloon occlusion for 15 minutes. Combined arterial injections and superselective sinus injections confirmed the extent of thrombosis. EVT was subsequently performed using a second-generation stent retriever, followed by intravascular optical coherence tomography (OCT) imaging to assess the luminal environment after thrombectomy.RESULTSThrombosis of the superior sagittal sinus, EVT, and subsequent OCT imaging were technically successful in 4 of the 5 swine. Recanalization of the sinus with a second-generation stent retriever was successful after one attempt in 3 of 4 swine (75%), and 1 swine required two attempts. OCT imaging after thrombectomy revealed regions of residual sinus luminal thrombus despite complete angiographic recanalization. Thrombosed bridging cortical veins were also observed before draining into the sinus, along with patent cortical veins.CONCLUSIONSThe authors describe a preclinical model to assess endovascular techniques and devices for the treatment of CVST. Repurposed devices from arterial stroke may not perform as expected, given the unique features of venous sinus thrombosis. Residual bridging cortical vein thrombus and residual sinus thrombus, visualized on intravascular OCT, may be present despite complete sinus recanalization on angiography, and this may be the etiology of the poor clinical outcome despite technical success. In the setting of bridging cortical vein thrombus after successful sinus thrombectomy, direct chemical thrombolysis may be warranted to dissolve the remaining clot. This model may be helpful in developing and testing a new generation of devices designed specifically for CVST treatment.

Near-infrared spectroscopy (NIRS) may provide a noninvasive way to monitor cerebral oxygenation in patients with traumatic brain injury, therein allowing for timely intervention aimed at reversing regional brain tissue hypoxia. We conducted a systematic review of NIRS-based oximetry measurements and their association with (A) patient functional outcome (B) other neurophysiological parameters. We searched MEDLINE, EMBASE, SCOPUS, BIOSIS, GlobalHealth and Cochrane Databases from inception to December 2018 and relevant conference proceedings published over the last 5 years. A total of 42 studies meeting our inclusion criteria were found (37 prospective observational, 5 retrospective designs). Seven studies reporting on the association between NIRS-based cerebral oxygenated hemoglobin measurements, mortality, modified Rankin Scale, Glasgow Outcome Scale, or Extended Glasgow Outcome Scale were identified. Forty-two studies exploring associations with neurophysiological parameters were included. Notwithstanding significant gaps in the currently available literature, our analysis suggests a link between NIRS-detected cerebral hypoxia during the acute phase of traumatic brain injury and poor functional outcome. NIRS measurements appear to reflect changes in intracranial pressure, invasively monitored brain tissue oxygen tension and various cerebrovascular reactivity indices although low quality contradicting data exist. More importantly, our review highlights the need for more prospective work before routine integration of NIRS-based techniques into multimodality monitoring regimen.

Introduction Cranial dural arteriovenous fistulas (DAVFs) are rare vascular lesions that often harbour complex angio-architectural features. This subtype of DAVF may require multiple, multimodality, or hybrid treatments. In this paper we aim to identify specific angio-architectural features that are present in complex cranial DAVFs and we report our series with respect to treatment modalities and outcomes. Methods Twenty-five cranial Borden type II and III cranial DAVFs were treated at our Institution from 2013 to 2017. We classified nine (36%) as complex based on specific angio-architectural features. Treatment strategies were based on fistula location, angiographic features and patient's presenting condition. Phone interviews were used to confirm outcome at 6 and 12 months. Results Four patients (45%) presented with acute hydrocephalus, and 3 (33%) with intracranial hemorrhage. Multiple and combined treatment sessions were needed for all complex DAVFs. Five patients required 2 endovascular procedures each. One patient had 2 surgeries. The first line of treatment was endovascular in 6 cases (67%) and surgery in 3 (33%). Two treatment-related (22%) complications occurred. Complete disconnection was achieved in 5 out of 9 patients (55%). Two patients with an incomplete disconnection refused further treatment and were well at last follow up, with a partially treated fistula and persistent CVR. The other 3 patients concluded treatment after the end of our data collection period. At 1 year, 7/9 patients had stable or improved clinical symptoms, and 8/9 patients had GOS of 4 or 5. Conclusions Complex cranial DAVF often require a multidisciplinary approach and multiple treatment sessions should be expected. Specific angio-architectural features that increase DAVF complexity include multiple arterial feeders, especially transosseous or pial, reflux into multiple cortical veins, sinus occlusion/entrapment, venous aneurysms, segmental stenosis, medial or deep location, and association with the deep venous system.

Background and Purpose:Large prospective observational studies have cast doubt on the common assumption that endovascular thrombectomy (EVT) is superior to intravenous thrombolysis for patients with acute basilar artery occlusion (BAO). The purpose of this study was to retrospectively review our experience for patients with BAO undergoing EVT with modern endovascular devices.Methods:All consecutive patients undergoing EVT with either a second-generation stent retriever or direct aspiration thrombectomy for BAO at our regional stroke center from January 1, 2013 to March 1, 2019 were included. The primary outcome measure was functional outcome at 1 month using the modified Rankin Scale (mRS) score. Multivariable logistic regression was used to assess the association between patient characteristics and dichotomized mRS.Results:A total of 43 consecutive patients underwent EVT for BAO. The average age was 67 years with 61% male patients. Overall, 37% (16/43) of patients achieved good functional outcome. Successful reperfusion was achieved in 72% (31/43) of cases. The median (interquartile range) stroke onset to treatment time was 420 (270–639) minutes (7 hours) for all patients. The procedure-related complication rate was 9% (4/43). On multivariate analysis, posterior circulation Alberta stroke program early computed tomography score and Basilar Artery on Computed Tomography Angiography score were associated with improved functional outcome.Conclusion:EVT appears to be safe and feasible in patients with BAO. Our finding that time to treatment and successful reperfusion were not associated with improved outcome is likely due to including patients with established infarcts. Given the variability of collaterals in the posterior circulation, the paradigm of utilizing a tissue window may assist in patient selection for EVT. Magnetic resonance imaging may be a reasonable option to determine the extent of ischemia in certain situations.

Ischemic stroke has been estimated to occur in up to 26% of patients with blunt cerebrovascular injury (BCVI). Antithrombotic therapy (AT) may be used for stroke prevention, but the role of endovascular treatment (ET) remains unclear. We systematically reviewed the literature on AT and ET for the treatment of patients with BCVIs.PubMed, EMBASE, Web of Science, and Cochrane were searched upon the PRISMA guidelines to include studies reporting the use of ET in BCVI patients. Post-ET neurologic outcomes, radiographic responses, and complication rates were assessed. A fixed-effect model meta-analysis was performed to compare treatment-related post-BCVI ischemic stroke rates between AT and ET protocols.We included 16 studies comprising 352 patients undergoing ET for BCVI. Mean post-ET rates of good neurologic outcomes and radiologic responses were 86.9% (range, 63.6-100%) and 94.0% (range 57.1-100%), respectively. Mean post-ET complication rate was 5.2% (range, 0-66.7%). Seven studies compared the roles of AT (delivered in 805 patients) and ET (performed in 235 patients) for preventing the onset of post-BCVI ischemic strokes. No significant difference in rates of post-BCVI ischemic stroke was found between patients receiving AT vs patients undergoing ET (OR 0.71, 95% CI: 0.35-1.42, p = 0.402).AT and ET may be comparable in preventing the occurrence of ischemic stroke following BCVIs. AT may be preferred as the less-invasive first-line therapy, but ET showed favorable rates of post-treatment clinical and radiologic outcomes, coupled with low rates of treatment-related complications.

Introduction : Embolization represents a minimally invasive treatment modality for arteriovenous malformations (AVMs), tumors, and other indications, but can be limited by currently available embolic agents, in terms of safety and efficacy. Discovery of new and improved agents could lead to better treatment outcomes. The goal of this project was to test a novel embolization methodology for the treatment of AVMs and tumors. Methods : We formulated low‐viscosity, shear‐thinning hydrogel formulations which were mixed with a photo‐initator agent and non‐ionic contrast medium. We then developed a method of intravascular hydrogel delivery with photo crosslinking at the tip of the catheter, using an integrated optical fibre. This allowed for rapid transition from a low viscosity liquid to a crosslinked solid‐state hydrogel to block blood flow to the vascular target. In addition, the UV intensity can be dynamically modulated, in real‐time, to modify the degree of crosslinking and thus the viscosity of the embolic agent. We utilized the swine rete mirabile as an animal model for AVMs, and the swine renal arterial tree (inferior segmental artery) as a model for hypervascular tumors. 5 animals were utilized without prior preparation. Embolization was graded based on degree of complete obliteration of the rete nidus or the renal arterial tree. Any non‐target embolization or other complications were recorded. Follow‐up angiography was performed at the 4‐week interval. Results : With a combination of shear‐thinning properties and dynamic modulation of photo crosslinking, we show that we are able to deliver an embolic agent with a viscosity range of up to 10^4 Pa*s through a single low viscosity precursor that is injectable through microcatheters (Figure 1). Using this methodology, hydrogel embolization was technically successful in all animals. Following embolization, 4/5 rete mirabile and 5/5 inferior renal arterial trees were completely obliterated. Representative angiographic images are shown in Figures 2 and 3. There were no instances of clinical or angiographic complications. Conclusions : We demonstrated a novel method of intravascular delivery of low viscosity photosensitive hydrogels, with photo crosslinking at the tip of the catheter, to successfully embolize animal models for AVMs and tumors. This promising technology will be investigated further with longer‐term comparative animal trials.

BACKGROUND Blunt cerebrovascular injuries (BCVIs) may occur following trauma and lead to ischemic stroke if untreated. Antithrombotic therapy decreases this risk; however, the optimal agent has yet to be determined in this population. The aim of this study was to compare the risk-benefit profile of antiplatelet (AP) versus anticoagulant (AC) therapy in rates of ischemic stroke and hemorrhagic complications in BCVI patients. METHODS We performed a retrospective review of BCVI patients at our tertiary care Trauma hospital from 2010 to 2015, and a systematic review and meta-analysis of the literature. The OVID Medline, Embase, Web of Science, and Cochrane Library databases were searched from inception to September 16, 2019. References of included publications were searched manually for other relevant articles. The search was limited to articles in humans, in patients 18 years or older, and in English. Studies that reported treatment-stratified clinical outcomes following AP or AC treatment in BCVI patients were included. Exclusion criteria included case reports, case series with n < 5, review articles, conference abstracts, animal studies, and non-peer-reviewed publications. Data were extracted from each study independently by two reviewers, including study design, country of origin, sex and age of patients, Injury Severity Score, Biffl grade, type of treatment, ischemic stroke rate, and hemorrhage rate. Pooled estimates using odds ratio (OR) were combined using a random-effects model using a Mantel-Hanzel weighting. The main outcome of interest was rate of ischemic stroke due to BCVI, and the secondary outcome was hemorrhage rate based on AC or AP treatment. RESULTS In total, there were 2044 BCVI patients, as reported in the 22 studies in combination with our institutional data. The stroke rate was not significantly different between the two treatment groups (OR, 1.27; 95% confidence interval, 0.40-3.99); however, the hemorrhage rate was decreased in AP versus AC treated groups (OR, 0.38; 95% confidence interval, 0.15-1.00). CONCLUSION Based on this meta-analysis, both AC and AP seem similarly effective in preventing ischemic stroke, but AP is better tolerated in the trauma population. This suggests that AP therapy may be preferred, but this should be further assessed with prospective randomized trials. LEVEL OF EVIDENCE Review article, level II.

BACKGROUND Angiogram-negative nontraumatic subarachnoid hemorrhage (SAH) can be diagnostically challenging, and a broad differential diagnosis must be considered. Particular attention to initial radiographic hemorrhage distribution is essential to guide adjunctive investigations. Posterior spinal artery aneurysms are rare clinical entities with few reported cases in the literature. An understanding of isolated spinal artery aneurysm natural history, diagnosis, and management is evolving as more cases are identified. OBSERVATIONS Isolated thoracic posterior spinal artery aneurysm can be the culprit lesion in perimesencephalic distribution SAH. Embolization resulted in complete aneurysm occlusion and did not result in periprocedural morbidity. At the 1-year follow-up, the patient was neurologically intact with no recurrence on magnetic resonance angiography. LESSONS This case report highlighted the presentation, diagnostic workup, clinical decision-making, and endovascular intervention for a woman who presented with SAH secondary to posterior spinal artery aneurysm. After initially negative results on vascular imaging, dedicated spinal vascular imaging revealed the location of the aneurysm. Multiple treatment modalities exist for isolated spinal artery aneurysms and must be selected on the basis of patient- and lesion-specific characteristics.

Cerebral cavernous malformations (CCMs) may be familial or nonfamilial. This systematic review compared the natural history of CCMs in familial compared with nonfamilial cases.We searched MEDLINE, Web of Science, and EMBASE for natural history studies on CCMs up to September 2018. We included studies that followed at least 20 untreated patients. Primary outcomes were hemorrhage, seizures, and neuroimaging changes in familial and nonfamilial cases. Incidence rate per person-year (PY) or lesion-year (LY) of follow-up were used to pool the data using fixed-effects or random-effects models. We used the incidence rate ratio for comparison.We could not compare hemorrhage rates between familial and nonfamilial cases mainly owing to mixtures of subgroups of patients. The seizure rate was similar in familial and nonfamilial cases with pooled incidence rate of 1.5%/PY (95% confidence interval 1.1%-2.2%). The reseizure rate was higher than the seizure rate (P0.001). New lesion development was higher in familial cases (32.1%/PY vs. 0.7%/PY, P0.001). Signal change on neuroimaging ranged from 0.2%/LY to 2.4%/LY in familial cases. In familial cases, incidence rate of size change was 8%/PY (95% confidence interval 5.2%-12.2%) and 1.1%/LY (95% confidence interval 0.6%-1.6%).Familial CCMs show higher dynamic changes than nonfamilial cases. However, the presence of actual dynamic changes needs further assessment in nonfamilial cases. CCMs demonstrate a low incidence of seizure. First-time seizure increases the chance of recurrent seizure. Seizure rate based on the location and type of the lesion should be investigated further.

OBJECTIVE Mechanical endovascular thrombectomy (EVT) is an increasingly relied-on treatment for clot retrieval in the context of ischemic strokes, which otherwise are associated with significant morbidity and mortality. Despite several known risks associated with this procedure, there is a high degree of technical heterogeneity across both centers and operators. The most common procedural complications occur at the point of transfemoral access (the common femoral artery), and include access-site hematomas, dissections, and pseudoaneurysms. Other interventional fields have previously popularized the use of ultrasound to enhance the anatomical localization of structures relevant to vascular access and thereby reducing access-site complications. In this study, the authors aimed to describe the ultrasound-guided EVT technique performed at a large, quaternary neurovascular referral center, and to characterize the effects of ultrasound guidance on access-site complications. METHODS A retrospective chart review of all patients treated with EVT at a single center between January 2013 and August 2020 was performed. Patients in this cohort were treated using a universal, unique, ultrasound-guided, single-wall puncture technique, which bears several theoretical advantages over the standard technique of arterial puncture via palpation. RESULTS There were 479 patients treated with EVT within the study period. Twenty patients in the cohort were identified as having experienced some form of access-site complication. Eight (1.67%) of these patients experienced minor access-site complications, all of which were groin hematomas and none of which were clinically significant, as defined by requiring surgical or interventional management or transfusion. The remaining 12 patients experienced arterial dissection (n = 5), arterial pseudoaneurysm (n = 4), retroperitoneal hematoma (n = 2), or arterial occlusion (n = 1), with only 1.04% (5/479) requiring surgical or interventional management or transfusion. CONCLUSIONS The authors found an overall reduction in total access-site complications as well as minor access-site complications in the study cohort compared with previously published randomized controlled trials and observational studies in the recent literature. The findings suggested that there may be a role for routine use of ultrasound-guided puncture techniques in EVT to decrease rates of complications.

Significance: Imaging of the spinal cord is challenging due to the surrounding bony anatomy, physiologic motion, and the small diameter of the spinal cord. This precludes the use of non-invasive imaging techniques in assessing structural changes related to trauma and evaluating residual function. Aim: The purpose of our research was to apply endovascular technology and techniques and construct a preclinical animal model of intrathecal spinal cord imaging using optical coherence tomography (OCT). Approach: Five animals (2 Yorkshire Swine and 3 New Zealand Rabbits) were utilized. Intrathecal access was gained using a 16-guage Tuohy, and an OCT catheter was advanced under roadmap technique into the cervical canal. The OCT catheter has a motorized pullback, and a total length of 54 mm of the spinal canal is imaged. Results: Image acquisition was successful for all animals. There were no instances of difficult catheter navigation, enabling OCT imaging rostrally to C2. The thecal sac provided excellent thoroughfare for the OCT catheter. The clear cerebrospinal fluid also provided an excellent medium for image acquisition, with no detectable artifact from the contents of the cerebrospinal fluid. The anatomical space of the spinal canal could be readily appreciated including: dural lining of the thecal sac, epidural veins, pial lining of the spinal cord, arachnoid bands, dentate ligaments, and nerve rootlets/roots. Conclusion: Minimally invasive intrathecal imaging using endovascular OCT was feasible in this preclinical animal study. The repurposing of an endovascular device for spinal imaging comes with limitations, and a spine-specific device is necessary.

The Woven EndoBridge (WEB) can be used to treat wide-necked aneurysms without antiplatelet medications, suggesting it may have advantages in the setting of aneurysmal subarachnoid hemorrhage (aSAH). The goal was assessment of safety and efficacy of WEB in aSAH given the delayed nature of aneurysmal thrombosis.An international retrospective analysis of patients with aSAH treated with WEB was conducted at 7 tertiary centers from 2016 to 2020. Outcomes included rates of rebleeding, retreatment, complications, and complete occlusion. Furthermore, a systematic review and meta-analysis was conducted from 2011 to 2020 assessing the same outcomes. All pooled event rates were calculated using a random effect model.Consecutive patients with aSAH harbored 25 aneurysms that were treated with 29 WEB devices. The mean age was 53 years, and 65% were female. Zero experienced rebleeding, 2 were retreated, 2 experienced complications, 16 were completely occluded at 3 months, and 21 were completed occluded at 9-12 months. Meta-analysis of 309 WEB treatments for aSAH from 7 case series revealed 2.5% (95% CI 1-5%) had rebleeding, 9% (95% CI 4-17%) were retreated, 17% (95% CI 10-30%) had complications, and 61% (95% CI 51-71%) were completely occluded at 3-6 months.WEB embolization in the setting of aSAH provides similar protection against rebleeding with comparable retreatment rates to traditional approaches. However, there is a higher rate of incomplete radiographic occlusion and operative complications compared to WEB embolization of unruptured aneurysms. Long-term prospective studies are needed to fully delineate the role of WEB embolization in aSAH.

BACKGROUNDThe purpose of the present case report is to highlight the presentation, workup, clinical decision making, and operative intervention for a 68-year-old woman who developed rapidly progressive myelopathy secondary to idiopathic cervical intramedullary abscess.OBSERVATIONSThe patient underwent laminectomy and aspiration/biopsy of the lesion. Intraoperatively, division of the posterior median sulcus released a large volume of purulent material growing the oral pathogens Eikenella corrodens and Gemella morbillorum. Broad-spectrum antibiotics were initiated postoperatively. At the 6-month follow-up, the patient had almost completely recovered with some persistent hand dysesthesia. Complete infectious workup, including full dental assessment and an echocardiogram, failed to reveal the source of her infection.LESSONSThe authors report the first case of cryptogenic spinal intramedullary abscess secondary to Eikenella spp. and Gemella spp. coinfection. Intramedullary abscesses are exceptionally rare and most commonly develop in children with dermal sinus malformations or in the context of immunosuppression. In adults without risk factors, they can readily be mistaken for more common pathologies in this age group, such as intramedullary neoplasms or demyelinating disease. Prompt diagnosis and management based on rapidly progressive myelopathy, assessment of infectious risk factors and/or symptoms, and targeted imaging are critical to avoid potentially devastating neurological sequelae.

Endovascular optical coherence tomography (OCT) is the highest resolution imaging modality currently available with spatial resolution of 10 µm. Although originally developed for interventional cardiology, the ability to visualize the luminal environment and anatomy, along with the stent-vessel interaction could be of great utility for various cerebrovascular diseases, and the adoption of endovascular OCT imaging in the evolving field of interventional neuroradiology seems instinctive. The purpose of this study is to conduct a systematic review of the literature regarding applications of endovascular OCT in the diagnosis and treatment of cerebrovascular diseases. In addition, the authors report their institutional experience with the use of OCT in carotid atherosclerotic disease, cerebral aneurysms, and acute ischemic stroke. A systematic review of the literature was undertaken. Peer-reviewed articles were collected through MEDLINE, Embase, Scopus, and Cochrane Central Register of Controlled Trials (CENTRAL) searches through March 2020. A total of 34 studies with 598 patients were included in the qualitative synthesis. These include 23 studies of carotid atherosclerotic disease, 7 studies of cerebral aneurysms, and 4 studies of non-aneurysmal posterior circulation pathology. OCT imaging was feasible in 94% of patients with 0.6% complication rate. Endovascular OCT appears to be safe and feasible, allowing clinicians to visualize stent-vessel interactions, aneurysmal healing, and vulnerable atherosclerotic plaque features. OCT carries great promise, however additional investigations are needed before any imposing statement can be made about the role of OCT in cerebrovascular imaging.

Background Carotid-cavernous fistulas (CCFs) are abnormal communications between the arterial and venous circulation within the cavernous sinus, manifesting in myriad neurological and ophthalmological sequalae. In rare circumstances patients' unique vascular anatomies preclude standard endovascular treatment for this pathology, warranting combined surgical and endovascular approaches wherein the cavernous sinus is accessed via superior ophthalmic vein (SOV) exposure, cutdown, and cannulation. Case Description We describe 3 cases of CCF treated at our quaternary neurovascular referral center between 2017 and 2019. The first is a 35-year-old man with symptomatic, traumatic, right-sided CCF, treated with endovascular therapy (transarterial detachable balloon placement). The other cases were treated with contrasting surgical and endovascular combined approaches because of unique vascular challenges. The second is a 71-year-old woman with spontaneous right-sided CCF whose carotid sinus was accessed and embolized through a transpalpebral cutdown of the SOV. The third case is a 70-year-old man with symptomatic, spontaneous bilateral CCF. After unsuccessful transarterial and transvenous endovascular approaches, transorbital (intracranial) SOV cutdown and cannulation were performed to embolize the shunting fistula. Conclusions Endovascular approaches are well described as the mainstay of treatment for CCF but are not possible for all patients. In circumstances where individual vascular anatomy is not amenable to transarterial or transvenous access or embolization, a combined surgical and endovascular approach may be appropriate. We describe 3 cases that illustrate the spectrum of interventions for CCF, as well as the technical aspects of treatment for 2 patients with complex, direct CCF, using an embolization approach reliant on SOV cutdown and cannulation.

OBJECTIVEPediatric rolandic arteriovenous malformations (AVMs) present a treatment challenge given the lifetime risk of hemorrhage, rehemorrhage, and associated long-term morbidity. Microsurgical resection has been recommended as the optimal treatment for AVMs in general, but there is no dedicated literature on the outcomes of resection of pediatric rolandic AVMs. Here, the study objective was to review the outcomes of microsurgical resection of pediatric rolandic AVMs in the modern era, together with the utilization of surgical adjuncts including navigation, intraoperative angiography, and neurophysiological monitoring.METHODSThe authors performed a retrospective review of patients 18 years of age and younger with cerebral AVMs microsurgically treated between January 2000 and May 2016 at The Hospital for Sick Children. Only those patients with an AVM whose nidus was located within the rolandic region were analyzed. A descriptive analysis was performed to identify patient demographics, preoperative AVM characteristics, and postoperative obliteration rates and neurological complications.RESULTSA total of 279 AVMs were evaluated in the study period. Twenty-three of these AVMs were rolandic, and the median age in the 11 microsurgically treated cases was 11 years (range 1–17 years). AVM hemorrhage was the most common presentation, occurring in 8 patients (73%). Lesions were either Spetzler-Martin grade II (n = 8, 73%) or grade III (n = 3, 27%). The postoperative obliteration rate of AVMs was 100%. The mean imaging follow-up duration was 33 months (range 5–164 months). There was no documented recurrence of an AVM during follow-up. One patient developed a transient postoperative hemiparesis, while another patient developed right fingertip hyperesthesia.CONCLUSIONSMicrosurgical resection of rolandic pediatric AVMs yields excellent AVM obliteration with minimal neurological morbidity in selected patients. The incorporation of surgical adjuncts, including neurophysiological monitoring and neuronavigation, allows accurate demarcation of functional cortex and enables effective resection.

Lumbar spinal stenosis is the most common indication for spinal surgery, and studies have shown that surgical treatment in selected patients is more successful than conservative measures. This chapter aims to investigate whether fusion surgery as an adjunct to decompression surgery resulted in better clinical outcomes than decompression alone in patients with lumbar spinal stenosis, with or without degenerative spondylolisthesis. A multicenter randomized control trial was conducted. Patients with symptomatic lumbar stenosis were recruited from October 2006 through June 2012 from seven Swedish hospitals. Exclusion criteria were spondylolysis, degenerative lumbar scoliosis, history of previous surgery for lumbar spinal stenosis or instability, stenosis not caused by degenerative change, stenosis caused by herniated disc, other spinal conditions, history of vertebral compression fracture in the affected segments, or psychological disorders. The role of fusion in degenerative spondylolisthesis and spinal stenosis is a hotly debated and controversial topic.

Background In low- and middle-income countries (LMICs), 11.8% of the need for neurosurgical care is met. Delays in seeking and receiving care may further exacerbate this situation. Objective analysis of delay and its consequences is contingent on reference to established resource-appropriate acceptable timeframes. This study sought to 1) establish an estimate of the landscape of care provided in LMICs and 2) explore reasonable timeframes for various stages of patient–health care interaction. Methods Consensus input from neurosurgeons in select LMICs was collected; 1 high-income country was included for comparison. In phase 1, participants were asked to select neurosurgical procedures performed at their centers. In phase 2, based on procedures shared among all LMICs, representative case scenarios were generated and participants provided input on acceptable timeframes for each stage of patient–health care interaction: 1) presentation to health services, 2) diagnosis by primary care physician, 3) referral to neurosurgical specialist care, and 4) definitive neurosurgical management. Results Twenty neurosurgeons across 18 centers were identified; 12 participated in phase 1 and 7 in phase 2. The range of procedures offered was broad, similar in scope to high-income countries, and included pediatric and adult neurosurgery, trauma, degenerative spine, and hemorrhagic stroke. Acceptable timeframes had wide ranges in certain cases; however, the overall trend showed agreement between the participants. Conclusions This exploratory analysis identified reasonable timeframes for the provision of neurosurgical care in LMICs. If validated, these data can be used to more objectively assess the prevalence of delay in neurosurgical care in individual LMICs, along with its consequences.

Objectives Despite the increasing awareness of scientific fraud, no attempt has been made to assess its prevalence in neurosurgery. The aim of our review was to assess the chronologic trend, reasons, research type/design, and country of origin of retracted neurosurgical publications. Methods Three independent reviewers searched the EMBASE and MEDLINE databases using neurosurgical keywords for retracted articles from 1995 to 2016. Archives of retracted articles ( retractionwatch.com ) and the independent Web sites of neurosurgical journals were also searched. Data including the journal, impact factor, reason for retraction, country of origin, and citations were extracted. Results A total of 97 studies were included for data extraction. Journal impact factor ranged from 0.57 to 35.03. Most studies (61) were retracted within the last 5 years. The most common reason for retraction was because of a duplicated publication found elsewhere (26), followed closely by plagiarism (22), or presenting fraudulent data (14). Other reasons included scientific errors/mistakes, author misattribution, and compromised peer review. Articles originated from several countries and some were widely cited. Conclusions Retractions of neurosurgical publications are increasing significantly, mostly because of issues of academic integrity, including duplicate publishing and plagiarism. Implementation of more transparent data-sharing repositories and thorough screening of data before manuscript submission, as well as additional educational programs for new researchers, may help mitigate these issues in the future.

Objective Results of previous studies examining seasonal variation in the incidence of aneurysmal subarachnoid hemorrhage (SAH) are conflicting. The aim of this brief report is to investigate whether there is a seasonal effect in online search queries for SAH that may reflect an association between meteorological factors and aneurysm rupture. Patients and methods We used the Google Trends data service to analyze the volume of internet queries for SAH on Google’s search engine from January 1, 2004 to November 2016. We used comprehensive search terms and collected data from: USA, Canada, and countries known for their high prevalence of SAH (Finland, and Japan), as well as worldwide search volume. Potential seasonal variations in the data were assessed by comparative non-parametric tests and curve-fit regression model. Results Our analyses revealed that USA had the highest median value in cumulative search scores (115 vs. 86, 46, 46 for Finland, Canada and Japan, respectively). The term “brain aneurysm” was the commonly used search term among countries, followed by “cerebral aneurysm”. There was no evidence of seasonality in any of the countries studied on both univariate tests and regression time-adjusted analysis. Conclusions There are no seasonal variations in internet search query volume for SAH. Further studies are needed to explore whether online search volumes correlate with the actual incidence of SAH.

Objective: Medical students at the University of British Columbia undertake a population health course that aims to cultivate social accountability and CanMEDS roles. Students choose between Discussion Group Option (DGO), Community Service Learning Option (CSLO), or Self-Directed Project Option (SDPO). The objective of this study was to evaluate the effectiveness of these three different learning options in developing social accountability and CanMEDS roles in medical students. Methods: Expert consultation and literature review were undertaken to develop a self-report survey. Students who had completed the course from 2009 to 2013 were surveyed. The results were analyzed to evaluate differences between groups. Results: We recruited 168 participants with equal representation from each option. CSLO and SDPO students reported greater development of social accountability and CanMEDS roles from the course compared to DGO students. In addition, CSLO and SDPO students reported greater academic output and satisfaction from their experience. Conclusion: Students who participated in community-based or project-based learning reported significantly better acquisition of social accountability and CanMEDS roles compared to students who engaged in group discussion. Résumé Objectif: Les étudiants en médecine de l’Université de la Colombie-Britannique suivent un cours sur la santé de la population qui vise à cultiver la responsabilité sociale et les rôles CanMEDS. Les étudiants choisissent entre l’option de discussion de groupe (DGO, de l’anglais), l’option d’apprentissage par l’engagement communautaire (CSLO, de l’anglais) ou l’option de projet autonome (SDPO, de l’anglais). L’objectif de cette étude était d’évaluer l’efficacité de ces trois options d’apprentissage différentes pour le développement de la responsabilité sociale et des rôles CanMEDS chez les étudiants en médecine. Méthodes: Des consultations d’experts et une revue de la littérature ont été entreprises afin de concevoir un sondage d’autodéclaration. Les étudiants ayant complété le cours de 2009 à 2013 ont été interrogés. Les résultats ont été analysés afin d’évaluer les différences entre les groupes. Résultats: Nous avons recruté 168 participants, avec une représentation égale pour chaque option. Les étudiants des groupes CSLO et SDPO ont déclaré plus de développement de leur sens de responsabilité sociale et des rôles CanMEDS à la suite du cours, en comparaison aux étudiants du groupe DGO. De plus, les étudiants des groupes CSLO et SDPO ont rapporté un plus grand nombre de réalisations scolaires et une meilleure satisfaction par rapport à leur expérience. Conclusion: Les étudiants qui ont participé à l’apprentissage par l’engagement communautaire ou par l’entremise d’un projet autonome ont rapporté une acquisition nettement meilleure de la responsabilité sociale et des rôles CanMEDS, en comparaison aux étudiants qui ont participé à une discussion de groupe.

Background Acupuncture is a common form of alternative medicine that is used for pain control among other modalities of treatment. It is a relatively safe procedure, but complications, including those of infectious etiology, may still occur. Case Description A 47-year-old immunosuppressed woman presented with fever, altered level of consciousness, dysphasia, and a left occipital subgaleal fluctuant mass after acupuncture for headaches in the same area. Imaging demonstrated subgaleal and epidural collection localized in the left occipital region. She underwent urgent surgical evacuation of both collections. Cultures from intraoperative specimens grew Streptococcus anginosus. The patient started targeted antibiotic treatment leading to complete recovery. Conclusions To our knowledge, this is the first report of intracranial abscess after acupuncture. Given the worldwide application of this alternative treatment, physicians, acupuncturists, and the general public should be aware of the possibility of this rare but serious complication.

Background: Results of previous studies examining seasonal variation in the incidence of aneurysmal subarachnoid hemorrhage (SAH) are conflicting. The aim of this study is to investigate whether there is a seasonal effect in online search queries for SAH that may reflect an association between meteorological factors and aneurysm rupture. Methods: We utilized the Google Trends data service to analyze the volume of internet queries for SAH on Google’s search engine from January 1, 2004 to November 2016. We used comprehensive search terms and collected data from: USA, Canada, Finland, and Japan, as well as worldwide search volume. Potential seasonal variations in the data were assessed by comparative non-parametric tests and curve-fit regression model. Results: Our analyses revealed that USA had the highest median search scores (115 vs. 86, 46, 46 for Finland, Canada and Japan, respectively). The term “brain aneurysm” was the commonly used search term among countries, followed by “cerebral aneurysm”. There was no evidence of seasonality in any of the countries studied on both univariate tests and regression time-adjusted analysis. Conclusions: There are no seasonal variations in internet search query volume for SAH. Further studies are needed to explore whether online search volumes correlate with the actual incidence of SAH.

Background: Despite increasing awareness of scientific fraud, no attempt has been made to assess its prevalence in neurosurgery. The aim of our review was to assess the chronological trend and reasons for the retraction of neurosurgical publications. Methods: We searched the EMBASE and MEDLINE databases using a comprehensive search strategy for retracted articles from January 1995 to December 2016. Archives of retracted articles on www.retractionwatch.com and the independent websites of neurosurgical journals were also searched. Data including the journal name and its impact factor, reason for retraction, country of origin, and citations were extracted. Results: A total of 72 studies were included for data extraction. Journal impact factor ranged from 0.24 to 14.4. Most studies(76%) were retracted within the last 5 years. The most common reason for retraction was because of a duplicated publication found elsewhere(25%), followed closely by plagiarism(21%), or falsifying data(17%). Other reasons included scientific errors/mistakes, author misattribution, and fraudulent peer review. Articles originated from several different countries and some were widely cited. Conclusions: Retractions of neurosurgical publications are increasing globally, mostly due to issues of academic integrity. Implementation of more transparent data sharing and screening as well as additional education for new researchers may help mitigate these issues moving forward.

The study of soot particulate distribution inside gas jet diffusion flames is important to the understanding of fundamental soot particle and thermal radiative transport processes, as well as providing findings relevant to spacecraft fire safety, soot emissions, and radiant heat loads for combustors used in air-breathing propulsion systems. Compared to those under normal gravity (1-g) conditions, the elimination of buoyancy-induced flows is expected to significantly change the flow field in microgravity (O g) flames, resulting in taller and wider flames with longer particle residence times. Work by Bahadori and Edelman demonstrate many previously unreported qualitative and semi-quantitative results, including flame shape and radiation, for sooting laminar zas jet diffusion flames. Work by Ku et al. report soot aggregate size and morphology analyses and data and model predictions of soot volume fraction maps for various gas jet diffusion flames. In this study, we present the first 1-g and 0-g comparisons of soot volume fraction maps for laminar acetylene and nitrogen-diluted acetylene jet diffusion flames. Volume fraction is one of the most useful properties in the study of sooting diffusion flames. The amount of radiation heat transfer depends directly on the volume fraction and this parameter can be measured from line-of-sight extinction measurements. Although most Soot aggregates are submicron in size, the primary particles (20 to 50 nm in diameter) are in the Rayleigh limit, so the extinction absorption) cross section of aggregates can be accurately approximated by the Rayleigh solution as a function of incident wavelength, particles' complex refractive index, and particles' volume fraction.

Results of a numerical solution for radiative heat transfer in homogeneous and nonhomogeneous participating media are presented. The geometry of interest is a finite axisymmetric cylindrical enclosure. The integral formulation for radiative transport is solved by the YIX method. A three-dimensional solution scheme is applied to two-dimensional axisymmetric geometry to simplify kernel calculations and to avoid difficulties associated with treating boundary conditions. As part of the effort to improve modeling capabilities for turbulent jet diffusion flames, predicted distributions for flame temperature and soot volume fraction are used to calculate radiative heat transfer from soot particles in such flames. It is shown that the nonhomogeneity of radiative property has very significant effects. The peak value of the divergence of radiative heat flux could be underestimated by 2 factor of 7 if a mean homogeneous radiative property is used. Since recent studies have shown that scattering by soot agglomerates is significant in flames, the effect of magnitude of scattering is also investigated and found to be nonnegligible.

A technique is presented that allows the spectral refractive indices, size, and number density of soot particles in flames to be inferred from a combination of single-wavelength light scattering and multiwavelength extinction measurements. In contrast to previous schemes for inferring optical properties, the present approach does not require the introduction of a model for the spectral dispersion of the refractive index; it employs Kramers-Kronig theory instead. When applied to spherical particles, the only approximations involved are the usual ones associated with using Kramers-Kronig theory to analyze actual data, that is, for those spectral regions where experimental data are not obtainable, extrapolations and interpolations must be made. The particles, however, may be of any size, including Rayleigh-size (for which it is particularly difficult to simultaneously infer particle size, concentration, and complex refractive index). The approach requires a combination of static (elastic) and dynamic (quasielastic) laser light scattering measurements plus measurements of the spectral transmittance. Closure is achieved in data analysis by the introduction of an exact (model-independent) Kramers-Kronig dispersion theory for scattering amplitude functions. The influence of various spectral extrapolation schemes (required because of the finite spectral width of the transmittance data) is thoroughly investigated.

Three approximate solutions for light scattering and absorption by agglomerated or arbitrarily-shaped particles have been investigated by comparing both their solution formulas and numerical results. Ranked according to the soundness of their derivation and resulting level of accuracy, the Iskander-Chen-Penner (I-C-P) solution is the best, followed in order by Purcell-Pennypacker (P-P) and Jones. The Jones solution is in general unreliable due to its inaccurate accounting for multiple-scattering effects. The P-P solution is almost identical to the I-C-P but without the self-interaction term, which has a significant effect on accuracy, especially for nonabsorbing particles. For the I-C-P solution, the range of validity is x < 0.8|(m2 + 5)/(2m2 + 1)| (x = cell size parameter) for a < 10% error on cross sections and near-forward scattering. This range of validity could be extended by 40% for highly absorbing particles with |m| < 2, but reduced by 20% for those with larger |m|. The Maxwell-Garnett relation has been shown to be an accurate optical mixing rule for light scattering by inhomogeneous particles. It is found that randomly-oriented, chain-like agglomerates of small particles, such as flame soot particles and other colloidal aggregates, have unique scattering characteristics. The extinction is roughly the same, whereas total and near-forward angular scattering are N times higher when comparing an agglomerate with the same number of individual spheres. Even randomly oriented, these chain-like agglomerates cannot be modeled by equivalent spheres, and they yield significant depolarized scattering.