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OBJECTIVE The coronavirus disease 2019 (COVID-19) pandemic has necessitated the use of telehealth visits (THVs). The effects on neurosurgical practice have not been well characterized, especially concerning new-patient THVs. Therefore, the authors of this study reviewed their institution’s experience with outpatient clinic visits and THVs from before the COVID-19 pandemic to the present to focus on clinical metrics, rates of surgery, and the effects of implementing THVs in order to better understand their implications for clinical practice as more data emerge over time. METHODS The authors reviewed 15,677 consecutive new outpatient in-person visits (IPVs), THVs, and neurosurgical procedures/cases proceeding from their institution between 2018 and 2022 for trends and associations related to THVs. RESULTS Among spine patients, there was no difference in the proportion of encounters that led to surgery (surgical conversion rate) between THVs and IPVs (p = 0.49). Among cranial patients, THVs were negatively associated with conversion (OR 0.73, p = 0.03). On average, patients using THVs lived further from the hospital (p < 0.001); however, the patient catchment area appeared unchanged. The median distance to the hospital among THV patients was counterbalanced by a decreased distance for spine patients pursing IPVs (p < 0.001), with no significant change to case volume. There was no change in distance to the hospital among cranial patients. For both cranial and spine patients, surgical conversion was more likely among those who lived a great distance from the hospital if their initial encounter was an IPV (p = 0.007 and < 0.001, respectively). However, there was no relationship between distance from the hospital and surgical conversion among THV patients (p = 0.565). The availability of THVs did not significantly affect follow-up time (p = 0.837). For new patients at IPVs, there was no difference in time to the operating room between cranial and spine cases; for new patients at THVs, however, time to the operating room was significantly faster for cranial cases than for spine cases (p = 0.0018). CONCLUSIONS Compared to IPVs, THVs lead to decreased surgical conversion for cranial patients but not spine patients. THVs do not appear to increase the catchment area. For patients who live far from the hospital, an IPV is associated with surgical conversion. Surgical conversion is faster following cranial THVs than after spine THVs. THVs did not increase the duration of follow-up.

Intracranial hemorrhage (ICH) is considered an emergency that requires rapid medical or surgical management. Previous studies have used artificial intelligence to attempt to expedite the diagnosis of this pathology on neuroimaging. However, these studies have used local, institution-specific data for training of networks that limit deployment of across broader hospital networks or regions because of data biases.To demonstrate the creation of a neural network based on an openly available imaging data tested on data from our institution demonstrating a high-efficacy, institution-agnostic network.A data set was created from publicly available noncontrast computed tomography images of known ICH. These data were used to train a neural network using distinct windowing and augmentation. This network was then validated in 2 phases using cohort-based (phase 1) and longitudinal (phase 2) approaches.Our convolutional neural network was trained on 752 807 openly available slices, which included 112 762 slices containing intracranial hemorrhage. In phase 1, the final network performance for intracranial hemorrhage showed a receiver operating characteristic curve (AUC) of 0.99. At the inflection point, our model showed a sensitivity of 98% at a threshold specificity of 99%. In phase 2, we obtained an AUC of 0.98 after analysis of 726 scans with a negative predictive value of 99.70% (n = 726).We demonstrate an effective neural network trained on completely open data for screening ICH at an unrelated institution. This study demonstrates a proof of concept for screening networks for multiple sites while maintaining high efficacy.

Introduction: Mechanical Thrombectomy (MT) is standard-of-care interventional management of Acute Ischemic Stroke (AIS) due to large vessel occlusions. However, patient outcomes remain variable after intervention, with unclear optimization strategies for patient selection. The NVQI-QOD registry documents detailed patient characteristics, pre-operative imaging, procedure metrics, and post-operative outcomes of neurointerventional procedures. Data are highly informative, but there is inherent uncertainty in all medical interventions. We introduce a probabilistic learning model that predicts the expected distribution of MT outcomes. Methods: We identified two groups of variables from the NVQI-QOD AIS Thrombectomy registry: 1) data available at the time of MT (Group-preop), and 2) data available 24 h after MT, which can be valuable for prognostication (Group-24h). After filtering missing values, there were 1174 and 1405 examples in the two groups, respectively. In each group, training and test datasets were split using a ratio of 8:2. A probabilistic Neural Network (NN) ( Fig. 1a ) was developed to predict the distribution of changes in pre- and post-MT NIH Stroke Scale (NIHSS) ( y ), and it was trained using both groups of variables as inputs. Results: After training, the probabilistic network accurately described the distributions of changes in the NIHSS (represented by predicted means and SDs) based on input variables ( Fig. 1b - upper ). Notably, in Group-preop, even patients with the worst predicted outcomes had an approximately 50% chance of improvement. Fig. 1b - lower demonstrates the relative importance of variables to the NN. Conclusions: This NN model demonstrates the utility of probabilistic learning in clinical decision-making and prognosis. Our results reinforce the substantial benefits of MT, that can still improve outcomes in nearly half of patients with the worst predicted change in NIHSS on pre-operative analysis.

OBJECTIVE Cerebral aneurysms in the pediatric population are rare and optimal treatment strategies are not as well characterized as in adults. The Pipeline embolization device (PED) is an endoluminal flow diverter that is commonly used to treat aneurysms in adults, but experience with this device in children is limited. The authors sought to further characterize PED use and outcomes in this specific population by performing both a systematic review of patient-level data from studies reporting the use of the PED to treat pediatric aneurysms and a retrospective review of their experience. METHODS A systematic review of the PubMed, Embase, and Scopus databases was performed to identify studies reporting the use of the PED in pediatric patients (age ≤ 18 years). Disaggregated data regarding demographics, aneurysm characteristics, treatment, and outcomes were collected. Retrospective data from the authors’ two institutions were also included. RESULTS Thirty studies comprising patient-level data on 43 pediatric patients with 47 aneurysms were identified. An additional 9 patients with 9 aneurysms were included from the authors' institutions for a total of 52 patients with 56 aneurysms. The mean patient age was 11.1 years. Presentations included aneurysm rupture (17.3%) and symptomatic mass effect (23.1%). Aneurysms were located in the anterior circulation in 55.4% of cases, and 73.2% were described as nonsaccular. Imaging follow-up was available for 89.3% with a mean follow-up of 13.3 months. Aneurysm occlusion was reported in 75%, with 1 case each (1.8%) demonstrating significant in-stent stenosis and parent vessel occlusion. Clinical follow-up was reported in 90.4% with a mean follow-up of 14.7 months. Good functional outcomes (modified Rankin Scale score of 0–1 or Glasgow Outcome Scale score of 5) were reported in 65.4% of the total population. Two major complications were reported, including 1 death. CONCLUSIONS Despite substantial differences in aneurysm location and type between published pediatric and adult patient populations treated with the PED, the use of the PED in the pediatric population appears to be safe. While the short-term effectiveness is also similar to that of adults, additional studies are needed to further characterize the long-term outcomes and better define the use of this device in pediatric patients.

Stroke is a major cause of morbidity and mortality. Neurosurgical decompression is often considered for the treatment of malignant infarcts and intraparenchymal hemorrhages, but this treatment can be frought with ethical dilemmas. In this article, the authors outline the primary principles of bioethics and their application to stroke care, provide an overview of key ethical issues and special situations in the neurosurgical management of stroke, and highlight methods to improve ethical decision-making for patients with stroke. Understanding these ethical principles is essential for stroke care teams to deliver appropriate, timely, and ethical care to patients with stroke.

Intracranial hemorrhage (ICH) is a devastating complication for patients with ventricular assist devices (VADs). The safety of emergent anticoagulation reversal with four-factor prothrombin complex concentrate (PCC) and optimal timing of anticoagulation resumption are not clear. In addition, lactate dehydrogenase (LDH) is used as a biomarker for thromboembolic risk, but its utility in guiding anticoagulation management after reversal with PCC has not be described. We retrospectively reviewed a consecutive series of patients with VADs presenting with ICH between 2014 and 2020 who received four-factor PCC for rapid anticoagulation reversal. We collected the timing of PCC administration, timing of resumption of anticoagulation, survival, occurrence of thromboembolic events, and LDH levels throughout hospitalization. We identified 16 ICH events in 14 patients with VADs treated with rapid anticoagulation reversal using four-factor PCC (11 intraparenchymal, 4 subdural, 1 subarachnoid hemorrhage). PCC was administered at a mean of 3.3 ± 0.3 h after imaging diagnosis of ICH. Overall mortality was 63%. Survivors had higher presenting Glasgow Coma Scale (median 15, interquartile range [IQR] 15–15 versus 14, IQR 8–14.7, P = 0.041). In all six instances where the patient survived, anticoagulation was resumed on average 9.16 ± 1.62 days after reversal. There were no thromboembolic events prior to resumption of anticoagulation. Three events occurred after anticoagulation resumption and within 3 months of reversal: VAD thrombosis in a patient with thrombosis at the time of reversal, ischemic stroke, and readmission for elevated LDH in the setting of subtherapeutic international normalized ratio. Our limited series found no thromboembolic complications immediately following anticoagulation reversal with PCC prior to resumption of anticoagulation. LDH trends may be useful to monitor thromboembolic risk after reversal.

The standard of care for idiopathic normal pressure hydrocephalus (iNPH) is placement of a ventriculoperitoneal (VP) shunt. However, VP shunts require intracranial intervention and are associated with notable postoperative complications, with some groups reporting complication rates for VP shunts ranging from 17 to 33%, along with failure rates up to 17.7%. Lumboperitoneal (LP) shunts are an alternative for cerebrospinal fluid diversion that do not require intracranial surgery, thus providing utility in patients where intracranial surgery is not possible or preferred. Here we retrospectively reviewed our 25 patients with LP horizontal-vertical (LP-HV) shunts placement for initial treatment for iNPH from 2014 to 2019. All patients had preoperative gait dysfunction, 16 (64%) had urinary incontinence, and 21 (84%) exhibited cognitive insufficiency. Two weeks post-shunt placement, 23/25 (92%) patients demonstrated improvement in gait, 11/16 (68%) had improvement in incontinence, and 14/21 (66%) had improvement cognitive insufficiency. At six months or greater follow up 13/20 (65%) had improvement in gait, 7/15 (47%) showed improvement in incontinence, and 11/15 (73%) demonstrated improvement in cognitive function. Six patients (24%) required at least one revision of the LP shunt. Shunt malfunctions resulted from CSF leak in one patient, shunt catheter migration in two patients, peritoneal catheter pain in one patient, and clinical symptoms for overdrainage in two patients. Thus, we demonstrate that LP-HV shunt placement is safe and efficacious alternative to VP shunting for iNPH, resulting in notable symptomatic improvement and low risk of overdrainage, and may be considered for patients where cranial approaches should be avoided.

Background Following publication of trials demonstrating the efficacy of thrombectomy, societal guidelines were revised in 2015 to recommend this procedure for large-vessel stroke. Purpose To evaluate real-world thrombectomy rates, adverse events, outcomes, and readmissions across the United States in the 2 years after large-scale adoption of thrombectomy for acute stroke. Materials and Methods In this retrospective study, the authors queried the National Inpatient Sample and Nationwide Readmissions Database for patients undergoing thrombectomy between 2016 and 2017. Thrombectomy rates were compared by using the χ

BACKGROUND AND PURPOSE: Published data regarding embolic protection device efficacy is mixed, and its use during carotid artery stent placement remains variable. We, therefore, examined the frequency of embolic protection device use and its association with outcomes after carotid artery stent placement using a national quality improvement data base. MATERIALS AND METHODS: Patients undergoing carotid artery stent placement with or without embolic protection devices were identified in the American College of Surgeons National Surgical Quality Improvement Program data base. The primary outcome was the incidence of major adverse cardiovascular events (defined as death, stroke, or myocardial infarction/arrhythmia) within 30 days. Propensity scoring was used to create 2 matching cohorts of patients using demographic and baseline variables. RESULTS: Between 2011 and 2018, among 1200 adult patients undergoing carotid artery stent placement, 23.8% did not have embolic protection devices. There was no trend toward increased embolic protection device use with time. Patients without embolic protection device use received preoperative antiplatelets less frequently (90.6% versus 94.6%, P = .02), underwent more emergent carotid artery stent placement (7.2% versus 3.6%, P = .01), and had a higher incidence of major adverse cardiovascular events (OR = 1.81; 95% CI, 1.11–2.94) and stroke (OR = 3.31; 95% CI, 1.71–6.39). After compensating for baseline imbalances using propensity-matched cohorts (n = 261 for both), carotid artery stent placement without an embolic protection device remained associated with increased major adverse cardiovascular events (9.2% versus 4.2%; OR = 2.30; 95% CI, 1.10–4.80) and stroke (6.5% versus 1.5%; OR = 4.48; 95% CI, 1.49–13.49). CONCLUSIONS: Lack of embolic protection device use during carotid artery stent placement is associated with a 4-fold increase in the likelihood of perioperative stroke. Nevertheless, nearly one-quarter of patients in the American College of Surgeons National Surgical Quality Improvement Program underwent unprotected carotid artery stent placement. Efforts targeting improved embolic protection device use during carotid artery stent placement are warranted.

Spinal pial arteriovenous fistulas (spAVFs) are believed to be congenital lesions, and the development of a de novo spAVF has not been previously described. A 49-year-old female with a childhood history of vascular malformation–induced right lower-extremity hypertrophy presented in 2004 with progressive pain in her right posterior thigh and outer foot. Workup revealed 3 separate type IV spAVFs, which were treated by combined embolization and resection, with final conventional angiography showing no residual spinal vascular lesion in 2005. Ten years later, the patient returned with new right lower-extremity weakness, perineal pain, and left plantar foot numbness. Repeat spinal angiography demonstrated 2 de novo intertwined conus medullaris spAVFs.

OBJECTIVEThe carotid cave is a unique intradural region located along the medial aspect of the internal carotid artery. Small carotid cave aneurysms confined within this space are bound by the carotid sulcus of the sphenoid bone and are thought to have a low risk of rupture or growth. However, there is a lack of data on the natural history of this subset of aneurysms.METHODSThe authors present a retrospective case series of 290 small (≤ 4 mm) carotid cave aneurysms evaluated and managed at their institution between January 2000 and June 2017.RESULTSNo patient presented with a subarachnoid hemorrhage attributable to a carotid cave aneurysm, and there were no instances of aneurysm rupture or growth during 911.0 aneurysm-years of clinical follow-up or 726.3 aneurysm-years of imaging follow-up, respectively.CONCLUSIONSThis series demonstrates the benign nature of small carotid cave aneurysms.

OBJECTIVEAlthough most patients with low-grade glioma (LGG) present after a seizure, a small proportion is diagnosed after neuroimaging is performed for a sign or symptom unrelated to the tumor. While these tumors invariably grow, some surgeons argue for a watchful waiting approach. Here, the authors report on their experience in the surgical treatment of patients with incidental LGG (iLGG) and describe the neurological outcomes, survival, and complications.METHODSRelevant cases were identified from a prospective registry of patients undergoing glioma resection at the University of California, San Francisco, between 1997 and 2019. Cases were considered iLGG when the lesion was noted on imaging performed for a reason unrelated to the tumor. Demographic, clinical, pathological, and imaging data were extracted from the electronic medical record. Tumor volumes, growth, and extent of resection were calculated from pre- and postoperative volumetric FLAIR sequences.RESULTSOne hundred thirteen of 657 (17.2%) first-time resections for LGG were for incidental lesions. The most common reasons for the discovery of an iLGG were headaches (without mass effect, 34.5%) or trauma (16.8%). Incidental tumors were no different from symptomatic lesions in terms of laterality or location, but they were significantly smaller (22.5 vs 57.5 cm3, p < 0.0001). There was no difference in diagnosis between patients with iLGG and those with symptomatic LGG (sLGG), incorporating both molecular and pathological data. The median preoperative observation time for iLGG was 3.1 months (range 1 month–12 years), and there was a median growth rate of 3.9 cm3/year. Complete resection of the FLAIR abnormality was achieved in 57% of patients with incidental lesions but only 23.8% of symptomatic lesions (p < 0.001), and the residual volumes were smaller for iLGGs (2.9 vs 13.5 cm3, p < 0.0001). Overall survival was significantly longer for patients with incidental tumors (median survival not reached for patients with iLGG vs 14.6 years for those with sLGG, p < 0.0001). There was a 4.4% rate of neurological deficits at 6 months.CONCLUSIONSThe authors present the largest cohort of iLGGs. Patient age, tumor location, and molecular genetics were not different between iLGGs and sLGGs. Incidental tumors were smaller, a greater extent of resection could be achieved, and overall survival was improved compared to those for patients with sLGG. Operative morbidity and rates of neurological deficit were acceptably low; thus, the authors advocate upfront surgical intervention aimed at maximal safe resection for these incidentally discovered lesions.

BackgroundAdmission neutrophil-lymphocyte ratio (NLR) is significantly correlated to clinical outcomes in acute ischemic stroke (AIS). We investigated follow-up NLR and temporal changes in NLR after endovascular thrombectomy (EVT) with respect to successful revascularization, clinical outcomes, symptomatic intracranial hemorrhage (sICH) and mortality.MethodsRetrospective analysis of EVT for anterior circulation emergent LVO was performed with both admission (NLR1) and 3–7 day follow-up NLR (NLR2) laboratory data. Patient demographics, National Institutes of Health Stroke Scale (NIHSS) presentations, reperfusion efficacy (modified Thrombolysis in Cerebral Infarction (mTICI) score), sICH, and clinical outcomes (modified Rankin Scale (mRS)) at 90 days were studied. Univariate analyses correlated NLR1, NLR2, and temporal change in NLR (NLR2-NLR1) with successful reperfusion (mTICI ≥2b), favorable outcomes (mRS ≤2), sICH, and mortality. Multivariable logistic regression model evaluated the independent effects of NLR2 on favorable outcomes.Results142 AIS patients with median NIHSS 17 underwent EVT within 24 hours, and met NLR laboratory inclusion criteria. Lower follow-up NLR2 and less temporal change in NLR over 3–7 days, but not admission NLR1, inversely correlated with successful reperfusion (pConclusionsFollow-up NLR is a readily available and modifiable biomarker that correlates with the degree of reperfusion after mechanical stroke thrombectomy. Lower follow-up NLR2 at 3–7 days is associated with successful reperfusion and an independent predictor of favorable clinical outcomes, with reduced risk for sICH and mortality.

Background In-stent thrombosis is a potentially dangerous complication of flow diversion for cerebral aneurysms. The optimal management strategy for such thrombosis is not known. Here we present a case of acute ischemic stroke caused by occlusion of a Pipeline Embolization Device (PED) construct placed 18 months earlier for treatment of a fusiform middle cerebral artery aneurysm. This was successfully treated with mechanical thrombectomy with good neurologic outcome. Case Description A 40-year-old woman presented with acute onset of left-sided weakness and occlusion of the right middle cerebral artery harboring a PED construct. Intraarterial glycoprotein IIb/IIIa inhibitor was administered without success. Mechanical thrombectomy was then performed using a stent retriever and aspiration, and the patient was loaded with dual antiplatelet therapy. The patient showed initial neurologic improvement but several hours later demonstrated recurrent symptoms due to reocclusion of the PED construct. This was again treated with mechanical thrombectomy followed by an intravenous P2Y12 inhibitor infusion. She ultimately made an excellent neurologic recovery with persistent patency of the PED construct. Conclusions Mechanical thrombectomy with a stent retriever and aspiration is a therapeutic option for treatment of delayed thrombosis of a flow-diverting stent.

Background Autologous bone resorption is a frequent complication of cranioplasty, often necessitating reoperation. The etiology of this phenomenon is unknown, although it has recently been associated with indolent Propionibacterium acnes infection. Case Description A 59-year-old man initially presented with a traumatic acute subdural hematoma treated with emergent decompressive hemicraniectomy and hematoma evacuation. His bone flap was cryopreserved. He underwent cranioplasty with autologous bone 3 months later. Over the subsequent 14 months, serial imaging demonstrated progressive bone flap resorption, ultimately requiring repeat cranioplasty with a custom allograft. Although there was no evidence of infection at the time of repeat cranioplasty, routine culture swabs were taken and grew P. acnes after the patient had been discharged home. Pathologic analysis of the fragments of the original bone flap that were removed demonstrated osteonecrosis with marrow fibrosis but no evidence of inflammation or infection. He was treated with 6 weeks of intravenous antibiotics and had no evidence of infection at 8-month follow-up. Conclusions Indolent P. acnes infection can precipitate autologous bone flap resorption. While the mechanism of this is unknown, pathologic analysis of a partially resorbed bone flap in the setting of an indolent P. acnes infection found no evidence of an infectious process or inflammation within the bone. Further studies are needed to elucidate the mechanism of action of P. acnes in bone flap resorption.

Background Basilar perforator aneurysms are rare causes of subarachnoid hemorrhage and their natural history is poorly characterized. Although various treatment strategies have been reported, conservative management is an option that has been associated with a high likelihood of spontaneous resolution. Case Description Here we present 2 cases of subarachnoid hemorrhage, 1 diffuse and the other perimesencephalic, due to small ruptured basilar perforator artery aneurysms. These aneurysms were only identified after repeat angiography. Conservative management with serial imaging was pursued. Both patients did well clinically and repeat imaging demonstrated spontaneous resolution of the ruptured aneurysms. We also provide a literature review of ruptured basilar perforator aneurysms, showing a ~10% re-rupture rate within the early post-rupture period but otherwise a high rate of spontaneous resolution. Conclusions Although basilar perforator aneurysms can re-rupture, there is also a high likelihood of spontaneous resolution. Given the challenges of treatment, conservative management is an option that can be considered.

Background Mobile calcified emboli are a rare cause of large vessel occlusion and acute ischemic stroke and pose unique challenges to standard mechanical thrombectomy techniques. Intracranial stenting has been reported as a rescue maneuver in cases of failed mechanical thrombectomy owing to dissection or calcified atherosclerotic plaques, but its use for calcified emboli is not well described. Case Description We present 2 cases of acute ischemic stroke caused by mobile calcified emboli. Standard mechanical thrombectomy techniques using aspiration catheters and stent-retrievers failed to remove these emboli, so intracranial stenting was successfully performed in each case, albeit after overcoming unique challenges associated with the stenting of calcified emboli. We also review the literature on intracranial stenting as a salvage therapy for failed mechanical thrombectomy. Conclusions Mobile calcified emboli are rare causes of acute ischemic stroke. Intracranial stenting can be used to successfully treat calcified emboli when mechanical thrombectomy has failed.

The introduction of carotid stenting (CAS) has led to numerous comparative trials with carotid endarterectomy (CEA).The objective of the study was to review real-world volumes, outcomes, and complications following CEA versus CAS over an extended period to identify durable changes in practice.Data were extracted from the National Inpatient Sample. Trends were assessed by annual percent change (APC), and adjusted risk ratios were calculated across the last 5 years of the study period.During 1997-2015, 199,330 symptomatic and 1,995,637 asymptomatic patients underwent carotid revascularization. In symptomatic patients, CEA declined (1997-2004; APC = -7.68%, P0.001) and CAS rose (1997-2008; APC = 15.48%, P0.001) during the first decade, subsequently becoming more muted. In asymptomatic patients, CEA decreased, whereas CAS initially increased (1997-2006; APC = 20.27%, P0.001) and then decreased (2007-2015; APC = -4.52%, P0.001). Routine discharge after symptomatic revascularization declined in CEA after 2003 and in CAS after 2006 (APC = -1.72% and -3.11%, respectively, P0.001 for both), corresponding to increasing patient comorbidity; similar trends were seen in asymptomatic patients. Death decreased after CEA (symptomatic and asymptomatic; APC = -4.85% and -3.53%, respectively, P0.001 for both) and CAS (asymptomatic only, APC = -2.53%, P = 0.04). CAS remained associated with a higher adjusted risk ratio for death, venous thromboembolism, and seizures in all patients and stroke and nonroutine discharge in symptomatic patients, during the last 5 years of the study period.Mortality has improved, but routine discharge has decreased following both CEA and CAS, congruent with increasing patient comorbidity. Trends in volumes, outcomes, and complication rates continue to favor CEA in real-world practice.

BackgroundHospital readmissions are costly and reflect negatively on care delivered.ObjectiveTo have a better understanding of unplanned readmissions after carotid revascularization, which might help to prevent them.MethodsThe Nationwide Readmissions Database was used to determine rates and reasons for unplanned readmission following carotid endarterectomy (CEA) and carotid artery stenting (CAS). Trends were assessed by annual percent change, modified Poisson regression was used to estimate risk ratios (RR) for readmission, and propensity scores were used to match cohorts.ResultsAnalysis yielded 522 040 asymptomatic and 55 485 symptomatic admissions for carotid revascularization between 2010 and 2015. Higher 30-day readmission rates were noted after CAS versus CEA in both symptomatic (9.1% vs 7.7%, pConclusionsReadmission is not uncommon after carotid revascularization, occurs more often after CAS, and is predicted by baseline factors and by preventable adverse events at initial admission.

To explore the difference in post-operative DVT, PE, and ICH complications following administration of prophylactic UFH or enoxaparin in patients undergoing craniotomy.A retrospective chart review was conducted for 542 patients at our institution receiving either 5000units/0.5 mL UFH (BID or TID; 180 patients) or single daily 40 mg/0.4 mL enoxaparin (362 patients) following craniotomy. Multivariate linear regression models were developed comparing rates of postoperative DVT, PE, and reoperation for bleeding in patients given enoxaparin versus UFH prophylaxis while controlling for age at surgery, history of VTE, surgery duration, number of post-operative hospital days, reoperation, post-operative infections, and reason for surgery (tumor type, genetics, etc.). Mann Whitney U tests were subsequently performed comparing rates of postoperative DVT, PE, and ICH for each group.Patients receiving prophylactic enoxaparin, when compared to UFH, exhibited similar rates of postoperative DVT (22 % vs 20.6 %, p = 0.86), PE (9.7 % vs 8.9 %, p = 0.86), and reoperation for bleeding (0.4 % vs 0.2 %, p = 0.58), while controlling for the factors described above.In patients undergoing craniotomy, rates for DVT, PE, and ICH were similar between patients treated with either prophylactic enoxaparin or UFH. Further studies are needed to understand whether a certain subset of patients demonstrate improved benefit from either prophylactic anticoagulant.

BACKGROUND: Experience with endoluminal flow diversion for the treatment of posterior circulation aneurysms is limited. PURPOSE: We sought to investigate factors associated with the safety and efficacy of this treatment by collecting disaggregated patient-level data from the literature. DATA SOURCES: PubMed, EMBASE, and Ovid were searched up through 2019 for articles reporting flow diversion of posterior circulation aneurysms. STUDY SELECTION: Eighty-four studies reported disaggregated data for 301 separate posterior circulation aneurysms. DATA ANALYSIS: Patient, aneurysm, and treatment factors were collected for each patient. Outcomes included the occurrence of major complications, angiographic occlusion, and functional outcomes based on the mRS. DATA SYNTHESIS: Significant differences in aneurysm and treatment characteristics were seen among different locations. Major complications occurred in 22%, angiographic occlusion was reported in 65% (11.3 months of mean follow-up), and good functional outcomes (mRS 0–2) were achieved in 67% (13.3 months of mean follow-up). Multivariate analysis identified age, number of flow diverters used, size, and prior treatment to be associated with outcome measures. Meta-analysis combining the current study with prior large nondisaggregated series of posterior circulation aneurysms treated with flow diversion found a pooled incidence of 20% (n = 712 patients) major complications and 75% (n = 581 patients) angiographic occlusions. LIMITATIONS: This study design is susceptible to publication bias. Use of antiplatelet therapy was not uniformly reported. CONCLUSIONS: Endoluminal flow diversion is an important tool in the treatment of posterior circulation aneurysms. Patient age, aneurysm size, prior treatment, and the number of flow diverters used are important factors associated with complications and outcomes.

Objective The benefit of balloon guide catheters (BGCs) in mechanical thrombectomy (MT) remains unclear. We examined the effect of BGC on procedural, radiographic, and clinical outcomes. Methods A systematic review was conducted using PubMed, Embase, and Scopus to identify studies comparing MT for acute ischemic stroke with and without the use of BGCs. Patient demographics, procedural metrics, and outcomes were abstracted. Three-month functional outcomes were based on the modified Rankin Score (mRS). Results Of the 2,181 resultant articles identified by the systematic review, 9 met inclusion criteria, comprising 2292 BGC and 1868 non-BGC patients. At baseline, the BGC group had a higher incidence of atrial fibrillation (43.3% versus 36.2%, p Conclusion BGC use during MT for acute ischemic stroke is associated faster to groin-to-recanalization times, improved TICI ≥2b reperfusion, lower incidence of sICH, and lower mortality. These data demonstrate the promise of BGC use for MT and warrant further study. Disclosures N. Shlobin: None. B. Jahromi: None. S. Ansari: None. M. Potts: None.

BACKGROUND AND PURPOSE: Acute stroke intervention refractory to mechanical thrombectomy may be due to underlying vessel wall pathology including intracranial atherosclerotic disease and intracranial arterial dissection or recalcitrant emboli. We studied the prevalence and etiology of refractory thrombectomy, the safety and efficacy of adjunctive interventions in a North American–based cohort. MATERIALS AND METHODS: We performed a multicenter, retrospective study of refractory thrombectomy, defined as unsuccessful recanalization, vessel reocclusion in

Background Direct extracranial to intracranial (EC-IC) bypass is a valuable treatment option for symptomatic occlusive cerebrovascular disease and complex intracranial aneurysms. Aneurysm formation at or near the anastomotic site is a rarely reported phenomenon, and the pathophysiology and appropriate management of such de novo aneurysms are not clear. Case Description Here we present the case of a superficial temporal to middle cerebral artery (STA-MCA) anastomosis that was complicated by aneurysm formation at the anastomotic site. This was treated with microsurgical clipping with preservation of the bypass. Pathologic analysis of the lesion was consistent with a pseudoaneurysm. We provide a literature review of this phenomenon, which is most often associated with low-flow STA-MCA bypasses, including review of the pathologic findings associated with it. Conclusion Pseudoaneurysm formation at the site of an EC-IC bypass is a rare phenomenon that should be recognized and treated to prevent further growth and rupture.

Purpose To evaluate the outcomes of combined preoperative embolization and microsurgical resection in comparison with microsurgical resection alone as the current standard of care for low-grade cerebral arteriovenous malformations (AVM) in the pediatric population. Materials & methods We performed a single-center retrospective study of pediatric patients presenting with Spetzler-Martin (SM) grade I and II cerebral AVMs at a high-volume tertiary pediatric hospital between January 2005 and September 2016. Low grade AVM patients were divided into two groups: pre-operative embolization with subsequent microsurgical resection or microsurgical resection alone. Patient demographics, clinical and imaging presentations, AVM morphological characteristics, post-operative complications, and mid to long-term clinical outcomes were studied. Post-embolization and post-surgical outcomes were assessed prior to and after treatment, at 3 months and at final follow-up using the modified Rankin Scale (mRS) to compare both final independent (mRS 0–2) and favorable (no change or improved mRS) clinical outcomes for comparison between study groups. Statistical associations of patient demographics, AVM characteristics/SM grading, and treatment modality group with post-operative complications were performed using univariate logistic regression analysis. Results Thirty-four patients with low grade cerebral AVMs met the study inclusion criteria (mean age 10.6 ± 3.4 years; range 3–16 years, 22M:12 F). Twenty patients (59%) presented with ruptured AVMs. Twenty-five patients (73.5%) underwent combined treatment with embolization and microsurgical resection, while 9/34 (26.5%) underwent microsurgical resection alone. A total of 35 embolization procedures performed in 25 patients (Mode, 1; Range, 1–7) were associated with two minor post-embolization and 7 subsequent post-surgical (28%) complications, resulting in clinical deterioration in a single patient. Microsurgical resection alone was associated with 3 post-surgical complications (33%), resulting in permanent neurological disability in a single patient. There was no significance association of post-operative complications with either treatment modality group, combined treatment versus surgical resection alone [OR:1.13; 95% CI:0.23–5.62; p-value 0.88]. SM Grade II and eloquent locations were found to be significantly associated with post-surgical complications of low grade pediatric cerebral AVMs [OR 13.2 and OR 8 respectively, p-value 0.004 and 0.005). On mean follow-up time of 35.7 months, final clinical outcome was favorable in the majority of both treatment arms with no dependent (mRS>2) patients in the combined endovascular and surgical cohort. Two patients in the surgical cohort failed to achieve independent functional status, primarily due to a pre-operative morbid status (p-value 0.015). However, there was no significant difference in favorable outcomes between the treatment groups [p-value 0.14]. Conclusion Our study suggests equivalent safety and favorable clinical outcomes related to combined endovascular embolization and microsurgical resection of low grade pediatric cerebral AVMs in comparison to microsurgical resection alone. On long term clinical follow-up, the vast majority of patients achieved an independent and favorable functional status irrespective of pre-operative embolization.

BACKGROUND AND PURPOSE: 3D high-resolution black-blood MRI or MR vessel wall imaging allows evaluation of the intracranial arterial wall and extraluminal pathology. We investigated the diagnostic accuracy and reliability of black-blood MRI for the intraluminal detection of large-vessel arterial occlusions. MATERIALS AND METHODS: We retrospectively identified patients with intracranial arterial occlusions, confirmed by CTA or DSA, who also underwent 3D black-blood MRI with nonenhanced and contrast-enhanced T1 sampling perfection with application-optimized contrasts by using different flip angle evolution (T1 SPACE) sequences. Black-blood MRI findings were evaluated by 2 independent and blinded neuroradiologists. Large-vessel intracranial arterial segments were graded on a 3-point scale (grades 0–2) for intraluminal baseline T1 hyperintensity and contrast enhancement. Vessel segments were considered positive for arterial occlusion if focal weak (grade 1) or strong (grade 2) T1-hyperintense signal and/or enhancement replaced the normal intraluminal black-blood signal. RESULTS: Thirty-one patients with 38 intracranial arterial occlusions were studied. The median time interval between black-blood MRI and CTA/DSA reference standard studies was 2 days (range, 0–20 days). Interobserver agreement was good for T1 hyperintensity (κ = 0.63) and excellent for contrast enhancement (κ = 0.89). High sensitivity (100%) and specificity (99.8%) for intracranial arterial occlusion diagnosis was observed with either intraluminal T1 hyperintensity or contrast-enhancement imaging criteria on black-blood MRI. Strong grade 2 intraluminal enhancement was maintained in >80% of occlusions irrespective of location or chronicity. Relatively increased strong grade 2 intraluminal T1 hyperintensity was noted in chronic/incidental versus acute/subacute occlusions (45.5% versus 12.5%, P = .04). CONCLUSIONS: Black-blood MRI with or without contrast has high diagnostic accuracy and reliability in evaluating intracranial large-vessel arterial occlusions with near-equivalency to DSA and CTA.

Background Venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE), and intracranial hemorrhage (ICH) may complicate the post-operative course of patients undergoing craniotomy. While prophylaxis with unfractionated heparin (UFH) has been shown to reduce VTE rates, twice-daily (BID) and three-times-daily (TID) UFH dosing regimens have not been compared in neurosurgical procedures. The objective of this study was to explore the association between UFH dosing regimen and rates of VTE and ICH in craniotomy patients. Methods A retrospective chart review was conducted for 159 patients at Northwestern University receiving 5000 units/0.5 mL UFH injections either BID (n = 132) or TID (n = 27). General linear regression models were run to predict rates of DVT, PE, and reoperation due to bleeding from UFH dosing regimen while controlling for age at surgery, sex, VTE history, craniotomy for tumor resection, surgery duration, length of stay, reoperation, infections, and IDH/MGMT mutations. Results Receiving UFH TID was significantly associated with a lower rate of PE when compared with receiving UFH BID (β = –0.121, P = 0.044; TID rate = 0%, BID rate = 10.6%). UFH TID also showed a trend toward lower rates of DVT (β = –0.0893, P = 0.295; TID rate = 18.5%, BID rate = 21.2%) when compared with UFH BID. UFH TID showed no significant difference in rate of reoperation for bleeding when compared to UFH BID (β = –0.00623, P = 0.725; TID rate = 0%, BID rate = 0.8%). Conclusions UFH TID dosing is associated with lower rates of PE when compared with BID dosing in patients undergoing craniotomy.

Background and Purpose: Intracranial hemorrhage (ICH) is considered an emergency that requires rapid medical or surgical management. Previous studies have utilized artificial intelligence to attempt to automate and expedite the diagnosis of this pathology on neuroimaging. However, these studies have utilized local, institution-specific data for training of these networks that limits the deployment of neural networks across broader hospital networks or regions due to data biases. We demonstrate the creation and validation of a neural network based on an openly available imaging data tested on data from our institution demonstrating a high-efficacy, institution-agnostic network. Methods: A retrospective study was completed after institutional review board approval. A dataset was created from de-identified, publicly available non-contrast computed tomography (CT) images of known ICH. This data was used to train a neural network using distinct windowing parameters and custom random augmentation. This network was then validated in two phases using cohort-based (phase 1) and longitudinal (phase 2) approaches. Results :Our CNN was trained on 752,807 openly available slices, which included 112,762 slices containing intracranial hemorrhage. In phase 1, final network performance for intracranial hemorrhage showed a receiver operating characteristic curve (AUC) was 0.99. At the inflection point, our model showed a sensitivity of 98% at a threshold specificity of 99%. In phase 2, we obtained an AUC of 0.99 after analysis of 726 scans with a negative predictive value of 99.70% (n=726). Conclusions: To our knowledge, this is the first report that demonstrates an effective neural network trained on completely open data for screening ICH at an unrelated institution. This study demonstrates a proof-of-concept for widespread deployment of screening neural networks to multiple sites, while maintaining high efficacy. Further studies are necessary in multiple hospital system types, with different patient populations, to understand site-specific characteristics that may limit network applicability. Funding Statement: None. Declaration of Interests: No relevant disclosures to report and no conflicts of interest. Ethics Approval Statement: A retrospective study was completed after institutional review board approval.

Dissections are an uncommon but important cause of acute ischemic stroke, often resulting in both a proximal flow-limiting lesion as well as an intracranial embolic occlusion. Strategies for treatment and management are described.

Background Postpartum vertebral artery dissections (ppVADs) are rare but potentially morbid conditions that occur in otherwise healthy patients. Objective To evaluate clinical characteristics of ppVADs. Methods Demographic, clinical, treatment, and outcome data were collected on ppVADs and are presented in a case series of 12 patients and compared to the general cohort. Results In total, 12 patients had ppVADs in our cohort of 310 patients with vertebral artery dissections (VADs). They occurred 11.27 days (95% CI, -0.85 to 23.39) postdelivery. Of these, there were 5 (42%) with a hypertensive disorder of pregnancy, and 4 (33%) who had migraines. A total of 3 (25%) had ischemic strokes and 1 (8%) had a subarachnoid hemorrhage. In total, 2 patients (17%) had unfavorable modified Rankin Scale (mRS, 2-6) at discharge from hospital. Patients with ppVADs more often had bilateral VADs (42% vs 17%, P = .03), had pseudoaneurysms (50% vs 18%, P = .0068), were younger (33.83 years vs 44.32 years, P = .018), and had lower Charlson Comorbidity Index (CCI = 0 vs 0.99, P = .0038). Anticoagulant treatment was used in a similar percentage of patients. Multivariate analysis revealed 3 factors were predictive of change in mRS: CCI (OR = 1.09, 95% CI, 1.02-1.15), stroke (OR = 0.78, 95% CI, 0.65-0.95), and mRS at hospital discharge (OR = 0.80, 95% CI, 0.74-0.87). Conclusion There are only 15 isolated ppVADs reported in the literature; this study adds 12 patients with 17 ppVADs. Postpartum VADs occur in younger, healthier patients than in the general cohort, raising questions about mechanism of injury. The majority of ppVADs have good neurological outcomes.

Intracranial hemorrhage (ICH) is a devastating complication for patients with ventricular assist devices (VADs). The safety of emergent anticoagulation reversal with four-factor prothrombin complex concentrate (PCC) and optimal timing of anticoagulation resumption are not clear. In addition, lactate dehydrogenase (LDH) is used as a biomarker for thromboembolic risk, but its utility in guiding anticoagulation management after reversal with PCC has not be described.We retrospectively reviewed a consecutive series of patients with VADs presenting with ICH between 2014 and 2020 who received four-factor PCC for rapid anticoagulation reversal. We collected the timing of PCC administration, timing of resumption of anticoagulation, survival, occurrence of thromboembolic events, and LDH levels throughout hospitalization.We identified 16 ICH events in 14 patients with VADs treated with rapid anticoagulation reversal using four-factor PCC (11 intraparenchymal, 4 subdural, 1 subarachnoid hemorrhage). PCC was administered at a mean of 3.3 ± 0.3 h after imaging diagnosis of ICH. Overall mortality was 63%. Survivors had higher presenting Glasgow Coma Scale (median 15, interquartile range [IQR] 15-15 versus 14, IQR 8-14.7, P = 0.041). In all six instances where the patient survived, anticoagulation was resumed on average 9.16 ± 1.62 days after reversal. There were no thromboembolic events prior to resumption of anticoagulation. Three events occurred after anticoagulation resumption and within 3 months of reversal: VAD thrombosis in a patient with thrombosis at the time of reversal, ischemic stroke, and readmission for elevated LDH in the setting of subtherapeutic international normalized ratio.Our limited series found no thromboembolic complications immediately following anticoagulation reversal with PCC prior to resumption of anticoagulation. LDH trends may be useful to monitor thromboembolic risk after reversal.

Background Vertebral artery dissections (VADs) are a rare cause of ischemic stroke that can occasionally lead to intracranial hemorrhage (ICH). This study aims to identify differences in predisposing factors, event characteristics, and outcomes between patients with only a VAD and patients with VAD and concomitant ICH. Methods We conducted a retrospective chart review of 301 patients who presented with VADs at our institution from 2004–2018. A total of 13 patients were identified with VAD and concomitant ICH. Data were collected on demographics, event characteristics, treatments, and neurologic outcomes, measured using the modified Rankin Scale (mRS). Results VAD+ICH and VAD-only groups were similar in terms of age, sex, and recorded comorbidities. Additionally, etiology of the dissections did not seem to vary between groups (P = 0.6), even when selecting for traumatic causes such as motor vehicle accidents (P = 0.22) and violence (P = 0.25). Concomitant strokes and aneurysms/pseudoaneurysms occurred in similar proportions as well, but cervical fractures were more common in the VAD+ICH group (P = 0.003). Using the mRS as a measure of neurological outcome, we found that the VAD+ICH group had worse neurologic function at discharge, 3-month follow-up, and last follow-up (P Conclusions Patients who experienced an ICH in addition to a VAD did not have any identifiable risk factors. Cervical spine fractures were more common in patients with VAD and ICH. VAD patients with a concomitant ICH have worse neurologic outcomes than patients with only a VAD.

Objective The “weekend effect” has been shown to affect outcomes in acute ischemic stroke. We sought to compare metrics and outcomes of emergent stroke thrombectomy at three affiliated comprehensive stroke centers on weekdays versus nights/weekends for a three-year period beginning in 2015, when thrombectomy became common practice for large vessel occlusion acute ischemic stroke. Methods We performed a retrospective analysis of all stroke thrombectomy patients treated from 2015 to 2018 to compare standard thrombectomy metrics and outcomes in patients presenting during weekdays or nights/weekends. Results Two hundred-sixteen mechanical thrombectomy cases were evaluated, with 50.9% of patients presenting on weekdays and 49.1% presenting on nights/weekends. There were no statistical differences in baseline characteristics in demographics, stroke risk factors, or stroke severity, but patients presenting on nights/weekends had longer times from last known normal to presentation (130 versus 72.5 minutes, p=0.03). Door-to-groin times were delayed in patients presenting on nights/weekends compared to weekdays (median 104.5 versus 86 minutes, respectively; p=0.007) but groin-to-reperfusion times were similar (51.5 versus 48 minutes, respectively; p=0.4). Successful reperfusion was similar in both groups (90.6% nights/weekends versus 90% weekdays; p=1.0) as were the incidence of symptomatic intracerebral hemorrhage (10.4% nights/weekend versus 7.3% weekdays; p=0.48) and 90-day good functional outcomes based on the modified Rankin Scale did not differ between the two groups in a shift analysis (p=0.545). Conclusions Despite delays in door-to-groin puncture times in acute ischemic stroke patients presenting on nights/weekends compared to weekdays, we did not identify significant differences in successful reperfusion or functional outcomes in this cohort. Further studies are warranted to continue to evaluate differences in stroke care on nights/weekends versus weekdays.

Background Minimally-invasive intraparenchymal hemorrhage (IPH) evacuation may provide a functional and mortality benefit, especially if there is minimal residual hematoma. Several methods have been used to confirm extent of IPH evacuation, including intraoperative computed tomography (CT). We sought to evaluate the feasibility of intraoperative CT in endoscopic-assisted IPH evacuation, with a focus on the operative workflow and imaging quality. Methods We retrospectively reviewed all endoscopic-assisted IPH evacuation procedures utilizing intraoperative CT performed at our institution over a 9-month period. We describe the operative room setup and workflow for using intraoperative CT and compare the intra- and postoperative imaging findings. Results Eight consecutive procedures were included in this study. Intraoperative CT provided useful information that informed intraoperative decision-making in each case. There were no clinically significant differences in residual hematoma volume or midline shift between intra- and postoperative CT scans. Streak artifact was present in all cases due to the head holder, but did not significantly inhibit image evaluation. Conclusion Intraoperative CT is an effective method of evaluating the extent of IPH evacuation in endoscopic-assisted procedures.

BACKGROUND Vertebral artery dissections (VADs) are rare yet potentially devastating events. While the etiology of these events is either traumatic or spontaneous, there is a paucity of quantitative literature comparing the two. OBJECTIVE To identify differences in predisposing factors, event characteristics, and clinical outcomes between traumatic VADs (tVADs) and spontaneous VADs (sVADs). METHODS We retrospectively identified patients with VADs presenting to our institution at VAD onset with at least a 3-mo follow-up. Demographics, event characteristics, treatment details, and neurological outcomes as modified Rankin scale (mRS) scores were collected. RESULTS Of the 310 patients sustaining 366 VADs total, 187 (60.3%) patients experienced a total of 221 (60.4%) sVADs and 123 (39.7%) patients experienced a total of 145 (39.6%) tVADs. sVADs were more likely to occur in the intracranial course of the artery (P = .042) and have a lower mRS at discharge, 3-month, and last clinical follow-up (P = 003, .002, and .001, respectively). tVADs were more likely associated with concomitant fractures (P

Background and Purpose: Hemorrhages are a serious complication of brain surgery, and magnesium has shown hemostatic properties in hemorrhagic stroke and non-neurological surgeries. External ventricular drain (EVD) insertion is an advantageous model of emergency neurosurgical hemorrhage risk because it is common, standardized, and the operator is blinded to the outcome during the procedure. We tested the hypothesis that low magnesium is associated with risk of hemorrhagic complications from EVD insertion. Methods: Patients with spontaneous intracerebral hemorrhage and aneurysmal subarachnoid hemorrhage were enrolled in a prospective, observational study. Demographic and clinical variables were prospectively recorded, including serum magnesium measurements. Catheter tract hemorrhage (CTH) was measured on postoperative head computed tomography within 48 hours of EVD insertion. Results: We observed 50 CTH among 327 EVD procedures (15.3%) distributed similarly among intracerebral hemorrhage (21/116 [18.1%]) and subarachnoid hemorrhage (29/211 [13.7%]). Magnesium was lower in patients with CTH compared with those without (median 1.8 versus 2.0 mg/dL, P P Conclusions: Lower magnesium at the time of EVD insertion was an independent predictor of hemorrhagic complications. Baseline risk was attenuated by preprocedural increases in magnesium, suggesting a therapeutic opportunity.

Purpose Blister intracranial aneurysms are a rare etiology of subarachnoid hemorrhage (SAH) accompanied by high morbidity and mortality rates. Digital subtraction angiography (DSA) and CT angiography (CTA) serve as the main imaging techniques for diagnosing the cause of SAH, yet blister aneurysms can remain occult on DSA or CTA imaging due to their small size, broad based morphology, and early transient thrombosis. In this case series of SAH patients that were diagnosed with ruptured blister aneurysms, we investigated the role of high-resolution (HR)-MRI Vessel Wall Imaging (VWI) in identifying culprit, ruptured aneurysm diagnoses. Methods and Materials We performed an IRB-approved retrospective review of patients diagnosed with SAH from 2010–2019 at our institution. We studied patient demographics, presentations, aneurysm size/locations, initial and follow-up imaging including CT, CTA/MRA, DSA, and MR VWII studies. Results Seven patients (1 Male: 6 Female, mean age: 52) with ruptured blister aneurysms were identified. Median of Hunt-Hess grade (range: 1–4) and Fisher grade (range: 2–4) at presentation were 1 and 3 respectively. Blister aneurysm were small 1–3 mm in mean size and broad based neck morphology in the anterior circulation. All but 2 of them were located in non-branching sites. Initial CTA was diagnostic for a ruptured blister aneurysm in 3/7 (43%), confirmed with DSA. In the remaining 4/7 cases CTA was negative, and DSA identified two of these occult ruptured blister aneurysm initially and two subsequently on 1 week follow-up DSA. HR-MR VWI was performed in 3/4 patients 1–3 days after presentation and revealed mild to moderate focal enhancement and/or T1 hyperintensity of the small aneurysm wall corresponding to the blister aneurysm sites confirmed by initial or follow-up DSA. Conclusion HR-MR VWI can provide adjunctive diagnostic information for the identification of occult ruptured blister aneurysm in SAH patients, when combined with conventional imaging studies such as CTA and DSA. HR-MR VWI may assist in accelerate the time to definite diagnosis in cases with negative initial CTA or DSA findings. Disclosures Y. Moazeni: None. R. Abdalla: None. M. Sukumaran: None. D. Cantrell: None. A. Shaibani: None. M. Hurley: None. B. Jahromi: None. M. Potts: None. S. Ansari: None.

Purpose Dissecting intracranial aneurysms (DIA) can present with subarachnoid hemorrhage or ischemia, and are more common in the posterior circulation. Radiographically, DIA have similar morphological features to fusiform and dolichoectatic atherosclerotic aneurysms, with difficult diagnosis on traditional CTA and MRI/MRA cross sectional imaging. In addition, the rebleeding risk from ruptured DIA is considerably higher reaching up to 71.4% with 46.7% mortality, necessitating early diagnosis and treatment. We aimed to distinguish specific imaging features of spontaneous DIA using high resolution MR vessel wall imaging (VWI). Methods In a retrospective analysis of our MR VWI database between Jan 2016 and March 2019, we identified patients with suspected DIA diagnosed by clinical history, CTA/MRA imaging findings, and conventional angiography. MRI 3D TOF and MR VWI were reviewed by two neuroradiologists for imaging findings that were diagnostic for DIA including intramural hematomas, intimal flaps and double lumen. Following diagnosis on MRI/3D TOF MRA, MR VWI was serially assessed for additional findings that could aid or confirm the diagnosis. Results Seven patients (4M:3F) with mean age 62± 13.7 were proven to have DIA, all located in the posterior circulation (6 vertebral:1 basilar). All patients presented with either severe headaches or diplopia/dizziness. There was no family history of IA, but high incidence of hypertension and hyperlipidemia (30%). On MRI/3D TOF MRA, intramural hemorrhage was observed to diagnose two DIAs, which was also confirmed with intramural T1 hyperintense signal on MR VWI. Two aneurysms demonstrated fusiform morphology with intraluminal thrombus on MRI/3D TOF MRA without diagnosis, however, MR VWI identified an enhancing dissection flap and double lumen pathology for definitive DIA diagnosis. Two DIA were suspected with suggestion of intimal flap on MRI/3DTOF MRA, but improved visualization of enhancing intimal flap on MR VWI confirmed the diagnosis. One aneurysm was diagnosed based on clinical history and an associated enhancing dissection flap with tapered occlusion of the contralateral vertebral artery, but no imaging features on 3D TOF MRA or MR VWI suggested a dissecting aneurysm. Conclusions Spontaneous DIA are more commonly diagnosed in the posterior circulation. MR VWI is a valuable tool in confirming the diagnosis and differentiating fusiform thrombosed aneurysms from DIA with improved visualization of T1 hyperintense intramural hemorrhage, and enhancing intimal flap, and/or double lumen intracranial dissection pathology. Disclosures R. Abdalla: None. Y. Moazeni: None. A. Shaibani: None. M. Hurley: None. M. Potts: None. B. Jahromi: None. S. Ansari: None.

Introduction While the Pipeline Embolization Device (PED, Medtronic) is safe and effective in the treatment of intracranial aneurysms in adults, less is known about its safety and effectiveness in pediatric patients. We aim to report clinical outcomes in patients aged 18 or younger undergoing flow diversion with PED for intracranial aneurysms. Methods PubMed, Embase, and Scopus were searched for reports of pediatric patients treated with PED. Disaggregated data was available for 44 pediatric patients with 48 aneurysms. Data regarding demographics, aneurysm characteristics, treatment, follow-up, clinical outcomes, and complications were collected. Results The average age of patients was 10.5 ± 4.3 years, 47.8% of whom were male, while 34.1% were female, and the sex of 18.1% was not reported. A total of 23 aneurysms (52.2%) were in the posterior circulation. Fourteen aneurysms (29.2%) were fusiform, and 12 (25.0%) were dissecting. Fifteen aneurysms (31.3%) were giant, 14 (29.2%) were small, and 9 (18.9%) were large. Fourteen aneurysms (29.2%) presented with mass effect, followed by 11 (22.9%) with subarachnoid hemorrhage, and 6 (12.5%) each with headache and recurrence. The number of PEDs used for an aneurysm was 2.0 ± 1.5, and 10 aneurysms (20.8%) were treated with adjunct coiling. The average imaging and clinical follow-up for the aneurysms were 10.1 ± 7.9 and 10.5 ± 8.1 months, respectively. Thirty-four aneurysms (70.8%) were completely occluded. Four patients (10.0%) experienced complications, including one death, recurrence, brainstem compression, and in-stent stenosis. Conclusions PED is safe and effective for intracranial aneurysm treatment in pediatric patients. Proper guidelines regarding use of PED in children should be created. Disclosures N. Shlobin: None. M. Potts: None.

Introduction Endovascular stroke thrombectomy is currently the standard of care for anterior circulation large vessel occlusions (LVO), based on multiple randomized control trials. Due to the grave consequences of posterior circulation occlusions, no randomized control trials have been performed to assess the benefit and outcome of mechanical thrombectomy in the posterior circulation. We aim to evaluate the real-world evidence for mechanical thrombectomy in posterior circulation LVO using the Neurovascular Quality Initiative (NVQI) registry. Methods Data from the NVQI registry database was analyzed and compared for anterior versus posterior circulation acute ischemic stroke treated with endovascular thrombectomy in 23 US centers (17 states) from February 2015 to October 2019. Mann Whitney and Fischer exact tests were used for continuous and categorical variables, respectively. Results Posterior circulation (PC) thrombectomy was performed in a minority of 9.2% (284/3103 patients) compared to anterior circulation (AC) thrombectomy. LVO sites were predominantly basilar artery occlusions (68% basilar trunk and 19.4% basilar apex/PCA) with the remainder as vertebral artery occlusions (12.7%). Mean age at the intervention was 66±15.5 years (61.6% male) PC versus 68.8±15.4 years AC, p=0.004. Mean NIHSS at presentation was 17±10.2 PC versus 15.8±6.8 AC, p=0.007. CT/CTA was performed in 94% of cases whereas MRI was performed in 19% of cases (versus 14% AC, p=0.03). Median arrival to groin puncture time was 110 min PC versus 87 min AC, onset to groin time was 375 min PC versus 291 min AC, and median procedure time was 38 min PC versus 33 min AC. Successful recanalization was achieved in 84.5% (TICI 2b/3) versus 84% AC (p=0.87) with 50.4% reporting single pass recanalization and 3.9% technical failures (3.2% access related). Intraprocedural complications were reported in 4.9% of cases (0.7% vessel perforations, 0.4% hemorrhagic transformations, 1.4% non-target embolization, and 1.8% iatrogenic dissections). Mean post-operative length of stay was 9.5±9.5 days, with 24.6% in hospital mortality versus 11.2% AC, (p Conclusion Real-world evidence from the NVQI procedural registry suggests posterior circulation stroke to be more common in younger patients with significantly higher NIHSS presentations, and increased utilization of preprocedural MRI for endovascular thrombectomy selection. Given the historical high morbidity and mortality of basilar artery occlusion, there is strong evidence for the benefit of mechanical thrombectomy in the posterior circulation with 3-month functional outcomes nearly identical to thormbectomy outcomes in the anterior circulation. Disclosures D. Cantrell: None. R. Abdalla: None. A. Shaibani: None. M. Hurley: None. B. Jahromi: None. M. Potts: None. S. Ansari: None.

Background and Purpose Multiple randomized controlled trials demonstrated the significant clinical benefit of endovascular stroke thrombectomy in anterior circulation large vessel occlusions (LVO) within 6 hours. More recent trials have shown the benefit to extend up to 24 hours with advanced imaging selection. We aim to present real-world evidence for endovascular thrombectomy (EVT) practiced in the United States using the Neurovascular Quality Initiative (NVQI) registry. Methods Data from the NVQI registry was analyzed for anterior circulation acute ischemic strokes treated with EVT in 23 US centers (17 states) from Feb 2015 to Oct 2019. Results Anterior circulation EVT was performed in 90.5% (2808/3103 patients). LVO sites were most common in the MCA (74%) vs. the ICA (25% cervical and/or terminus) with few isolated ACA occlusions (1%). Mean age at intervention was 68.8 ± 15.4 (48.6% male) presenting with a mean NIHSS of 15.8 ± 6.8. ASPECTS was reported in 69.2% of cases with only 47.9% presenting with ASPECTS≥7. CT/CTA was performed in 94% of cases whereas MRI/MRA was limited to 14%. The median arrival to groin puncture time was 87 min, onset to groin time was 291 min, and procedure time was 33 min. 43.1% of patients received IV rtPA. 84% of cases were successfully treated (TICI 2b/3 reperfusion), 45% reported single pass successful recanalization, with 3.9% technical failures (2.3% access related). Intraprocedural complications were reported in 4.6% of cases (0.4% vessel perforations, 0.5% hemorrhagic transformations, 1.1% non-target embolization, and 1.2% iatrogenic dissections). Mean post-operative length of stay was 8.5±11.4 days, with 11.2% in-hospital mortality. 90 day follow-up mRS was reported in 67.5% of cases with mRS≤2 achieved in 37.3% and 90-day mortality reported in only 1.3% of cases. Missing data were most common in technical failure, intraprocedural complications, and 90-day mRS amounting to 13.5%, 15.3% and 32.5% of cases, respectively. Conclusion Stroke thrombectomy practices, procedural metrics, and outcomes from the NVQI registry mirrors the findings from the HERMES meta-analysis confirming the real-world practice and evidence for EVT in the US. Stricter quality reporting guidelines, improving clinical follow up, and the potential for automated imaging data adjudication will transition quality reporting infrastructures to be utilized for regulatory device monitoring, expanding indications, clinical trials, and value-based reimbursements. Disclosures R. Abdalla: None. D. Cantrell: None. M. Potts: None. B. Jahromi: None. A. Shaibani: None. M. Hurley: None. S. Ansari: None.

Introduction Endovascular mechanical thrombectomy is the standard of care treatment for acute ischemic stroke secondary to large vessel occlusions, but racial disparities in stroke interventional management and outcomes are not well studied. Moreover, a robust analysis of multiple relevant variables, with consideration of possible confounders, has not been previously conducted. We aimed to evaluate real-world evidence for racial differences in stroke thrombectomy management, short- and long-term outcomes using the Neurovascular Quality Initiative-Quality Outcomes Database (NVQI-QOD) registry. Methods Data from the NVQI-QOD registry database were analyzed and compared for racial differences with respect to technical and functional outcomes of stroke thrombectomy in 3281 patients from 23 US centers (17 states) between Jan 2015 to March 2020. Race was classified into 4 groups: 1) Caucasian (n=2484), 2) African American (n=563), 3) Hispanic (n=109), and 4) Asian (n=105). Analysis of variances (ANOVAs), Chi-square tests, Mann Whitney U tests, and multivariate regression models were used to assess racial disparities for 10 outcome variables: final thrombolysis in cerebral infarction (TICI) grade (n=3182), 24 hour NIH stroke score (NIHSS) (n=2850), post-procedure length of stay (n=3257), ICU days (n=2787), in-hospital mortality (n=3259), discharge status (n=3281), discharge NIHSS (n=2426), discharge modified Rankin score (mRS) (n=996), 90 day re-admission rate (n=416), and 90 day mRS (n=1184). Regression models controlled for demographics, comorbidities, intravenous tPA thrombolysis, and pre-stroke functional measures. Results ANOVA and Chi-square tests revealed significant differences between racial group means including post-procedure length of stay (p Conclusion Evidence from the NVQI-QOD registry suggests that there are several racial disparities in stroke thrombectomy management and outcomes, with minorities exhibiting increased post-procedural NIHSS, length of stay, and ICU days. Although African Americans were noted to suffer less in-hospital mortality compared to Caucasians, this did not translate into increased odds of a favorable clinical outcome at 90 days. Disclosures V. Thirunavu: None. R. Abdalla: None. D. Cantrell: None. M. Hurley: None. A. Shaibani: None. B. Jahromi: None. M. Potts: None. S. Ansari: None. O. NVQI-QOD Registry: None.

BACKGROUND Vertebral artery dissections (VADs) are a common cause of stroke in young patients and can result in various secondary effects, including pseudoaneurysm formation. OBJECTIVE To identify differences in predisposing factors and outcomes for VADs with and without concomitant pseudoaneurysms. METHODS We retrospective chart reviewed patients who presented to our institution at the time of VAD with at least a 3-mo clinical follow-up. Demographics, VAD characteristics, treatment, and outcomes represented as modified Rankin scale (mRS) scores were collected. RESULTS Of 310 patients with a VAD included in this study, 301 patients had an identified pseudoaneurysm status, with 54 pseudoaneurysm-associated VADs and 247 VADs not associated with pseudoaneurysm. VAD patients with associated pseudoaneurysms were more likely to be female (P

Annually, 20% of all practicing neurosurgeons in the United States are faced with medical malpractice litigation. The average indemnity paid in a closed neurosurgical civil claim is $439,146, the highest of all medical specialties. The majority of claims result from dissatisfaction following spinal surgery, although claims after cranial surgery tend to be costlier. On a societal scale, the increasing prevalence of medical malpractice claims is a catalyst for the practice of defensive medicine, resulting in record-level healthcare costs. Outside of the obvious financial strains, malpractice claims have also been linked to professional disenchantment and career changes for afflicted physicians. Unfortunately, neurosurgical residents receive minimal practical education regarding these matters and are often unprepared and vulnerable to these setbacks in the earlier stages of their careers. In this article, the authors aim to provide neurosurgical residents and junior attendings with an introductory guide to the fundamentals of medical malpractice lawsuits and the implications for neurosurgeons as an adjunct to more formal residency education.