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BackgroundBleb presence in intracranial aneurysms (IAs) is a known indication of instability and vulnerability.ObjectiveTo develop and evaluate predictive models of bleb development in IAs based on hemodynamics, geometry, anatomical location, and patient population.MethodsCross-sectional data (one time point) of 2395 IAs were used for training bleb formation models using machine learning (random forest, support vector machine, logistic regression, k-nearest neighbor, and bagging). Aneurysm hemodynamics and geometry were characterized using image-based computational fluid dynamics. A separate dataset with 266 aneurysms was used for model evaluation. Model performance was quantified by the area under the receiving operating characteristic curve (AUC), true positive rate (TPR), false positive rate (FPR), precision, and balanced accuracy.ResultsThe final model retained 18 variables, including hemodynamic, geometrical, location, multiplicity, and morphology parameters, and patient population. Generally, strong and concentrated inflow jets, high speed, complex and unstable flow patterns, and concentrated, oscillatory, and heterogeneous wall shear stress patterns together with larger, more elongated, and more distorted shapes were associated with bleb formation. The best performance on the validation set was achieved by the random forest model (AUC=0.82, TPR=91%, FPR=36%, misclassification error=27%).ConclusionsBased on the premise that aneurysm characteristics prior to bleb formation resemble those derived from vascular reconstructions with their blebs virtually removed, machine learning models can identify aneurysms prone to bleb development with good accuracy. Pending further validation with longitudinal data, these models may prove valuable for assessing the propensity of IAs to progress to vulnerable states and potentially rupturing.

Traumatic peri-contusional penumbra represents crucial targets for therapeutic interventions after traumatic brain injury (TBI). Current resuscitative approaches may not adequately alleviate impaired cerebral microcirculation and, hence, compromise oxygen delivery to peri-contusional areas. Low-frequency oscillations in cerebral blood flow (CBF) may improve cerebral oxygenation in the setting of oxygen deprivation. However, no method has been reported to induce controllable oscillations in CBF and it hasn’t been applied as a therapeutic strategy. Electrical stimulation of the trigeminal nerve (TNS) plays a pivotal role in modulating cerebrovascular tone and cerebral perfusion. We hypothesized that TNS can modulate CBF at the targeted frequency band via the trigemino-cerebrovascular network, and TNS-induced CBF oscillations would improve cerebral oxygenation in peri-contusional areas. In a rat model of TBI complicated by hemorrhagic shock, TNS-induced CBF oscillations conferred significant preservation of peri-contusional tissues leading to reduced lesion volume, attenuated hypoxic injury and neuroinflammation, increased eNOS expression, improved neurological recovery and better 10-day survival rate, despite not significantly increasing CBF as compared with those in immediate and delayed resuscitation animals. Our findings indicate that low-frequency CBF oscillations enhance cerebral oxygenation in peri-contusional areas, and play a more significant protective role than improvements in non-oscillatory cerebral perfusion or volume expansion alone.

Introduction Quantitative magnetic resonance angiography and non-invasive optimal vessel analysis serve as powerful tools to collect and analyze hemodynamic data from pipeline embolization patients. At our institution, patients receive post-embolization quantitative magnetic resonance angiography within 24 h of treatment and within 6 months for follow-up to evaluate pipeline patency. Here, we aim to elucidate the long-term hemodynamic changes following pipeline embolization device placement and report two cases in which in-stent stenosis was detected. Methods Medical records of patients who underwent pipeline embolization device placement for an internal carotid artery aneurysm between 2017 and 2019 were reviewed. Patients who received post-procedure NOVA and follow-up NOVA were included in the study ( n = 32). Location and size of aneurysm, number of pipeline embolization device deployed, and complications were collected along with the non-invasive optimal vessel analysis report (flow volume rate (ml/min), mean, systolic, and diastolic flow velocities (cm/s), and vessel diameter (mm)). Internal carotid artery vessel flow rate was measured proximal to the pipeline embolization device. Derivations of hemodynamic parameters (pulsatility index, Lindegaard ratio, and wall shear stress) were calculated. Results The middle cerebral artery mean and diastolic flow velocities were significantly lower on the follow-up NOVA compared to the post-procedure NOVA. Moreover, follow-up NOVA demonstrated lower middle cerebral artery wall shear stress on the side with flow diversion compared to the post-procedure NOVA. In-stent stenosis, requiring intervention, was detected in two patients on follow-up NOVA. One patient had a successful balloon angioplasty of the stented internal carotid artery that resolved her stenosis. However, the second patient developed progressive stenosis and expired despite intervention. Conclusion Long-term hemodynamic adaptations post-pipeline embolization device demonstrate decreased wall shear stress and decreased mean and diastolic flow velocities in the distal middle cerebral artery, which suggest decreasing velocity of blood flow with endothelialization of the device. Furthermore, follow-up NOVA is a useful tool for detecting potential flow-related complications such as in-stent stenosis.

Introduction. The World Health Organization declared COVID-19 a global pandemic last year. While a clear impact of COVID-19 on the declining stroke volume has been reported, its overall impact on stroke presentation and clinical outcomes has not been established. The purpose of this study was to assess the impact of COVID-19 on acute ischemic stroke volume, presentation, treatment, and outcomes at comprehensive stroke centers. Methods. A retrospective review of patients with a discharge diagnosis of acute ischemic stroke from the Get With The Guidelines database was performed from January 1, 2019, to July 1, 2020. The following time periods were defined: Pre-COVID (January/February), Peak-COVID (March/April), and Post-COVID (May/June). Bivariate analyses were performed comparing the 2020 and 2019 time periods to determine differences in stroke volume, presentation, treatment, and outcomes. Results. Stroke volumes were significantly lower during the Peak-COVID period in 2020 compared to that in 2019, with an absolute decline of 49.5% ( P < 0.001 ). Patients were more likely to present after 24 hours from last known well during the 2020 Peak-COVID period ( P = 0.03 ). However, there was not a significant difference in the rate of treatment with either the tissue plasminogen activator (tPA) or mechanical thrombectomy during the Peak-COVID period. Interestingly, relative treatment rates increased during the 2020 Post-COVID period to 11.4% ( P = 0.01 ). Conclusions. The overall ischemic stroke volume decreased during the pandemic, and patients had a tendency to present later, beyond eligible treatment windows. However, rates of treatment, patient demographics, and stroke outcomes did not significantly change when compared to the prior year.

Background With recent advances in endovascular treatments of brain aneurysms such as flow diverters, the role of cerebral revascularization needs to be re-evaluated. Objective To evaluate the contemporary indications and outcomes of cerebral revascularization for brain aneurysms. Methods A retrospective evaluation of a prospectively maintained database was performed to review clinical and imaging data of all the patients who underwent cerebral revascularization for brain aneurysms over the past 10 yr. Results Among 174 cerebral revascularizations, 40 (in 36 patients) were done for the treatment of aneurysms. In total, 9 patients underwent combined endovascular treatment and surgical revascularization. Immediate aneurysm occlusion was achieved in 30 patients (83.3%). Immediate postoperative bypass patency was confirmed in 33 patients (92%). Postoperative neurological deficit was observed in 4 patients (11.1%). There were 2 mortalities in the postoperative period. Aneurysm total occlusion rate was 91% at 1 yr. Thirty patients had 1 yr clinical and radiological follow-up. Clinical evaluations showed modified Rankin Scale 2 or less in 25 patients at 1 yr. Bypass patency was confirmed in 27 (90%). Patients with fair/poor outcome were all in the subarachnoid hemorrhage group. Twenty-one patients had follow-up studies for 3 yr or beyond with no evidence of stroke or aneurysm recurrence. Conclusion Our results support that cerebral revascularization can be regarded as a viable and durable treatment option for these challenging aneurysms with acceptable morbidity. Cerebral bypass should be offered in selected cases where standard endovascular or surgical treatment is not efficacious or curative.

Objective To replace educational opportunities lost during the coronavirus disease 2019 (COVID-19) pandemic, the Department of Neurosurgery at Lenox Hill Hospital produced an open-access webinar series (“BRAINterns”) that covered a broad range of health care topics with a focus on neurosurgery. Methods This 8-week webinar series ran from July 1 to August 28, 2020. An optional exit survey was distributed to participants. Data were analyzed to characterize and better understand trends among a global cohort of participants. Results A total of 16,484 people registered for BRAINterns, and 6675 took the survey (40.5% response rate). Responders represented 87 countries, of which the majority were from the United States and Canada (90.48%, n = 6039). Responders were primarily female (82.9%, n = 5521). Racial and ethnic representation was majority Asian (42%, n = 2798), followed by White (22.7%, n = 1514), Hispanic/Latino (16.2%, n = 1080), and Black and African American (7.7%, n = 516). Participants reported hearing about BRAINterns through various social media platforms (72.18%, n = 4818)—the most popular was TikTok (33.4%, n = 2232). Overall, 93.4% of participants reported that the course was a good use of their time during the pandemic, and 86.7% reported that the course helped replace lost opportunities. Conclusions These data demonstrate that webinar-based education is an effective method of expanding access to careers in medicine and in particular, neurosurgery, to traditionally underrepresented populations. Social media can be a powerful tool to combat barriers to early exposure and vastly improve diversity within the field.

Background The use of liquid embolic agents in the endovascular treatment of dural arteriovenous (dAVFs) fistulas and brain arteriovenous malformations (AVMs) has become common practice. The use of dual lumen balloon microcatheters has greatly improved the efficacy of liquid embolization. The purpose of this series is to discuss our early experience with the Scepter Mini dual lumen balloon microcatheter. Methods A retrospective chart review was performed of all patients who underwent embolization with the Scepter Mini dual lumen balloon at a single institution. Technical details and procedural complications were recorded for each case. Results In total, 10 Scepter Mini dual lumen balloon microcatheters were used in nine patients. All patients except two were treated for AVMs. Technical success was achieved in all but one case where one balloon had to be discarded due to precipitation of the tantalum powder. Average vessel diameter where the balloon was inflated was 1.1 mm (0.8–2.4 mm). It provided flow arrest in 100% of cases with no cases of reflux of embolic material. Balloon “jump back” was found to occur in 44.4% (4/9) of cases. Seven out of nine cases used Onyx, and two cases used n-butyl cyanoacrylate. Conclusions The Scepter Mini is a new dual lumen balloon ideal for distal access and can be used for embolization with liquid embolic agents with a high degree of technical success. Its great benefit is the immediate and safe flow arrest of distal vasculature upon balloon inflation. One important consideration for effective embolization is early identification of balloon jump back.

Posterior fossa dural arteriovenous fistulas (dAVFs) are rare vascular lesions with variable risk of hemorrhage, mostly depending on the pattern of the venous drainage. While endovascular embolization is the mainstay treatment for most dAVFs, some posterior fossa lesions require a multidisciplinary approach including surgery. The goal of our study was to examine the outcome of an interdisciplinary treatment for posterior fossa dAVFs. A retrospective review of patients treated for posterior fossa dAVFs was conducted. A total of 28 patients with a mean age of 57.8 years were included. Patients presented with a Cognard grade I in 2 (7%), II a in 5 (18 %), II b in 7 (25%), II a + b in 5 (18%), III in 3 (11%), and IV in 6 (21%) cases. Hemorrhage was the initial presentation in 2 (22%) patients with Cognard grade IV, in 3 with Cognard grade III (33%), in 1 (11%) with Cognard II a + b, and 3 (33%) with Cognard II b. A complete angiographic cure was achieved in 24 (86%) patients—after a single-session embolization in 16 (57%) patients, multiple embolization sessions in 2 (7%), a multimodal treatment with embolization and surgical disconnection in 3 (11%), and with an upfront surgery in 3 (11%). Complete long-term obliteration was demonstrated in 18/22 (82%) at the mean follow-up of 17 months. Fistulas were converted into asymptomatic Cognard I lesion in 4 (14%) patients. Posterior fossa dAVFs represent a challenging vascular pathology; however, despite their complexity, an interdisciplinary treatment can achieve high rates of angiographic and symptomatic cure with low morbidity and mortality rates. Long-term surveillance is warranted as late recurrences may occur.

Introduction The concurrent use of endoluminal flow diversion with coils is a viable option when treating complex or large aneurysms. Alternatives to coil embolization as an adjunctive treatment are currently limited. The Food and Drug Administration recently approved the Woven EndoBridge (WEB) device (Microvention, Aliso Viejo, California) as an intrasaccular flow diverter for wide-neck bifurcation aneurysms. We present the technical aspects of combined WEB device plus endoluminal flow diversion for the treatment of complex wide-necked intracranial aneurysms. Methods A retrospective chart review of all patients treated via intrasaccular flow diversion at a single institution over the last 12 months was performed. Results In total, seven patients underwent treatment of eight aneurysms via combined intrasaccular and endoluminal flow diversion. Of the seven patients, six were treated in a single setting. The most common aneurysm location was the posterior communicating artery. The majority of the aneurysms required steam shaping of the Via deployment catheter to place the WEB device orthogonally to the aneurysm dome. There were no complications. Conclusions We believe this is one of the first series reporting the combined use of the WEB device and endoluminal flow diversion for the treatment of intracranial aneurysms. This series demonstrates that the concurrent use of the WEB device with endoluminal flow diversion is safe for achieving immediate aneurysm treatment and may enhance the long-term durability in complex aneurysms.

Background The use of an exoscope in neurosurgical procedures has been proposed to improve ergonomics and to overcome the limitations faced with the microscope and endoscope. However, there remains scarcity of data regarding its surgical utility and outcomes. Objectives The authors report their experience and evaluate the surgical outcomes using a high-definition 2-dimensional (HD-2D) stereotactic exoscope in the management of various cranial and spinal pathologies. Methods We retrospectively identified patients who underwent neurosurgical procedures using the HD-2D stereotactic exoscope over a 2-year period. Demographic and surgical characteristics were analyzed. Results Twenty-nine patients (70.7%) underwent cranial surgery, and 12 patients (29.3%) underwent spine surgery. In patients having brain tumor removal, gross total resection was achieved in 18 patients (62.1%); with an overall average pathology size of 4.2±1.6 cm. Adjuvant utilization of the microscope was required in 4 cranial cases (13.8%) to ensure optimal resection rate. Three complications and 2 mortalities were encountered in the cranial group during a mean follow-up of 4.6±3.3 months. In the spinal cohort, the HD-2D stereotactic exoscope was utilized for anterior decompression and fusion (n=5), posterior decompression and fusion (n=5), and microdiscectomy and foraminotomy (n=2). No complications were encountered in the spinal group during a mean follow-up of 3.8±2.7 months. Conclusion The HD-2D stereotactic exoscope offers a wider field of view, greater mean focal distance, enhanced ergonomics, and immersive stereotactic visual experience. The lack of stereopsis remains the principal limitation of its use, and further optimization of surgical outcomes might be achieved with newer 3D models.

Background Metastatic subdural hematoma with dural metastasis in the setting of an underlying malignancy is a rare condition that is difficult to diagnose and associated with a poor prognosis. Knowledge of this rare entity is of a paramount importance to neurosurgeons, as its diagnosis may affect the management plan and overall survival. Here, we report a rare case of atraumatic subdural hematoma with dural metastasis in a patient with poorly differentiated adenocarcinoma of unknown origin. Case Description A 34-year-old man presented with an insidious onset of headaches, severe light headedness, progressive low back pain, and generalized weakness for 2 weeks. On imaging, he was found to have left-sided acute on chronic subdural hematoma with midline shift. The patient underwent surgical evacuation of the hematoma and the subdural membrane was biopsied. Histopathologic examination revealed metastatic poorly differentiated adenocarcinoma of unclear origin. A full metastatic workup was unremarkable. Conclusions Metastatic subdural hematoma with dural metastasis should be included in differential diagnosis of subdural hematoma, especially in patients with atypical presentation and in the presence of an underlying malignancy, as it may affect the management plan and overall survival.

The trigeminal nerve, the fifth cranial nerve, is known to innervate much of the cerebral arterial vasculature and significantly contributes to the control of cerebrovascular tone in both healthy and diseased states. Previous studies have demonstrated that stimulation of the trigeminal nerve (TNS) increases cerebral blood flow (CBF) via antidromic, trigemino-parasympathetic, and other central pathways. Despite some previous reports on the role of the trigeminal nerve and its control of CBF, there are only a few studies that investigate the effects of TNS on disorders of cerebral perfusion (i.e., ischemic stroke, subarachnoid hemorrhage, and traumatic brain injury). In this mini review, we present the current knowledge regarding the mechanisms of trigeminal nerve control of CBF, the anatomic underpinnings for targeted treatment, and potential clinical applications of TNS, with a focus on the treatment of impaired cerebral perfusion.

Background The trigeminal nerve directly innervates key vascular structures both centrally and peripherally. Centrally, it is known to innervate the brainstem and cavernous sinus, whereas peripherally the trigemino-cerebrovascular network innervates the majority of the cerebral vasculature. Upon stimulation, it permits direct modulation of cerebral blood flow (CBF), making the trigeminal nerve a promising target for the management of cerebral vasospasm. However, trigeminally mediated cerebral vasodilation has not been applied to the treatment of vasospasm. Objective To determine the effect of percutaneous electrical stimulation of the infraorbital branch of the trigeminal nerve (pTNS) on the cerebral vasculature. Methods In order to determine the stimulus-response function of pTNS on cerebral vasodilation, CBF, arterial blood pressure, cerebrovascular resistance, intracranial pressure, cerebral perfusion pressure, cerebrospinal fluid calcitonin gene-related peptide (CGRP) concentrations, and the diameter of cerebral vessels were measured in healthy and subarachnoid hemorrhage (SAH) rats. Results The present study demonstrates, for the first time, that pTNS increases brain CGRP concentrations in a dose-dependent manner, thereby producing controllable cerebral vasodilation. This vasodilatory response appears to be independent of the pressor response induced by pTNS, as it is maintained even after transection of the spinal cord at the C5-C6 level and shown to be confined to the infraorbital nerve by administration of lidocaine or destroying it. Furthermore, such pTNS-induced vasodilatory response of cerebral vessels is retained after SAH-induced vasospasm. Conclusion Our study demonstrates that pTNS is a promising vasodilator and increases CBF, cerebral perfusion, and CGRP concentration both in normal and vasoconstrictive conditions.

Background Even in the modern endovascular era, the treatment of Vein of Galen Malformations (VOGM) is extremely challenging. While their natural history is very poor, endovascular embolization has emerged as the standard of care. These lesions often require multiple treatment sessions to decrease shunting, with each treatment including multiple pedicles. Here we present the first reported use of the Scepter Mini (Microvention, Aliso Viejo, CA) in the treatment of vein of Galen malformations. Clinical presentation A 7 month old female presented with an enlarging VOGM that was initially identified on prenatal ultrasound. Given the enlarging size of the lesion and failure to meet developmental milestones, the patient underwent planned endovascular embolization of the VOGM. The novel Scepter Mini balloon catheter was used for treatment of this lesion affording easy access to the target pedicle and immediate flow arrest which allowed for immediate cure of the lesion. Conclusion The novel Scepter Mini Balloon (Microvention, Aliso Viejo, CA) afforded excellent distal access with subsequent immediate flow arrest therefore facilitating endovascular cure. Initially, a staged approach was favored for the treatment of the lesion, but the flow arrest achieved by the Scepter mini facilitated immediate occlusion from a single pedicle.

INTRODUCTION Beginning in March, 2020, hospitals across the majority of the United States were required to cancel all elective surgery in preparation for a surge of patients with the coronavirus disease of 2019 (COVID-19). A large number of neurosurgical patients with less than emergency conditions had their surgery postponed indefinitely. METHODS The Delphi method was used to obtain consensus. Twenty-two neurosurgeons actively practicing in two separate geographic regions of the United States where “black level” COVID-19 surges occurred (New York Metropolitan Area and Detroit, Michigan) participated. A total of 86 neurosurgical case scenarios were categorized into six tiers of priority: emergent or within 24 hours, within 48 hours, within 1 week, within 2 weeks, within one month, or post hospital crisis/more than 4 weeks. Consensus was defined as 75% of participants reaching an agreement. Majority opinion (>50% agreement) was also reported. RESULTS 67 of the 86 surgical scenarios (78%) reached a consensus agreement with 85 out of 86 scenarios reaching at least a majority opinion. Only one scenario (central cord syndrome) did not reach any agreement. CONCLUSION The NNPI developed in this study can assist neurosurgical departments in prioritizing the timing of surgery, whether it be due to a pandemic, or any other scenario where the normal work flow has been severely disrupted and resources are limited.

Introduction The concurrent use of the Pipeline Embolization Device (PED) with coils has been shown to be beneficial when treating complex or large aneurysms. Alternatives to coiling as an adjunctive treatment are currently limited. The FDA recently approved the Woven EndoBridge (WEB) (Microvention, Aliso Viejo, California) device as an intrasaccular flow diverter for wide neck bifurcation aneurysms (FDA). Here in we present the technical aspects of combined WEB plus PED for the treatment of intracranial aneurysms. Methods A retrospective chart review of all patients treated via intrasaccular flow diversion at a single institution over the last 12 months was done. In total 34 aneurysms were treated via WEB intrasaccular flow diversion; however, only 7 of these aneurysms were treated with the pipeline embolization device as well. Technical aspects of each procedure were recorded. Results In total 6 patients underwent the treatment of 7 aneurysms via combined intrasaccular and endoluminal flow diversion. All aneurysm were treated in a single setting but for one patient. This patient came in with subarachnoid hemorrhage, had a WEB placed, and subsequently was found to have recanalized their aneurysm due to WEB compaction. This prompted placement of the a Pipeline 4 weeks after initial treatment. There were no complications associated with any treatment. Post embolization MRI/A showed no new infarcts in 3/7 patients and small punctate DWI changes in 4/7 patients with good stent flow in all cases. There were no bifurcation aneurysms: 5 posterior communicating, 1 superior hypophyseal, 1 vertebrobasilar. The majority of the aneurysms required steam shaping of the Via deployment catheter in order to place the WEB orthogonally to the aneurysm dome. The radial force of the Pipeline was able to push a herniated WEB device into the aneurysm in all but one case where a balloon was employed to angioplasty the stent. Conclusions We believe this is the first series reporting combined use of WEB and Pipeline for the treatment of intracranial aneurysms. Treatment failure rates of PED as a stand-alone treatment have been reported to be from 11.9% to 20%. Intrasaccular flow diversion with the WEB device allows for increased metal coverage at both the aneurysm neck, preventing inflow, and the aneurysm dome, protecting from rupture. For larger aneurysms the WEB device theoretically protects from a destabilizing mural thrombus. Also, in larger aneurysm were WEB devices have been shown to be less enduring, endoluminal remodeling provides a durable treatment. This series demonstrates the WEB device as a feasible and safe alternative to adjuvant coiling for achieving immediate intrasaccular flow diversion when using the PED. Disclosures T. White: None. K. Shah: None. J. Turpin: None. J. Katz: None. H. Woo: None.

Introduction Delayed cerebral ischemia (DCI) continues to be a challenging complication of subarachnoid hemorrhage. This study sought to examine the impact of intra-arterial therapy on patients with medically refractory DCI. More specifically it sought to determine comparative results of nicardipine and verapamil as well as to determine if there was a relationship between IA vasodilator dose and complication rate. Methods A retrospective chart review of all patients at a single institution undergoing endovascular IA therapy for vasospasm secondary to subarachnoid hemorrhage over a 30 month period was done. In total, 69 patients underwent 126 treatments for cerebral vasospasm in the setting of atraumatic subarachnoid hemorrhage (SAH). In total 91% of patients present with aneurysmal SAH while 9% had angiography negative SAH. 53.6% of patients had their aneurysm treated endovascularly. Median Hunt Hess grade was 3 and 88% of patients presented with Modified Fischer grade 3 or 4. Formal angiography was done in the setting of clinical vasospasm as determine by patients’ neurologic exams, velocity on transcranial doppler, and other clinical factors. The majority of patients underwent a single treatment (55%) while the most treatments for a single patient was 5 (4%). Results In total, 98% (123/126) of treatments led to an improved or stable neurological exam post treatment, and 3 patients developed a post-operative procedural neurological decline. Delayed cerebral ischemia, defined as a new neurological deficit, occurred in 55% (38/69) of patients in this cohort; however, the new neurological deficit was permanent in only 14% of patients (10/69). New infarcts were seen on imaging in 19% of patients (13/69) but were clinically silent in 3/60 patients. Patients with DCI were more likely to undergo multiple treatments of IA therapy (P 0.05). There was no differential risk of DCI in the nicardipine vs the verapamil group (P>0.05). Patients undergoing verapamil therapy were more likely to experience complications of IA therapy, 20% vs 5% in the nicardipine group (P Conclusion This report adds to the growing body of literature that endovascular rescue therapy offers a safe and effective option in managing medically refractory vasospasm in order to prevent DCI. Importantly, it also suggests that in select patients high dose therapy can be used for maximal benefit with a reasonable side effect profile. Importantly, this series also demonstrates an initial rate of DCI of 55% in patients with vasospasm undergoing IA therapy with only 14% of patient’s demonstrating permanent neurological deficit suggesting a significant overall benefit of treatment. The results of this initial study mandate further investigation into the safety and efficacy of intra-arterial verapamil and nicardipine for the treatment and prevention of DCI. More importantly it shows that dose optimization needs to be done prior to pursuing further trials. Disclosures T. White: None. J. Turpin: None. K. Shah: None. A. Dehdashti: None. J. Katz: None. H. Woo: None.

Introduction The Woven EndoBridge (WEB) device, an intrasaccular flow-diverter, was recently approved by the FDA to treat wide-neck bifurcation aneurysms. Accurate sizing of the WEB device is of critical importance as it determines procedural safety and successful occlusion. Oversized devices can protrude into the vessel lumen and lead to thromboembolic events, while undersized devices result in inadequate aneurysm occlusion. Conventionally, size selection of the WEB device is based on measurements of the fundus height and neck width on 3D rotational angiography. However, even multiple, orthogonal linear measurements incompletely describe the three-dimensional morphology of intracranial aneurysms and may mislead size selection of the WEB. An alternative method is volume-based segmentation, minimizing measurement error. The aim of this study was to assess the ability of auto-segmented aneurysm volume to assist in appropriate WEB size selection. Materials and Methods All patients with an intracranial aneurysm treated with the WEB SL or WEB SLS device between March 2019 and August 2019 were identified for this retrospective study. Aneurysm volumes were determined by using a three-dimensional volume segmentation software on an independent Syngo workstation (Siemens Healthineers AG). Pearson correlation coefficients were calculated for aneurysm auto-segmented volumes and WEB volumes, as well as for aneurysm height × width and WEB height × width at the time of initial treatment. Patients underwent follow-up angiography at least 6 months after embolization. Results Thirty-three aneurysms were evaluated by 3D rotational angiography. By volume, the largest aneurysm was 916.4 mm3, and the smallest was 14.0 mm3, with a median volume of 84.7 mm3. The smallest WEB device used was 4 × 2.6 SLS and the largest WEB device was 11 × 8 SL. The correlation with WEB size was larger for auto-segmented aneurysm volumes (r=0.979) compared to height × width (r=0.867). Using Fisher r-to-z transformations, we found the difference between the two correlations to be statistically significant (p=0.0007). Out of the patients who have undergone follow-up angiography thus far, 91% (10/11) have achieved adequate aneurysm occlusion (complete occlusion or residual neck). Conclusion Aneurysm volumes are highly correlated with WEB volumes, with auto-segmentation volumes displaying statistically significant difference against conventional height by width measurements. These results suggest that the WEB device is more accurately sized using auto-segmented aneurysm volumetric measurements rather than height and width measurements, which may improve long-term occlusion rates. Disclosures K. Shah: None. T. White: None. I. Teron: None. A. Dehdashti: None. J. Katz: None. H. Woo: None.

Introduction The Woven EndoBridge (WEB) is an intra-saccular flow-diverting device that is rapidly becoming popular in the treatment of wide-neck bifurcation aneurysms. However, several challenges remain, such as device compression, incomplete occlusion, and thromboembolic complications. Changes in intra-aneurysmal flow after the use of the WEB are not well understood and may be important in the performance of the device for aneurysm occlusion. The aim of this study was to characterize the degree of immediate aneurysm occlusion using color-coded quantitative digital subtraction angiography (DSA) after treatment with the WEB. Materials and Methods We retrospectively reviewed records of 34 patients treated with the WEB between March 2019 and February 2020. Eight patients were excluded from analysis for the use of a concurrent stent or intra-luminal flow-diverter. Measurements of contrast transit times on DSA were calculated with syngo iFlow (Siemens Healthineers AG). Regions of interest were selected within the parent vessel immediately proximal to the aneurysm and within the aneurysm dome before and after treatment with WEB (figure 1). The ratio of aneurysm contrast transit time to parent vessel contrast transit time was obtained before WEB placement and immediately after WEB placement. Transit time ratios were also compared with pre- and post-Pipeline (PED) cases matched for aneurysm size. Results Out of 26 aneurysms, 24 aneurysms demonstrated an increase in contrast transit time after WEB placement (2.06 s, p Conclusions High rates of immediate aneurysm contrast stagnation can be achieved with use of the WEB. As a flow-diverting device, the WEB offers a greater degree of immediate aneurysm occlusion than the PED. iFlow analysis provides a quantitative measure of post-treatment effect and could represent a predictive tool for successful long-term occlusion. Disclosures K. Shah: None. T. White: None. J. Turpin: None. I. Teron: None. J. Katz: None. H. Woo: None.

Giant and large pituitary adenomas (PA) constitute a specific subset of PAs, with gross total resection (GTR) rates frequently not exceeding 50%. Both an anatomical inaccessibility and an inadequate tumor visualization are thought to play a role. This study analyzes risk factors for postoperative residuals after endoscopic transsphenoidal pituitary surgery for large and giant pituitary adenomas. A retrospective analysis of patients with giant and large PA operated between 2015 and 2018 was performed. Forty patients (13 females, 27 males) were included in the analysis (30 large and 10 giant PAs). The mean MRI follow-up time was 5.9 ± 6.54 months. Overall, GTR was achieved in 29 patients (72.5%), subtotal resection in 9 (22.5%), and the inconclusive result was in 2 (5%). Unexpected residuals represented 7 (77.7%) of all 9 residual tumors. The most frequent intraoperative factor associated with unexpected residual tumors was improper identification of residual tumor due to obstruction of view in 2 (28.5%) cases and inability to distinguish normal tissue from tumor in the other two (28.5%). Sub-analysis based on tumor size revealed that with large PAs, GTR was achieved in 25 (83.3%), STR in 4 (13.3%), and inconclusive in 1 (3.3%) patient. In patients with giant PAs, GTR was achieved in 4 (40%), STR in 5 (50%), and inconclusive in 1 (10%). Analysis of preoperative factors showed a significant association of residual tumors with larger suprasellar AP distance (p = 0.041), retrosellar extension (p = 0.007), and higher Zurich Score (p = 0.029). Large and giant PAs are challenging lesions with high subtotal resection rates. Suprasellar AP distance, retrosellar extension, and higher Zurich Score seem to be significant predictors of degree of resection in these tumors. Improving the intraoperative ability to distinguish tumor from a normal tissue might further decrease the number of unexpected residuals.

Background and importance Cerebral hyperperfusion syndrome (CHS) is a well-known complication of superficial temporal artery (STA) to middle cerebral artery (MCA) bypass for ischemic cerebrovascular disease. While this argues against "low flow" in the bypass construct, flow rates in the graft have not been previously quantified in the setting of CHS. Clinical presentation A 58-yr-old man presented with recurrent left hemispheric ischemic strokes and fluctuating right hemiparesis and aphasia. Vascular imaging revealed left cervical internal carotid artery occlusion and perfusion imaging confirmed left hemispheric hypoperfusion. After failing to respond to maximal medical therapy, the patient underwent single-barrel STA-MCA bypass. Postoperatively, his symptoms resolved and blood pressure (BP) was strictly controlled within normal range. However, 2 d later, he developed severe expressive aphasia. CTA demonstrated a patent bypass graft and SPECT showed focal hyperperfusion in Broca's speech area. Seizure activity was ruled out. A high graft flow rate of 52 mL/min was documented by quantitative magnetic resonance angiography (MRA). Thus, the diagnosis of CHS was made and managed with strict BP control. The patient exhibited complete recovery of speech over a period of days and was discharged home. Repeat SPECT at 4 mo showed resolution of hyperperfusion and quantitative MRA demonstrated reduction of graft flow rate to 34 mL/min. Conclusion This is the first case of perfusion imaging-proven CHS after STA-MCA bypass, where high graft flow rates are objectively documented. Our observations constitute irrefutable evidence challenging the classic belief that the STA-MCA bypass is a low-flow construct.

Objective In this series, we present 3 cases that show the use of a skull-mounted tracker for image-guided navigation for anterior skull base surgery and ventricular catheter placement procedures. This system obviates fiducials or face masks during the surgical procedure itself and allows for the performance of facial incisions using the Weber-Ferguson approach. Methods Our series presents the use of a novel intraoperative navigational system that uses a skull-mounted tracker to navigated anterior skull base surgery. Results We present 3 cases using this new system: 1 anterior skull base tumor removal that was operated on without a facemask for navigation and 2 ventricular catheter placement procedures. Conclusions Intraoperative image-guided navigation has revolutionized neurosurgery. It undoubtedly increases the surgeon's confidence and the perception of safety. Although fiducials and facial masks are the most widely used tools for intraoperative navigation, their use is associated with certain complications. This technique permits free movement of the head during surgery, which in turn facilitates the exposure of head and neck lesions and expedites the approach to ventricular catheter placement. Our case series shows the precision and ease of our technique, which is less time consuming and less cumbersome than the traditional frame-based stereotaxy. In addition, the skull-mounted tracker system allows improved anatomic localization and shorter operating time and avoids the complications associated with the use of rigid fixating head frames.

The resection of tuberculum sellae meningiomas poses a challenge particularly when dealing with the medial aspect of the optic nerve. Dissection of the tumor off the optic nerve is usually carried out in the blind spot “behind” the optic nerve. We describe a contralateral approach for asymmetric tuberculum sellae meningiomas, allowing direct visualization of the medial optic nerve. Contralateral lateral supraorbital approach was performed, and complete tumor resection was achieved without any injury to the optic nerve. The contralateral approach for asymmetric tuberculum sellae meningioma is an efficient technique allowing improved visualization of the medial optic nerve.

Introduction Recurrent subdural hematoma (SDH) is commonly encountered in clinical practice. Multiple surgical techniques have been reported for the management of recurrent SDH with variable success and complication rates. We report an alternative technique to halt SDH re-accumulation in elderly patients with multiple recurrences despite multiple surgical evacuations via rescue craniectomy and subsequent cranioplasty. Methods The authors retrospectively identified all symptomatic recurrent SDH in elderly patients (age ≥60 years) who were surgically managed with rescue craniectomy with subsequent cranioplasty from November 2004 to January 2018. Patients’ demographics and radiological and surgical variables were recorded and analyzed. Results Of the 287 patients who received surgical treatment for SDH, 19 patients (6.6%) underwent SDH evacuation with rescue craniectomy and subsequent cranioplasty were included in the study. The median age of our cohort was 73 years (IQR: 62-78), with 13 males and 6 females. Trauma was the culprit in the majority of cases. Five patients had acute SDH, 4 cases had subacute SDH, and 10 cases had chronic SDH. Fourteen cases had only one recurrence of SDH requiring surgical re-evacuation while 5 cases had two recurrences. The median interval between craniectomy and cranioplasty was 64.5 days (interquartile range: 108.3 days). Four complications were encountered. After cranioplasty, 15 cases had no further hemorrhage or recurrence and 4 cases had stable subdural collection during an average follow-up period of 38.2±46.9 months. Conclusions Rescue craniectomy followed by cranioplasty is a safe and effective salvage technique for the management of symptomatic recurrent SDH in elderly patients.

Introduction Accurate sizing of the Woven EndoBridge (WEB) device is of critical importance as it determines procedural safety and successful occlusion of wide neck bifurcation aneurysms. The aim of this study was to assess the ability of aneurysm volume to assist in accurate WEB size selection. Methods All patients with an intracranial aneurysm treated with the WEB SL or WEB SLS device between March 2019 and October 2019 were identified for this retrospective study. Aneurysm volumes were calculated with auto-segmentation using a three-dimensional volume rendering program on an independent Syngo workstation (Siemens Healthineers AG). Pearson correlation coefficients were calculated for aneurysm auto-segmented volumes and WEB volumes, as well as for aneurysm height × width and WEB height × width. Follow-up angiographic outcomes were collected at 6–9 months post-procedure. Results Twenty-nine aneurysms were evaluated by 3D rotational angiography. The correlation coefficient with WEB size was larger for auto-segmented aneurysm volumes (r = 0.979) compared to height × width measurements (r = 0.867). Using Fisher r-to-z transformations, we found the difference between the two correlations to be statistically significant (p = 0.0007). Follow-up angiography available in 13 subjects demonstrated an 85% complete aneurysm occlusion rate. Conclusion Aneurysm volumes are highly correlated with WEB volumes, with auto-segmentation volumes displaying statistically significant difference against conventional height by width measurements. These results suggest that volumetric measurements of aneurysm size provide a useful adjuvant measure to assist in appropriate size selection of the WEB device.

OBJECTIVECerebral revascularization for carotid occlusion was previously a mainstay procedure for the cerebrovascular neurosurgeon. However, the 1985 extracranial-intracranial bypass trial and subsequently the Carotid Occlusion Surgery Study (COSS) provided level 1 evidence via randomized controlled trials against bypass for symptomatic atherosclerotic carotid occlusion disease. However, in a small number of patients optimal medical therapy fails, and some patients with flow-limiting stenosis develop a perfusion-dependent neurological examination. Therefore it is necessary to further stratify patients by risk to determine who may most benefit from this intervention as well as to determine perioperative morbidity in this high-risk patient population.METHODSA retrospective review was performed of all revascularization procedures done for symptomatic atherosclerotic cerebrovascular steno-occlusive disease. All patients undergoing revascularization after the publication of the COSS in 2011 were included. Perioperative morbidity and mortality were assessed as the primary outcome to determine safety of revascularization in this high-risk population. All patients had documented hypoperfusion on hemodynamic imaging.RESULTSAt total of 35 revascularization procedures were included in this review. The most common indication was for patients with recurrent strokes, who were receiving optimal medical therapy and who suffered from cerebrovascular steno-occlusion. At 30 days only 3 perioperative ischemic events were observed, 2 of which led to no long-term neurological deficit. Immediate graft patency was good, at 94%. Long term, no further strokes or ischemic events were observed, and graft patency remained high at 95%. There were no factors associated with perioperative ischemic events in the variables that were recorded.CONCLUSIONSCerebral revascularization may be done safely at high-volume cerebrovascular centers in high-risk patients in whom optimal medical therapy has failed. Further research must be done to develop an improved methodology of risk stratification for patients with symptomatic atherosclerotic cerebrovascular steno-occlusive disease to determine which patients may benefit from intervention. Given the high risk of recurrent stroke in certain patients, and the fact that patients fail medical therapy, surgical revascularization may provide the best method to ensure good long-term outcomes with manageable up-front risks.

Background The advent of the operating microscope (OM) revolutionized the field of neurosurgery. It allowed surgeons to operate on and effectively treat diseases previously inaccessible with conventional eyesight because of magnification and illumination. Improvements in the essential methods of visualization and the quality of the optics have plateaued. Another main limitation of the OM remains its ergonomics because of the need of the surgeon and assistant to directly interface with the OM objective. Recently, exoscopes have been introduced to overcome some shortcomings of the conventional OM. Objective To subjectively review the individual authors experience with the current exoscope platforms in an attempt to provide a resource to the neurosurgeon when considering imaging options. Methods Experts with previous use of each individual platform were contacted and asked to contribute their experiences. Results In total, 4 systems are discussed. They include the VITOM (Karl Storz, Tuttlingen, Germany), the Olympus ORBEYE (Olympus, Tokyo, Japan), the Synaptive Modus V (Synaptive Medical, Toronto, Canada), and the Zeiss KINEVO (Carl Zeiss AG, Oberkochen, Germany). Conclusion The advent of exoscopes has the potential to begin to allow surgeons to move beyond solely the microscope for intraoperative visualization while improving upon its ergonomic disadvantages.

Flow-replacement revascularization and/or flow augmentation surgery may be necessary for safe deconstruction of complex middle cerebral artery (MCA) aneurysms. Roughly 1% to 2% of all MCA aneurysms have angiographic features prohibiting standard microsurgical or endovascular management. Consent was obtained from the patient for the production of this video. No International Review Board approval was required for the creation of this video. A 17-yr-old female presented at the age of 15 with headaches. At the time of initial presentation, the patient was found to have an MCA bifurcation aneurysm. Initially, the aneurysm was managed conservatively and followed. However, on follow-up imaging, the aneurysm was found to have grown and developed into a large, complex MCA bifurcation aneurysm. Patient underwent planned trapping and deconstruction of the aneurysm. An internal maxillary artery (IMAX) to MCA bypass was performed using a cephalic vein graph to a robust inferior MCA branch combined with an in Situ MCA to MCA bypass. Follow-up angiography showed complete occlusion of the aneurysm. Patient was neurologically intact at 1-yr follow-up. Microsurgery continues to be the best treatment option for complex MCA aneurysms. A surgeon trained in bypass is an absolute prerequisite for management of those lesions. The IMAX offers an ideal high flow donor vessel for subcranial to intracranial flow replacement, which was required for re-establishment of flow to the robust inferior MCA branch in this case. The superior branch of the MCA was less robust. Therefore, by recreating a more distal bifurcation, the in Situ side-to-side MCA-MCA bypass simplified the revascularization strategy.

Intraoperative neurophysiologic monitoring (IONM) is quickly gaining popularity across the full spectrum of neurosurgical subspecialties. It is particularly useful during brain aneurysm surgery, given its ability to detect cerebral ischemia in a timely manner. This electrophysiologic feedback provides the neurosurgeon with an opportunity to undertake corrective surgical actions before irreversible brain injury occurs. In this chapter, we offer a practical review of the various IONM modalities used in aneurysm surgery, their indications, advantages, and limitations.

Neurenteric cysts are rare benign congenital tumors of endodermal origin that most commonly occur in the cervical and upper thoracic spine, with only about 10% to 18% of the reported cases occurring intracranially.1 A definitive preoperative diagnosis is complicated by the variable appearance of neurenteric cysts on magnetic resonance (MR) imaging.2 The recommended treatment of neurenteric cysts is complete surgical resection when possible.3,4 We present a case of a posterior fossa neurenteric cyst. A 33-yr-old man without medical history presented with left-sided headache and mild left-sided facial numbness and weakness. Admission MR imaging revealed a nonenhancing mass, which was hyperintense on T1-weighted MR images, compressing the brainstem anteriorly. The lesion was isointense on T2 FLAIR images and hypointense on diffusion-weighted imaging, initially read as possible epidermoid cyst. The patient underwent a left-sided retrosigmoid craniotomy via far lateral transcondylar approach. The tumor was adjacent to both vertebral arteries, the left PICA, and cranial nerves (CN) VII-XII with superior extension to CN V. The cyst was encased in a thin capsule, and its contents were yellowish in color and ranged from thick liquid to colloidal and caseous consistency. The cyst also contained heavily calcified portions, which were excised using sharp dissection. Images of the cyst wall show that it is focally lined with ciliated columnar epithelium with intracellular mucin confirming an endodermal or neurenteric cyst. After the operation, the patient's symptoms resolved, and he was discharged on postoperative day 4. Postoperative MR images confirmed gross total resection. The patient consented to video production.

Background During its development and preclinical assessment, a novel, 3-dimensional (3D), high-definition (4K-HD) exoscope system was formerly shown to provide an immersive surgical experience, while maintaining a portable, low-profile design. Objective To assess the clinical applicability of this 3D 4K-HD exoscope via first-in-man surgical use. Methods The operative workflow, functionality, and visual haptics of the 3D 4K-HD exoscope were assessed in a variety of microneurosurgical cases at 2 US centers. Results Nineteen microneurosurgical procedures in 18 patients were performed exclusively using the 3D 4K-HD exoscope. Pathologies treated included 4 aneurysms, 3 cavernous malformations (1 with intraoperative electrocorticography), 2 arteriovenous malformations, 1 foramen magnum meningioma, 1 convexity meningioma, 1 glioma, 1 occipital cyst, 1 chiari malformation, 1 carotid endarterectomy, 1 subdural hematoma, 1 anterior cervical discectomy and fusion, and 2 lumbar laminectomies. All patients experienced good surgical and clinical outcomes. Similar to preclinical assessments, the 3D 4K-HD exoscope provided an immersive 3D surgical experience for the primary surgeon, assistants, and trainees. The small exoscope frame, large depth of field, and hand/foot pedal controls improved exoscope mobility, decreased need to re-focus, and provided unobstructed operative corridors. Flexible positioning of the camera allows the surgeon's posture to be kept in a neutral position with uncompromised viewing angles. Conclusion The first-in-man clinical experience with the 3D 4K-HD exoscope confirms its excellent optics and ergonomics for the entire operative team, with high workflow adaptability for a variety of microneurosurgical cases. Expanded clinical use of the 3D 4K-HD exoscope is justified.

Background: Surgery on patients with lesions in the dominant hemisphere for language is best done with awake language mapping. Intraoperative MRI (iMRI) has also been proposed as an ideal method for tumor resection control in patients with primary brain tumors. Objectives: This study examines the feasibility of low-field iMRI during awake craniotomy and tumor resection. Methods: 36 patients underwent awake resection with a compact iMRI for guidance. Outcomes were grouped using an A–D classification. Outcome A was defined as gross total resection (GTR) without iMRI, B as GTR achieved secondary to iMRI findings, C as resection stopped due to mapping but prior to iMRI, and, finally, D as resection stopped after iMRI had showed residual tumor but subsequent mapping limited further resection. Results: Diagnoses included primary brain tumors in all but 2 patients: 1 had mesial temporal sclerosis and 1 cysticercosis. Overall, outcomes A and D were the most common with 12 patients each, outcome C was the least common occurring in only 3 patients, and outcome B occurred in 9 patients. Hence, in 12 patients, iMRI led to increased tumor resection while in another 12 brain mapping limited the extent of resection. Conclusions: Combined awake language and motor mapping and iMRI guidance is feasible for resection of brain lesions. A compact iMRI has unique advantages for this approach.

Meningiomas are most often benign primary intracranial tumors that are frequently found incidentally on imaging. Larger sized meningiomas may present with symptoms such as seizures and headaches. Smaller meningiomas are commonly asymptomatic and usually observed with serial imaging. We present two female patients, both of whom were found to have very small left frontal meningiomas that marginated Broca’s area. The first patient in this case series experienced episodes resembling seizures which consisted of weakness, vision loss, and slurred speech, as well as subtle language dysfunction in her day-to-day conversations. The second patient presented with headaches and an enlarging meningioma. Both meningiomas were surgically resected and the patients’ symptoms resolved. Small meningiomas should not be overlooked as they may very well be the source of neurologic symptoms.

The surgical management of deep brain tumors is often challenging due to the limitations of stereotactic needle biopsies and the morbidity associated with transcortical approaches. We present a novel microscopic navigational technique utilizing the Viewsite Brain Access System (VBAS) (Vycor Medical, Boca Raton, FL, USA) for resection of a deep parietal periventricular high-grade glioma as well as another glioma and a cavernoma with no related morbidity. The approach utilized a navigational tracker mounted on a microscope, which was set to the desired trajectory and depth. It allowed gentle continuous insertion of the VBAS directly to a deep lesion under continuous microscopic visualization, increasing safety by obviating the need to look up from the microscope and thus avoiding loss of trajectory. This technique has broad value for the resection of a variety of deep brain lesions.

A 64-year-old man with a midbrain cavernoma and prior bleeding presented with a 1-week history of diplopia, partial left oculomotor nerve palsy, and worsening dysmetria and right-sided weakness. MRI revealed a hemorrhagic left tectal plate and midbrain cavernoma. A left suboccipital supracerebellar transtentorial approach in the sitting position was performed for resection of his lesion utilizing the lateral mesencephalic sulcus safe entry zone. Postoperatively, he developed a partial right oculomotor nerve palsy; imaging depicted complete resection of the cavernoma. He recovered from the right third nerve palsy, weakness, and dysmetria, with significant improvement of his partial left third nerve palsy.The video can be found here: https://youtu.be/ofj8zFWNUGU.

Iatrogenic ventriculitis is a potential complication of ventriculostomy drain placement. In this study, an alcohol-impregnated external ventricular drain port cap was added to a standardized ventriculostomy placement bundle. Rates of ventriculitis were reduced postintervention, but this finding did not reach statistical significance.