Auricular Vagus Nerve Stimulation Mitigates Inflammation and Vasospasm in Subarachnoid Hemorrhage: A Randomized Trial.

Background: Inflammation contributes to morbidity following subarachnoid hemorrhage (SAH). Transauricular vagus nerve stimulation (taVNS) offers a noninvasive approach to target the inflammatory response following SAH. Methods: In this prospective, triple-blinded, randomized, controlled trial, twenty-seven patients were randomized to taVNS or sham stimulation. Blood and cerebrospinal fluid (CSF) were collected to quantify inflammatory markers. Cerebral vasospasm severity and functional outcomes (modified Rankin Scale, mRS) were analyzed. Results: No adverse events occurred. Radiographic vasospasm was significantly reduced (p = 0.018), with serial vessel caliber measurements demonstrating a more rapid return to normal than sham (p < 0.001). In the taVNS group, TNF-α was significantly reduced in both plasma (days 7 and 10) and CSF (day 13); IL-6 was also significantly reduced in plasma (day 4) and CSF (day 13) (p < 0.05). Patients receiving taVNS had higher rates of favorable outcomes at discharge (38.4% vs 21.4%) and first follow-up (76.9% vs 57.1%), with significant improvement from admission to first follow-up (p = 0.014), unlike the sham group (p = 0.18). The taVNS group had a significantly lower rate of discharge to skilled nursing facility or hospice (p = 0.04). Conclusion: taVNS is a non-invasive method of neuro- and systemic immunomodulation. This trial supports that taVNS following SAH can mitigate the inflammatory response, reduce radiographic vasospasm, and potentially improve functional and neurological outcomes. Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT04557618.

The effect of transcutaneous auricular vagus nerve stimulation on cardiovascular function in subarachnoid hemorrhage patients: a safety study.

Objective: Subarachnoid hemorrhage (SAH) is characterized by intense central inflammation, leading to substantial post-hemorrhagic complications such as vasospasm and delayed cerebral ischemia.2,6,7 Given the anti-inflammatory effect of transcutaneous auricular vagus nerve stimulation (taVNS) and its ability to promote brain plasticity, taVNS has emerged as a promising therapeutic option for SAH patients.3,8,9 However, the effects of taVNS on cardiovascular dynamics in critically ill patients like those with SAH have not yet been investigated. Given the association between cardiac complications and elevated risk of poor clinical outcomes after SAH, it is essential to characterize the cardiovascular effects of taVNS to ensure this approach is safe in this fragile population4. Therefore, we assessed the impact of both acute taVNS and repetitive taVNS on cardiovascular function in this study. Methods: In this randomized clinical trial, 24 SAH patients were assigned to either a taVNS treatment or a Sham treatment group. During their stay in the intensive care unit, we monitored patient electrocardiogram (ECG) readings and vital signs. We compared long-term changes in heart rate, heart rate variability, QT interval, and blood pressure between the two groups. Additionally, we assessed the effects of acute taVNS by comparing cardiovascular metrics before, during, and after the intervention. We also explored rapidly responsive cardiovascular biomarkers in patients exhibiting clinical improvement. Results: We found that repetitive taVNS did not significantly alter heart rate, corrected QT interval, blood pressure, or intracranial pressure. However, taVNS increased overall heart rate variability and parasympathetic activity from 5-10 days after initial treatment, as compared to the sham treatment. Acutely, taVNS increased heart rate, blood pressure, and peripheral perfusion index without affecting the corrected QT interval, intracranial pressure, or heart rate variability. The acute post-treatment elevation in heart rate was more pronounced in patients who experienced a decrease of more than 1 point in their Modified Rankin Score at the time of discharge. Conclusions: Our study found that taVNS treatment did not induce adverse cardiovascular effects, such as bradycardia or QT prolongation, supporting its development as a safe immunomodulatory treatment approach for SAH patients. The observed acute increase in heart rate after taVNS treatment may serve as a biomarker for SAH patients who could derive greater benefit from this treatment.

Non-invasive Auricular Vagus nerve stimulation for Subarachnoid Hemorrhage (NAVSaH): Protocol for a prospective, triple-blinded, randomized controlled trial.

Background: Inflammation has been implicated in driving the morbidity associated with subarachnoid hemorrhage (SAH). Despite understanding the important role of inflammation in morbidity following SAH, there is no current effective way to modulate this deleterious response. There is a critical need for a novel approach to immunomodulation that can be safely, rapidly, and effectively deployed in SAH patients. Vagus nerve stimulation (VNS) provides a non-pharmacologic approach to immunomodulation, with prior studies demonstrating VNS can reduce systemic inflammatory markers, and VNS has had early success treating inflammatory conditions such as arthritis, sepsis, and inflammatory bowel diseases. The aim of the Non-invasive Auricular Vagus nerve stimulation for Subarachnoid Hemorrhage (NAVSaH) trial is to translate the use of non-invasive transcutaneous auricular VNS (taVNS) to spontaneous SAH, with our central hypothesis being that implementing taVNS in the acute period following spontaneous SAH attenuates the expected inflammatory response to hemorrhage and curtails morbidity associated with inflammatory-mediated clinical endpoints. Materials and methods: The overall objectives for the NAHSaH trial are to 1) Define the impact that taVNS has on SAH-induced inflammatory markers in the plasma and cerebrospinal fluid (CSF), 2) Determine whether taVNS following SAH reduces radiographic vasospasm, and 3) Determine whether taVNS following SAH reduces chronic hydrocephalus. Following presentation to a single enrollment site, enrolled SAH patients are randomly assigned twice daily treatment with either taVNS or sham stimulation for the duration of their intensive care unit stay. Blood and CSF are drawn before initiation of treatment sessions, and then every three days during a patient's hospital stay. Primary endpoints include change in the inflammatory cytokine TNF-α in plasma and cerebrospinal fluid between day 1 and day 13, rate of radiographic vasospasm, and rate of requirement for long-term CSF diversion via a ventricular shunt. Secondary outcomes include exploratory analyses of a panel of additional cytokines, number and type of hospitalized acquired infections, duration of external ventricular drain in days, interventions required for vasospasm, continuous physiology data before, during, and after treatment sessions, hospital length of stay, intensive care unit length of stay, and modified Rankin Scale score (mRS) at admission, discharge, and each at follow-up appointment for up to two years following SAH. Discussion: Inflammation plays a central role in morbidity following SAH. This NAVSaH trial is innovative because it diverges from the pharmacologic status quo by harnessing a novel non-invasive neuromodulatory approach and its known anti-inflammatory effects to alter the pathophysiology of SAH. The investigation of a new, effective, and rapidly deployable intervention in SAH offers a new route to improve outcomes following SAH. Trial registration: Clinical Trials Registered, NCT04557618. Registered on September 21, 2020, and the first patient was enrolled on January 4, 2021.

In-hospital imaging utilization after elective endovascular brain aneurysm treatment: a surrogate metric for the value of hospitalization.

OBJECTIVE: Despite the adoption of same-day outpatient surgical procedures in some specialties, it remains common practice to admit patients for monitoring after elective endovascular treatment of brain aneurysms to monitor for complications. The necessity of such monitoring has not been fully characterized. Here, the authors reviewed the utilization of imaging during posttreatment hospitalization, a surrogate measure for workup of suspected complications requiring hospital resources, to infer the value of inpatient monitoring after endovascular aneurysm treatment. METHODS: Clinical and angiographic data from eligible patients were retrospectively assessed for demographic characteristics, imaging indications, timing of imaging, and imaging findings. Patients were included if they underwent elective endovascular brain aneurysm treatment, and patients were excluded if significant intraprocedural complications occurred. The recorded imaging modalities included CT, MRI, catheter-based imaging, and ultrasound; plain radiographs were excluded. Multivariable logistic regression analysis was performed to identify predictors of the need for posttreatment imaging. RESULTS: In total, 1229 elective endovascular procedures for brain aneurysm treatment were included. Patients underwent imaging before discharge in 13.4% (165/1229) of cases, with significant findings in 5.0% (61/1229) of cases. The median (interquartile range) time to first posttreatment imaging was 13.2 (4.2-22.8) hours. The need for imaging during posttreatment hospitalization was positively associated with larger aneurysm size (p < 0.05) and negatively associated with underlying cardiovascular disease (p < 0.05). CONCLUSIONS: More than 1 in 8 patients who underwent elective endovascular brain aneurysm treatment required imaging during posttreatment hospitalization, most within the first 24 hours, and 1 in 20 had significant findings. These results suggest the importance of short-term hospitalization after elective endovascular aneurysm treatment.

Peripheral macrophages in the development and progression of structural cerebrovascular pathologies.

The human cerebrovascular system is responsible for maintaining neural function through oxygenation, nutrient supply, filtration of toxins, and additional specialized tasks. While the cerebrovascular system has resilience imparted by elaborate redundant collateral circulation from supportive tertiary structures, it is not infallible, and is susceptible to developing structural vascular abnormalities. The causes of this class of structural cerebrovascular diseases can be broadly categorized as 1) intrinsic developmental diseases resulting from genetic or other underlying aberrations (arteriovenous malformations and cavernous malformations) or 2) extrinsic acquired diseases that cause compensatory mechanisms to drive vascular remodeling (aneurysms and arteriovenous fistulae). Cerebrovascular diseases of both types pose significant risks to patients, in some cases leading to death or disability. The drivers of such diseases are extensive, yet inflammation is intimately tied to all of their progressions. Central to this inflammatory hypothesis is the role of peripheral macrophages; targeting this critical cell type may lead to diagnostic and therapeutic advancement in this area. Here, we comprehensively review the role that peripheral macrophages play in cerebrovascular pathogenesis, provide a schema through which macrophage behavior can be understood in cerebrovascular pathologies, and describe emerging diagnostic and therapeutic avenues in this area.

Comparative cost analysis of endovascular and open approaches for elective treatment of middle cerebral artery aneurysms.

BACKGROUND: Intracranial aneurysms of the middle cerebral artery can be treated using several open surgical and endovascular approaches. Given the growing evidence of clinical equipoise between these various treatment strategies, there is a need to assess the costs associated with each. METHODS: Cost of aneurysm treatment was divided into two categories for comparison. "Initial cost" comprised the total in-hospital expenses for initial aneurysm treatment and "total cost" comprised initial aneurysm treatment and all expenses relating to readmission due to treatment-related complications, prescribed catheter angiograms for monitoring of treatment stability, and any retreatments needed for a given aneurysm. The open surgical group was subdivided into a pterional approach group and a lateral supraorbital (LSO) approach group for. RESULTS: Median initial cost was $37,152 (IQR $31,318-$44,947) for aneurysms treated with the pterional approach, $29,452 (IQR $27,779-$32,826) for aneurysms treated with the LSO approach, and $19,587 (IQR $14,125-$30,521) for aneurysms treated with endovascular approaches. The median total cost was $39,737 (IQR $33,891-$62,259) for aneurysms treated with the pterional approach, $31,785 (IQR $29,513-$41,099) for aneurysms treated with the LSO approach, and $24,578 (IQR $18,977-$34,547) for aneurysms treated with endovascular approaches. Analysis of variance test demonstrated variance across groups for both initial and total cost (p = 0.004, p = 0.008, respectively). In our subsequent analysis, initial cost and total cost were higher in the pterional group than the endovascular group (p = 0.003 and p = 0.006, respectively). CONCLUSIONS: Endovascular treatment of elective aneurysms has a significantly lower cost than open surgical treatment with the pterional approach, but not with the LSO approach. For aneurysms not amenable to endovascular treatment, a minimally invasive LSO approach carries a lower cost burden than a pterional approach.

Propofol Affords No Protection against Delayed Cerebral Ischemia in a Mouse Model of Subarachnoid Hemorrhage.

Delayed cerebral ischemia (DCI) is an important contributor to poor outcomes in aneurysmal subarachnoid hemorrhage (SAH) patients. We previously showed that volatile anesthetics such as isoflurane, sevoflurane and desflurane provided robust protection against SAH-induced DCI, but the impact of a more commonly used intravenous anesthetic agent, propofol, is not known. The goal of our current study is to examine the neurovascular protective effects of propofol on SAH-induced DCI. Twelve-week-old male wild-type mice were utilized for the study. Mice underwent endovascular perforation SAH or sham surgery followed one hour later by propofol infusion through the internal jugular vein (2 mg/kg/min continuous intravenous infusion). Large artery vasospasm was assessed three days after SAH. Neurological outcome assessment was performed at baseline and then daily until animal sacrifice. Statistical analysis was performed via one-way ANOVA and two-way repeated measures ANOVA followed by the Newman-Keuls multiple comparison test with significance set at p < 0.05. Intravenous propofol did not provide any protection against large artery vasospasm or sensory-motor neurological deficits induced by SAH. Our data show that propofol did not afford significant protection against SAH-induced DCI. These results are consistent with recent clinical studies that suggest that the neurovascular protection afforded by anesthetic conditioning is critically dependent on the class of anesthetic agent.

Isoflurane Conditioning Provides Protection against Subarachnoid Hemorrhage Induced Delayed Cerebral Ischemia through NF-kB Inhibition.

Delayed cerebral ischemia (DCI) is the largest treatable cause of poor outcome after aneurysmal subarachnoid hemorrhage (SAH). Nuclear Factor Kappa-light-chain-enhancer of Activated B cells (NF-kB), a transcription factor known to function as a pivotal mediator of inflammation, is upregulated in SAH and is pathologically associated with vasospasm. We previously showed that a brief exposure to isoflurane, an inhalational anesthetic, provided multifaceted protection against DCI after SAH. The aim of our current study is to investigate the role of NF-kB in isoflurane-conditioning-induced neurovascular protection against SAH-induced DCI. Twelve-week-old wild type male mice (C57BL/6) were divided into five groups: sham, SAH, SAH + Pyrrolidine dithiocarbamate (PDTC, a selective NF-kB inhibitor), SAH + isoflurane conditioning, and SAH + PDTC with isoflurane conditioning. Experimental SAH was performed via endovascular perforation. Anesthetic conditioning was performed with isoflurane 2% for 1 h, 1 h after SAH. Three doses of PDTC (100 mg/kg) were injected intraperitoneally. NF-kB and microglial activation and the cellular source of NF-kB after SAH were assessed by immunofluorescence staining. Vasospasm, microvessel thrombosis, and neuroscore were assessed. NF-kB was activated after SAH; it was attenuated by isoflurane conditioning. Microglia was activated and found to be a major source of NF-kB expression after SAH. Isoflurane conditioning attenuated microglial activation and NF-kB expression in microglia after SAH. Isoflurane conditioning and PDTC individually attenuated large artery vasospasm and microvessel thrombosis, leading to improved neurological deficits after SAH. The addition of isoflurane to the PDTC group did not provide any additional DCI protection. These data indicate isoflurane-conditioning-induced DCI protection after SAH is mediated, at least in part, via downregulating the NF-kB pathway.

A review of technological innovations leading to modern endovascular brain aneurysm treatment.

Tools and techniques utilized in endovascular brain aneurysm treatment have undergone rapid evolution in recent decades. These technique and device-level innovations have allowed for treatment of highly complex intracranial aneurysms and improved patient outcomes. We review the major innovations within neurointervention that have led to the current state of brain aneurysm treatment.

Early Brain Injury After Subarachnoid Hemorrhage: Incidence and Mechanisms.

Aneurysmal subarachnoid hemorrhage is a devastating condition causing significant morbidity and mortality. While outcomes from subarachnoid hemorrhage have improved in recent years, there continues to be significant interest in identifying therapeutic targets for this disease. In particular, there has been a shift in emphasis toward secondary brain injury that develops in the first 72 hours after subarachnoid hemorrhage. This time period of interest is referred to as the early brain injury period and comprises processes including microcirculatory dysfunction, blood-brain-barrier breakdown, neuroinflammation, cerebral edema, oxidative cascades, and neuronal death. Advances in our understanding of the mechanisms defining the early brain injury period have been accompanied by improved imaging and nonimaging biomarkers for identifying early brain injury, leading to the recognition of an elevated clinical incidence of early brain injury compared with prior estimates. With the frequency, impact, and mechanisms of early brain injury better defined, there is a need to review the literature in this area to guide preclinical and clinical study.

A pilot study of lymphoscintigraphy with tracer injection into the human brain.

Many groups have reported lymphatic and glymphatic structures in animal and human brains, but tracer injection into the human brain to demonstrate real-time lymphatic drainage and mapping has not been described. We enrolled patients undergoing standard-of-care resection or stereotactic biopsy for suspected intracranial tumors. Patients received peritumoral injections of 99mTc-tilmanocept followed by planar or tomographic imaging. Fourteen patients with suspected brain tumors were enrolled. One was excluded from analysis because of tracer leakage during injection. There was no drainage of 99mTc-tilmanocept to regional lymph nodes in any of the patients. On average, after correcting for radioactive decay, 70.7% (95% CI: 59.9%, 81.6%) of the tracer in the injection site and 78.1% (95% CI: 71.1%, 85.1%) in the whole-head on the day of surgery remained the morning after, with variable radioactivity in the subarachnoid space. The retained fraction was much greater than expected based on the clearance rate from non-brain injection sites. In this pilot study, the lymphatic tracer 99mTc-tilmanocept was injected into the brain parenchyma, and there was no drainage outside the brain to the cervical lymph nodes. Our work demonstrates an inefficiency of drainage from peritumoral brain parenchyma and highlights a therapeutic opportunity to improve immunosurveillance of the brain.

SIRT1 mediates hypoxic postconditioning- and resveratrol-induced protection against functional connectivity deficits after subarachnoid hemorrhage.

Functional connectivity (FC) is a sensitive metric that provides a readout of whole cortex coordinate neural activity in a mouse model. We examine the impact of experimental SAH modeled through endovascular perforation, and the effectiveness of subsequent treatment on FC, through three key questions: 1) Does the endovascular perforation model of SAH induce deficits in FC; 2) Does exposure to hypoxic conditioning provide protection against these FC deficits and, if so, is this neurovascular protection SIRT1-mediated; and 3) does treatment with the SIRT1 activator resveratrol alone provide protection against these FC deficits? Cranial windows were adhered on skull-intact mice that were then subjected to either sham or SAH surgery and either left untreated or treated with hypoxic post-conditioning (with or without EX527) or resveratrol for 3 days. Mice were imaged 3 days post-SAH/sham surgery, temporally aligned with the onset of major SAH sequela in mice. Here we show that the endovascular perforation model of SAH induces global and network-specific deficits in FC by day 3, corresponding with the time frame of DCI in mice. Hypoxic conditioning provides SIRT1-mediated protection against these network-specific FC deficits post-SAH, as does treatment with resveratrol. Conditioning-based strategies provide multifaceted neurovascular protection in experimental SAH.

Endovascular Treatment of Acute Stroke.

PURPOSE OF REVIEW: In the USA, around 30% of 795,000 strokes per year are due to proximal large-vessel occlusion, and these are a major cause of death and disability. We review the most recent advances regarding treatment of ischemic stroke amenable to mechanical thrombectomy. RECENT FINDINGS: In the last four years, clinical trial evidence has expanded the time window for successful endovascular treatment to 24 h. Current research is aimed at expanding patient selection to mild strokes, large ischemic cores and occlusions of smaller, more distal blood vessels. Further, we have developed understanding of how to manage blood pressure after thrombectomy and even had promising results for a neuroprotective agent in these patients. Thrombectomy has transformed the treatment of ischemic stroke due to large-vessel occlusion. Recent research has focused on expanding patient candidacy for endovascular treatment and improving medical management to support better neurologic outcomes.

Sirtuin 1 Mediates Protection Against Delayed Cerebral Ischemia in Subarachnoid Hemorrhage in Response to Hypoxic Postconditioning.

Background Many therapies designed to prevent delayed cerebral ischemia (DCI) and improve neurological outcome in aneurysmal subarachnoid hemorrhage (SAH) have failed, likely because of targeting only one element of what has proven to be a multifactorial disease. We previously demonstrated that initiating hypoxic conditioning before SAH (hypoxic preconditioning) provides powerful protection against DCI. Here, we expanded upon these findings to determine whether hypoxic conditioning delivered at clinically relevant time points after SAH (hypoxic postconditioning) provides similarly robust DCI protection. Methods and Results In this study, we found that hypoxic postconditioning (8% O2 for 2 hours) initiated 3 hours after SAH provides strong protection against cerebral vasospasm, microvessel thrombi, and neurological deficits. By pharmacologic and genetic inhibition of SIRT1 (sirtuin 1) using EX527 and global Sirt1-/- mice, respectively, we demonstrated that this multifaceted DCI protection is SIRT1 mediated. Moreover, genetic overexpression of SIRT1 using Sirt1-Tg mice, mimicked the DCI protection afforded by hypoxic postconditioning. Finally, we found that post-SAH administration of resveratrol attenuated cerebral vasospasm, microvessel thrombi, and neurological deficits, and did so in a SIRT1-dependent fashion. Conclusions The present study indicates that hypoxic postconditioning provides powerful DCI protection when initiated at clinically relevant time points, and that pharmacologic augmentation of SIRT1 activity after SAH can mimic this beneficial effect. We conclude that conditioning-based therapies administered after SAH hold translational promise for patients with SAH and warrant further investigation.

Return of the lesion: a meta-analysis of 1134 angiographically cured pediatric arteriovenous malformations.

OBJECTIVE: Brain arteriovenous malformations (AVMs) carry a risk of rupture and subsequent morbidity or mortality unless fully treated. AVMs in pediatric patients are known to occasionally recur after obliteration. The objective of this study was to characterize the risk of AVM recurrence following angiographically confirmed obliteration in children. METHODS: Consecutive pediatric AVMs treated at a single center were identified from a prospective database. Patients with angiographically confirmed AVM obliteration following treatment were included in this study. Associations between AVM recurrence and patient or procedural factors were characterized using the two-tailed Fisher exact test or Mann-Whitney U-test. A literature search was conducted using PubMed, Scopus, Embase, and the Clarivate Web of Science with defined search criteria, and eligible studies were included alongside this study cohort in a meta-analysis. Rates of AVM recurrence following obliteration were pooled across studies with a random-effects model and reported with 95% confidence intervals (CIs). RESULTS: Recurrence after angiographic confirmation of AVM obliteration was observed in 10.4% (7/67) of pediatric AVMs treated at the authors' center. Patients with recurrent AVMs were significantly younger than those without recurrence (p = 0.002). In the meta-analysis, which included 1134 patients across 24 studies, the rate of recurrence was 4.8% (95% CI 3.0%-6.7%). The rate of AVM recurrence following radiosurgery was 0.7% (95% CI 0%-1.6%), which was significantly lower than the 8.5% rate (95% CI 5.0%-12.0%) following microsurgery. CONCLUSIONS: Recurrence of obliterated brain AVMs is common in children. Recurrence is more common in young children and following microsurgery.

Endovascular Thrombectomy Treatment: Beyond Early Time Windows and Small Core.

ABSTRACT: Tremendous advancements in the treatment of acute ischemic stroke in the last 25 years have been based on the principle of reperfusion in early time windows and identification of small core infarct for intravenous thrombolysis and mechanical thrombectomy. Advances in neuroimaging have made possible the safe treatment of patients with acute ischemic stroke in longer time windows and with more specific selection of patients with salvageable brain tissue. In this review, we discuss the history of endovascular stroke thrombectomy trials and highlight the neuroimaging-based trials that validated mechanical thrombectomy techniques in the extended time window with assessment of penumbral tissue. We conclude with a survey of currently open trials that seek to safely expand eligibility for this highly efficacious treatment.

Endovascular Considerations in Traumatic Injury of the Carotid and Vertebral Arteries.

Cervical carotid and vertebral artery traumatic injuries can have a devastating natural history. This article reviews the epidemiology, mechanisms of injury, clinical presentation, and classification systems pertinent to consideration of endovascular treatment. The growing role of modern endovascular techniques for the treatment of these diseases is presented to equip endovascular surgeons with a framework for critically assessing patients presenting with traumatic cervical cerebrovascular injury.

Subtemporal, Transapical, and Transcavernous Approach to Clip Low-Lying Basilar Tip Aneurysm: 2-Dimensional Operative Video.

Basilar tip aneurysm clipping is technically challenging because of the depth of operative corridor, rarity in presentation, and important perforators supplying deep, critical structures. Two major approaches to basilar tip aneurysms include (1) a frontotemporal (transorbital) trans-sylvian approach for most aneurysms and (2) a modified subtemporal approach for aneurysms with low-lying necks. A 53-yr-old woman presented to our institution with a large unruptured basilar tip aneurysm notable for a low, broad neck (6.4 mm). After discussion of risks and benefits of endovascular vs surgical options, the patient consented to operative intervention. She underwent a right frontotemporal craniotomy with zygomatic osteotomy, intradural petrous apicectomy, elective sectioning of the fourth cranial nerve (CN IV), and intracavernous removal of the dorsum sellae and posterior clinoid process to provide more space for aneurysm dissection. After temporary clipping of the basilar artery, the perforating arteries were dissected free from the aneurysm and the aneurysm occluded with 2 fenestrated clips. Important technical nuances of the approach include (1) achieving ample working room for temporary occlusion aneurysm dissection, (2) careful dissection of the perforators and contralateral P1, and (3) utilization of 2 fenestrated clips to accommodate and preserve the ipsilateral P1 segment. Postoperative angiogram showed complete aneur-ysmal occlusion. Postoperatively, the patient demonstrated mild cognitive impairment and a right CN IV palsy. At 6-wk follow-up, cognition recovered to normalcy. More recently, at 12-mo follow-up, the patient noted intermittent diplopia. Formal neuro-ophthalmologic assessment confirmed persistence of a CN IV palsy treated with prism lenses but no other neurological deficits.