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BackgroundBlebs are important secondary structures of intracranial aneurysms associated with increased rupture risk and can affect local wall stress and hemodynamics. Mechanisms of bleb development and evolution are not clearly understood. We investigate the relationship between blebs with different wall characteristics and local hemodynamics and rupture sites.MethodsBlebs with different wall appearances in intra-operative videos were analyzed with image-based computational fluid dynamics. Thin red blebs were compared against thick atherosclerotic/hyperplastic white/yellow blebs. Rupture points were identified in videos of ruptured aneurysms harboring blebs.ResultsThin blebs tended to be closer to the inflow than atherosclerotic blebs of the same aneurysm (P=0.0234). Blebs near the inflow had higher velocity (P=0.0213), vorticity (P=0.0057), shear strain rate (P=0.0084), wall shear stress (WSS) (P=0.0085), and WSS gradient (P=0.0151) than blebs far from the inflow. In a subset of 12 ruptured aneurysms harboring blebs, rupture points were associated with thin blebs in 42% of aneurysms, atherosclerotic blebs in 25%, and were away from blebs in the remaining 33%.ConclusionsNot all blebs are equal; some have thin translucent walls while others have thick atherosclerotic walls. Thin blebs tend to be located closer to the inflow than atherosclerotic blebs. Blebs near the inflow are exposed to stronger flows with higher and spatially variable WSS than blebs far from the inflow which tend to have uniformly lower WSS. Aneurysms can rupture at thin blebs, atherosclerotic blebs, and even away from blebs. Further study of wall failure in aneurysms with different bleb types is needed.

BackgroundEndovascular embolization of cerebral arteriovenous malformations (AVM) with liquid n-butyl cyanoacrylate (n-BCA) serves multiple purposes including AVM occlusion and flow reduction in preparation for other treatment modalities. The objective was to study the clinical, structural, and angiographic factors affecting complications associated with AVM treatment by sequential n-BCA embolizations for nidal occlusion versus quantitative flow reduction in preparation for surgical resection or radiosurgery.MethodsWe performed a retrospective review of all patients who underwent endovascular embolization of cerebral AVM at our institution between 1998 and 2019, during which time the technique of traditional embolization evolved to a strategy of targeted sequential flow reduction guided by serial flow imaging based on quantitative magnetic resonance angiography, in conjunction with a shift away from nidal penetration.ResultsAmong 251 patients, 47.8% of patients presented with ruptured AVM. On average, each patient underwent 2.4 embolizations, for a total of 613 sessions. Major morbidity related to embolization occurred in 18 (7.2%) patients, but this occurred disproportionately in the traditional embolization strategy (n=16, 8%) in contrast with the flow-targeting strategy (n=2, 3.8%). Four patients (1.6%) died in the overall group, and these all occurred with the traditional embolization strategy (2% of 199 patients); no deaths occurred in the flow-targeting strategy (n=52).ConclusionEmbolization with n-BCA targeted to sequential flow reduction and feeder occlusion with limited nidal penetration prior to definitive surgical or radiosurgical treatment can be safely performed with low overall morbidity and mortality.

BackgroundBlebs are rupture risk factors in intracranial aneurysms (IAs), but their prevalence, distribution, and associations with clinical factors as well as their causes and effects on aneurysm vulnerability remain unclear.MethodsA total of 122 blebs in 270 IAs selected for surgery were studied using patient-specific vascular reconstructions from 3D angiographic images. Bleb geometry, location on the aneurysm, and frequency of occurrence in aneurysms at different locations were analyzed. Associations between gender, age, smoking, hypertension, hormone therapy, dental infection, and presence of blebs were investigated.ResultsOf all aneurysms with blebs, 77% had a single bleb and 23% had multiple blebs. Only 6% of blebs were at the neck, while 46% were in the body and 48% in the dome. Aneurysms with blebs were larger (pConclusionsBlebs are common in IAs, and most aneurysms harboring blebs have a single bleb. Blebs in the aneurysm neck are rare, but they are equally common in the body and dome. The presence of blebs in IAs was associated with dental infection, and negatively associated with hormone replacement therapy.

This case demonstrates a rare pathology of basilar artery pial arteriovenous shunting presenting with acutely progressive symptoms of brainstem compression, in which we applied a polytetrafluoroethylene-coated embolic device to achieve short-segment upper mid-basilar artery sacrifice. In addition to presenting a rare form of basilar arteriovenous fistula (AVF) (likely related to hereditary hemorrhagic telangiectasia) and discussing the extreme management challenges, this case demonstrates the unusual but successful application of a novel neurovascular device. Unanswered questions include the mechanism of development of this pathology and the optimum post-embolization anticoagulation plan. Reports of pial arteriovenous fistulas (AVFs) that occur in the posterior fossa are quite rare, occasionally appearing in general pial AVF case series or as individual case reports;1–6 in particular, direct AVFs originating off the basilar artery have not previously been reported. We present the case of a child with a basilar pial AVF with mass effect and progressively accelerating neurological decline and report on its management and outcome. A 3-year-old child with a history of ocular albinism and normal neurological milestones (walking at 10 months, speaking in full sentences) was noted to have several months of progressive gait instability, bilateral hand tremor, dysarthria, drooling, and intermittent esotropia, with accelerating worsening over the most recent 3 weeks. Her parents and three siblings were all healthy. On examination she had left eye intorsion and limitation of upgaze. She ambulated with a hyper-plantarflexed gait and became progressively unsteady on her feet, with axial ataxia. She had intention tremors bilaterally in the upper extremities. Over the course of observation of several days she developed swallowing difficulties and, as a result, had her oral intake progressively restricted, and showed progressive loss of motor and speech milestones. On MRI brain she was found to have an AVF that appeared to originate directly off the upper mid-basilar artery, with …

Occlusion of the basilar artery can be treated with endovascular thrombectomy, although the results have not been well studied. Persistent fetal cerebrovascular anatomy can lead to unusual presentation of carotid atherosclerotic disease and can be a barrier to successful mechanical thrombectomy if not recognized. This case presents a rare persistent carotico-basilar anastomosis which resulted in basilar occlusion via the persistent hypoglossal artery and coincident absence of contralateral vertebral arterial access due to a left vertebral artery terminating in the left posterior inferior cerebellar artery. Preoperative recognition of this anatomy afforded by review of cross-sectional imaging was critical to success during this emergent procedure.

Vertebral artery dissection (VAD) is an important cause of ischemic stroke and subarachnoid hemorrhage (SAH). Dissections presenting with ischemia rarely cause SAH after more than a few hours, especially without radiographic evidence of pseudoaneurysm. We successfully treated a patient for persistent vessel injury presenting with SAH 7 years after presenting with extracranial subocclusive dissection of the right vertebral artery and an associated right posterior inferior cerebellar artery stroke. This is one of only three reported cases of delayed SAH occurring more than 2 weeks after an initial ischemic presentation of a VAD, and the only one without radiographic evidence of pseudoaneurysm at standard follow-up duration.

Occlusion of the basilar artery can be treated with endovascular thrombectomy, although the results have not been well studied. Persistent fetal cerebrovascular anatomy can lead to unusual presentation of carotid atherosclerotic disease and can be a barrier to successful mechanical thrombectomy if not recognized. This case presents a rare persistent carotico–basilar anastomosis which resulted in basilar occlusion via the persistent hypoglossal artery and coincident absence of contralateral vertebral arterial access due to a left vertebral artery terminating in the left posterior inferior cerebellar artery. Preoperative recognition of this anatomy afforded by review of cross-sectional imaging was critical to success during this emergent procedure.

Introduction Aneurysms of the paraclinoid region of the internal carotid artery (ICA) and the interventions used to treat them often result in visual impairment. Because of the proximity of these aneurysms to the optic nerve and the ophthalmic artery, between 16% and 53% of patients present with visual deficits. While flow diversion is increasingly used throughout endovascular neurosurgery, few studies have reported the visual outcomes of treating paraclinoid aneurysms with this technique or compared it to coiling or clipping. Hypothesis In order to satisfy demand for data on the visual outcomes for this new endovascular treatment modality and inform the contemporary management of paraclinoid aneurysms, we performed a retrospective analysis of patients with paraclinoid aneurysms treated at our site with a Pipeline embolization device (PED). Methods We compiled visual outcome data for 20 patients presenting with 26 paraclinoid aneurysms and treated at our site with flow diversion, 10 of whom (totaling 13 aneurysms) presented with visual impairment. We then reviewed vision outcomes in these patients at discharge and at 6 months, noting improved, unchanged, deteriorated, or newly impaired vision. We also performed an extensive literature review to compile data (1447 cases from 21 sites) on vision outcomes for paraclinoid aneurysms treated with clips (534 cases), coils (638), or flow diverters (275). Results Of twenty patients with 26 paraclinoid aneurysms treated at our site with a PED, ten patients (totaling 13 aneurysms with an average diameter of 7.1 mm) presented with preoperative visual impairment. Visual deficits were improved in 8 patients (80%) and unchanged in 2 (20%) following treatment. No patients experienced sustained worsening of their existing visual impairment, however one patient acquired postoperative iatrogenic vision impairment (5%). A literature review of paraclinoid aneurysm treatment revealed visual improvement rates of approximately 41% for clipping, 54% for coiling, and 73% for flow diversion, visual deterioration rates of approximately 14%, 23%, and 2%, and newly impaired vision rates of 9%, 3%, and 4%. Conclusion Compared to clipping and coiling, flow diversion demonstrates a higher rate of visual improvement and a lower rate of visual decline in patients with visually symptomatic paraclinoid aneurysms, with comparable risk of iatrogenic vision impairment. We report strong visual outcomes in patients treated at our site for paraclinoid aneurysms with a PED, including small aneurysms. Our results suggest that this new treatment modality yields improved vision outcomes in patients with paraclinoid aneurysms compared to clipping and coiling. Disclosures M. Silva: None. A. See: None. H. Dasenbrock: None. P. Khandelwal: None. N. Patel: None. M. Aziz-Sultan: 2; C; Covidien.