Faculty Bibliography

Medium vessel occlusions represent a substantial proportion of patients with acute ischemic stroke. Recently presented randomized controlled trials, ESCAPE-MeVO (Endovascular Treatment to Improve Outcomes for Medium Vessel Occlusions), DISTAL (Endovascular Therapy Plus Best Medical Treatment [BMT] Versus BMT Alone for Medium Distal Vessel Occlusion Stroke), and DISCOUNT (Evaluation of Mechanical Thrombectomy in Acute Ischemic Stroke Related to a Distal Arterial Occlusion), did not demonstrate a clinical benefit of endovascular thrombectomy in distal and medium vessel occlusions, potentially generating uncertainty about optimal treatment strategies for medium vessel occlusions. Specifically, these results may lead clinicians to hesitate in performing endovascular thrombectomy for M2 occlusions, despite prior evidence indicating benefit in this subgroup. In this review, we critically examine current literature, focusing on anatomic and functional definitions of M2 segments, and highlight the significant heterogeneity in their classification. We place a particular emphasis on proximal as well as dominant M2 branches and the existing evidence, including observational studies, meta-analyses, and prior randomized trials. Additionally, we discuss methodological limitations and patient-selection biases of recent neutral trials, which may warrant caution in the broad application of their findings. Lastly, we propose recommendations for future research, emphasizing the need for refined patient-selection criteria to better identify subgroups most likely to benefit from endovascular thrombectomy, improved classification systems for M2 occlusions, and the exploration of adjunctive and alternative therapies.

BACKGROUND:Osteogenesis imperfecta (OI) is a connective tissue disorder characterized by fragile bones and vascular fragility, increasing the risk of vessel dissection and potentially complicating endovascular intervention. The authors present the first case of cranial bypass in a patient with OI. OBSERVATIONS/METHODS:A 38-year-old male with OI type I presented with a symptomatic left internal carotid artery (ICA) occlusive dissection managed with endovascular revascularization and stenting. Follow-up surveillance imaging identified an incidental right ICA dissection, also treated with stenting. Four years later, the patient experienced new right hemispheric symptoms. He was found to have progressive right ICA dissection on best medical management. Following an unsuccessful restenting attempt, he underwent a successful double-barrel superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass to restore cerebral perfusion with no perioperative complications. Six-month follow-up DSA confirmed a patent bypass with robust flow, and the patient remained asymptomatic 1 year postoperatively. LESSONS/CONCLUSIONS:STA-MCA bypass can serve as a viable and effective revascularization option in patients with OI, whose disease predisposes them to vascular dissection. In these high-risk patients, cranial bypass is a safe method for effective flow augmentation to hypoperfused brain regions when endovascular interventions fail. https://thejns.org/doi/10.3171/CASE25378.

BackgroundData on off-label use of flow diverter for ruptured distal anterior cerebral artery aneurysms (rDACAAs) are limited. The purpose of the present study is to evaluate the efficacy and safety of flow diversion for rDACAAs in a large multicenter cohort.MethodsA retrospective observational study on consecutive patients who were treated with flow diversion for rDACAAs at 8 centers in 4 countries was performed. Primary outcome was the occlusion rate of the target aneurysm at the last radiological follow-up. Secondary outcomes included good clinical outcome, retreatment, technical success, procedure-related complications, radiological outcome of the covered branches and mortality rate.ResultsA total of 21 patients with 21 rDACAAs were treated between January 2017 and December 2024. Thirteen patients were women (61.9%) and the median age was 54 years (IQR 46-66). The most common etiology was saccular (71.4%), followed by dissecting (23.8%) and mycotic (4.8%). In all patients a single stent was successful deployed. Median imaging follow-up was 9 (7-12) months. At last follow-up adequate occlusion was 95.2%. Symptomatic thromboembolic or hemorrhagic complications occurred in 9.5% of patients. Seventeen patients (81%) had good clinical outcome (mRS 0-2) with mortality rate of 9.5%. In-stent stenosis occurred in one case that was conservatively managed without major concerns.ConclusionsFlow diversion is feasible as a potential treatment strategy for acutely ruptured aneurysms arising from distal anterior cerebral artery. Flow diverter may represent a valid option whenever other treatments are considered challenging or high risk.

Definitive endoluminal reconstruction, widely known as flow diversion, revolutionized treatment of brain aneurysms. A range of targets, by location, size, etiology, and acuity, can be cured with an excellent risk/benefit profile. Requirement for effective antiplatelet state is balanced with superior treatment durability. Implant and delivery system technology continue to evolve. Some aneurysm types/locations remain undertreated. Maximizing efficacy while minimizing risks requires deep understanding of flow diversion principles, pathologic anatomy, endoluminal implants, delivery systems, and clinical management.

This article looks at the current state of aneurysm risk modeling, exploring the limitations of linear measurement. It reviews articles using Food and Drug Administration (FDA)-approved artificial intelligence-driven volumetric measurement tools both for evaluating potential aneurysm growth in patients being managed conservatively as well as in assessing morphologic change prerupture and postrupture. The challenges of defining the aneurysm boundary are explored, and a novel definition of aneurysm/parent artery interface is proposed.

Imaging follow-up is an established component of intracranial aneurysm management that allows ongoing assessment of rupture risk and timely intervention to maintain protection from bleeding. Yet the frequency, duration, and imaging modality for follow-up vary widely. This review outlines contemporary imaging techniques and practice for follow-up of treated and untreated aneurysms, highlighting existing knowledge gaps and technical limitations that limit standardization. Updated evidence on the expected evolution and long-term outcome of common treatment strategies is presented to guide accurate reporting of radiological outcome after treatment and considerations regarding follow-up regimen.

Although the concept of treating cerebral aneurysms by filling the sac from the inside (endosaccular) started many years ago first with detachable balloons and then coils, the use of a single metallic resheathable device acting as a flow disruptor is a much more recent innovation. The most studied device among these is certainly the WEB, which became part of standard clinical practice for treatment of wide-neck bifurcation aneurysms. This study reviews the most important features of the WEB device with a short summary of the most important literature. A small section at the end reviews also other endosaccular devices.

The anatomy of vertebrobasilar perforators has been widely studied in human cadavers, with most reports found in the neurosurgical literature. These arterial perforators are extremely hard to visualize consistently with traditional two-dimensional digital subtraction angiography, but are reliably visible with cross sectional cone beam CT techniques. A clear understanding of this specific neurovascular anatomy and pathology is essential for informed treatment decisions. This review analyzes the anatomy of vertebrobasilar perforators with a focus on practical implications for aneurysm treatment, particularly flow diversion.

BACKGROUND AND OBJECTIVES/OBJECTIVE:The Silk Vista Baby (SVB) flow diverter (FD) stent (Balt SAS) is the first device designed for treating distally located brain aneurysms. It can be delivered through a 0.017-inch ID microcatheter, enabling access to small, distal vessels. The aim of this study was to evaluate the effectiveness, safety, technical success, occlusion rate, and clinical outcomes of the SVB device. METHODS:This retrospective, multicenter study included data from 18 centers from November 2023 to September 2024. Procedures were performed by experienced neurointerventionalists following institutional standards of care. Outcomes analyzed included effectiveness, safety, and aneurysm occlusion rates. Descriptive analyses and Pearson χ2 or Independent t-Test were used for statistical evaluation. RESULTS:A total of 95 patients, mean age 55.4 years, were included. A total of 31% of aneurysms were ruptured at admission. Most (58.3%) were located in the anterior circulation, and 45% had previous treatment, mainly coiling (69.4%). Complication rates were higher for ruptured aneurysms (24.1%) compared with unruptured ones (9.2%). Two deaths occurred, 1 (1.1%) related to the procedure. At discharge, 87% of patients had modified Rankin Scale ≤2. The latest follow-up showed overall complete/near-complete occlusion rates of 76.1%, with 81.14% for ruptured and 73.43% for unruptured aneurysms. Technical success was higher in unruptured cases (100% vs 93.1%). CONCLUSION/CONCLUSIONS:Our case series demonstrated the efficacy of the SVB with a high rate of technical success. The occlusion rates for ruptured cases are comparable with those of other FDs. However, the rates are lower for unruptured cases. This discrepancy is likely due to the characteristics of the aneurysms, particularly in the presence of side branches in bifurcation lesions. The SVB safety profile is similar to other FDs in unruptured cases, while the ruptured group presented more complications.