Faculty Bibliography

BACKGROUND:The Society of Vascular and Interventional Neurology (SVIN) Guidelines and Practice Standards Committee issues Brief Practice Updates to provide concise, evidence-based recommendations and suggestions on focused topics relevant to vascular and interventional neurology. Currently, there is limited published guidance on the technical performance and interpretative parameters of cerebral digital subtraction angiography for the determination of cerebral circulatory arrest in patients being evaluated for brain death/death by neurological criteria. In this Brief Practice Update, we present consensus-based suggestions for standardizing the performance, interpretation, and application of digital subtraction angiography in this context. METHODS:This Brief Practice Update was developed using the SVIN Standards and Parameters for Guideline Development in the classification of evidence and Class of Recommendation when evidence is available and Expert Opinion recommendation when evidence is lacking. The Guidelines and Practice Standards committee convened a multidisciplinary writing group to establish key clinical questions and develop a survey assessing Expert Opinion on the role of digital subtraction angiography in cerebral circulatory arrest determination. Survey items addressed technical considerations, interpretation criteria, and clinical integration. Iterative refinement was achieved through group consensus, and the final survey was distributed to a panel of experts in neurointervention and neurocritical care. The SVIN Guidelines and Practice Standards Quality Committee reviewed the findings for adherence to SVIN's internal evidence evaluation guidelines before submission to the SVIN board for societal endorsement. RESULTS:Evidence was evaluated by the writing group when available, and Expert Opinion was assessed using survey results. Suggested recommendations follow the established SVIN guideline framework for Class of Recommendation and Level of Evidence, with an Expert Opinion endorsement category for areas lacking high-quality evidence at the time of publication. CONCLUSIONS:This update standardizes how to perform, interpret, and report digital subtraction angiography when used to assess cerebral circulatory arrest in brain death/death by neurological criteria evaluations, aiming to improve reproducibility across centers. It provides a structured framework to improve consistency and reliability among practitioners performing and interpreting cerebral angiography in this setting.

This chapter reviews the vascular anatomy of the brainstem and posterior circulation with emphasis on clinical neurology and angiographic interpretation. Using a caudal-to-cranial approach, we describe the vertebral artery at the craniocervical junction and its key branches, including meningeal, medullary, spinal, and posterior inferior cerebellar arteries (PICA), highlighting common variants and clinically important anastamoses. We then outline basilar artery segments, pontine perforator patterns, and vertebrobasilar perforator groups, linking lesion location to characteristic neurologic syndromes. The cerebellar arteries (PICA, AICA, and superior cerebellar artery) are discussed with attention to variant origins, shared trunks, and collateral pathways that influence infarct topography. Finally, we summarize basilar tip and posterior cerebral artery (PCA) anatomy, including fetal PCA configurations, and thalamoperforator variants, such as the artery of Percheron.

BACKGROUND/UNASSIGNED:Pituitary hyperemia and gland enlargement can be cardinal features of intracranial hypotension secondary to cavernous sinus and epidural venous plexus distention. This phenomenon can therefore complicate radiographic interpretation of sellar lesions when both diagnoses co-exist. We report a unique case of a rapidly enlarging pituitary macroadenoma in the setting of a thoracic cerebrospinal fluid (CSF)-venous fistula causing symptomatic intracranial hypotension. CASE DESCRIPTION/UNASSIGNED:A 53-year-old female with no prior neurosurgical history presented with recurrent orthostatic headache. Magnetic resolution imaging revealed a pituitary lesion along with pathopneumonic signs of intracranial hypotension. The tumor grew rapidly on surveillance imaging, prompting consideration of surgery. Further work-up, however, revealed a thoracic CSF-venous fistula. Endovascular embolization of the fistula led to near-complete resolution of her symptoms and durable radiographic tumor regression. CONCLUSION/UNASSIGNED:Pituitary macroadenomas are susceptible to local hemodynamic changes occurring as a sequelae of occult CSF leak. Identification and treatment of the underlying etiology were sufficient to induce tumor regression.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Hand-sewn (HS) microsuturing is limited by tremor and fatigue. Robotic systems may improve performance, but quantitative comparisons remain limited. This study evaluates the precision of robot-assisted vs manual suturing during end-to-side microanastomosis. METHODS:Under simulation, microsurgical robot-assisted and HS sutures for end-to-side microanastomosis were performed by a single surgeon. One thousand four hundred and ninety-four total frames were assessed within 4 videos. Each robotic clip was paired with a corresponding HS clip. Tracker software extracted 2-dimensional positional data. Motion trajectories were smoothed using Savitzky-Golay filtering for an ideal suture trajectory. Deviation from an ideal path was quantified using Euclidean distance. Mean and SD of path deviation were calculated. Group comparisons were made as fold-change reductions and standardized effect sizes (Cohen d) to quantify the magnitude of observed differences. RESULTS:Robotic-assisted sutures demonstrated significantly lower mean path deviation and variability than HS sutures, particularly for the dominant (right) hand, with consistently large effect sizes for the right hand (all = 1.2, r = 0.5) and smaller for the left hand (d = 0.36-0.71, r = 0.18-0.33). CONCLUSION/CONCLUSIONS:Robotic microsuturing with microsurgical assistant significantly improves path fidelity, particularly in dominant-hand tasks. Manual sutures showed larger deviations between the ideal suture and raw data, supporting robotic integration into cerebrovascular neurosurgery and warranting study in live models.

The Woven EndoBridge (WEB) device treats wide-necked bifurcation aneurysms, but occlusion rates vary. This study aims to identify factors associated with immediate WEB device occlusion. Data from patients treated with WEB devices across 36 sites were analyzed. Machine learning algorithms and ordinal regression models were developed to predict immediate incomplete occlusion for ruptured and unruptured aneurysms. The study included 1565 patients, with 436 ruptured and 1129 unruptured aneurysms. Immediate complete occlusion was achieved in 38.3% of ruptured and 32.8% of unruptured aneurysms. For ruptured aneurysms, the CatBoost classifier achieved an AUROC of 0.69. Key predictors of incomplete occlusion included pretreatment mRS, aneurysm diameter, and MCA location. Ordinal regression revealed that smoking history (OR: 1.95, p < 0.001), neck diameter (Odds Ratio [OR]: 1.50, p < 0.001), and presence of a branch from the aneurysm (OR: 2.06, p = 0.016) were associated with incomplete, while bifurcation aneurysms (OR: 0.55, p = 0.017) were associated with complete immediate occlusion. For unruptured aneurysms, the CatBoost classifier achieved an AUROC of 0.68. Significant predictors of immediate incomplete occlusion included aneurysm neck width, MCA location, and presence of daughter sac. Ordinal regression revealed that smoking history (OR: 1.29, p = 0.032), neck diameter (OR: 1.24, p < 0.001), and presence of a daughter sac (OR: 1.53, p = 0.005) were associated with incomplete, while bifurcation aneurysms (OR: 0.71, p = 0.02) and posterior circulation location (OR: 0.68, p = 0.01) were associated with complete immediate occlusion. Careful evaluation of patient demographics and specific aneurysm characteristics may help improve the outcomes of intracranial aneurysms treated with WEB device.

Despite continued advancement in thrombectomy devices and techniques, a small proportion, approximately 10%, of thrombectomy attempts result in failed reperfusion due to technical difficulties with reaching the clot or recanalizing the occluded vessel. Technically challenging thrombectomy cases are often longer, with more thrombectomy passes, resulting in poorer clinical outcomes and higher rates of complications. Factors causing difficulty during thrombectomy include tortuous vasculature preventing access, challenging clot location (tandem or distal occlusions), underlying vessel abnormality, and hard-to-retrieve clots. Anticipating potentially challenging or refractory thrombectomy cases allows one to plan appropriate procedural strategies with the goal of maximizing technical success and favorable clinical outcome. We review these challenging situations and discuss specific procedural techniques that can be employed in each scenario to overcome the barriers and achieve fast and successful reperfusion.

Carotid webs are increasingly recognized as an underdiagnosed etiology of ischemic stroke, especially in young, otherwise healthy patients. These fibrous intimal protrusions create regions of flow stasis within the internal carotid artery, predisposing to thromboembolism. Diagnosis remains challenging due to their subtle radiographic appearance and underappreciation in clinical practice. While antiplatelet therapy or anticoagulation used to be the cornerstone of management, medical therapy alone has been found to be insufficient for stroke prevention in symptomatic patients. Definitive intervention includes carotid artery stenting or carotid endarterectomy; both have demonstrated excellent safety and efficacy. Risk stratification for symptomatic and asymptomatic carotid webs remains an area of active research, with emerging evidence suggesting that specific anatomic features, termed the carotid web angioarchitecture, may help predict stroke risk. Further studies are needed to determine the role of preventative intervention. A deeper understanding of carotid web pathogenesis, natural history, and hemodynamic impact is critical for guiding clinical decision-making.

BACKGROUND:Data about the safety and the efficacy of flow diversion for distal anterior cerebral artery (DACA) aneurysms are limited. We present the largest multicenter analysis evaluating the outcomes of flow diversion in unruptured DACA aneurysm treatment. METHODS:Databases from 39 centers were retrospectively reviewed for unruptured DACA aneurysms treated with flow-diverting stents. Demographics, clinical presentation, radiographic characteristics, procedural complications, and outcomes were assessed. RESULTS:A total of 168 patients with 168 unruptured DACA aneurysms were treated between January 2018 and December 2022. One hundred and twenty-five were women (74.4%) and the median age was 61 (IQR 52-67) years. The most common morphology was saccular (91.7%), with branch involvement in 61.9% of cases. Median parent vessel diameter was 1.9 mm (IQR 1.7-2.2) and stents were successfully deployed in 99.4% of cases. In 96.4% a single stent was implanted, while 3.6% of cases required two stents. Median imaging follow-up was 16.5 (IQR 7-24) months. At last follow-up the rate of occlusion (O'Kelly-Marotta scale C or D) was 82.1%. Symptomatic thromboembolic or hemorrhagic complications occurred in 5.3% of patients and the mortality rate was 0.6%. The rate of retreatment was 1.2%. CONCLUSIONS:Flow-diverting stents are a reasonably safe and effective treatment option for unruptured DACA aneurysms.