Faculty Bibliography

BACKGROUND AND OBJECTIVES/OBJECTIVE:Trans-sonolucent cranioplasty ultrasonography (TCUS) has been explored as a noninvasive tool for evaluating superficial temporal artery (STA)-middle cerebral artery (MCA) bypass patency. Previous research has focused on early postoperative feasibility. Data on its long-term utility and correlation with formal angiography remain scarce. We aimed to evaluate TCUS' role in postoperative STA-MCA bypass graft monitoring and its concordance with formal angiography. METHODS:This retrospective study included 46 consecutive direct STA-MCA anastomoses in 40 patients (March 2021-May 2024), all with sonolucent polymethyl methacrylate cranioplasty. Patient records were reviewed for demographics, disease and surgical characteristics, and outcomes. Postoperative TCUS was performed outpatient to monitor anastomotic patency. Formal follow-up angiography was also conducted, and radiographic data were reviewed for graft patency assessment and qualitative correlation with TCUS. RESULTS:Follow-up angiography was performed for 41 of 46 anastomoses (digital subtraction angiography, n = 34; computed tomography angiography, n = 4; magnetic resonance angiography, n = 3) at a median of 1.1 years, demonstrating 97.6% patency (40/41). Outpatient TCUS was performed in 32 of 46 bypasses (69.6%) with 100% patency at first scan (median 28.5 days). A second TCUS (n = 19, 41.3%) at a median of 8.4 months (3.9-13.6 months) showed robust flow in 94.7% of cases. One bypass had asymptomatic slow flow with a narrowed anastomosis, and another showed a severely stenosed STA correlating with later digital subtraction angiography. In the broader cohort, third (n = 5, median 1.2 years) and fourth (n = 1, 1.4 years) TCUS assessments demonstrated 100% patency. Among bypasses undergoing both TCUS and angiography (n = 31, 67.4%), findings were concordant in all cases. CONCLUSION/CONCLUSIONS:TCUS demonstrated complete agreement with formal angiography in assessing bypass patency, supporting TCUS as a reliable, noninvasive monitoring tool. Future research should explore quantitative TCUS flow measurements and their relationship to intraoperative flow and long-term graft remodeling.

BackgroundThe Woven EndoBridge (WEB) device represents an innovative solution for cerebral aneurysm occlusion, particularly for challenging wide-neck bifurcation aneurysms. However, factors affecting sustained occlusion remain poorly understood. We utilized machine learning to attempt to identify predictors of favorable long-term outcomes following WEB treatment.MethodsIn this multicenter retrospective study, we collected patient demographics, aneurysm characteristics, procedural details, and clinical outcomes. The primary endpoint was improvement in occlusion status, defined as maintained Raymond-Roy Occlusion Classification (RROC) grade 1, or improvement from grade 2 to 1, or from grade 3 to either 2 or 1 on final angiographic follow up. The dataset was split into training (75%) and validation (25%) sets. The CatBoost algorithm was selected based on performance metrics, with Shapley Additive exPlanations (SHAP) values calculated to determine feature importance. Furthermore, a multivariable binomial logistic regression model was performed to validate machine learning findings.ResultsAmong 720 aneurysms from 36 hospitals, 84% showed improvement in occlusion at follow up. Both machine learning and multivariable logistic regression identified aneurysm height as the most consistent correlate of nonimprovement (odds ratio (OR) 0.90 per mm, p = 0.022). In the CatBoost model, the highest-ranking features by SHAP included aneurysm height, patient age, treatment acuity, ACom location, WEB-SLS device, bifurcation anatomy, aneurysm multiplicity, baseline modified Rankin Scale, access route, and partial thrombosis.ConclusionsMachine-learning and regression analyses identified consistent predictors of occlusion improvement after WEB treatment, with aneurysm height most strongly linked to nonimprovement. These insights may guide patient selection and follow up. Findings require cautious interpretation and external validation in larger cohorts.

BackgroundDuring mechanical thrombectomy for large-vessel occlusions, a ledge effect makes navigating the aspiration catheters (ACs) to the occlusion difficult. New large-bore macrowires minimize this while ensuring flexibility and navigational control. We evaluated the technical feasibility of delivering large-bore ACs to posterior circulation occlusions.MethodsThis retrospective multicenter study evaluated patients treated for posterior circulation strokes with adjunct-free macrowire-only direct aspiration first-pass technique (MO-ADAPT) using 0.024- and 0.035-in macrowires between October 2022 and December 2024. Primary outcomes included successful catheter delivery, successful MO-ADAPT (i.e. adjunct-free catheter delivery and successful clot aspiration), and first-pass reperfusion (i.e. modified thrombolysis in cerebral infarction (mTICI) score ≥ 2b after one MO-ADAPT pass).ResultsAmong 42 included patients (mean age 68.3 ± 15.4 years), adjunct-free delivery of ACs to the occlusion using macrowires only was successful in 95.2%. An MO-ADAPT primary approach achieved successful reperfusion in 81.0%, with first-pass reperfusion in 54.8%. Among patients with successful AC delivery, the aspiration success rate was 85.0%. Final mTICI scores of 3, 2c, and 2b after all procedures were seen in 78.6%, 14.3%, and 4.8%, respectively, regardless of thrombectomy method. No vascular complications were observed, and postprocedural intracranial hemorrhage and distal emboli occurred in 2.4% each. A favorable clinical outcome at 90 days was observed in 33.3% of cases. Multivariable analysis showed that underlying intracranial atherosclerotic disease was a negative predictor of both MO-ADAPT success and first-pass reperfusion; no factors predicted AC delivery success.ConclusionIn this retrospective series, MO-ADAPT appeared to be technically feasible for treating posterior circulation strokes, with promising procedural results and a low complication rate. Observed failures were mainly associated with underlying intracranial atherosclerotic disease requiring stent retriever-assisted mechanical thrombectomy. Given the limited sample size and study design, further studies, ideally with larger cohorts and comparative designs, are necessary to clarify the relative safety, efficacy, and cost effectiveness of MO-ADAPT.

PURPOSE/OBJECTIVE:Mechanical thrombectomy (MT) is standard care for acute large vessel occlusion (LVO), but it fails in 10-20% of cases, often due to underlying intracranial artery stenosis (ICAS). In such cases, rescue stenting (RS), with or without angioplasty, may improve recanalization, but its clinical benefit remains debated. The purpose of this study was to define predictors of clinical outcome in this patient population. METHODS:We conducted a retrospective multicenter study including 115 patients with ICAS-related occlusion of the middle cerebral artery (MCA) treated with MT and RS across 27 international stroke centers. Baseline, procedural, and post-procedural variables were analyzed. The outcome measure was the ordinal shift of the 90-day modified Rankin Scale (mRS) score. Stepwise multivariate regression and structural equation modeling (SEM) were used to identify outcome predictors and explore mediation pathways. RESULTS:Successful recanalization (modified Treatment in Cerebral Infarction (mTICI) score ≥ 2b) was achieved in 94.8% of patients, with 73.0% reaching mTICI 2c‑3. SEM showed that baseline Alberta Stroke Program Early CT Score (ASPECTS), stenting with angioplasty and achieving mTICI 2c‑3 were associated with improved functional outcome, mediated by higher post-procedural ASPECTS. Post-procedural ASPECTS influenced functional outcome both directly (estimate = -0.45, p < 0.001) and indirectly by reducing the occurrence of symptomatic intracranial hemorrhage (sICH) (estimate = -0.09, p = 0.004). This model explained 36.5% of the variance in 90-day mRS scores. CONCLUSION/CONCLUSIONS:In patients with acute ICAS-related MCA occlusion, stenting with angioplasty and achieving mTICI 2c-3 recanalization are associated with improved clinical outcome. These benefits are mediated by better post-procedural ASPECTS and reduced sICH. Prospective studies are warranted to confirm these findings.

Spinal dural arteriovenous fistulas (dAVFs) at the craniocervical junction are rare vascular lesions that can cause progressive myelopathy and paralysis. This video presents a 40-year-old male with a left C1 spinal dAVF, who experienced unsteadiness, dizziness, leg weakness, and intermittent facial numbness. Given the lesion's symptomatology, the patient underwent a C1 laminectomy and midline suboccipital craniectomy for definitive obliteration. The authors describe key surgical techniques for fistula exposure and obliteration, with intraoperative angiographic confirmation. Long-term follow-up confirmed complete persistent occlusion on angiography and resolution of his symptoms. This case highlights surgical strategies for managing dAVFs at the craniocervical level. The video can be found here: https://stream.cadmore.media/r10.3171/2025.7.FOCVID2573.

BACKGROUND:The Woven EndoBridge (WEB) device is a prevalent treatment for intracranial aneurysms. While many studies have assessed the obliteration rate post-WEB embolization, few have focused on long-term outcomes in partially thrombosed aneurysms. OBJECTIVE:To assess whether partially thrombosed aneurysms are at higher risk of recurrence or retreatment following WEB embolization compared with non-thrombosed aneurysms. METHODS:We evaluated data from 22 academic institutions, focusing on previously untreated cerebral aneurysms treated with the WEB device. Logistic regression was utilized to analyze factors predicting long-term aneurysm obliteration and retreatment necessity. RESULTS:Among 1303 patients, 26 presented with a partially thrombosed aneurysm. In the partially thrombosed group, the mean aneurysm maximal diameter was 10.7±4 mm with a neck ratio of 1.99±1.19 mm, larger than in the control group where the mean aneurysm maximal diameter was 6.81±2.37 mm with a neck ratio of 1.64±0.51 mm (P<0.001 for both maximal diameter and neck ratio). At the final follow-up, partially thrombosed aneurysms treated by the WEB device had a 38.5% retreatment rate, compared with 7.0% for non-thrombosed aneurysms (P<0.001). Among partially thrombosed aneurysms, the Raymond-Roy type IIIa/b occlusion rate was higher (38.5% vs 9.9%, P<0.001). On multivariate analysis, partially thrombosed aneurysms compared with non-thrombosed aneurysms had an increased rate of retreatment (OR 3.64, 95% CI 1.28 to 10.1). CONCLUSION/CONCLUSIONS:Partially thrombosed aneurysms are associated with a poorer occlusion rate and a higher rate of retreatment following WEB embolization. For partially thrombosed aneurysms, the WEB device appears suboptimal as a first-line treatment, and therefore alternative techniques should be prioritized.

BACKGROUND:Recent studies have suggested that favorable venous outflow (VO) may be a promising imaging biomarker to predict clinical outcomes following reperfusion therapy in patients with acute ischemic stroke caused by large vessel occlusion (AIS-LVO). METHODS:A comprehensive literature search was conducted in PubMed, Scopus, WOS, and Cochrane to identify studies that evaluated VO profiles, assessed using the Cortical Vein Opacification Score (COVES). The risk ratio (RR) and 95% confidence interval (CI) for the outcomes, including functional independence, assessed by modified rankin scale at 90 days (mRS 0-2), hemorrhagic infarction, parenchymal hematoma, 90-day mortality, intracranial hemorrhage (ICH), and symptomatic ICH (sICH), were calculated and analyzed using the 'meta' package in R version 4.4.1. RESULTS:A total of six studies encompassing 2249 patients were included. Patients with favorable VO had a higher likelihood of achieving functional independence at 90 days (RR = 2.15; 95% CI: 1.35, 3.42; p = 0.01) and a lower incidence of 90-day mortality (RR = 0.39; 95% CI: 0.30, 0.51; p < 0.01), parenchymal hematoma (RR = 0.36; 95% CI: 0.27, 0.47; p < 0.01). Furthermore, sICH was less frequent in patients with favorable VO (RR = 0.39; 95% CI: 0.17, 0.89; p = 0.03). However, hemorrhagic infarction and any ICH did not differ significantly between the two groups (p-values: 0.06 and 0.32, respectively). CONCLUSION/CONCLUSIONS:VO is a promising imaging biomarker for predicting outcomes in patients with AIS-LVO following reperfusion therapy. Prospective clinical trials are warranted to investigate the predictive value of VO, assessed on multiphasic computed tomography angiography (CTA), as a prognostic marker in this patient population.

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.