Faculty Bibliography

OBJECTIVE:The cause of perimesencephalic subarachnoid hemorrhage (pmSAH) is unclear but has historically been attributed to a venous source. The authors hypothesized that high-resolution cone-beam CT (CBCT) during angiography could better identify pmSAH etiology. METHODS:All patients with pmSAH treated at the authors' institution between January 2023 and December 2024 were retrospectively analyzed. Patients were excluded if CBCT was not performed as part of the digital subtraction angiography (DSA), if CBCT source data were not available for review, or if the images were deemed to be low quality. All images were reviewed by 2 neuroangiographers with extensive neurovascular imaging experience and discussed until consensus agreement. Data were recorded as counts and percentages. RESULTS:Among 152 patients who presented with spontaneous SAH in 2023-2024, 22 had a pmSAH defined according to the Rinkel criteria. These 22 patients had a catheter angiogram performed on 1 of 2 biplane machines. Thirteen of those patients had high-quality CBCT data available for review, 8 (61%) of whom were found to harbor a basilar perforator focal outpouching consistent with a site of rupture. All patients with pmSAH, including the 8 found to have a basilar perforator aneurysm, achieved an excellent neurological recovery with resolution of the basilar perforator finding on follow-up DSA with CBCT and without experiencing a re-rupture event or clinically significant vasospasm. CONCLUSIONS:In the setting of pmSAH, high-resolution CBCT acquired as part of catheter angiography frequently identifies a basilar perforator pseudoaneurysm. Conservative management was associated with excellent outcomes in this series. The authors propose that in the setting of pmSAH, a high suspicion of an arterial etiology should be considered until proven otherwise.

BACKGROUND AND IMPORTANCE/BACKGROUND:Rhino-orbital cerebral mucormycosis (ROCM) is an aggressive fungal infection involving the paranasal sinuses, orbit, and intracranial cavity, with a propensity for vascular invasion. This can lead to complications such as internal carotid artery (ICA) thrombosis and occlusion, presenting major neurosurgical challenges. Although surgical debridement and antifungal therapy are the mainstays of treatment, cases with significant neurovascular involvement require specialized intervention. We report a case of ROCM with severe flow-limiting ICA stenosis treated by direct extracranial-intracranial bypass. CLINICAL PRESENTATION/METHODS:tA 65-year-old man with diabetes presented with progressive left-sided blindness and facial numbness. Imaging revealed a left orbital mass extending into the paranasal sinuses and intracranially. Empiric antifungal therapy was started. Pathology confirmed Rhizopus species. Despite extensive surgical debridement and antifungal therapy, the patient developed progressive severe cavernous ICA stenosis, leading to watershed territory strokes. To restore cerebral perfusion, protect from distal emboli, and prepare for potential aggressive debridement, a flow-replacing direct (superficial temporal artery-middle cerebral artery (M2)) bypass was performed, and the supraclinoid carotid was trapped. Intraoperative angiography confirmed robust flow through the bypass. The patient was discharged on antifungal therapy and aspirin. At 6-month follow-up, the patient was neurologically intact with an modified Rankin Scale score of 1. Computed tomography angiography and transcranioplasty Doppler ultrasonography confirmed good flow through the bypass. CONCLUSION/CONCLUSIONS:In addition to antifungal therapy and surgical debridement, superficial temporal artery-middle cerebral artery bypass can be a lifesaving intervention in the management of ROCM with severe cerebrovascular compromise. This case highlights the critical role of cranial bypass in preserving cerebral perfusion in patients with flow-limiting ROCM-associated ICA invasion.

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.

IntroductionTraumatic intracranial aneurysms (TICAs) are rare, potentially fatal complications of traumatic brain injury (TBI) or iatrogenic insult. Often forming as pseudoaneurysms, TICAs result from direct arterial wall disruption. Their unique pathophysiology, delayed presentation, and high rupture risk pose diagnostic and therapeutic challenges. This review synthesizes current evidence on TICA pathogenesis, diagnosis, and treatment, with particular emphasis on the evolving role of angiographic diagnosis and endovascular intervention.MethodsA structured PubMed search was conducted, supplemented by manual citation screening. All study designs were considered with no date restrictions. Articles were included if they reported traumatic intracranial aneurysms in patients of any age and discussed diagnostic or therapeutic approaches. Data were synthesized thematically across epidemiology, pathophysiology, imaging, treatment (endovascular and surgical), and surveillance.ResultsTICAs typically arise at sites of direct injury or at fixed vessel segments (e.g., distal ACA, peripheral MCA, cavernous/supraclinoid ICA). Their delayed and subtle appearance necessitates high clinical suspicion and serial imaging. Digital subtraction angiography is the diagnostic gold standard, though immediate or early post-trauma studies may be negative. Endovascular techniques, particularly flow diversion, are increasingly favored for their minimally invasive nature and ability to achieve parent vessel reconstruction. Open surgery retains a role for lesions complicated by mass effect, intracerebral hematoma, or anatomy unsuitable for endovascular repair. Outcomes vary with aneurysm location, treatment timing, modality, and TBI severity.ConclusionTICAs represent a distinct, high-risk entity requiring timely diagnosis and individualized, multidisciplinary management. Endovascular approaches are increasingly favored. Further research is needed to guide optimal surveillance imaging protocols.

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.

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.

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.

OBJECTIVE:To validate the carotid web (CW) risk stratification assessment described in previous works within a larger cohort of patients with symptomatic and incidentally found asymptomatic CWs. METHODS:A retrospective analysis of our institution's electronic medical records identified all patients with a diagnosis of CW from 2017 to 2024. We included symptomatic patients and those with asymptomatic CWs, that is, incidentally found webs without history of stroke or transient ischemic attack. Patient charts were reviewed for demographics, imaging, comorbidities, and a diagnosis of stroke after diagnosis of asymptomatic CW. All angles were measured as described in previous work on a sagittal reconstruction of neck CT angiography in which the common carotid artery (CCA), external carotid artery, and internal carotid artery (ICA) were well visualized, together with the CW itself. Principal component analysis and logistic regression were performed to evaluate the association between high-risk angles and stroke risk.  RESULTS: Twenty-six symptomatic and 26 asymptomatic patients were identified. Of note, the number of patients with hypertension, hyperlipidemia, and smoking history was 17 (65.0%), 16 (62.0%), and 8 (31.0%) for symptomatic patients and 18 (69.0%), 17 (65.0%), and 15 (58.0%) for asymptomatic patients. All angular measurements showed statistically significant associations with stroke status. The CCA-web-pouch angle showed the strongest association (p=2.07×10⁻⁴), followed by the CCA-pouch-tip angle (p=3.23×10⁻⁴), ICA-web-pouch angle (p=0.004), and ICA-pouch-tip angle (p=0.005). Each additional high-risk angle increased the odds of stroke by 9.47-fold (p<0.0001). The associated probability of stroke increased from 6.3% with no high-risk angles to 39.1% with one high-risk angle and further to 85.9% with two high-risk angles. The model demonstrated high sensitivity, correctly identifying 84.6% of positive cases, and high specificity, correctly identifying 88.5% of negative cases. The F1 score was 0.863, indicating good overall model performance.  CONCLUSION: Given this successful stratification of CWs into high- and low-risk groups, the utilization of geometric CW parameters may play a role in improving patient selection for intervention in the setting of incidentally diagnosed CW. .

BACKGROUND:The Drivewire 24 (DW24) is a newly FDA-cleared 0.024 inch steerable guidewire. Its proximally controlled deflectable tip allows for intravascular steering to facilitate selective navigation of diagnostic or therapeutic catheters. We present the first clinical experience with the DW24. METHODS:All neurointerventional procedures using the DW24 from October 2024 to April 2025 were retrospectively reviewed. Indications, procedural details, DW24 performance, wire-related complications, and operator feedback were assessed. RESULTS:27 procedures were performed utilizing the DW24. Indications included aneurysm (n=16), stroke (n=5), arteriovenous fistula or malformation (n=4), and diagnostic venography (n=2). Technical success was achieved in 92.6% of cases. Target vessels included the MCA, anterior cerebral artery, posterior cerebral artery, internal carotid artery segments, transverse sinus, and torcula. The device's radiopaque, hydrophilic distal tip aided fluoroscopic visibility, and the variable support enabled articulation across a range of aspiration and delivery catheters without requiring additional support devices. The DW24's steerability enabled access to challenging cerebrovascular anatomy, including one stroke case where conventional guidewires failed to reach a distal M2 occlusion. The DW24's intravascular steering also allowed for the delivery of catheters for Pipeline Embolization Device (PED) deployment and facilitated PED post-processing to improve wall apposition without requiring wire removal, reshaping, or balloon angioplasty. Operators observed a short learning curve. There were no device-related complications, though the wire's response to rotational force was a limitation. CONCLUSION/CONCLUSIONS:The DW24 demonstrated a high technical success rate with no device-related complications. Its versatility across catheter sizes and precise controllability facilitate navigating complex cerebrovasculature. Further studies should assess efficacy in larger cohorts across additional clinical scenarios.

BACKGROUND AND OBJECTIVES/OBJECTIVE:Iatrogenic cerebrovascular injury can cause intracranial hemorrhage and pseudoaneurysm formation, putting patients at high risk for postoperative bleeding. No consensus for management exists. This study describes endovascular treatment of these acute injuries with flow diverter stents. METHODS:Electronic medical records were retrospectively reviewed for injury type and etiology, timing of diagnosis, and endovascular management, including antiplatelet regimens, embolization results, and clinical outcome. RESULTS:Six patients were included. Three suffered an injury to the internal carotid artery, 1 suffered an injury to the left anterior cerebral artery, 1 suffered an injury to the right posterior cerebral artery, and 1 suffered an injury to the basilar artery. Four of the 6 injuries occurred during attempted tumor resection, 1 occurred during cerebrospinal fluid leak repair, and 1 occurred during an ophthalmic artery aneurysm clipping. All injuries resulted in pseudoaneurysm formation. Four were immediately detected on angiography; 2 were initially negative on imaging. Five were treated with a pipeline embolization device, and 1 was treated with a Silk Vista Baby. Two were treated with 2 pipeline embolization devices telescopically overlapped across the pseudoaneurysm. All devices deployed successfully. No pseudoaneurysm recurrence or rebleeding occurred. No parent artery occlusion or stenosis was observed, and complete pseudoaneurysm occlusion was observed in 4 patients (in 2 patients, follow-up imaging could not be obtained). CONCLUSION/CONCLUSIONS:With proper antiplatelet regimens, flow diverter stents can be used safely to successfully treat complex acute iatrogenic injuries. Early repeat angiogram is needed when immediate postinjury imaging does not discover the point of vessel injury.