Faculty Bibliography

BACKGROUND:The new sonolucent cranioplasty implant (clear polymethyl methacrylate, PMMA) adds functionality besides surgical reconstruction. One possible application uses the transcranioplasty ultrasound (TCUS) technique after PMMA cranioplasty to assess graft patency of extracranial-intracranial (EC-IC) bypass procedures. OBJECTIVE:To report our early multicenter experience. METHODS:This is a multicenter analysis of consecutive EC-IC bypass patients from 5 US centers (2019-2022) with closure postbypass using PMMA implant. RESULTS:Forty-four patients (median age 53 years, 68.2% females) were included. The most common indication for bypass was Moyamoya disease/syndrome (77.3%), and superficial temporal artery to middle cerebral artery bypass was the most common procedure (79.5%). Pretreatment modified Rankin Scales of 0 and 1 to 2 were noted in 11.4% and 59.1% of patients, respectively. Intraoperative imaging for bypass patency involved a combination of modalities; Doppler was the most used modality (90.9%) followed by indocyanine green and catheter angiography (86.4% and 61.4%, respectively). Qualitative TCUS assessment of graft patency was feasible in all cases. Postoperative inpatient TCUS confirmation of bypass patency was recorded in 56.8% of the cases, and outpatient TCUS surveillance was recorded in 47.7%. There were no cases of bypass failure necessitating retreatment. Similarly, no implant-related complications were encountered in the cohort. Major complications requiring additional surgery occurred in 2 patients (4.6%) including epidural hematoma requiring evacuation (2.3%) and postoperative surgical site infection (2.3%) that was believed to be unrelated to the implant. CONCLUSION:This multicenter study supports safety and feasibility of using sonolucent PMMA implant in EC-IC bypass surgery with the goal of monitoring bypass patency using TCUS.

The persistent carotid-vertebrobasilar anastomoses are arterial communications between the anterior and posterior circulations due to the persistence of embryological connections. We here present an extremely rare instance of a transclival persistent carotid-vertebrobasilar anastomosis in a 10-month-old infant, which does not fit into any of the traditionally described categories, such as the trigeminal artery, hypoglossal artery, or proatlantal artery.

BACKGROUND:The superficial temporal artery (STA)-to-middle cerebral artery (MCA) bypass requires precise preoperative planning, and 3-dimensional virtual reality (VR) models have recently been used to optimize planning of STA-MCA bypass. In the present report, we have described our experience with VR-based preoperative planning of STA-MCA bypass. METHODS:Patients from August 2020 to February 2022 were analyzed. For the VR group, using 3-dimensional models from the patients' preoperative computed tomography angiograms, VR was used to locate the donor vessels, potential recipient, and anastomosis sites and plan the craniotomy, which were referenced throughout surgery. Computed tomography angiograms or digital subtraction angiograms were used to plan the craniotomy for the control group. The procedure time, bypass patency, craniotomy size, and postoperative complication rates were assessed. RESULTS:The VR group included 17 patients (13 women; age, 49 ± 14 years) with Moyamoya disease (76.5%) and/or ischemic stroke (29.4%). The control group included 13 patients (8 women; age, 49 ± 12 years) with Moyamoya disease (92.3%) and/or ischemic stroke (7.3%). For all 30 patients, the preoperatively planned donor and recipient branches were effectively translated intraoperatively. No significant difference were found in the procedure time or craniotomy size between the 2 groups. Bypass patency was 94.1% for the VR group (16 of 17) and 84.6% for the control group (11 of 13). No permanent neurological deficits occurred in either group. CONCLUSIONS:Our early experience has shown that VR can serve as a useful, interactive preoperative planning tool by enhancing visualization of the spatial relationship between the STA and MCA without compromising the surgical results.

There are multiple treatment alternatives for cavernous dAVFs, with transvenous routes being most common. Among these routes, occluded inferior petrosal sinus is well-described, and, apart from being imaginative and elegant, it is also safe and effective. Herein we describe the application of this method to reach the fistulous pouch of a cavernous dAVF via an occluded superior petrosal sinus.

BACKGROUND:We report the largest multicenter experience to date of utilizing the Comaneci device for endovascular treatment of refractory intracranial vasospasm. METHODS:Consecutive patients undergoing Comaneci mechanical dilatation for vasospasm were extracted from prospectively maintained registries in 11 North American centers (2020-2022). Intra-arterial vasodilators (IAV) were allowed, with the Comaneci device utilized after absence of vessel dilation post-infusion. Pre- and post-vasospasm treatment scores were recorded for each segment, with primary radiological outcome of score improvement post-treatment. Primary clinical outcome was safety/device-related complications, with secondary endpoints of functional outcomes at last follow-up. RESULTS:A total of 129 vessels in 40 patients (median age 52 years; 67.5% females) received mechanical dilation, 109 of which (84.5%) exhibited pre-treatment severe-to-critical vasospasm (ie, score 3/4). Aneurysmal subarachnoid hemorrhage was the most common etiology of vasospasm (85%), with 65% of procedures utilizing Comaneci-17 (92.5% of patients received IAV). The most treated segments were anterior cerebral artery (34.9%) and middle cerebral artery (31%). Significant vasospasm drop (pre-treatment score (3-4) to post-treatment (0-2)) was achieved in 89.9% of vessels (96.1% of vessels experienced ≥1-point drop in score post-treatment). There were no major procedural/post-procedural device-related complications. Primary failure (ie, vessel unresponsive) was encountered in one vessel (1 patient) (1/129; 0.8%) while secondary failure (ie, recurrence in previously treated segment requiring retreatment in another procedure) occurred in 16 vessels (7 patients) (16/129; 12.4%), with median time-to-retreatment of 2 days. Favorable clinical outcome (modified Rankin Scale 0-2) was noted in 51.5% of patients (median follow-up 6 months). CONCLUSIONS:The Comaneci device provides a complementary strategy for treatment of refractory vasospasm with reasonable efficacy/favorable safety. Future prospective trials are warranted.

Meaningful contributions to neurointerventional practice may be possible by considering the dynamic aspects of angiography in addition to fixed morphologic information. The functional approach to venous anatomy requires integration of the traditional static anatomic features of the system-deep, superficial, posterior fossa, medullary veins, venous sinuses, and outflow routes into an overall appreciation of how a classic model of drainage is altered, embryologically, or pathologically, depending on patterns of flow-visualization made possible by angiography. In this review, emphasis is placed on balance between alternative venous networks and their redundancy, and the problems which arise when these systems are lacking. The role of veins in major neurovascular diseases, such as dural arteriovenous fistulae, arteriovenous malformations, pulsatile tinnitus, and intracranial hypertension, is highlighted, and deficiencies in knowledge emphasized.

The aim of this review is to describe the acquisition and reformatting of state of the art high resolution cone beam CT (HR-CBCT) and demonstrate its role in multiple neurovascular conditions as a tool to improve the understanding of disease and guide therapeutic decisions. First, we will review the basic principle of CBCT acquisition, followed by the injection protocols and the reformatting paradigms. Next, multiple applications in different pathological conditions such as aneurysms, arteriovenous malformations, dural arteriovenous fistulas, and stroke will be described. HR-CBCT angiography, widely available, is uniquely useful in certain clinical scenarios to improve the understanding of disease and guide therapeutic decisions. It rapidly is becoming an essential tool for the contemporary neurointerventionalist.AChoAho.

Carotid web is considered to be a less common, but overlooked cause of recurrent cryptogenic ischemic stroke. It is defined as a fibromuscular dysplasia forming a shelf-like protrusion in the carotid bulb that alters regional hemodynamics with a high risk of blood clot formation and its embolization intracranially. The web could be well visualized on CTA; however, it can be missed in the absence of significant carotid stenosis or the presence of an intraluminal thrombus. Treatment includes antiplatelet therapy, but also interventions "“ carotid endarterectomy or endovascular stenting. The carotid web typically leads to ischemic stroke in younger patients without any other cardiovascular risk factors.

BACKGROUND:Intracranial stenosis (ICAS) is a common cause of stroke worldwide and patients with symptomatic ICAS exhibit a high rate of recurrence, particularly in the early period after the initial event. In this study, we aimed to study the association between borderzone infarct and recurrent ischemic stroke in patients hospitalized with symptomatic ICAS. METHODS:This is a retrospective single center study that included patients hospitalized with acute ischemic stroke in the setting of intracranial stenosis (50% or more and an acute ischemic stroke in the territory supplied by the stenosed artery) over a 32-month period. We excluded patients who did not receive a brain MRI or did not have an infarct on brain imaging. The primary predictor is infarct pattern (any borderzone vs. no borderzone infarct) and the primary outcome was recurrent cerebrovascular events (RCVE) within 90 days. We used unadjusted, and age and sex adjusted logistic regression models to determine associations between infarct pattern and RCVE at 90-days. RESULTS:Among 99 patients who met the inclusion criteria (4 tandem), the mean age was 70.1 ± 11.2 years and 41.4% were women; 43 had borderzone infarcts and 19 had RCVE. In adjusted binary logistic regression analysis, borderzone infarct was associated with increased risk of RCVE (adjusted OR 4.00 95% CI 1.33-11.99, p=0.013). The association between borderzone infarction and RCVE was not different among anterior circulation ICAD (adjusted HR 2.85 95% CI 0.64-12.76, p=0.172) vs. posterior circulation ICAD (adjusted HR 6.69 95% CI 1.06-42.11, p=0.043), p-value for interaction = 0.592. CONCLUSION/CONCLUSIONS:In real world post-SAMMPRIS medically treated patients with ICAD, the borderzone infarct pattern was associated with 90-day RCVE. Borderzone infarcts are likely a surrogate marker of impaired distal blood flow, highlighting the importance of targeting stroke mechanisms and developing alternative treatment strategies for high-risk cohorts.

BACKGROUND:Lesions of the internal auditory canal presenting with partial hearing loss are almost always vestibular schwannomas (VSs). Intracanalicular anterior inferior cerebellar artery (AICA) aneurysms are extremely rare but can mimic VS based on symptoms and imaging. The authors report the case of a flow-related intracanalicular AICA aneurysm from a pial brainstem arteriovenous malformation (AVM) masquerading as VS. OBSERVATIONS/METHODS:A 57-year-old male with partial left-sided hearing loss and an intracanalicular enhancing lesion was initially diagnosed with VS and managed conservatively at an outside institution with surveillance imaging over 3 years. When he was referred for VS follow-up, new imaging raised radiological suspicion for vascular pathology. Cerebral angiography revealed a small pial AVM located at the trigeminal root entry zone with an associated flow-related intracanalicular AICA aneurysm. The AVM was obliterated with open surgery, during which intraoperative angiography confirmed no AVM filling, preservation of the AICA, and no further aneurysm filling. LESSONS/CONCLUSIONS:Intracanalicular AICA aneurysms and other lesions, including cavernous malformations, can mimic radiographic features of VS and present with hearing loss or facial weakness. Modern vascular neurosurgical techniques such as endovascular intervention and open surgery in a hybrid operating room allowed definitive management of both lesions without untoward morbidity.