Abstract Number ‐ 141: Microemboli Monitoring After Intrasaccular Flow Disruption: Single‐center Experience

Introduction The management of wide‐necked bifurcation aneurysms can be challenging due to multiple factors. Intrasaccular flow disruption with the Woven EndoBridge (WEB) has demonstrated a safe and effective profile. Current microemboli data after the WEB device placement is non‐existent. We evaluated the rate of embolic signals (MES) after WEB device implantation. Methods We performed a retrospective analysis of a prospectively maintained database including patients who underwent WEB device implantation for the treatment of unruptured intracranial aneurysms between 2021 and 2022. Variables studied included patient demographics, modified Rankin Scale (mRS) before and 3 months post‐treatment, comorbidities, aneurysm characteristics, platelet inhibition tests, and activated clotting time. All patients were on aspirin and a P2Y12 inhibitor and had therapeutic levels on platelet aggregation assays. Intraoperative heparin was given in all cases to keep a therapeutic ACT. P2Y12 drugs were stopped after the procedure. In all patients, MES monitoring was performed in the immediate postoperative period and >12 hours after the procedure. Results 34 patients with 34 aneurysms were analyzed. Mean age was 67.4 years and 85% were females. Mean aneurysm size was 13.1 ± 2.0 mm and mean neck size 4.4 ± 1.5 mm. Locations were middle cerebral artery bifurcation and M1‐M2 segment (n = 13), basilar artery tip (n = 10), anterior communicating artery (n = 8), internal carotid artery terminus (n = 2) and pericallosal artery (n = 1). A single WEB was implanted in 100% of the cases. MES were negative in all cases. 3‐month mRS remained stable or improved in all cases. No procedure‐related complications were seen. Conclusions Our findings reinforce the safety profile of intrasaccular flow disruption. These findings differ from a previous analysis of unruptured aneurysms in our institution where a 7.7% incidence of MES was reported after endovascular treatment of unruptured aneurysms with primary or assisted coiling

Abstract Number ‐ 142: Flow Diversion for Posterior Communicating Artery Aneurysms: Systematic Review and Meta‐Analysis

Introduction Posterior communicating artery (PComA) aneurysms are common and have a high risk of rupture. Flow diverters (FD) have demonstrated a safe and effective profile. However, the use of FD in PComA aneurysms has shown controversial results with high rates of recurrence and a high risk of potential ischemic complications. There, we aimed to evaluate the safety and efficacy of flow diversion for the treatment of PComA aneurysms with a meta‐analysis of the literature. Methods We performed a systematic search in Scopus, Embase, Medline, and Web of Science from inception until May 2022 for all the studies that reported the safety and effectiveness of FD for the treatment of intracranial aneurysms located in the posterior communicating artery. The primary effectiveness endpoint was a complete aneurysm occlusion rate at final follow‐up. The primary safety endpoint was a composite measure of cumulative events that occurred during and after the procedure. Events included death and ischemic/hemorrhagic complications. Random‐effects meta‐analysis was used to calculate proportions. Statistical heterogeneity across studies was assessed with I2 statistics. Results A total of 13 studies with 397 patients harboring 403 aneurysms were included in our analysis. Mean age was 48 years and mean aneurysm size was 5.3 mm. Complete aneurysm occlusion at final follow‐up was 74% (95% CI 66–81%; I2 = 54%). The primary safety composite outcome was 5% (95% CI 3–9%; I2 = 0%). The mortality rate was 1% (95% CI 0–2%; I2 = 0%). Subgroup analysis showed that patients with a non‐fetal PComA had a higher rate (76%; 95% CI 62%‐86%; I2 = 53%) of complete aneurysm occlusion compared to those with a fetal PComA (36%; 95% CI 21%‐54%; I2 = 0%). Conclusions Our findings show that flow diversion for the treatment of aneurysms located in the PComA is effective and safe. However, the same treatment for aneurysms located in a fetal‐type PComA did not show the same efficacy profile suggesting that these cases might require an alternative treatment to achieve permanent occlusion rates

Head-Mounted Augmented Reality in the Planning of Cerebrovascular Neurosurgical Procedures: A Single-Center Initial Experience.

BACKGROUND: Augmented reality (AR) technology has played an increasing role in cerebrovascular neurosurgery over the last 2 decades. Hence, we aim to evaluate the technical and educational value of head-mounted AR in cerebrovascular procedures. METHODS: This is a single-center retrospective study of patients who underwent open surgery for cranial and spinal cerebrovascular lesions between April and August 2022. In all cases, the Medivis Surgical AR platform and HoloLens 2 were used for preoperative and intraoperative (preincision) planning. Surgical plan adjustment due to the use of head-mounted AR and subjective educational value of the tool were recorded. RESULTS: A total of 33 patients and 35 cerebrovascular neurosurgical procedures were analyzed. Procedures included 12 intracranial aneurysm clippings, 6 brain and 1 spinal arteriovenous malformation resections, 2 cranial dural arteriovenous fistula obliterations, 3 carotid endarterectomies, two extracranial-intracranial direct bypasses, two encephaloduroangiosynostosis for Moyamoya disease, 1 biopsy of the superficial temporal artery, 2 microvascular decompressions, 2 cavernoma resections, 1 combined intracranial aneurysm clipping and encephaloduroangiosynostosis for Moyamoya disease, and 1 percutaneous feeder catheterization for arteriovenous malformation embolization. Minor changes in the surgical plan were recorded in 16 of 35 procedures (45.7%). Subjective educational value was scored as very helpful for cranial, spinal arteriovenous malformations, and carotid endarterectomies; helpful for intracranial aneurysm, dural arteriovenous fistulas, direct bypass, encephaloduroangiosynostosis, and superficial temporal artery-biopsy; and not helpful for cavernoma resection and microvascular decompression. CONCLUSIONS: Head-mounted AR can be used in cerebrovascular neurosurgery as an adjunctive tool that might influence surgical strategy, enable 3-dimensional understanding of complex anatomy, and provide great educational value in selected cases

Abstract Number ‐ 21: Mechanical Thrombectomy versus Medical Management in Patients with acute LVO and Pre‐morbid Disability: Meta‐analysis

Introduction Actual guidelines offer little guidance for endovascular treatment of patients with acute ischemic stroke (AIS) and pre‐morbid disability (PMD). Often, patients with a mRS >2 are not considered for mechanical thrombectomy (MT) and might not be given the best chance of achieving recovery. Three recent meta‐analysis have showed conflicting results regarding the benefit of MT, while persistently showing a significant increase in mortality. Methods We conducted a systematic search in Embase, Medline, and Web of Science for studies of patients with AIS and PMD who were treated with MT or MM. We included all definitions of PMD, main outcomes were favorable functionality at 90‐days (mRS 0–2 or return to baseline mRS), symptomatic ICH, and mortality. We performed meta‐analyses using a random‐effect model, and I2 to evaluate heterogeneity. Subgroup analyses were used when appropriate. Results 2 studies contained data comparing PMD patients treated with MT versus MM, 14 studies contained data only of patients treated with MT, and 10 only of patients treated with MM; they provided data of 1071 patients in the MT group and 4547 in the MM group. Pooled rates in the MT group were 28% (95% CI 0.24‐0.32) for favorable functionality, 7% (95% CI 0.04‐0.12) for sICH, 43% (95% CI 0.36‐0.51) for 90‐days mortality, 18% (95% CI 0.14‐0.23) for intra‐hospital mortality, and pooled reperfusion rate (mTICI 0–2) of 80% (95% CI 0.72‐0.86). In a meta‐analysis of proportion with the treatments modalities as subgroups, including only studies with a similar definition of PMD, we obtained: for favorable functionality, MT = 26% (95% CI 0.23‐0.30) vs. MM = 35% (95% CI 0.22‐0.51); for sICH, MT = 6% (95% CI 0.05‐0.08) vs. MM = 6% (95% CI 0.05‐0.08); for 90‐days mortality, MT = 48% (95% CI 0.44‐0.52) vs. MM = 34% (95% CI 0.27‐0.41); and for in‐hospital mortality, MT = 18% (95% CI 0.14‐0.23) vs. MM = 22% (95% CI 0.17‐0.28). Additionally, meta‐analysis for 90‐days mortality in MT studies, showed a pooled rate of 49% (95% CI 0.45‐0.53) for the high tPA rate subgroup, and 30% (95% CI 0.19‐0.44) for the low tPA rate subgroup. Conclusions Up to one third of PMD patients who undergo MT might achieve favorable functionality, without increasing the risk of sICH and with rates similar to those obtained with MM. Furthermore, we observed a high 90‐day mortality rate, in both MT and MM groups. In subgroups exploration, there is trend of high tPA rates to be associated with the increased mortality. It is urgent to identify PMD patients who will benefit from MT and factors associated with poor outcomes

Abstract Number ‐ 140: Transcranial Doppler Emboli Monitoring for Stroke Prevention after Flow Diversion: A Single Center Experience

Introduction Following the favorable clinical and radiographical results of flow diversion, its use has continually expanded for the treatment of complex intracranial aneurysms. The high metal surface of flow diverters (FD) increases the risk of thromboembolic complications. Current emboli monitoring data after FD placement is limited. Transcranial doppler (TCD) offers a non‐invasive evaluation of microembolic signals and might be a valuable tool to prevent ischemic complications. We evaluated the rate of embolic signals and their management after FD implantation. Methods We performed a retrospective, single‐center evaluation of adult patients who underwent a FD procedure with the Pipeline Embolization Device (PED) for unruptured intracranial aneurysms between 2012 and 2016. Covariates included patient demographics, comorbidities, aneurysm characteristics, procedure characteristics, and post‐procedure TCD emboli monitoring (immediate and >12 hours post‐operative). TCD emboli signals were classified as positive (15 signals). The primary outcome was the rate of symptomatic stroke at 2 and 12 weeks in these patients. Results 105 patients with 132 aneurysms were analyzed. Mean age was 59.7 years, and 78% were females. Mean aneurysm size was 7.8 ± 6.4 mm. Most of them were located in the paraclinoid region (40%). Two PEDs were implanted in 12 (11%) cases and adjunctive coiling was performed in 15 (14%) cases. Microemboli were detected in 11.4% of cases (12/105 patients) after PED deployment. In 5/12 patients, the emboli resolved upon repeat testing with no intervention. In 6/12 patients, further heparinization, additional clopidogrel administration, or change in antiplatelet agents were needed. These treatments reduced the microembolic events. In 1 patient who was clopidogrel‐resistant and a ticagrelor super‐responder, mechanical thrombectomy was necessary due to acute in‐stent thrombosis. There were no symptomatic strokes at 2 and 12 weeks. Conclusions TCD emboli monitoring can be a powerful non‐invasive tool for the early identification and prevention of thromboembolic events after FD implantation. Early detection of microembolic signals offers the possibility to modify postoperative management, avoid silent emboli, and potentially avoid symptomatic strokes

Abstract Number ‐ 45: Curative Embolization for Pediatric Low‐Grade Brain Arteriovenous Malformations

Introduction Improvements in the safety and efficacy of curative embolization for brain arteriovenous malformations (bAVMs) have allowed to achieve comparable results to microsurgical resection and radiosurgery, especially for low‐grade bAVMs (Spetzler Martin [SM] grade I and II). However, whether this treatment modality is beneficial in the pediatric population remains unknown. Hence, we assessed the safety and efficacy of curative embolization for low‐grade bAVMs in children. In addition, we determined predictors of intraprocedural complications and predictors of complete occlusion in one embolization session. Methods Between 2010 and 2022, a retrospective analysis of all pediatric (≤18 years) patients who underwent curative embolization for low‐grade bAVMs was conducted at two institutions. Demographic data, clinical presentation, SM grade, and procedural characteristics were retrieved. The safety (intraprocedural complications and mortality) and efficacy (complete angiographic obliteration after the last embolization session) were evaluated. Multivariable logistic regression analysis was performed to identify potential predictive factors of intraprocedural complications and complete occlusion in one session. For selected variables, odds ratios (OR) with 95% confidence intervals (CI) and p value of the likelihood‐ratio test were presented. Results Sixty‐eight patients (41 females; mean age 12.9 ± 3.6 years) underwent a total of 102 embolization sessions. Fifty‐one bAVMs (75%) presented ruptured, and headache was the most common clinical presentation (50%). There were 24 (35%) SM grade I lesions and 44 (65%) grade II. Onyx was the most used embolic agent (33%) and the transarterial approach was the most common (93%). The mean volume of embolic agents in each patient was 2.4 ml (range 0.2 to 7.5 ml). Fourteen intraprocedural complications (14% of procedures) were observed and no deaths were reported. The most common complication was microcatheter‐related vessel perforation (6%). Single venous drainage decreased the risk of intraprocedural complications (OR = 0.19; 95% CI 0.04 – 0.78). Complete angiographic obliteration was achieved in 44 patients (65%). In 35 patients (52%) the bAVM was occluded with a single session. A small bAVM size was predictor of complete occlusion in one session (OR = 0.42; 95% CI 0.21 – 0.73). Conclusions Curative embolization in pediatric low‐grade bAVMs can be performed with an acceptable complete occlusion rate but with a high rate of intraprocedural complications. The risk of intraprocedural complications was low in bAVMs with a single venous drainage. The odds of complete occlusion in one session are high in small bAVMs. Curative embolization should be selected on an individual basis in order to achieve optimal results

Abstract Number ‐ 210: Curative Embolization of Ruptured Pediatric Cerebral Arteriovenous Malformations

Introduction The incidence of ruptured cerebral arteriovenous malformations (AVMs) has increased as a consequence of the publication of the ARUBA trial. In the setting of ruptured AVMs, target embolization of high‐risk features can be considered to decrease the risk for recurrent hemorrhage. However, embolization with the intention to cure has not been well studied in ruptured AVMs. Furthermore, the role of primary curative embolization of pediatric AVMs is uncertain. Hence, we aimed to characterize the safety and efficacy of curative embolization for ruptured AVMs in pediatric patients. Methods Between 2010 and 2022, a retrospective analysis of all pediatric (≤18 years) patients who underwent curative embolization for ruptured AVMs was conducted in two institutions. Demographic data, clinical presentation, Spetzler‐Martin (SM) grade, associated high‐risk vascular structures, and procedural characteristics were retrieved. The safety (intraprocedural complications and mortality) and efficacy (complete angiographic obliteration after the last embolization session) were evaluated. Results Sixty‐eight patients (38 females; mean age 12.4 ± 3.4 years) underwent a total of 109 embolization sessions. The most frequent clinical presentation was headache (79%). There were 15 (22%) SM grade I lesions, 34 (51%) grade II, 14 (21%) grade III, and 4 (6%) grade IV. In 21 patients, twenty‐three high‐risk structures were observed (3 prenidal aneurysms, 12 intranidal aneurysms, 3 venous aneurysms, 2 varicose veins, 3 arteriovenous fistulae). Decompressive craniectomy with intracerebral hemorrhage evacuation was performed in 15 patients (22%). The mean number of sessions per patient was 1.6 (range 1 to 6) and n‐butyl cyanoacrylate was the most used embolic agent (30%). The transarterial approach was the most common (91%). The mean volume of embolic agents in each patient was 2.1 ml (range 0.1 to 6 ml). Seventeen intraprocedural complications (16% of procedures) were observed and no deaths were reported. In patients with high‐risk structures the rate of intraprocedural complications was 24%. The most common complication was microcatheter‐related vessel perforation (7%). Complete angiographic obliteration was achieved in 42 patients (62%). In 30 patients (44%) the AVM was occluded with a single embolization session. The rate of complete obliteration in patients with high‐risk structures was 62%. Conclusions Curative embolization of ruptured pediatric AVMs shows a high rate of intraprocedural complications, especially when high‐risk associated vascular structures are present. In addition, acceptable complete obliteration rates were found. Appropriate long‐term follow‐up in prospective studies tailored to the pediatric population are required to determine the best therapeutic approach

Surgical management of craniospinal axis malignant peripheral nerve sheath tumors: a single-institution experience and literature review

Abstract Background Malignant peripheral nerve sheath tumor (MPNST) is an exceedingly rare and aggressive tumor, with limited literature on its management. Herein, we present our series of surgically managed craniospinal MPNSTs, analyze their outcomes, and review the literature. Methods We retrospectively reviewed surgically managed primary craniospinal MPNSTs treated at our institution between January 2005 and May 2023. Patient demographics, tumor features, and treatment outcomes were assessed. Neurological function was quantified using the Frankel grade and Karnofsky performance scores. Descriptive statistics, rank-sum tests, and Kaplan–Meier survival analyses were performed. Results Eight patients satisfied the inclusion criteria (4 male, 4 female). The median age at presentation was 38 years (range 15–67). Most tumors were localized to the spine (75%), and 3 patients had neurofibromatosis type 1. The most common presenting symptoms were paresthesia (50%) and visual changes (13%). The median tumor size was 3 cm, and most tumors were oval-shaped (50%) with well-defined borders (75%). Six tumors were high grade (75%), and gross total resection was achieved in 5 patients, with subtotal resection in the remaining 3 patients. Postoperative radiotherapy and chemotherapy were performed in 6 (75%) and 4 (50%) cases, respectively. Local recurrence occurred in 5 (63%) cases, and distant metastases occurred in 2 (25%). The median overall survival was 26.7 months. Five (63%) patients died due to recurrence. Conclusions Primary craniospinal MPNSTs are rare and have an aggressive clinical course. Early diagnosis and treatment are essential for managing these tumors. In this single-center study with a small cohort, maximal resection, low-grade pathology, young age (< 30), and adjuvant radiotherapy were associated with improved survival

Embolization as stand-alone strategy for pediatric low-grade brain arteriovenous malformations.

OBJECTIVES: We evaluated the safety and efficacy of endovascular embolization as first-line stand-alone strategy for the treatment of low-grade brain arteriovenous malformations (bAVMs) (Spetzler Martin [SM] grade I and II) in pediatric patients. In addition, we assessed the predictors of procedure-related complications and radiographic complete obliteration in a single session. MATERIAL AND METHODS: We conducted a single center retrospective cohort study of all pediatric (≤18 years) patients who underwent embolization as a stand-alone strategy for low-grade bAVMs between 2010 and 2022. Safety was measured by procedure-related complications and mortality. Efficacy was defined as complete angiographic obliteration after the last embolization session. RESULTS: Sixty-eight patients (41 females; median age 14 years) underwent a total of 102 embolization sessions. There were 24 (35%) SM grade I lesions and 44 (65%) grade II. Six procedure-related complications (5.8% of procedures) were observed and no deaths were reported. All the complications were intraoperative nidus ruptures. A single draining vein was the only significant predictor of procedure-related complications (OR=0.10; 95% CI 0.01 - 0.72; p=0.048). Complete angiographic obliteration was achieved in 44 patients (65%). In 35 patients (51%) the bAVM was completely occluded in one session. The bAVM nidal size was a predictor of complete obliteration in one session (OR=0.44; 95% CI, 0.21-0.80; p=0.017). CONCLUSION: Endovascular treatment as a stand-alone strategy for pediatric low-grade bAVMs is an adequate first-line approach in high volume centers with endovascular expertise. Nidal size evaluation is relevant in order to optimize patient selection for embolization as a stand-alone treatment modality