Comparison of Thromboembolic Events Between Pipeline Embolization Device (PED) Shield and PED/PED Flex: A Propensity Score-Matched Analysis.

BACKGROUND AND OBJECTIVES: The pipeline embolization device (PED) Flex with Shield technology is a third-generation flow diverter used for intracranial aneurysm treatment designed to decrease thrombogenicity through a phosphorylcholine coating. Herein, we aim to compare the rate of thromboembolic events in PED with Shield technology and PED without it through propensity score matching. METHODS: We conducted a retrospective analysis of aneurysms treated with PED first-generation/PED Flex and PED with Shield between 2013 and 2023 at a single academic institution. Patients were matched through propensity score by controlling for confounding factors including age, smoking history, diabetes, previous subarachnoid hemorrhage, modified Rankin Scale pretreatment, location, aneurysm size, previous treatment, and clopidogrel or aspirin resistance. After matching, we evaluated for periprocedural and postoperative thromboembolic events. Data analysis was performed using Stata 14. RESULTS: A total of 543 patients with 707 aneurysms treated in 605 procedures were included in the analysis. From these, 156 aneurysms were treated with PED with Shield (22.07%) and 551 (77.93%) without Shield technology. Propensity score matching resulted in 84 matched pairs. The rate of thromboembolic events was 3.57% for PED Shield and 10.71% for PED first-generation/PED Flex (P = .07), while retreatment rates were 2.38% for PED Shield and 8.32% for PED Flex (P = .09). Complete occlusion at first (P = .41) and last imaging follow-up (P = .71), in-stent stenosis (P = .95), hemorrhagic complications (P = .31), and functional outcomes (P = .66) were comparable for both groups. CONCLUSION: This is the first study in the literature performing a propensity scored-matched analysis comparing PED with PED with Shield technology. Our study suggests a trend toward lower thromboembolic events for PED Shield, even after controlling for aspirin and clopidogrel resistance, and a trend toward lower aneurysm retreatment rates with PED Shield, without reaching statistical significance.

Cerebral artery overexpression of the NMUR1 gene is associated with moyamoya disease: a weighted gene co-expression network analysis.

INTRODUCTION: This study aimed to elucidate mechanisms underlying moyamoya disease (MMD) pathogenesis and to identify potential novel biomarkers. We utilized gene coexpression networks to identify hub genes associated with the disease. METHODS: Twenty-one middle cerebral artery (MCA) samples from MMD patients and 11 MCA control samples were obtained from the Gene Expression Omnibus (GEO) dataset, GSE189993. To discover functional pathways and potential biomarkers, weighted gene coexpression network analysis (WGCNA) was employed. The hub genes identified were re-assessed through differential gene expression analysis (DGEA) via DESeq2 for further reliability verification. An additional 4 samples from the superficial temporal arteries (STA) from MMD patients were obtained from GSE141025 and a subgroup analysis stratified by arterial type (MCA vs. STA) DGEA was performed to assess if the hub genes associated with MMD are expressed significantly greater on the affected arteries compared to healthy ones in MMD. RESULTS: WGCNA revealed a predominant module encompassing 139 hub genes, predominantly associated with the neuroactive ligand-receptor interaction (NLRI) pathway. Of those, 17 genes were validated as significantly differentially expressed. Neuromedin U receptor 1 (NMUR1) and thyrotropin-releasing hormone (TRH) were 2 out of the 17 hub genes involved in the NLRI pathway (log fold change [logFC]: 1.150, p = 0.00028; logFC: 1.146, p = 0.00115, respectively). MMD-only subgroup analysis stratified by location showed that NMUR1 is significantly overexpressed in the MCA compared to the STA (logFC: 1.962; p = 0.00053) which further suggests its possible localized involvement in the progressive stenosis seen in the cerebral arteries in MMD. CONCLUSION: This is the first study to have performed WGCNA on samples directly affected by MMD. NMUR1 expression is well known to induce localized arterial smooth muscle constriction and recently, type 2 inflammation which can predispose to arterial stenosis potentially advancing the symptoms and progression of MMD. Further validation and functional studies are necessary to understand the precise role of NMUR1 upregulation in MMD and its potential implications.

Management of Intracranial Aneurysms that Do Not Occlude on Initial Follow-up After Treatment With the Pipeline Embolization Device.

BACKGROUND AND OBJECTIVES: The pipeline embolization device (PED) has become widely accepted as a safe and efficacious treatment for intracranial aneurysms with high rates of complete occlusion at initial follow-up. For aneurysms that are not completely occluded at initial follow-up, further treatment decision-making is varied. Furthermore, the risk of aneurysmal rupture in these incompletely occluded aneurysms after PED is not known. The objective of this study was to determine treatment decision-making that results in increased occlusion status at final follow-up and to evaluate risk of rupture in those aneurysms that do not go onto occlusion. METHODS: This study is a retrospective review of prospective data for intracranial aneurysms treated with PED at two institutions from 2013 to 2019. Aneurysms with near-complete or incomplete occlusion at initial follow-up were included in the statistical analysis. RESULTS: There were 606 total aneurysms treated at two academic institutions with PED with incomplete occlusion at initial follow-up in 134 aneurysms (22.1%). Of the 134 aneurysms that were nonoccluded at initial follow-up, 76 aneurysms (56.7%) went on to complete or near complete occlusion with final complete or near complete occlusion in 90.4% of all aneurysms treated. The time to final imaging follow-up was 28.2 months (13.8-44.3) Retreatment with a second flow diverter was used in 28 aneurysms (20.9%). No aneurysms that were incompletely occluded at initial follow-up had delayed rupture. Furthermore, older patient age was statistically significant for incomplete occlusion at initial follow-up ( P = .05). CONCLUSION: Intracranial aneurysms treated with the PED that do not occlude at initial follow-up may go on to complete occlusion with continuous observation, alteration in antiplatelet regimens, or repeat treatment. Delayed aneurysmal rupture was not seen in patients with incomplete occlusion.

Flow Diversion for the Treatment of Posterior Inferior Cerebellar Aneurysms: A Novel Classification of Posterior Inferior Cerebellar Artery Origin.

BACKGROUND AND OBJECTIVES: Flow diversion (FD) for posterior circulation aneurysms, such as proximal posterior inferior cerebellar artery (PICA) aneurysms, remains "off-label" and controversial. Although there are reports of using FD in the vertebral artery (VA) to treat PICA aneurysms, the differences between structural PICA-origin variants have not been explored. We analyzed PICA aneurysms treated with FD, assessed radiographic and clinical outcomes, and presented a novel classification of the PICA origin in relationship to aneurysm anatomy. METHODS: We performed a retrospective study of prospective data for intracranial aneurysms treated with FD at a major academic institution from 2013 to 2022. Proximal PICA aneurysms that underwent FD placement in the V4 segment of the vertebral artery were included for analysis. A literature review was performed on PubMed to evaluate previously published cases. The PICA origin was characterized by 4 distinct subtypes. Type 1 describes the PICA originating adjacent/separate to the aneurysm neck, Type 2 with the PICA originating from the aneurysm neck, Type 3 with the PICA originating from the aneurysm dome, and Type 4 (True PICA aneurysm) with the aneurysm located proximally on PICA, distal to the PICA-VA junction. RESULTS: Thirteen proximal PICA aneurysms were identified and included in the analysis. Patients were primarily female (76.9%), with a median age of 62 years. The aneurysm median maximum diameter was 5.8 mm. From the total sample (institutional and literature review cases), type 1 had a 100% complete and near-complete occlusion rate, type 2 had 75.0%, type 3 had 88.9%, and type 4 had 75%. The overall complete and near-complete occlusion rate was 83.3% (20/24). CONCLUSION: FD in the V4 VA segment is an effective way to treat proximal PICA aneurysms. Exploring the relationship between PICA origin is a helpful method in predicting occlusion rates for proximal PICA aneurysms and may lead to improved treatment considerations.

Acute Coiling With Delayed Flow Diversion for Posterior Communicating Segment Internal Carotid Artery Aneurysms: A Multicenter Case Series.

BACKGROUND AND OBJECTIVES: In ruptured posterior communicating artery (PcomA) aneurysms, the protection of the aneurysm dome alone with initial subtotal coiling decreases the risk of rerupture in the acute setting but does not provide durable/definitive long-term protection against delayed rupture. Delayed flow diverter (FD) placement can be a potential alternative to definitively secure these aneurysms without increasing the risk of complications and PComA occlusion. We analyzed PComA aneurysms treated with a planned delayed FD after primary coiling and assess radiographic and clinical outcomes. METHODS: We performed a retrospective study of prospectively collected data for intracranial aneurysms treated with planned FD at 2 institutions from 2013 to 2022. PComA aneurysms that underwent primary coiling and delayed FD placement were included for analysis. RESULTS: There were 29 PComA aneurysms identified that were included in the analysis. Patients were mostly female (79.3%), with a median age of 60 years. The mean aneurysm maximum diameter was 7.2 mm ± (5.3). Immediate Raymond-Roy occlusion grade after primary coiling was I in 48.3%, II in 41.4%, and III in 10.3% of aneurysms. The median time from initial coiling to planned delayed FD placement was 6.3 months (3.2-18.6). A total of 21 (72.4%) aneurysms underwent follow-up radiological imaging. Complete and near-complete occlusion status was achieved in 76.2% of the evaluated aneurysms. There were no retreatments and no evidence of delayed aneurysm rupture. One case (3.5%) presented thromboembolic complications and 1 (3.5%) intracranial hemorrhagic complication after FD placement, which was associated with mortality. Most patients (90.5%) had a modified Rankin scale of ≤2 on the last follow-up. CONCLUSION: Primary coiling with planned staged FD placement is effective for treating ruptured PComA aneurysms with high occlusion rates and low complications.

Surgery in octogenarians with intracranial meningiomas improves functional outcome at 1 year.

PURPOSE: The population is aging, and age remains an important factor in deciding surgical candidacy for intracranial tumors. The natural history and surgical behavior of meningiomas in octogenarians are not well understood. We evaluated the surgical and functional outcomes, including survival, among octogenarians with intracranial meningiomas in a single institution. METHODS: The Tumor Registry (2004-2021) was used to identify octogenarian patients (ages 80-89) diagnosed with intracranial meningioma. Primary endpoints were 1-year survival and functional outcome measured with mRS postsurgery. Kaplan-Meier, univariable Log-rank tests, and multivariable Cox hazards proportional regression models were used for assessing factors associated with overall survival (OS) in octogenarians with meningiomas who underwent surgery; logistic regression and McNemar's were used to further characterize risk factors affecting functional surgical outcome at 1 year. RESULTS: Thirty octogenarians with intracranial meningioma who underwent surgery were identified. Median age was 82.5 years and 66.6% were female patients. The 1-year median postsurgical survival probability for all octogenarians with meningioma was 86.3% and no intraoperative mortality was observed. Frailty (mFI-5, p = 0.84), tumor grade (p = 0.11), tumor size (p = 0.22), extent of resection (p = 0.35), and Karnofsky scale on admission (p = 0.93) did not significantly affect the survival in octogenarians with meningiomas which were treated surgically. The 1-year postoperative functional status of octogenarian meningioma patients who underwent surgery was significantly improved compared to pre-op mRS (McNemar's chi-squared = 9.6, df = 1, p-value = 0.001946). CONCLUSION: In octogenarians with meningiomas, surgical intervention significantly improves the pre-operative modified Rankin Scale at 1 year postsurgery in this cohort.

Octogenarian Brain Tumor Registry: Single-Institution Surgical Outcomes and Mortality Study.

BACKGROUND: Surgical intervention for brain tumor patients aged 80 to 89 years is controversial, as the comorbidities and physiology associated with aging are often thought to increase surgical risks. Surgical outcomes, however, are not well characterized for octogenarians. This review therefore assessed the outcomes and mortality risk associated with tumor removal in octogenarians at our academic institution. METHODS: Retrospective review of patients aged 80 to 89 who underwent craniotomy for tumor resection (CTR) at our institution between 2004-2021 and who were diagnosed with meningioma, glioblastoma, or metastatic disease. Primary outcome was 30-day mortality. RESULTS: Sixty-one CTRs were included in analysis. Median age was 83 (interquartile range 81-85) years, and the most common preoperative comorbidity was hypertension (n=44). Most patients (n=35) had a preoperative modified Rankin Scale (mRS) score between 0-2. Seventeen (27.9%) patients experienced postoperative complications (i.e., urinary tract infection, deep venous thrombosis, etc.), and 26.2% (n=16) experienced new-onset neurologic deficits postoperatively (i.e., aphasia, motor deficits, etc.). Upon discharge, most patients (n=43) had an mRS score of 3-4. Within 30 days of surgery, 14.8% (n=9) of patients were readmitted to the hospital and 8.2% (n=5) of patients died: 2 with meningioma, 1 with glioblastoma, and 2 with metastatic disease. The most common cause of death was intracranial hemorrhage (n=3). Three-month mortality was 23.0% (n=14). Mean survival after surgery was 33 months for meningioma patients, 6.9 months for glioblastoma patients, and 15 months for patients with metastatic lesions. CONCLUSION: Our review found a 30-day mortality rate of 8.2% across all tumor types, and mean survival was similar to that previously reported for patients across all age groups. Surgical intervention for octogenarian tumor patients is therefore feasible, safe, and likely worthwhile for extending and improving lives.

Predictors of extended length of stay related to craniotomy for tumor resection.

Background: Hospital length of stay (LOS) related to craniotomy for tumor resection (CTR) is a marker of neurosurgical quality of care. Limiting LOS benefits both patients and hospitals. This study examined which factors contribute to extended LOS (eLOS) at our academic center. Methods: Retrospective medical record review of 139 consecutive CTRs performed between July 2020 and July 2021. Univariate and multivariable analyses determined which factors were associated with an eLOS (≥8 days). Results: Median LOS was 6 days (IQR 3-9 days). Fifty-one subjects (36.7%) experienced an eLOS. Upon univariate analysis, potentially modifiable factors associated with eLOS included days to occupational therapy (OT), physical therapy (PT), and case management clearance (p < .001); and discharge disposition (p < .001). Multivariable analysis revealed that pre-operative anti-coagulant use (OR 10.74, 95% CI 2.64-43.63, p = .001), Medicare (OR 4.80, 95% CI 1.07-21.52, p = .04), ED admission (OR 26.21, 95% CI 5.17-132.99, p < .001), transfer to another service post-surgery (OR 30.00, 95% CI 1.56-577.35, p = .02), and time to post-operative imaging (OR 2.91, 95% CI 1.27-6.65, p = .01) were associated with eLOS. Extended LOS was not significantly associated with ED visits (p = .45) or unplanned readmissions within 30 days of surgery (p = .35), and both (p = .04; p = .04) were less likely following a short LOS (<5 days). Conclusion: While some factors driving LOS related to CTR are uncontrollable, expedient pre- and post-operative management may reduce LOS without compromising care.

Flow diversion: a disruptive technology coming of age. Lessons learned and challenges for the future.

Intracranial aneurysm treatment has been revolutionized over the last decade with the development of flow diversion technology. The use of this technology has evolved rapidly and has proven that cerebrovascular disease treatment remains one of the forefront innovation areas in neurosurgery. The good results on the treatment of internal carotid artery aneurysms up to the communicating segment have motivated the use of flow diversion beyond the circle of Willis and in the posterior circulation. Further advances and innovations of flow-diverting devices are underway and intended to improve the safety and efficacy of this therapy. This review article provides a detailed discussion about the origin, mechanism of action, initial experience, complications, types of devices, and future perspectives of flow diversion technology.

Unruptured Intradural Posterior Circulation Dissecting/Fusiform Aneurysms Natural History and Treatment Outcome.

BACKGROUND: The natural history and outcome of unruptured posterior circulation dissecting fusiform aneurysms is not fully understood. These have a high risk of morbidity and mortality, not only due to natural history but also due to the challenging and controversial treatment approaches currently available compared to other types of intracranial aneurysms. METHODS: We performed a retrospective study of a prospectively collected aneurysm database at a quaternary neurovascular hospital. We included consecutive patients with unruptured intradural vertebrobasilar dissecting aneurysms between January 2000 and July 2016 who were followed to 2020. Description of baseline, procedural, and outcomes data was performed. Comparisons of patient who had aneurysm rupture on follow-up, increase in 2 or more points of mRS in follow-up and progression of the aneurysm was performed. RESULTS: Seventy patients with 78 fusiform posterior circulation aneurysms were identified. Thirty-nine (55.7%) patients were male with a mean age of 51.7 years (SD ± 17.6). When multiple, aneurysms were more likely to be fusiform (60%) than saccular (40.0%). Baseline diameter (measured on CTA/MRA/DSA), length as well as symptomatic presentation were significantly higher in aneurysms which grew over time. Coronary disease, diabetes and growth were associated an >2 increase in mRS. Diabetes as well as initial symptomatic presentation were associated with rupture. CONCLUSIONS: Unruptured dissecting/fusiform aneurysm are associated with a considerable rate of rupture during follow-up. Growth is associated with morbidity even in the absence of rupture. Initial large size, coronary disease, diabetes, and to a lesser extent female gender may merit closer follow-up and/or prophylactic treatment.

Cerebrospinal Fluid Shunting for Idiopathic Intracranial Hypertension: A Systematic Review, Meta-Analysis, and Implications for a Modern Management Protocol.

BACKGROUND: Cerebrospinal fluid (CSF) shunting is widely used in refractory idiopathic intracranial hypotension (IIH). Although multiple reviews have assessed its efficacy compared with other surgical treatments, there is no detailed analysis that evaluates the clinical outcomes after CSF shunting. OBJECTIVE: To conduct a meta-analysis of the clinical impact of CSF shunting for refractory IIH and use this in conjunction with existing information on other treatment modalities to develop a modern management protocol. METHODS: PubMed and Embase were systematically searched for studies describing CSF shunting for medically refractory IIH. Relevant information including study characteristics, patient demographics, clinical outcomes, periprocedural complications, and long-term outcomes were subjected to meta-analysis. RESULTS: Fifteen studies published between 1988 and 2019 met our inclusion and exclusion criteria, providing 372 patients for analysis. The mean age was 31.2 years (range 0.5-71) with 83.6% being female. The average follow-up was 33.9 months (range 0-278 months). The overall rate of improvement in headache, papilledema, and visual impairment was 91% (95% CI 84%-97%), 96% (95% CI 85%-100%), and 85% (95% CI 72%-95%), respectively. Of 372 patients, 155 had 436 revisions; the overall revision rate was 42% (95% CI 26%-59%). There was no significant correlation between average follow-up duration and revision rates in studies ( P = .627). Periprocedural low-pressure headaches were noted in 74 patients (20%; 95% CI 11%-32%). CONCLUSION: CSF shunting for IIH is associated with significant improvement in clinical symptoms. Shunting rarely causes periprocedural complications except overdrainage-related low-pressure headache. However, CSF shunting has a relatively high revision rate.

Middle Meningeal Artery Embolization with Isolated Use of Coils for Treatment of Chronic Subdural Hematomas: A Case Series.

BACKGROUND: Middle meningeal artery embolization (MMAE) is a novel approach for treatment of chronic subdural hematoma (cSDH). Studies comparing different procedural techniques for MMAE are lacking. It is unclear whether isolated use of coils results in suboptimal outcomes compared to when particle embolization is also performed. The objectives of this study are to describe the outcomes of coil-only MMAE and compare them with those of combined use of coils and particles. METHODS: A single-institution retrospective study of cSDH cases treated by MMAE was performed. Clinical outcomes, need for rescue surgery, and changes in hematoma's size were compared between the coil-only and coil + particle groups. RESULTS: Ninety-four hematomas in 78 patients were included. Twelve cases were treated by a coil-only MMAE procedure, often due to presence of dangerous ophthalmic collaterals. No treatment-related complications were observed in the coil-only group. There was no significant difference between the coil-only and coil + particle groups in baseline hematoma axial thickness, volume, midline shift, and duration of follow-up. The rate of need for rescue surgery was similar between the 2 groups (8.3% vs. 8.5%; P = 0.98). Coiling alone resulted in a similar percentage of reduction in cSDH volume (68.3% vs. 71.8%; P = 0.8) and rate of achieving ≥50% reduction in volume (81.8% vs. 76.3%; P = 0.68) compared to coils + particles. CONCLUSIONS: Isolated use of coils for endovascular treatment of cSDHs can be as effective as adjunct use of particle embolization. This method eliminates the risks of cranial nerve and visual complications associated with MMAE, can prevent procedural abortion due to presence of dangerous anastomoses, and reduces the technical complexity of the procedure.

Safety and Efficacy of the Off-Label Use of Pipeline Embolization Device Based on the 2018 Food and Drug Administration-Approved Indications for Intracranial Aneurysms: A Single-Center Retrospective Cohort Study.

BACKGROUND: The pipeline embolization device (PED; ev3/Covidien) has proven safe and effective for treating selected intracranial aneurysms. This device's versatility and popularity have driven increased interest in expanding the latest 2018 Food and Drug Administration-approved indications. OBJECTIVE: To compare "off-label" and "on-label" PED treatment. METHODS: Retrospective analysis of aneurysms treated with PED at a single center from 2013 to 2019. Comparisons were made based on the 2018 Food and Drug Administration-approved indications. RESULTS: A total of 492 treated aneurysms were included (65.2% on-label and 34.8% off-label). Aneurysm complete and near-complete occlusion rate was nonsignificantly lower in the off-label group (80.9% vs 85.7%; P = .19). Off-label treatment had higher rate of poor functional outcomes (modified Rankin Scale [mRS] >2: 10.3% vs 3.5%; P = .002). Although pretreatment mRS was already higher in the off-label group (5.3% vs 0.3%; P < .001) and there were no differences in mRS worsening during follow-up (5.5% vs 2.9%; P = .15). We also found a trend to a higher rate of intracranial hemorrhagic complications in the off-label group (4.7% vs 1.6%; P = .05), but there were no differences in hemorrhages requiring surgical intervention (1.8% vs 1.3%; P = .65). There were no differences in retreatment, thromboembolic complications, and mortality rates. CONCLUSION: Off-label PED treatment may be considered for select aneurysms, which are challenging to treat with other techniques. These cases have similar complete and near-complete occlusion rates compared with on-label cases. There are, however, higher risks of poor functional outcomes despite similar rates of thromboembolic and hemorrhagic complications. This is partly explained by the significantly higher pretreatment mRS score in the off-label group.

Effect of cerebrospinal fluid drainage on clinical outcomes following aneurysmal subarachnoid hemorrhage.

OBJECTIVES: We study the relationship between external ventricular drainage (EVD) of cerebrospinal fluid output and functional outcomes in patients with aneurysmal subarachnoid hemorrhage (aSAH). METHODS: A retrospective chart review of patients presenting to a single center with aSAH was performed. The primary outcome was good functional outcomes assessed by a composite of the modified Rankin scale (mRS 0-2) at last follow-up. Secondary outcomes were clinical and radiographic vasospasm. For data analysis, multivariable generalized estimating equations adjusting for potential confounders were used. RESULTS: A total of 119 patients were included; 91 (75.6%) presented with a modified Fisher grade 4 and 76 (63.9%) had hydrocephalus. The median EVD duration was 13 days. On average, most EVDs were set at 15 cmH2O (50, 42%). Follow-up was available in 109 patients; median time was 10.7 months; 69 (63.3%) had good outcomes. Multivariable analysis showed that EVDs set at 10 cmH2O had increased odds of good outcomes for every ml increase in the EVD output (OR = 1.02; 95% CI 1.01-1.03; p = 0.001). Post estimation analyses show that EVDs at 10 cmH2O with output close to 200 ml predicted a 50% probability of good outcomes. CONCLUSIONS: Increased EVD outputs were associated with favorable outcomes at the last follow-up.

Middle meningeal artery embolization for treatment of chronic subdural hematomas: does selection of embolized branches affect outcomes?

OBJECTIVE: Middle meningeal artery (MMA) embolization (MMAE) is a new therapeutic modality for chronic subdural hematoma (cSDH). There is limited evidence comparing various MMAE procedural techniques, resulting in significant variations in technique and procedural planning. The objective of this study was to compare outcomes of MMAE by the number and location of MMA branches that were embolized. METHODS: A single-center retrospective study of patients with cSDH treated by MMAE was conducted. Clinical outcomes, need for re-intervention, and changes in hematoma size were compared between different MMAE techniques. RESULTS: Ninety-four cSDHs in 78 patients were included. Embolization of the proximal trunk only, distal branches only, or proximal trunk plus distal branches resulted in similar rates of need for rescue surgery (7.4%, 13.0%, and 6.8%, respectively; p = 0.66) and rates of reducing the volume of the hematoma by at least 50% (74.1%, 80.0%, and 77.5%, respectively; p = 0.88). Embolization of only one branch had similar outcomes to embolization of more than one branch, as rescue surgery rates were 9.3% and 7.8% (p = 0.80), and rates ≥ 50% volume reduction were 75.6% and 78.3% (p = 0.76), respectively. Selective embolization of the dominant MMA branch was not associated with significantly different outcomes. CONCLUSIONS: Outcomes of distal, proximal, or combined proximal and distal MMAE in cSDH are not significantly different. Embolization of more than one branch is not associated with improved treatment efficacy. Arguably, targeting any location in the MMA provides sufficient flow restriction to enable spontaneous hematoma resolution. Accordingly, a technical planning algorithm for cSDH MMAE is suggested.