Intracranial Vascular Malformations Research Articles

Pediatric Cerebral Vascular Malformations : Current and Future Perspectives.

Intracranial vascular malformations typically encountered by pediatric neurosurgeons include arteriovenous malformations, vein of Galen malformations and cavernous malformations. While these remain amongst some of the most challenging lesions faced by patients and caregivers, the past decade has produced marked advances in the understanding of the pathophysiology of these conditions, with concomitant innovations in treatment. This article will highlight present and future perspectives relevant to these diseases, with a focus on an emerging approach utilizing disease-specific mutations to develop a novel taxonomy for these conditions.

Congenital Intracranial Vascular Malformations in Children : Radiological Overview.

Prompt medical attention is crucial for congenital intracranial vascular malformations in children and newborns due to potential severe outcomes. Imaging is pivotal for accurate identification, given the diverse risks and treatment strategies. This article aims to enhance the identification and understanding of congenital intracranial vascular abnormalities including arteriovenous malformation, arteriovenous fistula, cavernous malformation, capillary telangiectasia, developmental venous anomaly, and sinus pericranii in pediatric patients.

Addressing barriers and identifying facilitators to support informed consent and recruitment in the Cavernous malformations A Randomised Effectiveness (CARE) pilot phase trial: insights from the integrated QuinteT recruitment intervention (QRI)

It was anticipated that recruitment to the Cavernous malformations: A Randomised Effectiveness (CARE) pilot randomised trial would be challenging. The trial compared medical management and surgery (neurosurgical resection or stereotactic radiosurgery) with medical management alone, for people with symptomatic cerebral cavernous malformation (ISRCTN41647111). Previous trials comparing surgical and medical management for intracranial vascular malformations failed to recruit to target. A QuinteT Recruitment Intervention was integrated during trial accrual, September 2021-April 2023 inclusive, to improve informed consent and recruitment. The QuinteT Recruitment Intervention combined iterative collection and analysis of quantitative data (28 trial site screening logs recording numbers/proportions screened, eligible, approached and randomised) and qualitative data (79 audio-recorded recruitment discussions, 19 interviews with healthcare professionals, 11 interviews with patients, 2 investigator workshops, and observations of study meetings, all subject to thematic, content or conversation analysis). We triangulated quantitative and qualitative data to identify barriers and facilitators to recruitment and how and why these arose. Working with the chief investigators and trial management group, we addressed barriers and facilitators with corresponding actions to improve informed consent and recruitment. Barriers identified included how usual care practices made equipoise challenging, multi-disciplinary teams sometimes overrode recruiter equipoise and logistical issues rendered symptomatic cavernoma diagnosis and assessment for stereotactic radiosurgery challenging. Facilitators identified included the preparedness of some neurosurgeons' to offer surgery to people otherwise offered medical management alone, multi-disciplinary team equipoise, and effective information provision presenting participation as a solution to equipoise regarding management. Actions, before and during recruitment, to improve inclusivity of site screening, approach and effectiveness of information provision resulted in 72 participants recruited following a 5-month extension, exceeding the target of 60 participants. QuinteT Recruitment Intervention insights revealed barriers and facilitators, enabling identification of remedial actions. Recruitment to a definitive trial would benefit from further training/support to encourage clinicians to be comfortable approaching patients to whom medical management is usually offered, and broadening the pool of neurosurgeons and multi-disciplinary team members prepared to offer surgery, particularly stereotactic radiosurgery. National Institute for Health and Care Research.

Perioperative Considerations in Patients with Vein of Galen Malformations Undergoing Embolization–A Single-Institution Case Series

AbstractVein of Galen malformation (VOGM) is a congenital, intracranial vascular malformation, with an extracardiac shunt. Neonates can present with high output cardiac failure, pulmonary hypertension, or multiorgan failure and are at high risk of perioperative complications, especially in remote locations. We conducted a retrospective single-center analysis of the perioperative management of patients with VOGM presenting for embolization. Patients were identified by querying both the hospital billing dataset using International Classification of Diseases-10 diagnosis or billing code and the Neuro-interventional Radiology Database, from January 2011 to March 2020. As many as 14 patients were identified, 12 of which underwent definitive treatment. Six patients who underwent embolization in the neonatal period had pulmonary hypertension. Those children required varying degrees of hemodynamic and respiratory support preoperatively and experienced significant intraoperative events, including one intraoperative cardiac arrest. Caring for these critically ill patients in a remote location requires proper planning to prevent adverse outcomes.

A Rare Case of Pial Arteriovenous Fistula in an Infant – A Case Report

Introduction: Pial arteriovenous fistula (PAVF) is a rare intracranial vascular malformation with diverse clinical presentations. Early diagnosis and intervention are crucial due to its poor natural history. Endovascular treatment has emerged as a preferred option with promising results. Case Report: We report a case of an 8-month-old infant who presented with recurrent focal seizures and acute intraparenchymal hematoma. Further investigation with magnetic resonance angiography and digital subtraction angiography confirmed the presence of a PAVF. Results: Endovascular embolization successfully obliterated the PAVF with no postprocedural complications. Clinical follow-up demonstrated a favorable outcome. Conclusion: This case highlights the significance of early detection through suitable imaging modalities and timely intervention in preventing life-threatening complications associated with PAVFs. Endovascular embolization offers an effective and safe treatment option for pediatric PAVFs, leading to positive outcomes in this rare entity.

Management of sporadic intracranial vascular malformations in pregnancy: a retrospective analysis

BackgroundSporadic intracranial vascular malformations can pose significant risk to parturients, and additional reports of management may inform patient care. Here we describe the peripartum management of parturients with intracranial vascular malformations. MethodsAfter Institutional Review Board approval, we performed a retrospective analysis of parturients with a known sporadic intracranial vascular malformation including cavernous malformation, developmental venous anomaly, or arteriovenous malformation who delivered at our institution between 2007 and 2020. ResultsWe identified 10 parturients (five cavernous malformations, three developmental venous anomalies, and two arteriovenous malformations) with 16 deliveries. Among all deliveries, 13 (81.3%) were cesarean deliveries without trial of labor; 11 of these (84.6%) received a single-shot spinal and two (15.4%) received an epidural for surgical anesthesia. Two deliveries (12.5%) began with attempted trial of labor but ultimately required cesarean delivery for failure to progress; one of these cases received epidural anesthesia and the other received combined spinal-epidural anesthesia. One delivery was via spontaneous vaginal delivery with epidural analgesia. Overall, our study’s cesarean delivery rate was 93.8% and spontaneous vaginal delivery rate was 6.2%.Three of 16 pregnancies were complicated by seizure, obstructive hydrocephalus, or intracranial hemorrhage. There were no intensive care unit admissions or maternal deaths. ConclusionsIn our case series of 16 deliveries, there were no complications directly resulting from neuraxial procedures. It remains unclear whether intracranial developmental venous anomalies or unruptured arteriovenous malformations impart increased risk during pregnancy. Antepartum planning with a multidisciplinary team approach enables risk stratification and optimal management.

Discovery and Characterization of Ephrin B2 and EphB4 Dysregulation and Novel Mutations in Cerebral Cavernous Malformations: In Vitro and Patient-Derived Evidence of Ephrin-Mediated Endothelial Cell Pathophysiology.

Intracranial vascular malformations manifest on a continuum ranging from predominantly arterial to predominantly venous in pathology. Cerebral cavernous malformations (CCMs) are capillary malformations that exist at the midpoint of this continuum. The axon guidance factor Ephrin B2 and its receptor EphB4 are critical regulators of vasculogenesis in the developing central nervous system. Ephrin B2/EphB4 dysregulation has been implicated in the pathogenesis of arterial-derived arteriovenous malformations and vein-based vein of Galen malformations. Increasing evidence supports the hypothesis that aberrant Ephrin B2/EphB4 signaling may contribute to developing vascular malformations, but their role in CCMs remains largely uncharacterized. Evidence of Ephrin dysregulation in CCMs would be important to establish a common link in the pathogenic spectrum of EphrinB2/Ephb4 dysregulation. By studying patient-derived primary CCM endothelial cells (CCMECs), we established that CCMECs are functionally distinct from healthy endothelial cell controls; CCMECs demonstrated altered patterns of migration, motility, and impaired tube formation. In addition to the altered phenotype, the CCMECs also displayed an increased ratio of EphrinB2/EphB4 compared to the healthy endothelial control cells. Furthermore, whole exome sequencing identified mutations in both EphrinB2 and EphB4 in the CCMECs. These findings identify functional alterations in the EphrinB2/EphB4 ratio as a feature linking pathophysiology across the spectrum of arterial, capillary, and venous structural malformations in the central nervous system while revealing a putative therapeutic target.

Surgical Treatment of Cerebral cavernous Malformations: Report of 6 Cases and pertinent Literature review

Cerebral cavernous Malformation (CCM) is a rare neurovascular malformation accounting 0.5% to 4% of all intracranial vascular malformations. People harboring CCM may be symptomatic or may present with seizure, hemorrhage or progressive neurological deficit. Asymptomatic CCM needs no treatment. The symptomatic CCM may or may not require intervention. The best treatment for symptomatic CCM is microsurgical excision. Over a period of five years we have been managing I2 patients with CCM, and out of them 6 patients who were symptomatic required microsurgical excision. Here, we discuss these 6 surgically managed patients and appropriate literature related to CCMs would be reviewed.

Cystic Cerebral Cavernous Malformations: Report of Five Cases and a Review of Literature.

Introduction Cerebral cavernous malformations (CCMs) account for about 5 to 13% of intracranial vascular malformations. Cystic cerebral cavernous malformations (cCCMs) are a rare morphological variant and can cause diagnostic and therapeutic dilemmas. We describe our five such cases and review the existing literature on this entity. Methods A search of the PubMed database for cCCMs was done, and all articles in English emphasizing the reporting of cCCMs were selected. A total of 42 publications describing 52 cases of cCCMs were selected for analysis. Epidemiological data, clinical presentation, imaging features, the extent of resection, and outcome were analyzed. Radiation-induced cCCMs were excluded. We have also described five of our cases of cCCMs and reported our experience. Results The median age at presentation was 29.5 years. Twenty-nine patients had supratentorial lesions, 21 had infratentorial lesions, and 2 had lesions in both compartments. Among our four patients, three had infratentorial lesions, whereas one had a supratentorial lesion. Multiple lesions were seen in four patients. A majority (39) had symptoms of mass effect (75%), and 34 (65.38%) had raised intracranial pressure (ICP), whereas only 11 (21.15%) had seizures. Among our four operated patients, all of them had symptoms of mass effect, and two of them also had features of raised ICP. The extent of resection was gross total in 36 (69.23%), subtotal in 2 (3.85%), and not reported in 14 (26.93%). All four of our operated patients underwent gross total resection, but two of them underwent a second surgery. Of the 48 patients in whom the surgical outcome was reported, 38 improved (73.08%). One showed a transient worsening followed by improvement, one developed a worsening of the pre-existing focal neurological deficit (FND), two developed a new FND, and 5 had no improvement in their FNDs. Death occurred in one patient. All four of our operated patients improved after surgery, although three of them showed a transient worsening of FNDs. One patient is under observation. Conclusion cCCMs are rare morphological variants and can cause considerable diagnostic and therapeutic dilemmas. They should be considered in the differential diagnosis of any atypical cystic intracranial mass lesion. Complete excision is curative, and the outcome is generally favorable; although transient deficits may be seen.

Spontaneous thrombosis of vein of Galen malformation managed with surgical resection: a case‑based review.

Vein of Galen malformation (VOGM) is an exceptionally uncommon form of congenital intracranial vascular malformations. It is highly unusual for this lesion to spontaneously thrombose. The clinical presentation of a patient may range from being asymptomatic to critically ill. The underlying pathophysiological mechanisms that cause spontaneous thrombosis are still poorly understood. The literature on spontaneous thrombosis of VOGM was systematically reviewed, analyzed, and summarized with a focus on its pathophysiology, types, clinical presentations, diagnosis, management, and outcomes. It was also illustrated with a case presentation. The case presents an unusual presentation and location of a VOGM in a 2-year-old boy who was successfully treated with surgical resection. A handful of cases of thrombosed VOGM have been reported worldwide where surgery was used to treat the condition. Low-flow fistulas of the mural type are prone to spontaneous thrombosis, have delayed clinical presentations, and are typically diagnosed in young children. Among the many possible manifestations, hydrocephalus is by far the most common. In the absence of blood flow, MRI is the diagnostic test of choice. Depending on the patient's symptoms, surgery to either remove the aneurysm or divert the cerebrospinal fluid usually results in a good prognosis.

Dural Fistula of the Superior Cerebellar Artery: A Case Report

Dural arteriovenous fistulas are rare intracranial vascular malformations with a propensity for hemorrhage. The Cognard classification system is the most widespread classification system wherein type IIB through V must be promptly treated to avoid the risk of hemorrhage. The case presented herein reports a 65 -year-old male presenting with vague non-hemorrhagic neurologic deficits found to have a Cognard type I right dural superior cerebellar arteriovenous fistula. Although quite obvious in retrospect, a DAVF can be missed even by an astute radiologist. This should be considered a “never miss” diagnosis as it carries a risk of intracranial hemorrhage and death.

Abstract Number ‐ 78: An Unusual Cause Of Progressive Visual Loss – Vein Of Galen Malformation

Introduction Vein of Galen Malformations (VOGM) are rare vascular conditions resulting from anomalous vascular shunts between primitive choroidal vessels and the Markowski Prosencephalic Vein (MPV). They comprise only 1% of all intracranial vascular malformations with a high mortality rate up to 76.7% if untreated. In this case report, we aim to bring awareness of this condition as a cause of progressive visual loss with the objective of making it relevant in our medical community. Methods We discuss the case of a truck driver who progressively and slowly lost his vision as a consequence of a VOGM. Results In this case report we present a 49‐year‐old man with a past medical history of hypertension and renal insufficiency who initially presented to his ophthalmologist for progressive vision loss accompanied by headaches. Bilateral papilledema was seen on examination as well as near complete vision loss on the right eye and 20/40 visual acuity on the left eye. He was referred to neurosurgery for suspicion of elevated intracranial pressure. CT angiogram demonstrated multiple areas of fistualization to the VOGM, including branches from the meningeal hypophyseal divisions, bilateral distal PICA divisions, and the thalamic striate divisions. A multisession endovascular treatment with multiple embolizations was pursued. Initially, the patient underwent a transarterial embolization of the left middle meningeal artery (MMA) and left occipital artery (OA) followed by embolization of the 4 branches of the right MMA. Then, he underwent embolization of 8 large feeding branches and three weeks later, transvenous coiling of the MPV was done. Post‐embolization angiograms showed progressive decrease in the size of the malformation, the degree of the shunt and, and in cortical venous reflux with near normalization of the capillary and venous phases timing in the left and right hemispheres. Although, the patient did not recover from prior visual deficits, his symptoms remained stable. Conclusions It is important to keep this unusual cause of progressive vision loss within the differential diagnosis. The earlier this diagnosis is made, the quicker patients can receive treatment preventing long term deficits, morbidity and mortality.

Radiosurgery for Cerebral Arteriovenous Malformations

Arteriovenous malformations (AVMs) are the most common intracranial vascular malformation that we encounter in our clinical practice. Patients may present with either headaches, seizures, or bleed. There are several classification systems described in literature to aid in management. Most of them look into the size of the nidus and the status of the draining veins. Any nidus which is compact, superficial, and in a surgically safe area are offered surgery. Most of the other AVMs are managed by radiosurgery or embolization either as a single treatment modality or in combination.

NOTCH4 Single-Nucleotide Polymorphism Is Associated with Brain Arteriovenous Malformation in a Chinese Han Population

Introduction: Brain arteriovenous malformations (BAVMs) are high-flow intracranial vascular malformations characterized by the direct connection of arteries to veins without an intervening capillary bed. They are one of the main causes of intracranial hemorrhage and epilepsy, although morbidity is low. Angiogenesis, heredity, inflammation, and arteriovenous malformation syndromes play important roles in BAVM formation. Animal experiments and previous studies have confirmed that NOTCH4 may be associated with BAVM development. Our study identifies a connection between NOTCH4 gene polymorphisms and BAVM in a Chinese Han population. Methods: We enrolled 150 patients with BAVMs confirmed by digital subtraction angiography (DSA) in the Department of Neurosurgery, Zhujiang Hospital, Southern Medical University from June 2017 to July 2019. Simultaneously, 150 patients without cerebrovascular disease were confirmed by computed tomography angiography/magnetic resonance angiography/DSA. DNA was extracted from peripheral blood and NOTCH4 genotypes were identified by PCR-ligase detection reaction. The χ² test or Fisher’s exact test was used to evaluate the differences in allele and genotype frequencies between the BAVM group, control group, bleeding group, and other complications. Results: Two single-nucleotide polymorphisms (SNPs), rs443198 and rs438475, were significantly associated with BAVM. No SNP genotypes were significantly associated with hemorrhage or epilepsy. SNPs rs443198_AA-SNP and rs438475_AA-SNP may be associated with a lower risk of BAVM (p = 0.011, odds ratio (OR) = 0.459, 95% confidence interval (CI): 0.250–0.845; p = 0.033, OR = 0.759, 95% CI: 0.479–1.204). Conclusion: NOTCH4 gene polymorphisms were associated with BAVM and may be a risk factor in a Chinese Han population.

In Response to: Dicpinigaitis AJ, Ogulnick JV, Mayer AS, Gandhi CD, Al‐Mufti F. Increase in Ruptured Cerebral Arteriovenous Malformations and Mortality in the United States: Unintended Consequences of the ARUBA Trial

In Response to: Dicpinigaitis AJ, Ogulnick JV, Mayer AS, Gandhi CD, Al‐Mufti F. Increase in Ruptured Cerebral Arteriovenous Malformations and Mortality in the United States: Unintended Consequences of the ARUBA Trial

Role of Stereotactic Radiosurgery in the Management of Dural AV Fistula.

Dural arteriovenous fistulas (DAVFs) are a relatively rare intracranial vascular malformation. The various treatment options for DAVFs include observation, compression therapy, endovascular therapy, radiosurgery, or surgery. A combination of these therapies may also be used. The treatment choice for DAVFs depends on the type of fistula, the severity of symptoms, DAVF angioarchitecture, and the efficacy and safety of treatments. The use of stereotactic radiosurgery (SRS) in DAVFs started in the late 1970s. There is a delay before the fistula gets obliterated after SRS and there is a risk of hemorrhage from the fistula till the fistula gets obliterated. Initial reports described the role of SRS in small DAVFs without severe symptoms, which were inaccessible by endovascular or surgical measures or in combination with embolization in larger DAVFs. SRS can be appropriate for indirect cavernous sinus DAVF fistulas (Barrow type B, C, and D). Borden types II and III and Cognard types IIb-V DAVFs have a high risk of hemorrhage and are traditionally considered less favorable to be treated with SRS as immediate treatment is required to decrease the risk of hemorrhage. However, recently SRS has been tried in these high-grade DAVF as a monotherapy. Factors that have a positive impact on the obliteration rates of DAVF following SRS are the location of DAVF with the cavernous sinus DAVF having much better obliteration rates than DAVF located at other locations, Borden Type I or Cognard Types III or IV DAVFs, absence of CVD, hemorrhage at the time of initial presentation, and target volume lesser than 1.5 mL.

Arterial approach in vein of Galen aneurysmal malformation: Coils and EVOH

BackgroundThe vein of Galen aneurysmatic malformation VAGM, is a rare intracranial vascular malformation, that represents approximately 1 % of neurovascular malformations and 20–30 % of all pediatric vascular malformations, although it has high rates of morbidity, it can be treated with an endovascular approach, with better results. Material and methodsWe made a retrospective, monocentric study with a total of 4 patients with a diagnostic vein of Galen malformation over a period of 9 years, reviewing medical charts, and diagnostic imaging studies, using the Bicêtre score to decide treatment, and using new techniques, combining materials in one or multiple sessions. ResultsComplete occlusion was achieved in all cases, almost all cases (75 %) had a better clinical presentation from the first session with just one embolization session, in 50 % of patients (2/4) both with a mural feeders type 2 and 1, respectively. The case with the lowest score 8/21, died after the first embolization session due to multiorgan dysfunction syndrome. ConclusionAn endovascular arterial approach combining EVOH, and coils is considered the best technique to treat vein of Galen aneurysmal malformation, because it has better control of the embolization, adding security and precision in the right hands, while also enhancing the cost-effectiveness of the procedure.

Vein of Galen Aneurysmal Malformation with Anomalous Right Superior Vena Cava to the Left Atrium Leading to Atypical Clinical and Echocardiographic Findings.

Vein of Galen aneurysmal malformation (VGAM) is a rare intracranial vascular malformation which typically presents in a critically ill newborn with intractable heart failure, severe pulmonary hypertension, and right heart dilation. We report two unusual cases of neonates with VGAM and anomalous connection of right superior vena cava to the left atrium. Both neonates were diagnosed with VGAM in utero and were clinically stable after birth with dilation of the left atrium and left ventricle and no evidence of pulmonary hypertension. One case with hydrocephalus underwent transcatheter embolization at 1week of age. The other case without hydrocephalus underwent elective transcatheter embolization at 4months. We postulate that the presence of a right superior vena cava to the left atrium provides a physiological advantage and counters the left-to-right shunt from the arteriovenous malformation. This provides insight to a potential treatment strategy to improve outcomes in patients with severe heart failure and pulmonary hypertension secondary to VGAM.

Cerebral Arteriovenous Malformation, Cerebral Cavernoma, and Cerebral Aneurysm: Management and Outcome During Pregnancy and Puerperium with Focus on Neurosurgical Side

Background: Cerebral cavernoma, cerebral arteriovenous malformation, and incidental cerebral aneurysm are rare but challenging conditions during pregnancy and puerperium. The primary diagnostic and identification techniques used to determine and evaluate these conditions in terms of morphology, location, and presentation are brain CT scan, MRI, and DSA. With ideal treatment of these conditions still unclear, neurosurgery is the most commonly preferred intervention technique. Objective: The aim of extracting data from the published studies to identify the most common neurosurgical procedures used for successful management and outcomes of CCM, cerebral AVM, and incidental cerebral aneurysms during pregnancy and puerperium. Methods: It was performed as comprehensive search into PubMed, Google Scholar, Science Direct, PubMed Central, Medline, and Research Gate databases for studies published between January 2000 to 20th January 2022. The search terms were "Cerebral cavernoma" or "cavernous cerebral malformation" or "CCM" or "cavernoma in pregnancy and puerperium"; "cerebral arteriovenous malformations" or "arteriovenous malformations" or "AVM"; "cerebral incidental aneurysm" or "intracranial aneurysm" or "incidental aneurysm" or "cerebral aneurysm in pregnancy"; "intracranial vascular malformations"; "neurosurgical treatments in pregnancy and puerperium"; "management of vascular malformation." Results: A total of 11 studies met our inclusion criteria and were included for the review. From the studies reviewed, the significant neurosurgical intervention performed among the participants were craniotomy, surgical resection, endovascular techniques, surgical clipping, surgical evacuation, embolization, and dissection. Conclusion: It concluded that effective management and treatment must be done independently and specific to each case presented. The multidisciplinary treatment option is fundamental for successful management outcomes during pregnancy and puerperium.

Prognosis of Rotational Angiography-Based Stereotactic Radiosurgery for Dural Arteriovenous Fistulas: A Retrospective Analysis.

Cerebral dural arteriovenous fistulas (DAVFs) are intracranial vascular malformations with fine, abnormal vascular architecture. High-resolution vascular imaging is vital for their visualization. Currently, rotational angiography (RA) provides the finest 3-dimensional visualization of the arteriovenous shunt with high spatial resolution; however, the efficacies of the integration of RA have never been studied in stereotactic radiosurgery (SRS) for DAVFs until now. Since 2015, our institution has integrated RA into SRS (RA-SRS) to provide more conformal planning, thereby decreasing overtreatment and undertreatment. To analyze the outcomes of RA-SRS for DAVFs. We retrospectively analyzed the outcomes of 51 patients with DAVFs and compared those of 20 DAVFs treated with RA-SRS with those of 31 DAVFs treated with conventional SRS (c-SRS). The time to obliteration was shorter in the RA-SRS group (median, 15 months vs 26 months [cumulative rate, 77% vs 33% at 2 years, 77% vs 64% at 4 years]; P = .015). Multivariate Cox proportional hazards analysis demonstrated that RA-SRS (hazard ratio 2.39, 95% CI 1.13-5.05; P = .022) and the absence of cortical venous reflux (hazard ratio 2.12, 95% CI 1.06-4.25; P = .034) were significantly associated with obliteration. The cumulative 5-year post-SRS stroke-free survival rates were 95% and 97% in the RA-SRS and c-SRS groups, respectively ( P = .615). Neurological improvement tended to occur earlier in the RA-SRS group than in the c-SRS group (median time to improvement, 5 months vs 20 months, log-rank test; P = .077). RA-based SRS may facilitate earlier fistula obliteration and may contribute to early neurological improvement.