Multiple skull base defects in the setting of spontaneous cerebrospinal fluid rhinorrhea; a dual institution view.

PURPOSE: Idiopathic intracranial hypertension (IIH) is a condition of high cerebrospinal fluid (CSF) pressure that presents with CSF leak. The implications of multiple skull base defects (SBD) and associated synchronous CSF leaks have not been previously explored. MATERIALS AND METHODS: A dual institutional case-control study examined multiple SBD's and encephaloceles on the risk of CSF leak and postoperative failures post-repair. IIH patients with CSF leaks and IIH controls without leaks were selected retrospectively. Chi square analysis evaluated for statistically significant alterations in probability with CSF leak development. RESULTS: 192 patients were selected with 108 IIH controls and 84 spontaneous CSF leak cases. Signs and symptoms for IIH controls and CSF leak cases respectively were pulsatile tinnitus (60.2 % and 29.8 %), headaches (96.3 % and 63.1 %), papilledema (74.1 % and 12.5 %), visual field defects (60.8 % and 13 %) (p < 0.001). Encephalocele formation in controls was 3.7 % compared to cases at 91.6 % (p < 0.001). Multiple SBD's in controls compared cases was 0.9 % and 46.4 % respectively (p < 0.001). Subgroup analysis of CSF leak cases showed 15 patients with two CSF leak repairs due to a recurrence. 27 (39.1 %) single leak cases had multiple SDB's while 12 (80 %) recurrent leaks had multiple SDB's (p = 0.004). CONCLUSIONS: Patients with radiographic evidence of multiple SBD's and encephaloceles represent a high-risk population with a propensity for CSF leaks. Secondary SBD's are common in patients with spontaneous CSF rhinorrhea and higher in patients with a recurrence.

Brain Atrophy and Leukoaraiosis Correlate with Futile Stroke Thrombectomy.

INTRODUCTION: Although mechanical thrombectomy (MT) is a proven therapy for acute large vessel occlusion strokes, futile recanalization in the elderly is common and costly. Strategies to minimize futile recanalization may reduce unnecessary thrombectomy transfers and procedures. We evaluated whether a simple and rapid visual assessment of brain atrophy and leukoaraiosis on a plain head CT correlates with futile stroke recanalization in the elderly. METHODS: Consecutive stroke patients admitted for thrombectomy, older than 65 years of age, all with TICI 2b/3 recanalization rates were retrospectively studied from multiple comprehensive stroke centers. Brain atrophy and leukoaraiosis were visually analyzed from pre-intervention plain head CTs using a simplified scheme based on validated scales. Baseline demographics were collected and the primary outcome measure was 90-day modified Rankin score (mRS). Cochran-Armitage trend test was applied in analyzing the association of the severity of brain atrophy and leukoaraiosis with 90-day mRS. RESULTS: Between 2017 and 2019, 175 patients > 65 years who underwent thrombectomy with TICI 2b/3 recanalization from two comprehensive stroke centers were evaluated. The median age was 77 years. IV-tPA was given in 59% of patients, average initial NIHSS was 19, average baseline mRS was 0.77 and median time to recanalization was 300 minutes. Age and severity of atrophy/leukoaraiosis was categorized into three groups of increasing severity and associated with 90 day mRS 0-3 rates of 62%, 49% and 41% (p=0.037) respectively. CONCLUSIONS: A simplified, visual assessment of the degree of brain atrophy and leukoaraiosis measured on plain head CT correlates with futile recanalization in patients age >65 years. Although additional validation is needed, these findings suggest that brain atrophy and leukoaraiosis may have value as a surrogate marker of prestroke functional status. In doing so, simplified visual plain head CT grading scales may minimize elderly futile recanalization.

Trends in United States neurosurgery residency education and training over the last decade (2009-2019).

OBJECTIVE: Postgraduate training in medicine has been under scrutiny in the last 10 years, with a focus on improving residents' education. The aim of this study was to quantify trends in neurosurgery residency (NSR) training and education over the last 10 years. METHODS: The authors assessed Accreditation Council for Graduate Medical Education (ACGME), National Resident Matching Program, and American Board of Neurological Surgeons records and searched PubMed to collate 2009-2019 data. Analyzed trends included residents' demographic data, programs' characteristics, graduation and attrition rates, match data, resident case logs, and qualitative educational curriculum changes. RESULTS: Significant increases in residents' demographic data (p < 0.05) included the number of female residents (from 12.7% to 17.6%) and the absolute number of residents (from 1112 to 1462). Age (mean 28.8 years), ethnicity, and number of residents per program (mean 13 residents per program) were unchanged. There were 16 new ACGME NSR programs, with currently 115 programs nationwide. The number of applicants per year (324 applicants per year) and the matching rate (mean 64%) remained stable. The mean attrition rate of 2.6% (range 2%-4%) was higher than the mean 2.1% ACGME attrition rate, a rate that decreased from 3% in 2009 to 1.6% in 2019. Education curriculum changes aimed at the standardization of training across the US included residents' boot camp (2009), the Milestones project (2012), and mandatory 7-year training initiated in 2013. An increase in endovascular, functional, trauma, and spine resident caseload was noted. The number of yearly publications about US NSR education has significantly increased (p < 0.05). CONCLUSIONS: NSR education has received greater attention over the last decade in the US. Standardization of training has been implemented. A steady number of students remain interested in neurosurgery, with an increased number of women entering the field. Attention to wellness, in addition to high-quality education, should be further assessed as a factor to improve the overall NSR training and retention rate.

Introduction: Endovascular Neurosurgery.

Remarkable developments in the field of endovascular neurosurgery have been witnessed in the last decade. The success of endovascular therapy for ischemic stroke treatment is now irrefutable, making it an accepted standard of care. Endovascular treatment of cerebral aneurysms is no longer limited to primary coiling but now includes options such as stent or balloon assistance and flow diversion and applications utilizing neck reconstruction, intrasaccular, and bifurcation-specific devices. Balloons, liquid embolic agents, and flow-directed catheters have revolutionized the treatment of arteriovenous malformations and fistulae. The ongoing development of endovascular tools has led to novel and expanding approaches (for example, transvenous arteriovenous malformation embolization and transradial access). With improved technology, transposterior communicating artery access and other endovascular strategies are being applied successfully across the anterior and posterior circulations and to lesions once deemed only surgically approachable. Yet, we would be remiss to attribute the successes of endovascular strategies only to the development of their tools. Improvements in both noninvasive and angiographic imaging (such as three-dimensional road map guidance) have provided a greater understanding of pathologic entities and allowed the pursuit of endovascular cures.In this issue of Neurosurgical Focus, we present a wide range of endovascular strategies for a variety of neurovascular pathologies. We hope this video supplement will not only demonstrate the applicability of tried-and-true endovascular strategies to difficult clinical situations but also highlight new and developing endovascular technologies. We thank the authors for their outstanding contributions.

Stent anchor technique to reduce microcatheter loop for stent-assisted coiling of anterior communicating artery aneurysm.

Stent-assisted coiling offers a potential solution for coil embolization of broad-based aneurysms. Challenges associated with navigating a microcatheter beyond these aneurysms sometimes require looping the microcatheter within the aneurysm dome. Reducing microcatheter loops within domes can be difficult, and anchor techniques have been described, including balloon anchor, stent-retriever anchor, and stent anchor techniques. The authors present a patient requiring stent-assisted coiling of an anterior communicating artery aneurysm in whom a stent anchor technique was used to reduce a microcatheter loop within an aneurysm dome before coil embolization. Postembolization angiographic runs showed complete coil occlusion of the aneurysm with approximately 35% packing density.The video can be found here: https://youtu.be/zHR1ZOArUro.

Deployment of distal posterior cerebral artery flow diverter in tortuous anatomy.

Progressive deconstruction with flow diversion using a Pipeline embolization device (PED; Medtronic) can be utilized to promote thrombosis of broad-based fusiform aneurysms. Current flow diverters require a 0.027-inch microcatheter for deployment. The authors present a patient with a fusiform P2-3 junction posterior cerebral artery aneurysm in which they demonstrate the importance of haptics in microwire manipulation to recognize large-vessel anatomy versus perforator anatomy that may overlap, especially when access is needed in distal tortuous circulations. In addition, the authors demonstrate the need for appropriate visualization before PED deployment. Postembolization runs demonstrated optimal wall apposition with contrast stasis within the aneurysm dome.The video can be found here: https://youtu.be/8kfsSvN3XqM.

KX2-361: a novel orally bioavailable small molecule dual Src/tubulin inhibitor that provides long term survival in a murine model of glioblastoma.

PURPOSE: A major challenge to developing new therapies for patients with malignant brain tumors is that relatively few small molecule anticancer drugs penetrate the blood-brain barrier (BBB) well enough to provide therapeutically effective concentrations in brain tissue before drug exposure in non-CNS tissues results in unacceptable toxicity. METHODS: KX2-361, a member of a novel family of compounds with Src-kinase and tubulin polymerization inhibitory activity, demonstrates good oral bioavailability and readily crosses the BBB in mice. The objective of this study was to investigate the activity of KX2-361 against human and murine glioma cells and assess its therapeutic effect in a syngeneic orthotopic model of glioblastoma. RESULTS: In addition to reducing the level of Src autophosphorylation in the GL261 murine glioblastoma cell line, KX2-361 binds directly to tubulin and disrupts microtubule architecture in glioma cells maintained in culture. CONCLUSIONS: The drug is active in vivo against orthotopic GL261 gliomas in syngeneic C57BL/6 mice. Long term survival is not observed in mice lacking an adaptive immune system, indicating that KX2-361 works in concert with the host immune system to control tumor growth and promote long-term survival in the GL261 glioma model.

Compressive optic neuropathy secondary to a lateral rectus muscle dermoid cyst.

A 48-year-old man presented 2 weeks after sudden OS vision loss. On examination, the patient had decreased OS visual acuity, an ipsilateral afferent pupil defect, and proptosis. MRI of the orbit with and without gadolinium showed a large, enhancing heterogeneous mass extending to the orbital apex. Uncomplicated resection was performed and pathology was consistent with a dermoid cyst. Postoperatively, the patient had improved visual acuity and minimal lateral rectus dysfunction. There are only 4 reported cases of dermoid cysts located within the lateral rectus muscle, albeit this is the first case describing a compressive optic neuropathy in the setting of an orbital dermoid cyst.

Dendritic-cell exosomes cross-present Toll-like receptor-ligands and activate bystander dendritic cells.

Dendritic cells (DCs) are the major sentinel, antigen-presenting and regulatory components of the immune system. One of the central DC functions is to rapidly sense and alert host immune system of a pathogen invasion. In the present study, we investigated the role of DC exosomes (DCex) in this sentinel function. We demonstrated that DCex could bind bacterial Toll-like-receptor ligands (TLR-Ls), and acquire their ability to strongly activate bystander DCs. Consequently, bystander DCs enhance the expression of transmembrane tumor necrosis factor, secretion of proinflammatory cytokines and cross-talk with natural killer cells leading to the elevated secretion of IFNγ. These findings newly show that DCex can bind and cross-present TLR-Ls to innate-immunity effector cells, and indicate a potent mechanism to systemically alert the host immune system of pathogen invasion. They also suggest a potential novel strategy to generate effective vaccines by binding TLR-L-immune adjuvants to DCex.

"Contrast-less" stent-assisted coiling of an A1 aneurysm.

BACKGROUND: Iodine-based contrast medium used in diagnostic and therapeutic cerebrovascular imaging may cause renal toxicity, especially in patients with underlying renal impairment. Contrast dilution may impede efforts of the neurointerventionalist to treat intracranial vascular pathology. METHODS: A 36-year-old man with renal impairment presented with an unruptured A1 segment anterior cerebral artery aneurysm. Previously obtained magnetic resonance angiography was fused with intraoperative noncontrast computed tomography and live 2-dimensional fluoroscopic images. The aneurysm was successfully treated with stent-assisted coil embolization without the use of contrast. RESULTS: Neurointervention without contrast was feasible, and although the presented case is one example, the imaging fusion techniques used in this case can substantially decrease the exposure to contrast and subsequent risk of renal injury during intracranial procedures. CONCLUSIONS: Further development of and experience with this technique is needed to improve its safety and efficacy.

Surgical Strategies in the Treatment of Giant Pituitary Adenomas.

BACKGROUND AND OBJECTIVES: The management of giant pituitary adenomas (GPAs) is challenging due to associated endocrinopathies and the close proximity of these tumors to critical structures, such as the optic nerves, structures of the cavernous sinus, and hypothalamus. The objective of this review article was to summarize the current management strategies for giant pituitary adenomas, including the role of open and endoscopic surgical approaches and the role of medical and radiation therapy in conjunction with surgery. METHODS: We conducted a retrospective review of GPAs operated at our institute between January 2010 and March 2023. Surgical approaches, extent of resection, and associated complications were documented. Furthermore, we conducted a thorough literature review to identify relevant studies published in the past decade, which were incorporated along with insights gained from our institutional case series of GPAs to analyze and integrate both the existing knowledge base and our institution's firsthand experience in the management of GPAs. RESULTS: A total of 46 giant pituitary adenomas (GPAs) were operated on, using various surgical approaches. Transsphenoidal approach was used in 25 cases and a staged approach using transsphenoidal and pterional was used in 15 cases. Other approaches included transcortical-transventricular, transcallosal, pterional/orbitozygomatic, and subfrontal approaches. Complications and technical nuances were reported. CONCLUSION: The management of giant pituitary adenomas remains complex, often involving several modalities-open or endoscopic resection, radiosurgery, and medical management of both the tumor and associated endocrinopathies. Surgical resections are often challenging procedures that require careful consideration of several factors, including patient characteristics, tumor location, and size, and the experience and skill of the surgical team.

Comparison of Radial Versus Femoral Access for Neuroendovascular Procedures in Very High Body Mass Index Individuals.

BACKGROUND: Femoral access (TFA) for neuroendovascular procedures may present a challenge in very high body mass index (BMI) individuals. Whether radial access (TRA) confers a comparative benefit in this specific population has not been studied. METHODS: We retrospectively identified all patients undergoing neuroendovascular procedures at our center between 2017 and 2021 with BMI ≥35 kg/m2. A total of 335 patients met our inclusion criteria, with 224 undergoing femoral access and 111 undergoing radial access. Electronic medical records were reviewed for baseline clinical and angiographic characteristics and procedural outcomes. RESULTS: The primary outcome of any bleeding complication occurred in 7% of the femoral group and 2% of the radial group (odds ratio 4.2, 95% confidence interval 1.0-18.6, P = 0.0421). Radial access was also associated with significantly shorter mean procedure times (median 43 minutes for radial, median 58 minutes for femoral, P = 0.0009) and mean fluoroscopy exposure times (median 15 minutes for radial, median 20 minutes for femoral, P = 0.0003). There were no significant differences in nonaccess site complications, procedural failure, length of stay, or deaths during hospitalization. CONCLUSIONS: When compared to TRA, TFA was associated with a significantly greater rate of bleeding complications in very high BMI patients undergoing neuroendovascular procedures. Procedure time and fluoroscopy time were both significantly longer when using TFA compared to TRA in this patient population.

Thrombectomy With the pRESET vs Solitaire Stent Retrievers as First-Line Large Vessel Occlusion Stroke Treatment: A Randomized Clinical Trial.

Importance: Stent retriever-based thrombectomy is highly beneficial in large vessel occlusion (LVO) strokes. Many stent retriever designs are currently available, but comparison of these technologies in well-conducted studies is lacking. Objective: To determine whether thrombectomy for LVO stroke with the pRESET stent retriever is noninferior to treatment with the Solitaire stent retriever. Design, Setting, and Participants: This study was a multicenter, prospective, randomized, controlled, open-label, adaptive, noninferiority trial with blinded primary end point evaluation. Between October 2019 and February 2022, multicenter participation occurred across 19 research hospitals and/or universities in the US and 5 in Germany. Patients with LVO stroke were enrolled and included up to 8 hours after symptom onset. Interventions: Patients underwent 1:1 randomization to thrombectomy with the pRESET or Solitaire stent retriever. Main Outcomes and Measures: The primary outcome was the difference in the rate of 90-day functional independence across the 2 devices, using a -12.5% noninferiority margin for the lower bound of the 1-sided 95% CI of the difference between pRESET and Solitaire retrievers. Results: Of 340 randomized patients, 170 (50.0%) were female, and the median (IQR) age was 73.0 (64.0-82.0) years. The study procedure was completed in 322 of the 340 randomized patients. The primary end point of 90-day functional independence was achieved by 95 patients (54.9%; 95% CI, 48.7-61.1) in the pRESET group and in 96 (57.5%; 95% CI, 51.2-63.8) in the Solitaire group (absolute difference, -2.57%; 95% CI, -11.42 to 6.28). As the lower bound of the 95% CI was greater than -12.5%, the pRESET retriever was deemed noninferior to the Solitaire retriever. The noninferiority of pRESET over Solitaire was also observed in the secondary clinical end point (90-day shift in modified Rankin Scale score) and in both angiographic end points (Expanded Treatment in Cerebral Infarction [eTICI] score of 2b50 or greater within 3 passes: 146 of 173 [84.4%] vs 149 of 167 [89.2%]; absolute difference, -4.83%; 95% CI, -10.84 to 1.19; eTICI of 2c or greater following the first pass: 76 of 173 [43.7%] vs 74 of 167 [44.3%]; absolute difference, -0.63%; 95% CI, -9.48 to 8.21). Symptomatic intracranial hemorrhage occurred in 0 patients in the pRESET group and 2 (1.2%) in the Solitaire group. Mortality occurred in 25 (14.5%) in the pRESET group and in 24 (14.4%) in the Solitaire group at 90 days. Findings of the per-protocol and as-treated analyses were in concordance with findings of the intention-to-treat analysis. Conclusions and Relevance: In this study, among patients with LVO stroke, thrombectomy with the pRESET stent retriever was noninferior to thrombectomy with the Solitaire stent retriever. Findings suggest that pRESET offers a safe and effective option for flow restoration and disability reduction in patients with LVO stroke.

Evolution of Transradial Access for Mechanical Thrombectomy-A Single Center Experience.

BACKGROUND: Transradial access (TRA) recently has gained popularity among neurointerventionalists. However, hesitation to its use for mechanical thrombectomy (MT) remains. OBJECTIVE: To evaluate and describe the evolution of TRA for MT. METHODS: We performed a retrospective analysis of patients undergoing TRA for MT. We performed a chronological ternary analysis to assess the impact of experience. We assessed the impact of a guide catheter designed specifically for TRA. RESULTS: We identified 53 patients who underwent TRA for MT. There was a statistically significant decrease in contrast use (148.9 vs 109.3 vs 115.2 cc), procedure time (62.4 vs 44.7 vs 41.3 minutes), fluoroscopy time (39.2 vs 44.7 vs 41.3 minutes), and puncture-to-recanalization time (40.6 vs 27.3 vs 29.4) over time. There was trend toward improved thrombolysis in cerebral infarction ≥ 2b recanalization rate (72.2% vs 77.8% vs 100%) over time. The introduction of a radial-specific catheter had a statistically significant positive impact on contrast use (133.8 vs 93 cc, P = .043), procedure time (54.2 vs 36.4 minutes, P = .003), fluoroscopy time (33.7 vs 19.8 minutes, P = .004), puncture-to-recanalization time (35.8 vs 25.1 minutes, P = .016), and thrombolysis in cerebral infarction ≥ 2b recanalization rate (71.4% vs 100%, P = .016). CONCLUSION: TRA is a safe and effective route of endovascular access for MT. Experience with this technique improves its efficacy and efficiency. The introduction of a TRA-specific catheter expands the armamentarium of the neurointerventionalist and may facilitate lesion access during MT procedures. Continued development of radial-specific devices may further improve MT outcomes.

Feasibility of robotic neuroendovascular surgery.

BACKGROUND: Several recent reports of CorPath GRX vascular robot (Cordinus Vascular Robotics, Natick, MA) use intracranially suggest feasibility of neuroendovascular application. Further use and development is likely. During this progression it is important to understand endovascular robot feasibility principles established in cardiac and peripheral vascular literature which enabled extension intracranially. Identification and discussion of robotic proof of concept principals from sister disciplines may help guide safe and accountable neuroendovascular application. OBJECTIVE: Summarize endovascular robotic feasibility principals established in cardiac and peripheral vascular literature relevant to neuroendovascular application. METHODS: Searches of PubMed, Scopus and Google Scholar were conducted under PRISMA guidelines1 using MeSH search terms. Abstracts were uploaded to Covidence citation review (Covidence, Melbourne, AUS) using RIS format. Pertinent articles underwent full text review and findings are presented in narrative and tabular format. RESULTS: Search terms generated 1642 articles; 177, 265 and 1200 results for PubMed, Scopus and Google Scholar respectively. With duplicates removed, title review identified 176 abstracts. 55 articles were included, 45 from primary review and 10 identified during literature review. As it pertained to endovascular robotic feasibility proof of concept 12 cardiac, 3 peripheral vascular and 5 neuroendovascular studies were identified. CONCLUSIONS: Cardiac and peripheral vascular literature established endovascular robot feasibility and efficacy with equivalent to superior outcomes after short learning curves while reducing radiation exposure >95% for the primary operator. Limitations of cost, lack of haptic integration and coaxial system control continue, but as it stands neuroendovascular robotic implementation is worth continued investigation.

Femoral access site complications following neurointerventional procedures: economic implications at a single center.

OBJECTIVE: Transfemoral access (TFA) has been the traditional route of arterial access for neurointerventional procedures. Femoral access site complications may occur in 2%-6% of patients. Management of these complications often requires additional diagnostic tests or interventions, each of which may increase the cost of care. The economic impact of a femoral access site complication has not yet been described. The objective of this study was to evaluate the economic consequences of femoral access site complications. METHODS: The authors conducted a retrospective review of patients undergoing neuroendovascular procedures at their institute and identified those who experienced femoral access site complications. The subset of patients experiencing these complications during elective procedures was matched in a 1:2 fashion to a control group undergoing similar procedures and not experiencing an access site complication. RESULTS: Femoral access site complications were identified in 77 patients (4.3%) over a 3-year period. Thirty-four of these complications were considered major, requiring blood transfusion or additional invasive treatment. There was a statistically significant difference in total cost ($39,234.84 vs $23,535.32, p = 0.001), total reimbursement ($35,500.24 vs $24,861.71, p = 0.020) and reimbursement minus cost (-$3734.60 vs $1326.39, p = 0.011) between the complication and control cohorts in elective procedures, respectively. CONCLUSIONS: Although occurring relatively infrequently, femoral artery access site complications increase the cost of care for patients undergoing neurointerventional procedures; how this influences the cost effectiveness of neurointerventional procedures warrants further investigation.

Multimodal monitoring to guide neurosurgical intervention in high-grade aneurysmal subarachnoid hemorrhage: illustrative case.

BACKGROUND: Multimodal monitoring to guide medical intervention in high-grade aneurysmal subarachnoid hemorrhage (aSAH) is well described. Multimodal monitoring to guide surgical intervention in high-grade aSAH has been less studied. OBSERVATIONS: Intracranial pressure (ICP), brain lactate to pyruvate ratio (L/P ratio), and brain parenchymal oxygen tension (pO2) were used as surrogates for clinical status in a comatose man after high-grade aSAH. Acute changes in ICP, L/P ratio, and pO2 were used to identify brain injury from both malignant cerebral edema and delayed cerebral ischemia, respectively, and decompressive hemicraniectomy with clot evacuation and intraarterial nimodipine were used to treat these conditions. The patient showed marked improvement in multimodal parameters following each intervention and eventually recovered to a modified Rankin score of 2. LESSONS: In patients with a limited neurological examination due to severe acute brain injury in the setting of aSAH, multimodal monitoring can be used to guide surgical treatment. With prompt, aggressive, maximal medical and surgical interventions, otherwise healthy individuals may retain the capacity for close to full recovery from seemingly catastrophic aSAH.

The Rist radial access system: a multicenter study of 152 patients.

BACKGROUND: Transradial access (TRA) for neurointervention is becoming increasingly popular as experience with the technique grows. Despite reasonable efficacy using femoral catheters off-label, conversion to femoral access occurs in approximately 8.6-10.3% of TRA cases, due to an inability of the catheter to track into the vessel of interest, lack of support, or radial artery spasm. METHODS: This is a multicenter, retrospective case series of patients undergoing neurointerventions using the Rist Radial Access System. We also present our institutional protocol for using the system. RESULTS: 152 patients were included in the cohort. The most common procedure was flow diversion (28.3%). The smallest radial diameter utilized was 1.9 mm, and 44.1% were performed without an intermediate catheter. A majority of cases (96.1%) were completed successfully; 3 (1.9%) required conversion to a different radial catheter, 2 (1.3%) required conversion to femoral access, and 1 (0.7%) was aborted. There was 1 (0.7%) minor access site complication and 4 (2.6%) neurological complications. CONCLUSIONS: The Rist catheter is a safe and effective tool for a wide range of complex neurointerventions, with lower conversion rates than classically reported.