BACKGROUND: Given the benefits of neuroendovascular simulation to resident education, this study aimed to assess the efficacy of simulation-based training for neuroendovascular intervention with primary and secondary catheters using a transradial approach (TRA).
METHODS: Five neurosurgical residents (PGY 1-3) from our institution enrolled in a standardized pilot training protocol. Trainees used the Mentice (Gothenburg, Vastra Gotaland, Sweden) Visit G5 simulator with a type II arch using a right TRA.
RESULTS: All participants improved their total time to complete the task from the first trial to the last trial. Residents improved the overall time required to complete the task by 111.8 ± 57 seconds (52% improvement; P = 0.012). Participants reported improved knowledge of Simmons catheter formation from 1.6 ± 0.8 to 2.8 ± 1 (P = 0.035) and improved knowledge of transradial vessel selection technique from 1.6 ± 0.9 to 2.8 ± 1.1 (P = 0.035). All residents were able to illustrate a bovine arch and types 1-3 arches post-simulation. Residents rated the simulation usefulness as 4.6 ± 0.548 (scale 1 [not useful] to 5 [essential]) with 4 of the 5 residents (80%) identifying this exercise as essential. All residents rated the hands-on component of the training exercise as the most important.
CONCLUSIONS: Residents demonstrated proficiency at Simmons catheter formation and vessel selection in a type II arch over a short time period (4 attempts and <1 hour total). Residents can use simulator-based training to increase their proficiency of vessel selection using a primary or secondary catheter for a TRA.

Neuroendovascular rescue of patients with acute ischemic stroke caused by a large arterial occlusion has evolved throughout the first quarter of the present century, and continues to do so. Starting with the intra-arterial instillation of thrombolytic agents via microcatheters to dissolve occluding thromboembolic material, the current status is one that includes a variety of different techniques such as direct aspiration of thrombus, removal by stent retriever, adjuvant techniques such as balloon angioplasty, stenting, and tactical intra-arterial instillation of thrombolytic agents in smaller branches to treat no-reflow phenomenon. The results have been consistently shown to benefit these patients, irrespective of whether they had already received intravenous tissue-type plasminogen activator or not. Improved imaging methods of patient selection and tactically optimized periprocedural care measures complement this dimension of the practice of neurointervention.

Intrasaccular flow modification with devices like the Woven EndoBridge (WEB, MicroVention, Inc., Aliso Viejo, California, US) is an increasingly utilized endovascular treatment for bifurcation aneurysms. Among the potential complications of the procedure is branch vessel occlusion. There are no previous publications of rescue stenting for inadvertent branch vessel occlusion with the WEB device. We report two cases of rescue stenting following branch vessel occlusion after cerebral aneurysm embolization with the WEB device. In both cases, rescue stenting with a Neuroform Atlas stent Stryker, Fremont, CA, US) successfully revascularized the occluded vessel and led to good patient outcomes.

BACKGROUND: There have been immense advancements in the hardware and software of digital subtraction angiography systems over the last several years. These advancements continue to make progress toward the goals of offering better visualization and reducing radiation exposure. A newer advancement in this arena is presenting three-dimension data over time resulting in four-dimensional-digital subtracted angiography visualization. We have evaluated these protocols related to the evaluation of the treatment of intracranial aneurysms with pipeline flow diversion.
METHODS: Four-dimensional-digital subtracted angiography imaging was acquired on an Artis Q Biplane angiographic system (Siemens Healthcare AG, Forchheim, Germany). A six second four-dimensional-digital subtracted angiography protocol was performed pre and post flow diverter placement. Pre and post reconstructed images were sent through a dedicated prototype research workstation (Syngo X-Workplace; Siemens Healthineers AG) for further flow evaluation.
RESULTS: The treatment of an aneurysm with flow diversion led to a filling delay of 0.278 ± 0.422 s inside the aneurysms, whereas distal to the aneurysms the filling of the vessel segment occurred earlier post procedural (negative filling delay of -0.15 ± 0.31 s. The flow ratio inside the aneurysm decreased to 63.6 ± 23% of its pre-treatment value and distal to the aneurysm the flow remained substantially the same (flow ratio: 95.6 ± 0.29%). Data showed a relative filling delay of the aneurysm normalized to the distal vessel of 0.43 ± 0.36 s. The relative flow ratio of the aneurysm in comparison to the distal parent vessel was 72.2 ± 31%.
CONCLUSIONS: Analysis of a four-dimensional-digital subtracted angiography acquisition allows assessment of the effects of flow diversion treatment on aneurysm hemodynamic parameters and shows a significant decrease in flow inside the aneurysm compared to the parent vessel distal to the aneurysm.

BACKGROUND: Onyx embolization has emerged as a promising technique for spinal tumor embolization due to its high devascularization rate and low incidence of complications.
OBJECTIVE: Evaluate the safety and efficacy of Onyx embolization in spinal tumor procedures.
METHODS: Following the PRISMA guidelines, we conducted a systematic review and meta-analysis. To be included, the articles had to report specific outcomes of Onyx embolization for spinal tumors (complications, mortality, blood loss, tumor devascularization, or reduction in tumor blush).
RESULTS: We selected 11 out of 2941 articles, encompassing 127 patients. Among them, no major complications or persistent neurological deficits were reported, and no deaths occurred as a result of the embolization procedure. Of the 63 patients with available data, two complications were observed: one infarct leading to transient neurological deficit and one clinically silent vessel perforation related to the microcatheter. Thus, the complication rate was 1% (95% confidence interval (CI): 0% to 6%). Blood loss during surgery ranged from 100 to 1500 mL (four studies). Complete tumor blush reduction was achieved in 52% of the cases (95% CI: 16% to 88%) across 32 patients. Three studies reported a median percentage of tumor devascularization of 91% (86.1% to 97.5%).
CONCLUSIONS: Onyx embolization for spinal tumor procedures appears to be a safe technique, as evidenced by the absence of major complications or deaths. However, the determination of its efficacy remains challenging due to limited data availability and substantial heterogeneity across studies. These findings highlight the need for future research to address this knowledge gap and further validate our results.

BACKGROUND: Dual antiplatelet therapy is used to reduce the risk of thromboembolic complications in neuroendovascular surgery. However, the predictive utility of preoperative platelet-sensitivity testing for decreasing bleed risk in patients undergoing endovascular neurointervention remains unclear.
OBJECTIVE: We conducted a systematic review and meta-analysis to illustrate the association between platelet response and risk of hemorrhagic complications from neuroendovascular surgery, examine the efficacy of the VerifyNow platelet reactivity unit (PRU) assay in predicting hemorrhagic outcomes, and assess whether a clinically useful threshold for platelet response can be defined to standardize guidelines.
METHODS: PubMed, Embase, and Scopus were searched. Articles were screened for relevance by title and abstract, followed by full text.
RESULTS: Of 735 resultant articles, 17 studies of 2084 patients undergoing neuroendovascular intervention were included. Diagnoses included both intracranial and extracranial pathologies, of which 37.8% were treated with flow diversion, 22.4% with stent-assisted coil embolization, 14.3% with intracranial stenting, 12.8% with simple coil embolization, 5.8% with balloon-assisted coil embolization, 2.0% with extracranial stenting, and 4.8% with an alternate method. Precisely, 52.9% (9 out of 17) of studies determined platelet hyperresponse to be an independent predictor of postoperative hemorrhagic complications, with 11.8% (2 out of 17) of studies reporting a similar but non-statistically significant trend. 35.3% (6 out of 17) of studies found no relationship between platelet response and postoperative hemorrhagic complications. The estimated clinical threshold for PRU to prevent hemorrhagic complications varied considerably across studies (range: <46-118 PRU). Meta-analysis found platelet hyperresponse to have more than a 3-fold increased risk of hemorrhagic complications compared to normoresponders (relative risk = 3.2, p = 0.001).
CONCLUSIONS: Although this meta-analysis shows the predictive utility of the P2Y12 assay for postoperative hemorrhagic complications in neuroendovascular surgery, the optimal therapeutic threshold for minimizing bleeding risk is still uncertain. To better understand the utility of the P2Y12 assay in the perioperative period, further prospective research is needed.

BACKGROUND: Despite the heavily debated use of routine platelet-function testing, the VerifyNow Platelet Reactivity Unit (PRU) assay has been increasingly adopted as standard of care for assessing risk of postoperative thromboembolic complications of neuroendovascular surgery.
OBJECTIVE: We conducted a systematic review and meta-analysis to examine the relationship between platelet response and risk of ischemic events from neuroendovascular surgery, assess the efficacy of point-of-care platelet-function testing in predicting thromboembolic outcomes, and assess whether a clinically useful threshold for platelet response can be defined in order to standardize guidelines.
METHODS: PubMed, Embase, and Scopus were searched. Following deduplication, articles were first screened for relevance by title and abstract, followed by full text.
RESULTS: Of 735 resultant articles, 22 studies consisting of 3266 patients undergoing neuroendovascular intervention were included. Diagnoses included both intracranial and extracranial pathologies, of which 45.8% were treated with flow diversion, 16.4% with stent-assisted coil embolization, 15.8% with intracranial stenting, 12.0% with simple coil embolization, 3.4% with balloon-assisted coil embolization, 3.6% with extracranial stenting, and 3.0% with an alternate method. 54.5% (12/22) of studies determined platelet hyporesponse to be an independent predictor of postoperative thromboembolic complications, with 27.3% (6/22) of studies reporting a similar, but non-statistically significant trend. 18.2% (4/22) of studies found no relationship between platelet response and postoperative thromboembolic complications. The estimated clinical threshold for PRU to prevent thromboembolic complications varied greatly across studies (Range: > 144-295 PRU). Meta-analysis found platelet hyporesponse to have a 2.23-fold increased risk of thromboembolic complications compared to normoresponders (RR = 2.23, P = 0.03).
CONCLUSIONS: While PRU demonstrates a significant predictive value for postoperative thromboembolic complications of neuroendovascular surgery, the target therapeutic threshold for minimizing ischemic events remains unclear. Further studies, such as large multicenter cohorts of the existing data, are needed to standardize guidelines.

Although periprocedural antiplatelet therapy for the treatment of unruptured intracranial aneurysms (UIAs) using flow-diverter stents (FDSs) is necessary to avoid thromboembolic complications, a definite antiplatelet therapy has not been established. We aimed to evaluate the safety and efficacy of periprocedural antiplatelet management in UIA treatment with FDS.
A single-center retrospective analysis of consecutive patients with UIAs treated with FDSs between September 2013 and January 2022 was conducted. Patients received dual antiplatelet therapy (DAPT) (aspirin and clopidogrel) for 14-day before and 3-6 months after FDS placement. Platelet aggregation was evaluated prior to treatment using light transmission aggregometry, which was classified into 3 grades; 1-3: promoted, 4-6: appropriate, and 7-9: non-responder, for adenosine diphosphate (ADP) and collagen. By this classification, the antiplatelet regimen was modified. Outcome included hemorrhagic and ischemic events.
193 patients with 200 UIAs underwent 213 FDSs placement. The median platelet aggregability grade before treatment was 5 for ADP and 4 for collagen. Antiplatelet therapy modification was performed in 62 patients (32.1%). The median postoperative DAPT duration was 94 days. Antiplatelet medicine-related hemorrhagic events occurred in 4 patients (2.1%) and ischemic events occurred in 6 patients (3.1%). These patients had no morbido-mortality.
Periprocedural antiplatelet management based on the value of platelet aggregability was relatively safe and effective for treating UIA with FDS.

BACKGROUND: Chronic subdural hematoma (cSDH) in children is associated with several etiologies, one of which is nonaccidental trauma (NAT). Performed alone or as an adjunct to surgical intervention, middle meningeal artery (MMA) embolization may be effective in resolving and preventing the recurrence of cSDH in adult patients. However, MMA embolization for pediatric cSDH has not been adequately evaluated, and there exists no consensus on the appropriate selection of pediatric patients for this minimally invasive procedure. Appreciating the variable underlying pathophysiology of pediatric cSDH will enable the development of guidelines for patient selection.
METHODS: A 14-month-old female patient presented with depressed consciousness, seizure-like activity, and apneic episodes. She was diagnosed with bilateral subacute on chronic SDH associated with NAT, and imaging revealed diffuse brain atrophy. Despite undergoing burr hole drainage, she developed refractory cSDH and was treated with bilateral MMA embolization. At her 10-month follow-up, magnetic resonance imaging revealed a decrease in the size of the subdural collections, and she was tolerating feeds, at her neurological baseline, and seizure-free.
CONCLUSIONS: Infants and young children with symptomatic cSDH secondary to NAT, whose tissue dynamics are reminiscent of cSDH in elderly patients with diffuse brain atrophy, may derive the most benefit from MMA embolization.

Transradial access is an important tool for many neuroendovascular procedures. Occlusion of the radial or ulnar artery is not uncommon after transradial or transulnar access and can present a challenge for patients requiring repeat angiography.
Between March 2022 and June 2023, patients undergoing transradial or transulnar angiography who were found to have a radial artery occlusion or ulnar artery occlusion were identified. Repeat catheterization of the occluded artery was attempted using a 21-gauge single wall puncture needle and a 0.021-inch wire to traverse the occlusion and insert a 23-cm sheath into the brachial artery.
A total of 25 patients undergoing 26 angiograms during the study period were found to have a radial artery occlusion or ulnar artery occlusion. Successful repeat catheterization of the occluded artery was achieved in 21 of 26 cases (80.7%). Outer diameter sheath size ranged from 5 Fr (0.0655 inch) to 8 Fr (0.1048 inch). No access complications were encountered. Number of prior angiograms, time since prior angiogram, and prior angiogram procedure time were associated with lower likelihood of successful access.
Transradial or transulnar neuroangiography through an occluded radial or ulnar artery is safe and feasible by traversing the occlusion into the brachial artery with a 23-cm sheath. Repeat catheterization is most successful in patients with an arterial occlusion <6 months old. This technique is important in patients who have limited options for arterial access, avoiding access site complications inherent in transfemoral access, and in patients who specifically require radial or ulnar artery access.