A new definition for wide-necked cerebral aneurysms

Initial experiences with the target tetra coils: An illustrated case series

IntroductionThe management and treatment of intracranial aneurysms have substantially evolved with advancements in neuroendovascular technologies. Among the latest developments are the Target® Tetra™ coils (Stryker Neurovascular, Kalamazoo, MI, USA). In this non-industry funded illustrated case series we examine the efficacy and safety of Target® Tetra™ and describe nuances of their usage.MethodsA retrospective two-centre study examined the usage and outcomes of Target® Tetra™ coil usage in a consecutive series of ruptured and unruptured aneurysms. Data was collected on clinical, technical, and imaging characteristics associated with their usage.ResultsThe dataset consisted of information from a total of 75 patients and 80 aneurysms (mean age 55.7 years). 56/75 (74.7%) aneurysms were treated in the setting of aneurysmal subarachnoid haemorrhage. 80/80 (100%) of the aneurysm treatments were technically successful. 2/80 (2.5%) of the cases encountered technical issues, with 1/80 (1.2%) case of coil migration and 1/80 (1.2%) case where the coil could not be detached. The median clinical follow-up time was 5 months. All-cause mortality was 8%, all occurring in ruptured aneurysms. There was 1/75 (1.3%) rebleed at the time of follow-up. 45% aneurysms patients had imaging follow-up at a median of 5 months. Excluding treatments involving stenting, flow-diversion, and intra-saccular devices the adequate occlusion rate at follow-up was 19/21 (90.5%) for ruptured and 6/6 (100%) for unruptured aneurysms, with an overall rate of 25/27 (92.6%).ConclusionsInitial short-term results suggest the safety and efficacy of the Tetra™ coils. Long-term outcomes in terms of aneurysm occlusion require further study.

Impact of A1 hypoplasia on endovascular treatment outcomes for anterior communicating artery aneurysms: implications for follow-up strategies

BACKGROUND

A1 hypoplasia is associated with anterior communicating artery (AcomA) aneurysms, but optimal imaging follow-up timing remains unclear. This study aimed to investigate whether concomitant A1 hypoplasia influences the post-treatment outcomes of AcomA aneurysms.

METHODS

This retrospective cohort study (2013-24) included patients treated endovascularly for AcomA aneurysms, grouped by the presence or absence of A1 hypoplasia. Outcome measures included complete occlusion and good clinical outcomes at short term and long term follow-up, aneurysm recurrence, retreatment rates, and procedure related complications. Subgroup analysis compared treatment modalities within the A1 hypoplasia group.

RESULTS

298 AcomA aneurysms were included (median age 58 years, 63% women), with 205 in the symmetric group and 93 in the A1 hypoplasia group. Anterior dome projection was more common with A1 hypoplasia (61% vs 46%; P=0.01), as were recurrence rates (31% vs 15%; P=0.005). A1 hypoplasia correlated with reduced long term complete occlusion rates (OR 0.32, P=0.01). In A1 hypoplasia patients, coiling/balloon assisted coiling showed lower long term occlusion rates (P=0.008), higher recurrence (P=0.049), and a trend toward increased retreatment (P=0.07). Stent assisted coiling was linked with higher long term occlusion rates (P=0.009) and a trend toward reduced retreatment (P=0.07). Flow diverter treatment showed no significant effect.

CONCLUSION

In this study, A1 hypoplasia affected long term outcomes of endovascular treatment for AcomA aneurysms, leading to lower occlusion and higher recurrence rates. Closer long term monitoring is needed in these patients.

Stable and Thin-Polymer-Based Modification of Neurovascular Stents with 2-Methacryloyloxyethyl Phosphorylcholine Polymer for Antithrombogenicity

The advent of intracranial stents has revolutionized the endovascular treatment of cerebral aneurysms. The utilization of stents has rendered numerous cerebral aneurysm amenable to endovascular treatment, thereby obviating the need for otherwise invasive open surgical options. Stent placement has become a mainstream approach because of its safety and efficacy. However, further improvements are required for clinically approved devices to avoid the frequent occurrence of thrombotic complications. Therefore, controlling the thrombotic complications associated with the use of devices is of significant importance. Our group has developed a unique stent coated with a 2-methacryloyloxyethyl phosphorylcholine (MPC)-based polymer. In this study, the surface characteristics of the polymer coating were verified using X-ray photoelectron spectroscopy and atomic force microscopy. Subsequently, the antithrombotic properties of the coating were evaluated by measuring platelet count and thrombin-antithrombin complex levels of whole human blood after 3 h of incubation in a Chandler loop model. Scanning electron microscopy was utilized to examine thrombus formation on the stent surface. We observed that MPC polymer-coated stents significantly reduced thrombus formation as compared to bare stents and several clinically approved devices. Finally, the coated stents were further analyzed by implanting them in the internal thoracic arteries of pigs. Angiographic imaging and histopathological examinations that were performed one week after implantation revealed that the vascular lumen was well maintained and coated stents were integrated within the vascular endothelium without inducing adverse effects. Thus, we demonstrated the efficacy of MPC polymer coating as a viable strategy for avoiding the thrombotic risks associated with neurovascular stents.

Low-Profile Visualized Intraluminal Support Device for Y-Stent-Assisted Coiling of Wide-Neck Intracranial Aneurysms: A Single-Center Experience

BACKGROUND

The Low-Profile Visualized Intraluminal Support (LVIS) device has been frequently used as an intracranial stent for treating intracranial aneurysms. However, the feasibility and efficacy of LVIS devices in Y-stent-assisted coiling (Y-SAC) have remained contentious. This study aimed to evaluate long-term angiographic and clinical outcomes of Y-SAC using LVIS devices.

METHODS

We retrospectively reviewed the clinical presentation and angiography data of patients treated with Y-SAC using LVIS stents. The vascular angle geometry between the parent and the 2 branch vessels, before and after stent deployment and after coiling, were analyzed. Based on the Raymond-Roy Occlusion Classification (RROC), aneurysm occlusion status was classified. Clinical outcomes were assessed using the modified Rankin Scale.

RESULTS

Forty patients with 40 aneurysms were included in this study. Immediate postprocedural angiograms showed complete/near-complete occlusion (RROC 1 and 2) in 31 aneurysms (77.5%). The long-term follow-up angiographic studies were available in 32 patients and showed RROC class 1 and 2 in 93.8% of patients. Y-SAC with LVIS devices significantly decreased the angle between the bifurcation branches from 171.90° ± 48.0° (standard deviation) to 130.21° ± 46.3° (standard deviation) (P < 0.0001). Periprocedural complications occurred in 5 patients (12.5%) including 4 in-stent thromboses (10.5%). Thirty-six patients (90.0%) had favorable clinical outcomes at the final follow-up. Univariate analysis showed that World Federation of Neurological Societies grade 3-5, thickness of subarachnoid hemorrhage on head computed tomography, intraprocedural complications, and in-stent thrombosis were predictors of poor outcome.

CONCLUSIONS

Y-SAC using the LVIS device for intracranial bifurcation aneurysms is a feasible and relatively safe procedure with favorable long-term angiographic and clinical outcomes.

Microsurgical Clipping of a Ruptured Wide-Neck Basilar Tip Aneurysm by an Extended Transsylvian Transcavernous Approach: 2-Dimensional Operative Video

Basilar tip aneurysms are difficult to treat due to their deep location, proximity to cranial nerves and brainstem, and risk of perforator stroke.1-3 A 49-year-old woman presenting to the emergency department with subarachnoid hemorrhage was found to have a wide-neck basilar tip aneurysm measuring 8.6 mm × 5.6 mm × 7.6 mm. The aneurysm had a 4.9-mm wide neck located at the level of the dorsum sellae.4,5 Microsurgical clipping was recommended to the patient due to the complexity of the aneurysm neck, the patient's young age, the expertise of the surgical-anesthetic team, treatment durability, and the low risk of recurrence.2,6-9 We used an extended transsylvian transcavernous approach to expose the aneurysm (Video 1). We preferred this anterolateral approach over the more lateral subtemporal transzygomatic approach because of its versatility in providing better visualization of the bilateral posterior cerebral arteries and superior cerebellar arteries.10 The surgical exposure to the proximal basilar artery was gained by drilling the posterior clinoid process and dorsum sellae. Two titanium clips were applied across the aneurysm neck, and indocyanine green angiography confirmed complete aneurysm obliteration. Protection of critical brainstem perforators was ensured using the rubber-dam technique. The patient tolerated the procedure well with no deficits at the 12-month follow-up. We review the microsurgical nuances of treating complex wide-neck basilar tip aneurysms that are not good candidates for endovascular treatment. Although endovascular tools are favored as the first-line treatment choice for most cerebral aneurysms, microsurgical clipping techniques remain an important tool in the contemporary cerebrovascular neurosurgeon's toolkit.2,6,11-15.

Innovation in Neurosurgery: Lessons Learned, Obstacles, and Potential Funding Sources

Innovation is central to neurosurgery and has dramatically increased over the last twenty years. Although the specialty innovates as a whole, only 3-4.7% of practicing neurosurgeons hold patents. Various roadblocks to innovation impede this process such as lack of understanding, increasing regulatory complexity, and lack of funding. Newly emerging technologies allow us to understand how to innovate and how to learn from other medical specialties. By further understanding the process of innovation, and the funding that supports it, Neurosurgery can continue to hold innovation as one of its's central tenets.

Microsurgical clipping vs Woven EndoBridge (WEB) device for the management of unruptured wide-neck bifurcation aneurysms

The Woven EndoBridge device (WEB) was introduced in 2010 to treat wide-neck bifurcation aneurysms (WNBAs). Three landmark studies have been conducted to assess its safety and efficacy: WEBCAST, WEBCAST 2, and French Observatory Study. However, these studies have not compared its safety and efficacy to other treatment modalities. In this study, we compare WEB versus microsurgical clipping in the management of unruptured WNBA. We conducted a retrospective study of unruptured WNBA meeting the morphological criteria to be amenable for WEB treatment operated on at our institution. Surgical morbidity, mortality, and occlusion rates were assessed. We compared our results to those reported in the cumulative population of the three WEB landmark studies at 1 year. A total of 84 patients with 89 WNBA were included. The most common aneurysm location was the middle cerebral artery bifurcation (n = 67/89, 75%). No operative mortality was observed. Morbidity comprised small-vessel vasospasm (n = 1/89, 1%) resulting in hemiparesis vs. 3% morbidity for WEB (p = .324). All but one (n = 1/89, 1%) WNBA were completely occluded vs WEB occlusion rate of 53% at 1 year, statistically significantly worse (p < .001). In our analysis, we were not able to show superiority of WEB in terms of procedural morbidity in comparison to microsurgical clipping, defined as worsening in mRS. Microsurgical clipping achieves statistically significantly higher rates of complete aneurysm occlusion, thus posing the question of whether the WEB should be presented as a viable, comparable alternative to patients amenable to surgical treatment.

Endovascular treatment of medium and large intracranial aneurysms with large volume coils: A single-center experience

Background:

Large volume coils are an alternative to conventional coils for the treatment of intracranial aneurysms. However, there are no published reports documenting occlusion and complication rates in medium and large intracranial aneurysms. Therefore, we present our results in this subgroup of aneurysms.

Methods:

A single-center, retrospective analysis of consecutive patients treated with Penumbra coils 400 in aneurysms ≥7 mm was performed. Demographics, aneurysm features, procedural details, intraoperative complications, clinical outcomes, and occlusion rates were analyzed.

Results:

Thirty-three patients were included for analysis, and a total of 33 intracranial aneurysms were analyzed. Mean age was 57.6 years (SD ± 12.4) and 85% of the patients were women. Large aneurysms represented 46% of cases. Paraclinoid (55%) followed by posterior communicating (30.3%) aneurysms was the most frequently treated. Ruptured and saccular aneurysms were found in 49% and 63% of the cases, respectively. The mean aneurysmal dimensions were 14.2 mm width, 11.9 mm length, 5.4 mm neck, and 2.4 dome-to-neck ratio. A dome-neck ratio <2 was identified in 39% of cases. The mean number of coils per aneurysm was 4.8. Immediate modified Raymond–Roy Grades 1, 2, and 3A were achieved in 15%, 21%, and 64%, respectively. Twenty-six patients were evaluated at a mean follow-up period of 11 months, with an adequate occlusion of 92% and a good clinical outcome (modified Rankin score ≤2) in 96% of patients.

Conclusion:

Endovascular treatment with PC400 coils is an effective and safe option for medium and large intracranial aneurysms with high occlusion rates, few complications, and good clinical outcomes at follow-up.

VICTORIA: VIrtual neck Curve and True Ostium Reconstruction of Intracranial Aneurysms

Purpose

For the status evaluation of intracranial aneurysms (IAs), morphological and hemodynamic parameters can provide valuable information. For their extraction, a separation of the aneurysm sac from its parent vessel is required that yields the neck curve and the ostium. However, manual and subjective neck curve and ostium definitions might lead to inaccurate IA assessments.

Methods

The research project VICTORIA was initiated, allowing users to interactively define the neck curve of five segmented IA models using a web application. The submitted results were qualitatively and quantitatively compared to identify the minimum, median and maximum aneurysm surface area. Finally, image-based blood flow simulations were carried out to assess the effect of variable neck curve definitions on relevant flow- and shear-related parameters.

Results

In total, 55 participants (20 physicians) from 18 countries participated in VICTORIA. For relatively simple aneurysms, a good agreement with respect to the neck curve definition was found. However, differences among the participants increased with increasing complexity of the aneurysm. Furthermore, it was observed that the majority of participants excluded any small arteries occurring in the vicinity of an aneurysm. This can lead to non-negligible deviations among the flow- and shear-related parameters, which need to be carefully evaluated, if quantitative analysis is desired. Finally, no differences between participants with medical and non-medical background could be observed.

Conclusions

VICTORIAs findings reveal the complexity of aneurysm neck curve definition, especially for bifurcation aneurysms. Standardization appears to be mandatory for future sac-vessel-separations. For hemodynamic simulations a careful neck curve definition is crucial to avoid inaccuracies during the quantitative flow analysis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13239-021-00535-w.