An assessment of how the anterior cerebral artery anatomy impacts ACoA aneurysm formation based on CFD analysis

OBJECTIVE

The aim of this study was to identify independent anatomic, morphologic and hemodynamic features of the ACoA (anterior communicating artery) complex that serve as risk factors for the occurrence of ACoA aneurysms.

METHODS

Fifteen consecutive patients with 15 ACoA aneurysms were included. Computational fluid dynamics (CFD) simulations based on patient-specific models were carried out using 3D time-of-flight magnetic resonance angiography (3D-TOF-MRA) images. A reverse reconstruction technique was used to generate a pre-aneurysm vessel anatomy. Geometric parameters and hemodynamic changes were compared and evaluated.

RESULTS

The overall prevalence of symmetric, dysplastic, and absent A1 segments were 53.3%, 26.7%, and 20%. The mean wall shear stress (WSS) of the absent group (AG) was significantly higher than that of the symmetric group (SG) and dysplastic group (DG). The absolute mean A1 artery flow rate (410.2 ± 88 versus 439.4 ± 101 mL/min; p = .45) of the aneurysm side was similar between the SG and DG but significantly higher in the AG (528.1 ± 77 mL/min; p < .05). The A1-A2 angles of the aneurysm side showed no significant differences among the 3 groups (p = .32). However, the mean A1-A2 angle on the aneurysm side was smaller than the contralateral A1-A2 angle (101.9 ± 9.1˚ versus 120.3 ± 7.7˚; p <.05). A regression analysis demonstrated that high WSS was significantly associated with a large A1-A2 ratio (R2=0.52; p <.05).

CONCLUSIONS

ACoA aneurysms are a high-WSS pathology. Severe flow impingement and the anatomic vasculature structures play a role in triggering the occurrence of ACoA aneurysms.

Classification of anterior communicating aneurysms on a basis of endovascular treatments

BACKGROUND AND PURPOSE

The anterior communicating artery (Acoma) aneurysms are difficult to understand because of their anatomical variations. This study reported a new classification of Acoma aneurysms on a basis of endovascular treatments.

METHODS

This retrospective study enrolled consecutive 94 patients harbored 100 Acoma aneurysms treated with coil embolization. All Acoma aneurysms were classified into 5 orientations (straight, superior, inferior, anterior, and posterior) based on the axis connecting A1 origin and the base of the aneurysm. Aneurysm characteristics, endovascular treatments, angiographic, and clinical outcomes were evaluated using this classification.

RESULTS

According to this classification, there were 64 (64%) straight, 16 (16%) inferior, 16 (16%) superior, 2 (2%) anterior, and 2 (2%) posterior projection aneurysms. There were significant differences between different groups in aneurysm height (p=0.009) and aneurysm neck size (p = 0.003), and in endovascular treatments (p=0.006). There was a significant difference in the proportion of rupture presentation among the three groups of straight, inferior, and superior (p = 0.019). There was no difference in the results of postoperative angiography (p = 0.090). An excellent functional outcome with an mRS ≤1 was achieved in 91 (96.8%) patients.

CONCLUSIONS

This classification of Acoma aneurysms based on the axis connecting A1 origin and the base of the aneurysm is associated with aneurysm height, aneurysm neck size, and in need for stent-assisted therapy. Endovascular embolization can provide the same effective treatment for aneurysms in all directions.

Retrospective Application of Risk Scores to Unruptured Anterior Communicating Artery Aneurysms

BACKGROUND

Treatment decisions for unruptured intracranial aneurysms (UIAs) pose a challenge for neurosurgeons, prompting the development of clinical scales assessing hemorrhage risk to provide management guidance. This study compares recommendations from the PHASES and UIA treatment scores (UIATS) applied to anterior communicating artery (AComA) UIAs against real-world management.

METHODS

While UIATS recommends management, for PHASES, an aneurysm with score of 10 or more was considered "high-risk". Analysis involved assessing the concordance in each group alongside comparison to real-word management.

RESULTS

Among 129 patients, 46.5% were observed and 53.5% were treated. PHASES scores were significantly higher in the treatment group (p = 0.00002), and UIATS recommendations correlated with real-world decisions (p < 0.001). We observed no difference in the frequencies of UIATS recommendations between high- and low-risk groups. When comparing the UIATS and PHASES, 33% of high-risk aneurysms received a UIATS conservative management recommendation. In 39% of high-risk aneurysms, the UIATS recommendation was not definitive. Conversely, 27% of low-risk aneurysms obtained a UIATS UIA repair recommendation. Overall, concordance between PHASES and UIATS was 32%.

CONCLUSIONS

Significant discordance in therapeutic suggestions underscores the predominant influence of center experience and individual assessments. Future studies should refine and validate decision-making strategies, potentially exploring alternative applications or developing tailored scales.

Endovascular Treatment of Anterior Communicating Artery Aneurysms: A Single-Center Experience from a Developing Country

Objective  In recent years, endovascular methods have been developed to treat intracranial aneurysms. To date, results of endovascular treatment (EVT) for anterior communicating aneurysms (ACoAs) have never been investigated in Iran. Thus, we sought to assess the mid-term angiographic and clinical outcomes of patients with ACoAs who underwent EVT in a tertiary center. Materials and Methods  Electronic health documents of patients with ACoAs who underwent EVT from March 2019 to July 2021 were retrospectively reviewed. Demographic and clinical characteristics of patients, procedural and clinical complications along with immediate and 12 months' postprocedural angiographic and clinical results were included in the analysis. Aneurysm occlusion status was classified based on the Raymond-Roy Occlusion Classification (RROC), and clinical outcomes were assessed using the modified Rankin Scale (mRS). Results  Of 38 patients with 38 ACoAs, 32 patients (84.21%) presented with subarachnoid hemorrhage of whom 23 (60.52%) had ruptured ACoAs. EVT included simple coiling in 29 patients (76.32%), balloon-assisted coiling in 6 (15.79%), and stent-assisted coiling in 3 (7.89%). Immediate and 12-month postprocedural angiograms demonstrated complete/near-complete occlusion (RROC I and II) in 32 (84.21%) and 35 patients (97.22%), respectively. Periprocedural complications occurred in five patients (13.15%), and the mortality rate was 5.26%. Thirty-two patients (84.21%) had favorable outcomes (mRS 0-2) at the last follow-up. Conclusion  EVT is a safe and beneficial procedure with favorable mid-term clinical and angiographic outcomes for ACoAs. Our results can lay the foundation for further studies in developing countries and are satisfactory enough for neurointerventionists to put EVT on the therapeutic agenda of ACoAs.

Endovascular treatment of traumatic anterior communicating artery-cavernous sinus fistula

Traumatic anterior communicating artery (AcomA)-cavernous sinus (CS) fistula is rare. Flow diverter (FD) deployment associated with coiling may be an alternative but has never been reported. We reported such a case. A 61-year-old man who was involved in a traffic accident presented with progressive exophthalmos for 2 weeks. Digital subtraction angiography showed a fistula between the AcomA and CS. First, the fistula was coiled. Then, the FD was deployed to cover the rupture point of the AcomA. The fistula was obliterated. Postoperatively, the patient recovered well, and his eye symptoms disappeared. Follow-up angiography showed no recurrence of the fistula. Therefore, for traumatic AcomA-CS fistula, FD deployment associated with coiling may be a feasible alternative.

Unruptured Anterior Communicating Artery Aneurysms: Management Strategy and Results of a Single-Center Experience

Although anterior communicating artery (AComA) unruptured intracranial aneurysms (UIAs) comprise one of the largest aneurysm subgroups, their complex adjacent neurovasculature and increased risk of rupture impede optimal management. In the present study, we analyzed the results of our diverse strategy in AComA UIAs with the additional goal of assessing the risk of treatment and the incidence of hemorrhage. We analyzed 131 patients, of which each was assessed by a multidisciplinary neurovascular team and assigned to observation (45.8%), endovascular treatment (34.4%) or microsurgery (19.8%). Median aneurysm sizes were 3, 7.2 and 7.75 mm, respectively. In the observation group, four (7.1%) aneurysms (initially <5 mm) grew over a median time of 63.5 months and were treated endovascularly. We found that fewer patients in the observation group were smokers (p = 0.021). The aneurysm size ratio was different between the combined treatment versus the observation group (p < 0.0001). Noteworthily, there were no hemorrhages in the observational group. Mortality for all patients with available follow-up was 2.4% (3/124) and permanent morbidity was 1.6% (2/124) over a mean follow-up of 64.2 months. These compelling rates refer to a high-risk group with potentially devastating consequences in which we have decreased the annual risk of hemorrhage to 0.14%.

Importance of Preoperative Vertical Geometric Analysis in Surgery for Anterior Communicating Artery Aneurysm

OBJECTIVE

In this study, we analyzed the vertical geometry of the anterior communicating artery (AComA) complex with the aim to improve the surgical site orientation during aneurysm operations. Further, the geometric data that can contribute to the success of the surgical technique applied for AComA aneurysms are reported.

METHODS

Computed tomography angiography data of the cerebral arteries of 100 patients who visited our clinic were analyzed. A three-dimensional examination was performed according to the Frankfurt horizontal plane (FHP) using the RadiAnt DICOM Viewer (Medixant, Poznan, Poland), and vertical measurements of the AComA complex were calculated.

RESULTS

The Willis polygon values were found to be consistent with those in the literature. The mean height of the AComA complex was 30.58 ± 4.80 mm according to the FHP.

CONCLUSIONS

Preoperative evaluation of the vertical geometry of the AComA complex is essential for AComA aneurysm surgery. The height of the AComA complex is a key parameter affecting intraoperative surgical site visibility. Preoperative calculation of the height of the AComA complex relative to FHP can facilitate intraoperative surgical site orientation.

Anatomical variations in the Circle of Willis and the formation and rupture of intracranial aneurysms: A systematic review and meta-analysis

Background

The anterior (AcomA) and posterior communicating arteries (PcomA) are two of the most frequent sites for intracranial aneurysms. Anatomical variations in the Circle of Willis (COW) are frequently observed in patients with AcomA and PcomA aneurysms. Strong evidence is needed to determine the pooled estimate of the effect of COW variations on the formation and rupture of these aneurysms.

Aim

This systematic review and meta-analysis aimed to establish the effect of COW variations on the formation and rupture of AcomA and PcomA aneurysms using available studies.

Summary of review

PubMed, Embase, and Web of Science databases were systematically searched for studies published in English before September 21, 2022. Studies investigating AcomA aneurysms and the hypoplastic/aplastic A1 segment of the anterior cerebral artery and PcomA aneurysms and hypoplastic/aplastic PcomA or fetal-type posterior cerebral artery (FTP) were included. The heterogeneity of the studies was assessed using Cochran Q-test and I² statistic. Pooled estimate was assessed using either a random- or fixed-effects model based on the heterogeneity of the studies. Among the 4,932 studies, 21 were eligible and included in the analysis. The presence of hypoplastic/aplastic A1 was significantly correlated with the formation [OR (95% confidence interval [CI]) = 7.97 (5.58, 11.39), P < 0.001] and rupture [OR (95%CI) = 1.87 (1.29, 2.72), P < 0.001] of AcomA aneurysms. Significant associations between FTP and both the formation [OR (95%CI) = 2.15 (1.41, 3.30), P < 0.001] and rupture [OR (95%CI) = 1.72 (1.26, 2.36), P < 0.001] of PcomA aneurysms were observed.

Conclusions

Significant associations were observed between COW variations and both the formation and rupture of AcomA and PcomA aneurysms. This can help in determining interventions for patients with aneurysms.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=225149, identifier: CRD42021225149.

Flow Diverter Devices in the Treatment of Anterior Communicating Artery Region Aneurysms: Would the Regional Anatomy and the Aneurysm Location Affect the Outcomes?

BACKGROUND

In this study, the authors evaluated the efficacy and the safety of flow diverter devices (FDD) in anterior communicating artery (ACoA) region aneurysms, focusing on anatomical factors that could affect the outcome, such as the location of the aneurysm along the ACoA (centered on ACoA or decentered on the A1-A2 junction) and the anatomy of the ACoA region.

METHODS

Clinical, procedural and follow-up data were analyzed. Aneurysms were classified according to the location along the ACoA (centered or decentered on the A1-A2 junction) and on the basis of the anatomical configuration of the ACoA region. Safety was assessed by recording intraprocedural, periprocedural and delayed complications to determine the morbidity and mortality rates. The functional outcome was evaluated with the modified Rankin scale (mRS) prior to and after the endovascular procedure. To assess the efficacy, midterm and long-term clinical, angiographic and cross-sectional imaging follow-ups were recorded. Subgroup analysis according to the different ACoA regional anatomical configurations and the ACoA aneurysm locations were performed.

RESULTS

33 patients (17 males; 16 females) with ACoA region aneurysms were treated with FDDs. 27 aneurysms were located at the A1-A2 junction (82%) while the remaining six aneurysms were centered on the ACoA. No mortality was recorded. The overall morbidity rate was 6% (2/33 procedures). Major complications occurred in 33% (2/6) of ACoA aneurysms and in the 0% of A1-A2 junction aneurysms. Mid-term and long-term neuroimaging follow-ups showed the occlusion of the aneurysm in 28/33 cases (85%). Complete occlusion rates were 93% in the A1-A2 junction aneurysms and 50% in ACoA aneurysms.

CONCLUSIONS

The FDD is a safe and effective tool that can be used in the treatment of selected cases of ACoA region aneurysms. The location of the aneurysm along the ACoA and the regional anatomy of the ACoA complex could affect the efficacy and safety.

Outcome of ruptured anterior communicating artery aneurysm treatment compared between surgical clipping and endovascular coiling: A single-center analysis

The optimal treatment modality for ruptured anterior communicating artery (ACoA) aneurysms is unclear. Therefore, in this study, we aimed to compare the outcomes of endovascular coiling and surgical clipping to treat ruptured ACoA aneurysms. A retrospective analysis of 213 consecutive patients with ruptured AcoA aneurysms, who were treated with coiling or clipping between January 2010 and December 2020, was conducted. Of the 213 patients, 94 and 119 underwent clipping and coiling, respectively. The mean age was higher in the coiling group than in the clipping group (60.3 ± 13.2 vs. 53.5 ± 13.4, P < .001). The mean diameter of the aneurysmal neck was larger in the clipping group (3.4 mm vs. 3.0 mm, P = .022), whereas the dome-to-neck ratio (1.53 ± 0.52 vs. 1.70 ± 0.60, P = .031) and aspect ratio (1.67 ± 0.51 vs. 1.92 ± 0.77, P = .005) were larger in the coiling group. The prevalence of vasospasm was higher in the clipping than in the coiling group (42.6% vs. 26.9%, P = .016). The coiling group had a shorter mean intensive care unit hospitalization (18.3 vs. 12.1, P = .002) and more frequently showed favorable outcomes (Glasgow Outcome Scale 4, 5; 57.4% vs 73.1%, P = .016) compared to the clipping group. Multivariable logistic analysis showed that good initial WFNS grade (odds ratio [OR] = 6.69, 95% confidence interval [CI]: 2.69-16.65, P < .001), treatment with coiling (OR = 3.67, 95% CI: 1.70-7.90, P = .001), and absence of the need for cerebrospinal fluid diversion (OR = 5.21, 95% CI: 2.38-11.39, P < .001) were independent predictors of favorable outcomes in patients with ruptured ACoA aneurysms. Ruptured ACoA aneurysms can be safely and effectively treated using both clipping and coiling modalities. However, it may be beneficial to consider coiling as the first option for treating these aneurysms.

A Neuropsychological Rehabilitation Framework to Address Cognitive and Neurobehavioral Impairments After Strokes to the Anterior Communicating Artery

Patients with strokes to the Anterior Communicating Artery (ACoA) pose an important challenge to rehabilitation teams due to a particular mix of cognitive and behavioral impairments (anosognosia, anterograde amnesia, prospective memory problems, and executive dysfunction). These deficits often compromise engagement with rehabilitation, learning and generalization. The goal of this article is to describe the long-term presentation of a patient with an ACoA stroke (Mrs. B, a 60-year-old electric engineer) as well as her rehabilitation needs and the many challenges experienced by the rehabilitation team when attempting to facilitate functional, vocational and psychosocial recovery. Based on this case, and the existing literature, a neuropsychological rehabilitation framework to understand and address the specific problems and needs of this population is proposed. This framework demands rehabilitation teams to consider: the slow pattern of recovery of this population, the interaction between cognitive and behavioral impairments, the relevance of physical and social environments, the value of personal projects and the need to include psychological and relational interventions.

Horizontal stenting via retrograde route for recurrent ruptured posterior communicating artery aneurysm after clipping: A case report and literature review

Treatment of recurrent ruptured aneurysms incorporating a branch vessel arising from the dome is challenging. Here, we attempted horizontal stent-assisted coil embolization via a retrograde route from the contralateral internal carotid artery to treat a small ruptured posterior communicating artery aneurysm incorporating a fetal variant posterior cerebral artery after clipping.

Clipping Could Be the Best Treatment Modality for Recurring Anterior Communicating Artery Aneurysms Treated Endovascularly

BACKGROUND

The anterior communicating artery (AcoA) is the most common location for intracranial aneurysms.

OBJECTIVE

To present occlusion outcomes, complication rate, recurrence rate, and predictors of recurrence in a large cohort with AcoA aneurysms treated primarily with endosaccular embolization. We also attempt to present data on the most effective treatment modality for recurrent AcoA aneurysms.

METHODS

This is a retrospective, single-center study, reviewing the outcomes of 463 AcoA aneurysms treated endovascularly between 2003 and 2018.

RESULTS

The study cohort consisted of 463 patients. Adequate immediate occlusion was achieved in 418 (90.3%). Independent functional status at discharge was observed in 269 patients (58.0%), and the mortality rate was 6.8% (31). At 6 months, adequate occlusion was achieved in 418 (90.4%). Of all the patients, recurrence was observed in 101 cases (21.8%), and of those, 98 (22.4%) underwent retreatment. The combined frequency of retreatment for the coiling group was 42.4%, which was significantly higher than the 0 incident of retreatment in the clipping group (P < .0001). Among the retreatment cohort, there was a significantly higher subsequent retreatment rate in the endovascular group (0% in the clipping group vs 42.4% in the endovascular group, P < .0001).

CONCLUSION

Coiling with and without stent/balloon assistance is a relatively safe and effective modality for the treatment of AcoA aneurysms; however, in the setting of recurrence, microsurgical reconstruction leads to improved outcomes regarding durable occlusion, thus avoiding the potential for multiple interventions in the future.

Flow diversion in anterior cerebral artery aneurysms

INTRODUCTION

Anterior cerebral artery (ACA) aneurysms are commonly encountered in clinical practice but can be challenging to treat. Flow diversion is a viable treatment in this population.

METHODS

We retrospectively evaluated patients treated at our center from May 2017 to December 2020 who underwent flow diversion for an ACA aneurysm at or distal to the anterior communicating artery (ACOM). We defined ACA aneurysms as any aneurysm involving the ACOM itself, at the junction of the ACA with the ACOM (A1/A2), or in distal A2/A3 branches; both ruptured and unruptured aneurysms were included. Baseline and follow-up clinical and angiographic data were collected; the primary measure was elimination of the aneurysm on follow-up angiogram. Patients underwent flow diversion with a Pipeline stent. A single flow diverting stent was placed in the dominant ACA spanning from the A2 segment extending into the A1 segment; two patients required H-pipe technique. Distal aneurysms were treated with a single Pipeline device deployed across the parent vessel, covering the aneurysm.

RESULTS

Two-seven patients underwent a total of 28 flow diversion procedures; median age was 57 and 16 (59.3%) were male. Thirteen (48.2%) patients presented with subarachnoid hemorrhage; of these, four were treated within 6 weeks of the index hemorrhage. Most patients (22; 81.5%) had significant ACA asymmetry. There was one postoperative intracerebral hemorrhage and one groin complication. Follow-up data were available for 19 patients, 15 (78.9%) of which showed no residual aneurysm and 17 (89.5%) had protection of the dome.

CONCLUSION

Flow diversion of ACA aneurysms can be a primary treatment modality in an unruptured aneurysm or a complement to initial coil protection of a ruptured aneurysm. Further studies are needed to confirm these results.

Partial Gyrus Rectus Resection as a Technique to Improve the Exposure to the Anterior Communicating Artery Complex through the Junctional Triangle: A Quantitative Study

Objective  The junctional triangle, formed by the distal A1 anterior cerebral artery (ACA) segment, the proximal A2 ACA segment, and the medial surface of gyrus rectus (GR), is a corridor of access to superiorly and posteriorly projecting anterior communicating artery (AComA) aneurysms that is widened by GR retraction or resection. Exposure of the AComA complex through the junctional triangle after GR resection has not been previously quantitatively evaluated. Design  GR resection extent and increase in artery exposure through the junctional triangle were assessed in this study. Setting  This study was conducted in the laboratory with a pterional approach, exposing the AComA complex. Participants  Ten sides of five cadaveric heads were considered. Main Outcome Measures  Exposure extent of ipsilateral and contralateral A1, A2, and AComA and accessibility of branches coming off the AComA complex were measured before and after GR resection. The GR was resected until sufficient bilateral A2 and contralateral A1 exposures were achieved. GR resection span was measured. Results  The mean (standard deviation) resected span of GR was 7 ± 3.9 mm. After GR resection, the exposed span of the ipsilateral A2 increased from 2 ± 0.7 mm to 4 ± 1.1 mm ( p  = 0.001); contralateral A2 exposure increased from 3 ± 1.5 mm to 4 ± 1.1 mm ( p  = 0.03). Contralateral recurrent artery of Heubner (RAH) and orbitofrontal artery were accessible in five and eight specimens, respectively, before GR resection and in all 10 after resection. Conclusion  GR resection improves exposure of bilateral A2 segments through the junctional triangle. Exposure improvement is greater for the ipsilateral A2 than contralateral A2. The junctional triangle concept is enhanced by partial GR resection during surgery for superior and posterior AComA aneurysms.

Evaluation of the Safety and Effectiveness of Coil Embolization for Anterior Communicating and Anterior Cerebral Artery Aneurysms

Objective

Endovascular coil embolization for anterior communicating artery (ACoA) and anterior cerebral artery (ACA) aneurysms is associated with high total and near-total occlusion rates, but the complication rate is high. The development of newer endovascular technologies may improve the clinical outcomes. This study investigated the status of endovascular treatment of ACoA and ACA aneurysms by comparing our results with past reports.

Methods

Between January 2006 and December 2018, we investigated 50 patients who were followed for 12 months or longer to clarify the outcomes of coil embolization. The outcomes of embolization were evaluated using time-of-flight MRA. The safety was evaluated based on procedure-related complications that affected clinical outcomes.

Results

Initial assessments demonstrated complete obliteration in 84% (42 of 50 patients) and a residual neck in 14% (7 of 50 patients). Procedure-related complications developed in 12% (6 of 50 patients). The procedure-related morbidity rate was 2% (1 of 50 patients) and there was no procedure-related death. Recanalization was noted in 14% (7 of 50 patients, median follow-up period, 57 months). The recanalized aneurysms were significantly smaller than the stable aneurysms in maximum size (4.3 mm vs. 5.8 mm; p = 0.017) and height (3.7 mm vs. 4.3 mm; p = 0.035).

Conclusion

We demonstrated the safety and effectiveness of endovascular coil embolization for ACoA and ACA aneurysms. The small size of aneurysms may be related to recanalization.

Collateral flow at circle of Willis in healthy condition

Experimental simulation of cerebrovascular system would be very beneficial tool to evaluate millions of human body cascade sequence. The Circle of Willis (CoW) recently named Cerebral Arterial Circle (CAC) is a main loop structure of cerebral circulatory system which positioned at the cranium base. In this research, we investigate cerebral artery flow pattern in cerebral arteries including afferent, Willisian, and efferent arteries of CAC emphasizing on communicating and connecting arteries which are main routes in CAC and as a risky sites when autoregulation is occurred in terminal parts of middle cerebral arteries (MCAs) by PMMA (Polymethyl methacrylate) chip and high quality camera which depict Sequential images. This novelty study analyze flow pattern in CAC that have been challenging subject area for many years which have investigated by scientists yet, because flow pattern in CAC indicate complication progression. This research tries to construct new platform in cerebral circulation analyzing method by reliable experimental in-vitro approach. The outcomes of this study demonstrate that communicating arteries especially anterior communicating artery (ACoA) is main artery in CAC flow distribution.

Endovascular Treatment of Ruptured Wide-Necked Anterior Communicating Artery Aneurysms Using a Low-Profile Visualized Intraluminal Support (LVIS) Device

Objective: To evaluate the safety and efficacy of low-profile visualized intraluminal support (LVIS) stent-assisted coiling for the treatment of ruptured wide-necked anterior communicating artery (ACoA) aneurysms.

Methods: The clinical and angiographic data of 31 acutely ruptured wide-necked ACoA aneurysms treated with LVIS stent-assisted coiling between January 2014 and December 2018 were retrospectively reviewed.

Results: All stents were successfully deployed. The immediate angiographic results were modified Raymond-Roy class I in 27 cases, modified Raymond-Roy class II in 2 cases, and modified Raymond-Roy class IIIa in 2 cases. Intraoperative thrombosis and postoperative aneurysmal rebleeding occurred in one case each. Two patients (6.5%) who were admitted due to poor clinical grade conditions died during hospital admission as a result of initial bleeding. Angiographic follow-up (mean: 12.9 months) was performed for 26 patients, the results of which demonstrated that 25 aneurysms were completely occluded and one was class II. The last clinical follow-up (mean: 25.3 months) outcomes demonstrated that 27 patients had favorable clinical outcomes and two had poor clinical outcomes.

Conclusion: LVIS stent-assisted coiling for ruptured wide-necked ACoA aneurysms was safe and effective, with a relatively low rate of perioperative complications and a high rate of complete occlusion at follow-up.

Anatomical variations and morphometric properties of the circulus arteriosus cerebri in a cadaveric Malawian population

BACKGROUND

Knowledge of the anatomy of the circulus arteriosus cerebri (CAC) is important in understanding its role as an arterial anastomotic structure involved in collateral perfusion and equalisation of pressure, and may explain observed variations in neurovascular disease prevalences across populations. This study was aimed at understanding the anatomical configuration and morphometric properties of the CAC in Malawian population.

MATERIALS AND METHODS

Brains were collected from 24 recently-deceased black Malawian human cadavers during medico-legal autopsies. Photographs of the CACs were taken using a camera placed at a 30 cm height from the base of the brain. Whole-circle properties and segmental vessel parameters were analysed using the OSIRIS computer programme, paying attention to completeness, typicality, symmetry, and segmental vessel diameters and lengths.

RESULTS

The complete-circle configuration was found in 69.57% of the CACs. Of these, 37.5% were typical, representing an overall typicality prevalence of 26.09%. Vessel asymmetry was observed in 30.43% of cases. There were 7 cases of vessel aplasia and 12 cases of vessel hypoplasia. The posterior communicating artery (PcoA) was the most variable (with 12 variations), widest (7.67 mm) and longest (27.7 mm) vessel while the anterior communicating artery (AcoA) was the shortest (0.78 mm). Both the AcoA and the PcoA were the narrowest vessels (0.67 mm) in this study. CAC variations in Malawian populations appeared to be similar to those observed in diverse populations.

CONCLUSIONS

Anatomical variations of the CAC exist in Malawian population and should be taken into consideration in clinical practice.

Morphological evaluation of the distal medial striate artery. A study with cadaveric material

OBJECTIVE

To evaluate the morphology of the distal medial striated artery, taking into account biometric variables useful for clinical and surgical management.

METHODS

A descriptive transversal study was performed with a sample of brains, who underwent autopsy at the Institute of Legal Medicine and Forensic Sciences of Bucaramanga-Colombia, which were evaluated using the perfusion technique of vascular structures with polyester resin.

RESULTS

The distal medial striated artery was presented in 1.4% and 4.2% duplicated in the right and left hemispheres respectively. Agenesis was presented in 2.8% in the left hemisphere. Its origin was 44.6% of the anterior cerebral artery junction site with the anterior communicating artery and was observed in 6 cases (4.2%) presented with a common trunk with the orbitofrontal artery. The main qualitative finding was the sinuous trajectory that was observed in 57.7% on the right side and 45.1% in the left hemisphere. Also, an important alteration found at the biometric analysis was hypoplasia that could be related to the decreased blood supply to the basal nuclei. The diameter was 0.5 ± 0.2 mm and its total length was 20.3 ± 4.1 mm.

CONCLUSIONS

The topographical knowledge of this structure determines the vulnerability of its morphology because it can complicate surgical procedures performed in the anterior segment of the arterial circle of the brain. Besides, the observed collateral circulation contributes to the blood supply and the perfect functionality of the subcortical nervous structures.

Current Treatment of Anterior Communicating Artery Aneurysms: Single Center Study

INTRODUCTION

Anterior communicating artery aneurysms (ACoAAs) are the most frequent intracranial aneurysms treated at neurosurgical departments with a vascular program.

MATERIAL AND METHODS

We reviewed patients with ACoAAs in a single institution over ten years (2008-2017). The focus was on the final outcome; complications, age, and clinical condition with respect to modalities were analyzed.

RESULTS

A total of 198 patients treated during this period was included in the study: 176 patients had a ruptured ACoAA and 22 had an unruptured ACoAA. Then, 127 (71%) were treated surgically and 51 (29%) by endovascular means. Out of the whole series, a good recovery occurred in 123 patients (62%), moderate disability in 11 (5.5%), severe disability in 19 (10%), vegetative state in 11 (5.5%), and death in 34 (17%). In the 157 patients (72.5%) with a subarachnoid hemorrhage (SAH), both modalities had a favorable outcome: 27.5% had an unfavorable outcome, 12% had complications in surgery versus 17.6% during endovascular treatment. No statistical difference in outcome, complications, and age was noted between modalities. Surgical treatment was more frequently adopted for patients in a better clinical condition (p ≤ 0.05).

CONCLUSION

More than two thirds of the patients (72.5%) reached a favorable outcome. There was no difference in age between the treatment modalities. Risks of complications are present and specific for both modalities.

Recurrence of Previously Clipped Anterior Communicating Aneurysm: The Surgical Techniques and Strategies: A Case Series

Background:

Microsurgical aneurysm (MSA) clipping is considered as the standard therapy with the endovascular coiling. Microsurgical clipping is considered superior to endovascular in terms of the recurrence rate. The management of recurrent aneurysm following previous microsurgical clipping is challenging. The management of recurrent aneurysm following previous microsurgical clipping is challenging. This study aims to explore the management of recurrent aneurysm of the anterior communicating artery (ACoM).

Materials and Methods:

This is a case series of three elder women who had a recurrence of ACoM aneurysm after MSA clipping. All the three patients were operated with microsurgical clipping. We studied the preoperative images of the first surgery of all the patients. The detailed case-by-case analysis was performed based on preoperative, postoperative, and follow-up radiologic examinations and operative findings.

Results:

All three patients who had a recurrence after MSA clipping of ACoM aneurysm and were asymptomatic. At presentation, they were diagnosed at the postoperative imaging at follow-up. The earliest recurrence was 1 year while in one patient; the recurrence was detected 8 years after the initial MSA clipping. The cerebral aneurysms were posteriorly directed in the initial preoperative images in all the cases.

Conclusion:

This study revealed the recurrence as the residual neck or the enlargement of the aneurysm even after MSA in these cases of ACoM aneurysm. Even with the complete clipping, there can be recurrence at the clip site due to the change in hemodynamics over the time. We should follow-up the patients regularly even after microsurgical clipping.

Impact of Postoperative Infarcts in Determining Outcome after Clipping of Anterior Communicating Artery Aneurysms

Background

Development of cerebral infarcts following clipping of ruptured intracranial aneurysm is one of the major determinants of functional outcome in patients with subarachnoid hemorrhage (SAH). The aim of this study is to evaluate the factors affecting development of postoperative infarcts, its incidence, pattern, and functional outcome.

Material and Methods

This study includes 118 patients of spontaneous SAH because of ruptured anterior communicating artery aneurysm, who underwent clipping. Relevant points in history, preoperative and intraoperative findings, and postoperative outcome are evaluated.

Results

29 of 118 (24.5%) patients developed postoperative radiological infarcts. Approximately 37.9%, 17.2%, and 3.4% patients developed isolated infarcts, respectively, in anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA) territory. About 20.7% patients developed infarcts in deep perforator territory. Nine of 29 (31.3%) patients developed multiple-vessel territory infarcts. Patients with poor preoperative neurologic status, prior history of seizure, and history of intraoperative rupture had higher chances of development of infarcts. Development of infarct was irrespective of temporary clipping (TC), duration of clipping, and elective versus rescue clipping. Development of infarcts adversely affected the outcome in significant proportions. Among patients with infarcts, unilateral ACA territory infarcts showed best prognosis, whereas all patients with multiple territory infarcts and PCA territory infarcts died. Age or sex of the patients did not affect the functional outcome. Timing of development of infarcts has no influence on functional recovery.

Conclusion

Development of symptomatic infarct is the sole important predictor of functional outcome. A crowded neurovascular neighborhood and complex variations in local angioarchitecture make anterior communication (ACOM) territory predisposed to operative insults. Elective TC and aggressive management of cerebral vasospasm are recommended to prevent development of infarcts.

Microsurgical Clip Suspension to Prevent Optic Neuropathy Following Ligation of Anterior Communicating Artery Aneurysm: A Technical Report and Surgical Video

Anterior communicating artery (ACoA) aneurysms are among the most common intracerebral aneurysms. Complications of ACoA aneurysm include subarachnoid hemorrhage, which may occur spontaneously or as a result of trauma. While prognosis of microsurgical clip ligation is excellent, iatrogenic afferent pupillary defect secondary to mechanical compression of the optic nerve by the clips is a known complication. Our report presents a case of a 59-year-old female status post resection of a pituitary macroadenoma one year ago with a three- to four-week history of progressively worsening headache found to have a 6.5 x 5.4 mm wide neck and irregularly dysplastic aneurysmal dilation of the ACoA. During the operation, two of the longer clips appeared to be touching the optic nerve and we utilized a clip suspension technique to relieve compression. This gently elevated and suspended the two clips up to the dura, allowing for a 2 mm gap between the optic nerve and clips. This maneuver relieved mechanical compression against the optic nerve and potentially mitigated the need for surgical re-exploration in the future. 

An Institutional Experience of Fenestrated T-Bar Clip Use in The Management of Intracranial Aneurysms

Surgical management of an intracranial aneurysm is mainly clipping. Various types of clips have been designed for complex, giant, and other aneurysms. Recently, the Yasargil-fenestrated T-bar clip has been introduced for the management of such complicated aneurysms. The literature regarding its efficacy, limitations, and method of application in complicated aneurysms is limited. We used the fenestrated T-bar clip in four patients of intracranial aneurysms - middle cerebral artery cortical branch aneurysm, anterior communicating artery partially thrombosed aneurysm, internal carotid artery paraclinoid simple aneurysm, and giant aneurysm. All aneurysms were successfully clipped with no residue or branch occlusion. The recovery of all patients was satisfactory. The fenestrated T-bar clip effectively reconstructed the parent artery and occluded the aneurysm in all cases. The application of this clip may be advantageous over the clip application in some uniquely challenging cases.

Safety and efficacy of anterior communicating artery compromise during endovascular coil embolization of adjoining aneurysms

OBJECTIVE

In the presence of symmetric A1 flow, the safety and efficacy of compromising the anterior communicating artery (ACoA) during coil embolization of ACoA aneurysms has yet to be evaluated. Herein, the authors describe their experience, focusing on procedural safety.

METHODS

Between October 2012 and July 2017, 285 ACoA aneurysms with symmetric A1 flows were treated at the authors' institution by endovascular coil embolization. Clinical and angiographic outcome data were subjected to binary logistic regression analysis.

RESULTS

ACoA compromise was chosen in the treatment of 71 aneurysms (24.9%), which were completely (n = 15) or incompletely (n = 56) compromised. In the remaining 214 lesions, the ACoA was preserved. Although 9 patients (3.2%) experienced procedure-related thromboembolisms (compromised, 4; preserved, 5), all but 1 patient (with ACoA compromise) were asymptomatic. In multivariate analysis, subarachnoid hemorrhage at presentation was the sole independent risk factor for thromboembolism (OR 15.98, p < 0.01), with ACoA compromise being statistically unrelated. In 276 aneurysms (96.8%) with follow-up of > 6 months (mean 20.9 ± 13.1 months, range 6-54 months), recanalization was confirmed in 21 (minor, 15; major, 6). A narrow (≤ 4 mm) saccular neck (p < 0.01) and ACoA compromise (p = 0.04) were independently linked to prevention of recanalization.

CONCLUSIONS

During coil embolization of ACoA aneurysms, the ACoA may be compromised without serious complications if A1 flows are symmetric. This approach may also confer some long-term protection from recanalization, serving as a valid treatment option for such lesions.

Side-to-Side Bypass between Bilateral Distal Anterior Cerebral Arteries and Surgical Trapping of a Pseudoaneurysm from the Anterior Communicating Artery: Lessons Learnt

Background:

Treatment options for a ruptured anterior communicating artery (ACoA) pseudoaneurysm are limited. In most cases trapping of the ACoA is the best treatment option. Occasionally, bypass surgery is warranted to ensure blood flow to the contralateral anterior cerebral artery (ACA) in cases with one dominant A1. We report a case of an ACoA pseudoaneurysm presenting with delayed subarachnoid hemorrhage following surgical clipping of an unruptured ACoA aneurysm, with a review of the literature.

Case description:

A 74-year-old female had undergone surgical clipping of a 1.2-cm-sized unruptured ACoA aneurysm through the left supraorbital keyhole approach. During the operation, there had been a small tear between the aneurysm neck and the right proximal A2, and the tear point was controlled by clipping of the tear site. One month later, she was admitted again because of subarachnoid hemorrhage. Cerebral angiography showed a probable pseudoaneurysm from the previous tear site. The patient had a dominant left A1 with a right A1 aplasia. The pseudoaneurysm was treated with side-to-side bypass between the distal ACAs and subsequent trapping of the ACoA harboring a pseudoaneurysm. Both the distal ACAs were preserved; however, post-hemorrhagic neurological sequelae remained.

Conclusions:

Side-to-side bypass between distal ACAs and surgical trapping of the ACoA for the ruptured ACoA pseudoaneurysm was a good rescue option to prevent rebleeding and preserve blood supply to the contralateral ACA territory.

A Median Artery of the Corpus Callosum

The anterior communicating artery is one of the main components of the vascular network that delivers blood to the brain. Therefore, a good understanding of the normal anatomy and its variations is important to neurologists, neurosurgeons, and other health care providers dealing with the central nervous system. Here, we present a case of a median artery of the corpus callosum found in a cadaver, with consideration of cerebral hemodynamics implications.

The Impact of Variational Primary Collaterals on Cerebral Autoregulation

The influence of the anterior and posterior communicating artery (ACoA and PCoA) on dynamic cerebral autoregulation (dCA) is largely unknown. In this study, we aimed to test whether substantial differences in collateral anatomy were associated with differences in dCA in two common types of stenosis according to digital subtraction angiography (DSA): either isolated basal artery and/or bilateral vertebral arteries severe stenosis/occlusion (group 1; group 1A: with bilateral PCoAs; and group 1B: without bilateral PCoAs), or isolated unilateral internal carotid artery severe stenosis/occlusion (group 2; group 2A: without ACoA and with PCoA; group 2B: with ACoA and without PCoAs; and group 2C: without both ACoA and PCoA). The dCA was calculated by transfer function analysis (a mathematical model), and was evaluated in middle cerebral artery (MCA) and/or posterior cerebral artery (PCA). Of a total of 231 non-acute phase ischemic stroke patients who received both dCA assessment and DSA in our lab between 2014 and 2017, 51 patients met inclusion criteria based on the presence or absence of ACoA or PCoA, including 21 patients in the group 1, and 30 patients in the group 2. There were no significant differences in gender, age, and mean blood pressure between group 1A and group 1B, and among group 2A, group 2B, and group 2C. In group 1, the PCA phase difference values (autoregulatory parameter) were significantly higher in the subgroup with patent PCoAs, compared to those without. In group 2, the MCA phase difference values were higher in the subgroup with patent ACoA, compared to those without. This pilot study found that the cross-flow of the ACoA/PCoA to the affected area compensates for compromised dCA in the affected area, which suggests an important role of the ACoA/PCoA in stabilizing cerebral blood flow.

Microsurgical clipping for anterior communicating artery aneurysm associated with the accessory anterior cerebral artery via the pterional approach

BACKGROUND

Accessory anterior cerebral artery (ACA), a type of median artery of anomalous triplicate ACA, is not rare, but aneurysms of the anterior communicating artery (ACoA) associated with accessory ACA can be a considerable challenge to treat surgically based on the morphological features of the ACoA complex.

CASE DESCRIPTION

A 35-year-old man was admitted to our hospital with severe headache and subsequent loss of consciousness. Initial computed tomography (CT) showed typical findings of subarachnoid hemorrhage in the basal cistern and three-dimensional CT angiography revealed an ACoA aneurysm arising from the trifurcation of the accessory ACA, the branching point of the ACoA, and the right A1 or A2 segment of the ACA. The aneurysmal fundus projected superolaterally to the right, and was treated via a right-sided pterional approach. The aneurysm was behind the ipsilateral A2 segment of the ACA and the accessory ACA was hidden behind the aneurysm. The aneurysm was successfully obliterated with clipping using a straight fenestrated Yasargil titanium clip. Complete aneurysm occlusion and patency of both the A2 segment of the ACA and the accessory ACA were confirmed intraoperatively by indocyanine green angiography.

CONCLUSION

In treating this aneurysm via the pterional approach, selection of approach side it is critical to preserve prevent the patency of the accessory ACA and to simultaneously perform aneurysm clipping without leaving a neck remnant. Selecting the optimal approach based on preoperative neuroimaging of which side will allow both these actions is important.

Memory Impairment Due to a Small Acute Infarction of the Columns of the Fornix

BACKGROUND

Clinically infarction of the columns of the fornix is very rare. It is also easy to be overlooked during imaging examination due to the special anatomical localization and features of columns of the fornix. In the meantime, with memory disorder to be its most prominent manifestation, it is very easily false diagnosed as other diseases when the lesion focus is overlooked, causing unnecessary invasive examinations like cerebrospinal fluid tests.

METHODS

Case report and Literature review.

RESULTS

We presented a 66-year-old woman with memory impairment due to a small acute infarction of the columns of the fornix. Through her diagnosis and treatment, we believed that early diagnosis and treatment were important to these patients who were enduring the disease. In addition, literature review informed us that for those unwilling to undergo cerebral angiography or for small cerebrovascular lesions that cannot be detected by angiography, 7T magnetic resonance imaging (MRI) might be an ideal diagnostic method.

CONCLUSION

This case illustrated the significance of MRI in diagnosis for patients with acute memory impairment. When reading MRI results, one needs to pay attention to identify small lesions at special locations. In addition, cerebral apoplexy is still the first consideration of diagnosis when acute memory impairment occurs in patients with cerebrovascular disease risk factors.

Evaluation of an ischemic model in ischemia prone and general Mongolian gerbils by neurological symptom, injury, and sex difference

BACKGROUND

In the previous study, we established an ischemia-prone gerbil population (IG), which was selectively bred to increase the incidence of unilateral carotid arterial occlusion (UCO)-induced ischemia in Mongolian gerbils. However, if the characteristics of ischemia model in IG are the same as those in general gerbils (GG), and if the neurological symptoms are associated with the neurological insults in IG is still unclear.

METHODS

In the present study, we evaluated the UCO model in IG by analyzing neurological symptoms, neurological injury in the hippocampal CA1 region and compared with GG.

RESULTS

The data showed that the ratios of neurological symptom scores ≥ 2 in the IG and GG groups were 65.0% vs 30.0%, respectively, and were significantly different (P < .01).The neuronal damage following a UCO ischemic insult in the IG group was more severe compared to the GG group. There was a high correlation between the neurological insults' scale and the neurological symptom score in the IG and GG groups (r = .979 and .943 in the IG and GG groups, respectively). In animals with mild neurological symptom scores (2 and 3), the neuronal insults were significantly different between female and male gerbils in both IG and GG.

CONCLUSION

Our findings suggest that IG population would likely be more advantageous to establish an ischemic model.

Rupture of a non-traumatic anterior communicating artery aneurysm: Does location of aneurysm associate with functional independence following post-acute in-patient neurorehabilitation?

OBJECTIVE

Patients with non-traumatic rupture of an aneurysm located at the anterior communicating artery (ACoA) often experience cognitive disabilities. It is unknown whether location of aneurysm also affects the possibility for improvement in functional independence compared to patients with an aneurysmal subarachnoid hemorrhage (a-SAH) located elsewhere. The aim was to explore the association between location of aneurysm (ACoA versus other) and level of functional independence, measured by Functional Independence Measure (FIM), at discharge from rehabilitation. Additionally, age and FIM at admission were explored.

METHOD

Historical cohort study among 107 patients with a-SAH based on data from a clinical database and a population-based register. Data were analyzed using multivariable logistic regression.

RESULTS

Patients with ACoA were admitted with poorer cognitive FIM (median 6 (IQR 5-14) compared to patients with aneurysms located elsewhere (median 12 (IQR 6-23) (p = 0.0129); no difference at discharge. No association between aneurysm location and functional independence was observed. Higher age was associated with poorer outcome in bowel management OR 0.54 (95% CI 0.31-0.92), bladder management OR 0.59 (95% CI 0.35-0.98), comprehension OR 0.53 (95% CI 0.30-0.94), and memory OR 0.48 (95% CI 0.25-0.93). Overall, FIM at admission was associated with functional independence at discharge with the exception of stair walking and bladder management which did not reach statistical significance.

CONCLUSION

ACoA was not associated with poorer level of functional independence compared to patients with a-SAH located elsewhere. Higher age was associated with poorer outcome in continence, comprehension, and memory, whereas higher FIM was associated with better functional independence across items at discharge.

Safety and efficacy of balloon angioplasty of the anterior cerebral artery for vasospasm treatment after subarachnoid hemorrhage

Balloon angioplasty is often performed for symptomatic vasospasm following aneurysmal subarachnoid hemorrhage. Angioplasty of the anterior cerebral artery (ACA), however, is perceived to be a challenging endeavor and not routinely performed due to technical and safety concerns. Here, we evaluate the safety and efficacy of balloon angioplasty of the anterior cerebral artery for vasospasm treatment. Patients with vasospasm following subarachnoid hemorrhage who underwent balloon angioplasty at our institution between 2011 and 2016 were retrospectively reviewed. All ACA angioplasty segments were analyzed for pre- and post-angioplasty radiographic measurements. The degree of vasospasm was categorized as mild (<25%), moderate (25-50%), or severe (>50%), and relative change in caliber was measured following treatment. Clinical outcomes following treatment were also assessed. Among 17 patients, 82 total vessel segments and 35 ACA segments were treated with balloon angioplasty. Following angioplasty, 94% of segments had increased caliber. Neurological improvement was noted in 75% of awake patients. There were no intra-procedural complications, but two patients developed ACA territory infarction, despite angioplasty treatment. We demonstrate that balloon angioplasty of the ACA for vasospasm treatment is safe and effective. Thus, ACA angioplasty should be considered to treat vasospasm in symptomatic patients recalcitrant to vasodilation infusion therapy.

Is there an inherited anatomical conformation favoring aneurysmal formation of the anterior communicating artery?

OBJECTIVE The pathophysiological mechanisms responsible for the formation of intracranial aneurysms (IAs) remain only partially elucidated. However, current evidence suggests a genetic component. The purpose of this study was to investigate the specific anatomical variations in the arterial complex that are associated with the presence of anterior communicating artery (ACoA) aneurysms in the familial forms of IAs. METHODS This multicenter study investigated bifurcation IAs in patients who had a sporadic ACoA IA without a family history of IA (SACAA group), in patients who had an ACoA IA with a family history of IA (FACAA group), and in their healthy first-degree relatives (HFDRs). Through the use of MR angiography (MRA) reconstructions, the symmetry of the A₁ segments and the angle between the A₁ and A₂ segments were analyzed on 3D models for each group. These measurements were then compared among the 3 groups. RESULTS Twenty-four patients with SACAA, 24 patients with FACAA, and 20 HFDRs were included in the study. Asymmetrical configuration of the A₁ segments was more frequent in the FACAA group than in the HFDR group (p = 0.002). The aneurysm-side A₁-A₂ angle was lower in the FACAA group (p = 0.003) and SACAA group (p = 0.007) than in the HFDR group. On the contralateral side, there was no difference in A₁-A₂ angles between groups. CONCLUSIONS The anatomical shape of the ACoA complex seems to be similarly associated with the presence of ACoA IAs in both the FACAA and SACAA groups. This highlights the role played by hemodynamic constraints in aneurysm formation and questions the hypothesis of the hereditary character of these anatomical shapes.

High resolution MRI in treatment decision of anterior communicating artery aneurysm accompanied by visual symptoms: Endovascular treatment or surgical clipping? A report of two cases and literature review

Anterior communicating artery (AComA) aneurysm accompanied by visual symptoms is rarely reported. The first case is an asymptomatic 65-year-old woman who presented with an AComA aneurysm, and the pre-procedure high-resolution magnetic resonance imaging (MRI) revealed an AComA aneurysm compressed the left optic nerve and the chiasma with a size of 8.3 × 9.2 mm. She suffered a sudden onset of left eye visual loss and the temporal hemianopia of the right eye after endovascular embolization. She had a light sensation of the left eye and minor enlargement of the visual field in the right eye at the six-month follow-up. The second case is a symptomatic 55-year-old woman suffering a visual loss in the left eye and inferior nasal quadrantanopsia in her right eye. Pre-operative high-resolution MRI found an AComA aneurysm compressing the left part of the chiasma with a size of 7.1 × 8.3 mm. Her visual symptoms improved after surgical clipping. High-resolution MRI could depict the anatomic relationship between the AComA aneurysm and the surrounding optic pathways. Endovascular treatment of an AComA aneurysm may result in visual deterioration due to the mass effect or ischemia after the procedure. Surgical clipping of the AComA aneurysm could relieve the compression symptoms.

Safety of coil occlusion of the parent artery for endovascular treatment of anterior communicating artery aneurysm

Many studies lay emphasis on the clinical importance of perforating branches of the anterior communicating artery (ACoA) and report that vascular damage of the perforators from ACoA aneurysm during surgery cause subsequent postoperative amnesia. The purpose of our study was to analyze the safety of parent artery occlusion for ACoA aneurysm coiling based on the anatomical features of the ACoA complex in 13 patients with 13 ACoA aneurysms. All patients underwent coiling of the aneurysm sac and ACoA. Aneurysm characteristics including size, dome-to-neck ratio, anterior/posterior orientation of the aneurysm dome with respect to the axis of the pericallosal artery, location of the aneurysm neck with respect to the A1-A2 segment of the anterior cerebral artery (ACA) or the ACoA, and the presence of hypoplasia/aplasia of A1 segment were assessed. The aneurysm neck was located directly on the ACoA in five aneurysms (38%), whereas eight (62%) had the neck located at the A1-A2 junction. Of the five patients whose aneurysm neck was located in the ACoA, four patients had infarcts in the basal forebrain. Three of the patients complained of amnesia. None of the aneurysms with the neck located at the A1-A2 junction were associated with infarction. There has been little evidence thus far that parent vessel occlusion of ACoA aneurysms is a safe method for the treatment of aneurysms. Patients with the aneurysm neck located at the A1-A2 junction and without A1 aplasia, who were treated with aneurysm sac and ACoA embolism, were potentially safe.

Anterior communicating artery aneurysm: Accuracy of CT angiography in determination of inflow dominance

BACKGROUND

Preoperative assessment of anterior communicating artery (AcoA) aneurysms with cerebral angiography is common, but not without risk. Computed tomography angiography (CTA) is a widely available imaging modality that provides quick acquisition, low morbidity, and low cost. One disadvantage is that it does not provide dynamic information. In this study, the authors sought to determine whether CTA alone can reliably predict the inflow dominance to an AcoA aneurysm.

METHODS

Eighty-three patients with ruptured AcoA aneurysms were reviewed retrospectively. Only those patients with both preoperative CTA and cerebral angiogram were included, thus excluding six patients. Four independent observers reviewed the CTAs and attempted to identify the dominant A1. Additionally, three mathematical models were created to identify the dominant A1. These responses were compared to cerebral angiograms.

RESULTS

Four observers were correct in judging the dominant A1 an average of 93% of the time. Seventeen cases were read incorrectly by only one of four observers, and three cases were read incorrectly by two observers. For cases with incorrect readings, the average percentage difference in A1 sizes was 19.6%. For cases read unanimously correct, the average percentage difference in A1 sizes was 42.7%. Mathematical model #3 correctly evaluated the dominant A1 in 97% of the cases.

CONCLUSIONS

This study found CT angiograms can be reliable in predicting the inflow dominance to the majority of AcoA aneurysms.

Height of aneurysm neck and estimated extent of brain retraction: powerful predictors of olfactory dysfunction after surgery for unruptured anterior communicating artery aneurysms

OBJECTIVE

The highest incidence of olfactory dysfunction following a pterional approach and its modifications for an intracranial aneurysm has been reported in cases of anterior communicating artery (ACoA) aneurysms. The radiological characteristics of unruptured ACoA aneurysms affecting the extent of retraction of the frontal lobe and olfactory nerve were investigated as risk factors for postoperative olfactory dysfunction.

METHODS

A total of 102 patients who underwent a pterional or superciliary keyhole approach to clip an unruptured ACoA aneurysm from 2006 to 2013 were included in this study. Those patients who complained of permanent olfactory dysfunction after their aneurysm surgery, during a postoperative office visit or a telephone interview, were invited to undergo an olfactory test, the Korean version of the Sniffin' Sticks test. In addition, the angiographic characteristics of ACoA aneurysms, including the maximum diameter, the projecting direction of the aneurysm, and the height of the neck of the aneurysm, were all recorded based on digital subtraction angiography and sagittal brain images reconstructed using CT angiography. Furthermore, the extent of the brain retraction was estimated based on the height of the ACoA aneurysm neck.

RESULTS

Eleven patients (10.8%) exhibited objective olfactory dysfunction in the Sniffin' Sticks test, among whom 9 were anosmic and 2 were hyposmic. Univariate and multivariate analyses revealed that the direction of the ACoA aneurysm, ACoA aneurysm neck height, and estimated extent of brain retraction were statistically significant risk factors for postoperative olfactory dysfunction. Based on a receiver operating characteristic (ROC) analysis, an ACoA aneurysm neck height > 9 mm and estimated brain retraction > 12 mm were chosen as the optimal cutoff values for differentiating anosmic/hyposmic from normosmic patients. The values for the area under the ROC curves were 0.939 and 0.961, respectively.

CONCLUSIONS

In cases of unruptured ACoA aneurysm surgery, the height of the aneurysm neck and the estimated extent of brain retraction were both found to be powerful predictors of the occurrence of postoperative olfactory dysfunction.

Clipping of a ruptured anterior communicating artery aneurysm with right A1-A2 sectioning and reanastomosis

We showcase the microsurgical clipping of a previously coiled and ruptured anterior communicating artery aneurysm, done through a right-sided approach. Initial clipping with a fenestrated clip occluded the flow in the right A2. After temporary clipping of both A1 and A2 vessels, we cut the right A1 and A2, clipped the aneurysm with a straight clip while preserving the flow in the left A1 and A2 and then performed reanastomosis of the right A1-A2 in an end to end fashion. This strategy allowed for complete obliteration of the aneurysm while preserving the flow in all four vessels. The video can be found here: http://youtu.be/4Y024zU5NVo.

Clipping and STA-MCA bypass for unruptured AcomA aneurysm associated with unilateral MCA occlusion

The authors show a surgical technique of clipping in conjunction with superficial temporal artery (STA)-middle cerebral artery (MCA) bypass to treat unruptured anterior communicating artery (AcomA) aneurysm associated with unilateral MCA occlusion. First, through MCA occlusion side, fronto-temporal craniotomy, extra-dural drilling of lesser sphenoid wing, and followed by wide exposure of Sylvian fissure, STA-MCA bypass was performed. Then, through trans-Sylvian, fronto-basal, and lateral trajectory, interhemispheric fissure was dissected from the base, which enabled good exposure and clipping of high positioned AcomA aneurysm. The video can be found here: http://youtu.be/GWItnRSs3m4 .

Relationship between the morphology of A-1 segment of anterior cerebral artery and anterior communicating artery aneurysms

BACKGROUND

The anterior communicating artery (ACoA) is one of the most frequent sites for cerebral aneurysm. The peculiar directions of projection of aneurysms offer great challenges to clinical treatment.

OBJETIVES

To establish the relationship between morphology of A-1 segment of anterior cerebral artery (ACA) and aneurismal projection.

METHODS

Randomly selected digital subtraction angiography data of 264 anterior communicating artery aneurysms (ACoAA) cases and 296 cases of other cerebral vascular diseases in the same period were retrospectively analyzed.

RESULTS

Among 264 ACoAA patients, the morphology of A-1 segment showed type 1a in 158 sides, type 1b in 11, type 2a in 35, type 1 2b in 87, type 3 in 171 and absence in 66. The morphology of A-1 segment in 296 patients with other cerebral vascular diseases displayed type 1a in 195 sides, type 1b in 20, type 2a in 47, type 2b in 74, type 3 in 217 and absence in 39. The non-visualization of A-1 segment in the group of ACoAA occurred more than in the control group (χ(2)=11.482, p=0.001). The classifications of ACoAAs in 264 patients were confirmed as anterior-superior type in 121 cases, anterior-inferior type in 105, complicated type in 16, posterior-inferior type in 12 and posterior-superior type in 10. The correlation between morphology of A-1 segment of ACA and classifications of ACoAA was significant (p=0.000; C=0.619, p=0.000). The direction of ACoAA was downward when the A-1 segment of ACA was Type 1a or Type 2a, and was upward when it was Type 1a or Type 2a and was upward or downward or complicated when it was Type 3.

CONCLUSION

The relationship between morphology of A-1 segment of ACA and classification of ACoAA is clarified in the present study, which is helpful to surgical treatment.

Anterior communicating artery aneurysm presenting with vision loss

Anterior communicating artery aneurysm rarely presents with symptoms of compression of anterior visual pathways. We report a case of 65 years old man, who had complete loss of vision in right eye and temporal hemianopsia in left eye due to giant anterior communicating artery aneurysm.

[Microsurgical anatomy importance of A1-anterior communicating artery complex]

BACKGROUND

The anterior cerebral artery originates from the bifurcation of the internal carotid artery lateral to the optic chiasm, then joins with its contralateral counterpart via the anterior communicating artery. A1-anterior communicating artery complex is the most frequent anatomical variants and is the major site of aneurysms between 30 to 37%.

OBJECTIVE

Know the anatomy microsurgical, variants anatomical and importance of complex precommunicating segment-artery anterior communicating in surgery neurological of the pathology vascular, mainly aneurysms, in Mexican population.

METHODS

The study was performed in 30 brains injected. Microanatomy was studied (length and diameter) of A1-anterior communicating artery complex and its variants.

RESULTS

60 segments A1, the average length of left side was 11.35 mm and 11.84 mm was right. The average diameter of left was 1.67 mm and the right was 1.64 mm. The average number of perforators on the left side was 7.9 and the right side was 7.5. Anterior communicating artery was found in 29 brains of the optic chiasm, its course depended on the length of the A1 segment. The average length of the segment was 2.84 mm, the average diameter was 1.41 mm and the average number of perforators was 3.27. A1-anterior communicating artery complex variants were found in 18 (60%) and the presence of two blister-like aneurysms.

CONCLUSION

It is necessary to understand the A1-anterior communicating artery complex microanatomy of its variants to have a three-dimensional vision during aneurysm surgery.

Regulation of pre-natal circle of Willis assembly by vascular smooth muscle Notch signaling

The circle of Willis (cW) is a major arterial collateral structure interconnecting hemispheric circulation within the brain, and in humans, anatomical variation of the cW is linked to stroke risk. Our prior studies on adult mice deficient in vascular smooth muscle cell (vSMC) Notch signaling revealed altered cerebroarterial maturation and patterning, including an anatomically incompetent cW similar to human variants. However, a developmental dependency on Notch signaling for cW formation in this model remained uncharacterized. Through temporospatial embryonic analyses, we now demonstrate that cW assembly is a pre-natal process highly sensitive to vSMC Notch signals, whose absence results in delayed nascent vascular plexus formation and under-development of the cW including the key anterior communicating artery (AComA) interconnecting anterior forebrain circulation. Mutant embryos additionally feature reduced vSMC coverage, non-uniform calibers and asymmetric branching at bifurcations of the major proximal cerebral arteries. At the cellular level, a notable reduction in vascular endothelial cell proliferation exists in the region of AComA assembly despite the presence of Vegfa. Furthermore, Notch signaling-deficient vSMCs in developing cerebral vessels feature reduced Pdgfrβ and Jagged1 levels and impaired proliferation. These collective findings in the embryonic brain support studies in adult animals demonstrating a reliance on intact vSMC Notch signaling for optimal neovascular responses to angiogenic stimuli. Importantly, the new data provide unique insights into the native formation of the cW and underscore a pioneering developmental role for vSMC Notch signaling in regulating temporospatial assembly of the clinically relevant cW.

Microsurgical clipping of previously coiled intracranial aneurysms

OBJECTIVE

Endovascular coiling techniques for the treatment of intracranial aneurysms have rapidly developed as an alternative option to surgical clipping. A distinct problem after endovascular coiling is the management of a residual aneurysm neck due to incomplete filling, compaction of coils or regrowth of the aneurysm. Treatment options in this situation include surgical clipping, re-coiling, stent implantation or observation.

METHODS

From June 2006 to August 2011, 15 patients underwent surgical clipping of residual or recurrent aneurysms after previous endovascular treatment. The mean age of the patients was 50.6 years (range, 27-85 years). The mean interval between coiling and clipping was 76.5 weeks (range, 0-288 weeks).

RESULTS

Thirteen patients revealed a regrowth of coiled aneurysms, and in 5 patients compaction of coils was present. Coil extrusion was observed in 9 patients intraoperatively. In case of coil obstruction at the aneurysmal neck during surgery, coils were partially or completely removed. In all cases complete occlusion of the aneurysms was surgically achieved.

CONCLUSION

Coiled aneuryms with incomplete occlusion, coil compaction or regrowth of the aneurysmal neck can be successfully treated with microsurgical clipping. Coil extrusion was more often observed intraoperatively than expected. Complete occlusion of the aneurysm can be performed safely, even if loops of coils protrude into the aneurysmal neck. In these cases intraoperative removal of the coils enables secure closure of the aneurysm with a surgical clip.

Unilateral subfrontal approach to anterior communicating artery aneurysms: A review of 28 patients

BACKGROUND

The pterional approach is the most common for AComm aneurysms, but we present a unilateral approach to a midline region for addressing the AComm complex. The pure subfrontal approach eliminates the lateral anatomic dissection requirements without sacrificing exposure. The subfrontal approach is not favored in the US compared to Asia and Europe. We describe our experience with the subfrontal approach for AComm aneurysms treated at a single institution.

METHODS

We identified 28 patients treated for AComm aneurysms through the subfrontal approach. Patient records and imaging studies were reviewed. Demographics and case data, as well as clinical outcome at 6 weeks and 1 year were collected.

RESULTS

Mean patient age was 48 (range 21-75) years and 64% suffered subarachnoid hemorrhage (SAH). All aneurysms were successfully clipped. Gyrus rectus was resected in 57% of cases, more commonly in ruptured cases. Intraoperative rupture occurred in 11% of cases. The average operative time was 171 minutes. There were two patient deaths. Ninety-two percent of patients had a Glasgow Outcome Scale (GOS) of 5 at 6 weeks. All unruptured patients had a GOS of 5. At 12 months, 96% of all patients had a GOS of 5.

CONCLUSIONS

The subfrontal approach provides an efficient avenue to the AComm region, which reduces opening and closing friction but still yields a comprehensive operative window for access to the anterior communicating region.

Ruptured anterior communicating artery aneurysm causing bilateral oculomotor nerve palsy: a case report

A rare case of bilateral third cranial nerve palsy due to a ruptured anterior communicating artery aneurysm is presented. A 68-yr-old woman was semicomatose with bilaterally fixed dilated pupil, abducted eyes, and ptosis. A computed tomography demonstrated extensive hemorrhage spreading around the both Sylvian and interhemisheric fissure without focal mass effect. Intracranial pressure via extraventricular drainage before surgery was 15-50 mmHg. Three months later, brain MRI showed infarction of left posterior cerebral artery territory and lacuna infarction of the pons. Eleven months after aneurysm repair, nerve palsy improved slowly and recovered partially. The patient communicated well with simple words. The author reviewed and discussed the possible mechanism of this rare neuro-ophthalmological manifestation in view of a false localizing sign.

Influence of lamina terminalis fenestration on the occurrence of the shunt-dependent hydrocephalus in anterior communicating artery aneurysmal subarachnoid hemorrhage

Recently, it was reported that fenestration of the lamina terminalis (LT) may reduce the incidence of shunt-dependent hydrocephalus in aneurysmal subarachnoid hemorrhage (SAH). The authors investigated the efficacy of the LT opening on the incidence of shunt-dependent hydrocephalus in the ruptured anterior communicating artery (ACoA) aneurysms. The data of 71-ruptured ACoA aneurysm patients who underwent aneurysmal clipping in acute stage were reviewed retrospectively. Group I (n=36) included the patients with microsurgical fenestration of LT during surgery, Group II (n=35) consisted of patients in whom fenestration of LT was not feasible. The rate of shunt-dependent hydrocephalus was compared between two groups by logistic regression to control for confounding factors. Ventriculo-peritoneal shunts were performed after aneurysmal obliteration in 18 patients (25.4%). The conversion rates from acute hydrocephalus on admission to chronic hydrocephalus in each group were 29.6% (Group I) and 58.8% (Group II), respectively. However, there was no significant correlation between the microsurgical fenestration and the rate of occurrence of shunt-dependent hydrocephalus (p>0.05). Surgeons should carefully decide the concomitant use of LT fenestration during surgery for the ruptured ACoA aneurysms because of the microsurgical fenestration of LT can play a negative role in reducing the incidence of chronic hydrocephalus.