Dome Projection Research Articles

Ruptured middle cerebral artery bifurcation aneurysms with concomitant intracerebral hematoma: Clinical and morphological risk factors.

The prognosis for intracerebral hematoma (ICH) following the rupture of a middle cerebral artery bifurcation (Mbif) aneurysm is poor. We compared patients with isolated diffuse subarachnoid hemorrhage (SAH) (without ICH) following Mbif aneurysm rupture to those with both SAH and ICH to evaluate clinical and morphological risk factors for ICH. A retrospective study was conducted on 112 patients with ruptured Mbif aneurysms treated between July 2016 and December 2021. We investigated age, sex, medical history (hypertension, diabetes mellitus, and smoking), rebleeding, aneurysm neck and dome size, bottleneck factor, aspect ratio, dome projection, trunk diameters and ratios, parent artery (M1) dimensions, angles between both trunks (γ1, γ2, γ3), as well as M1 length and diameter, and internal carotid artery/M1 (α) and internal carotid artery/anterior cerebral artery (β) angles. These measurements were obtained using computerized tomography angiography to assess risk factors. A total of 88 patients (78.6%) with ruptured Mbif aneurysms who met the inclusion criteria were included in the study. A total of 39 (44.3%) patients had SAH with ICH, while 49 (53.7%) patients had pure diffuse SAH. Rebleeding was significantly higher in patients with ICH (P = .02). Morphological analysis revealed that the decrease in M1 diameter and α angle, along with an increase in aneurysm size and neck, were significantly different in the ICH group (P = .025, P = .012, P = .009, and P = .005, respectively). Receiver operating characteristic curve analysis showed that a cutoff value of α = 125° had the highest diagnostic accuracy (area under the curve = 0.71), with a sensitivity of 86.26% and specificity of 68.7%. The formation of ICH following the rupture of Mbif aneurysms is associated with specific morphological parameters.

The Importance of Aneurysm Morphology and Perianeurysmal Environment in Aneurysmal Subdural Hematomas

Aim: Aneurysmal subdural hematoma (anSDH) is an uncommon condition associated with significant mortality risk. This study focused on the relationship between morphology and the perianeurysmal environment by comparing aneurysm location and clinical outcomes. Material and Methods: A total of 486 patients with aneurysmal subarachnoid hemorrhage were retrospectively analyzed for accompanying subdural hematoma (SDH) cases. Demographic information, rebleeding, discharge, and 6 months of the modified Rankin scale scores (favorable and unfavorable) were recorded. The aneurysms were divided into 3 groups: internal carotid artery (ICA), anterior cerebral artery (ACA), and middle cerebral artery (MCA). Other parameters included aneurysm morphology, SDH width, intracerebral hematoma (ICH) volume, the presence of intraventricular hematoma, and distance to the subdural space. Results: Concomitant SDH was detected in 19 (3.9%) patients. Aneurysms were located in the ICA, 10 (52.6%); MCA, 8 (42.1%); and ACA, one (5.3%). The mean size was 9.5±4.3 mm, and there was a significant difference in aneurysm size between the ICA and MCA (p=0.025). In six supraclinoid aneurysms (posterior communicating and anterior choroidal arteries), the aneurysm dome was in the inferior lateral projection. No significant differences were observed between patients with favorable and unfavorable modified Rankin scale in terms of clinical and aneurysm morphological characteristics, except for increased ICH volume (p=0.020) and shift effects (p=0.030). Conclusion: The size and dome projection of ICA supraclinoid segment aneurysms may be important risk factors for SDH. We also believe that aneurysm localization may have a limited impact on clinical outcomes in the context of SDH.

Correlation Between Aneurysm Dome Direction and Patient Outcomes Following Surgery for Ruptured Anterior Communicating Artery Aneurysms.

Background Anterior communicating (Acom) artery aneurysms are the most common type of intracranial aneurysms. Despite the enormous advancements in the field of endovascular surgery for intracranial aneurysms, open surgical clipping of aneurysms remains the most durable management of Acom aneurysms. There have been various studies based on the clinical-radiological profile and outcome of open clipping for intracranial aneurysms, but the correlation of the direction of the aneurysm with the surgical outcome remains incompletely defined. Aim To analyze the correlation between the direction of the aneurysm dome and patient outcomes after surgery for ruptured Acom artery aneurysms. Materials and methods CT angiography of the brain was done in all patients pre-operatively as part of the standard treatment protocol. Retrospective data was collected from an inter-departmental computerized database, which included the patient's details, history, investigations, a course in the hospital from admission to discharge, and an operative note by the surgeon. Prospective data was collected from patients with ruptured Acom artery aneurysms. We analyzed the relationship between the direction of the dome of the Acom aneurysm and preoperative, intraoperative, and postoperative variables. Results Of the 48 patients who underwent surgery for ruptured aneurysms, 34 (70.8%) were female and 14 (29.2%) were male. Among the 27 cases with anteriorly projecting aneurysms, 11 (40.7%) experienced postoperative complications. Of the five cases with posteriorly projecting aneurysms, two (40%) experienced postoperative complications. One-third of cases of the inferior dome direction and 10% of cases of the superior direction of the dome of aneurysm were also found to have postoperative complications. However, using the chi-square test, the association between postoperative complications and the direction of the aneurysm was determined to be statistically non-significant (p-value = 0.93). Conclusion The findings of our investigation indicate that aneurysms with superior projection exhibit the lowest likelihood of experiencing intraoperative rupture. However, it was seen that the outcome was influenced by dome projection throughout the three-month follow-up. The findings of our study indicate that aneurysms with a superior orientation exhibit the least likelihood of experiencing intraoperative rupture.

Impact of Morphological Factors on the Future Growth of Unruptured Posterior Communicating Artery Aneurysms

No previous study has established the factors associated with intracranial aneurysm growth using imaging data obtained before the appearance of morphological changes. Therefore, we investigated the factors related to future aneurysm growth in posterior communicating artery (Pcom) aneurysms. Using a longitudinal database of intracranial aneurysm cases, we reviewed the findings for consecutive patients with unruptured Pcom aneurysms admitted to our institute from 2012 to 2021. Magnetic resonance images obtained over time were used to evaluate aneurysm growth. Aneurysms showing growth over time (group G) and unchanged aneurysms (group U) were compared in terms of background data and morphological factors. 93 Pcom aneurysms (group G: 25 aneurysms, 25%; group U: 68 aneurysms, 75%) were eligible for the present study. Six aneurysm rupture events occurred in group G (24%). Among morphological factors, Pcom diameter (1.2±0.3mm vs. 0.8±0.7mm, P<0.01), bleb formation (group G: 39% vs. group U: 10%; odds ratio, 5.6; P=0.01), and the lateral projection of the dome (group G: 52% vs. group U: 13%; odds ratio, 3.2; P=0.023) were significantly different between the 2 groups. The sensitivity and specificity of a cutoff Pcom diameter of 0.73mm for predicting enlargement were 96% and 53%, respectively. Pcom diameter, bleb formation, and lateral dome projection were associated with growth of Pcom aneurysms. Aneurysms with these risk factors require careful follow-up imaging, which may facilitate early detection of aneurysm growth and prevention of rupture through therapeutic interventions.

Impact of dome projection on operative steps during clipping of a ruptured pure posteriorly directed posterior communicating artery aneurysms

Background: Ruptured posterior communicating artery (PCoA) aneurysms are common; they usually present with subarachnoid haemorrhage (SAH) and oculomotor nerve palsy. The aneurysmal dome projection may influence the safety access and aneurysmal neck clipping. Here, we discuss additional intraoperative steps that may be required to widen the surgical field to ensure safe surgical clipping of a rupture pure posteriorly directed PCoA aneurysm. Case description: A previously healthy 38-year-old male reported sudden severe headache and disturbed level of consciousness with a Glasgow coma scale (GCS) of 13. His initial computed tomography (CT) scan of the head showed SAH in the basal cistern. 3D-constructed CT angiography (CTA) revealed a left pure posteriorly directed PCoA aneurysm. In the surgery, through the left pterional approach, all intraoperative steps were carried out. Additional steps were performed as well. Three additional intraoperative steps were contemplated because a pure posteriorly directed PCoA aneurysm is not well appreciated and is often hidden behind the supra cliniold internal carotid artery (ICA). First, the extension of Sylvian fissure dissection to include the distal part and the proximal. Second, temporal pole mobilization is performed by cutting small anterior temporal veins. Third, a brain retractor is placed on the temporal lobe to gently tract the superficial part of the lobe. All these steps widened the surgical corridor to ensure the aneurysm's safe clipping. Conclusion: Surgical clipping is influenced by the aneurysmal dome projection. In a ruptured pure posteriorly directed PCoA aneurysm, further intraoperative steps may facilitate complete access and safe clipping of the aneurysm.

Microneurosurgical management of aneurysms of the A1 segment of the anterior cerebral artery: Anatomy and surgical technique.

Background: Aneurysms of the A1 segment of the anterior cerebral artery (ACA) are rare and have characteristics differentiating them from other intracranial aneurysms. Their microsurgical management is challenging and requires different strategies. In this article, we review the surgical anatomy of the A1 segment of the ACA with cadaveric dissections and describe the microsurgical management of complex A1 aneurysms with illustrative cases.Methods: A right pterional craniotomy and Sylvian dissection were performed on a formalin-fixed and silicone-injected cadaver head to depict the key anatomic structures and surgical corridors for microsurgical clipping of A1 segment aneurysms. The microneurosurgical management of ruptured and unruptured aneurysms of the A1 segment of the ACA is described with case illustrations.Results: The A1 segment of the ACA can be subdivided into proximal, middle, and distal subsegments, the former having abundant perforating branches. Both patients treated with microsurgical clipping had excellent and durable outcomes and postoperative cerebral angiograms showed complete aneurysm occlusion.Conclusion: Small A1 aneurysms may require early treatment as their rupture risk appears to be higher. A1 aneurysms are usually embedded in perforators, especially those arising from the proximal A1 subsegment, and require careful distal to proximal microdissection and strategic placement of the aneurysm clip blades. The approach, arachnoid dissection, and angles of attack are carefully planned after accounting for the aneurysm dome projection, precise location of the aneurysm neck and perforators, and the presence or absence of subarachnoid hemorrhage.

A comparative analysis of the endoscopic endonasal and pterional approaches for clipping anterior communicating artery aneurysms on three-dimensional printed models.

A comparative analysis of the endoscopic endonasal and pterional approaches for clipping anterior communicating artery aneurysms on three-dimensional printed models.

Microsurgical Management of the Middle Cerebral Artery Bifurcation Aneurysms: An Anatomic Feasibility Study

Background: The proper head positioning decreases the surgical complications by enabling a better surgical maneuverability. Middle cerebral artery (MCA) bifurcation aneurysms have been classified by Dashti et al. [Surg Neurol. 2007 May;67(5):441–56] as the intertruncal, inferior, lateral, insular, and complex types based on dome projection. Our aim was to identify the optimum head positions and to explain the anatomic variables, which may affect the surgical strategy of MCA bifurcation aneurysms. Methods: The lateral supraorbital approach bilaterally was performed in the 4 cadaveric heads. All steps of the dissection were recorded using digital camera. Results: The distal Sylvian fissure (SF) dissection may be preferred for insular type and the proximal SF dissection may be preferred for all other types. Fifteen degrees head rotation was found as the most suitable position for the intertruncal, lateral type and subtype of complex aneurysms related with superior trunk. Thirty degrees head rotation was found the most suitable position for the inferior type, insular type, and subtype of complex aneurysms related with inferior trunk. Conclusions: The head positioning in middle cerebral bifurcation aneurysms surgery is a critical step. It should be tailored according to the projection and its relationship with the parent vessels of the middle cerebral bifurcation.

Monumentos Virtuais e Memória:

Este artigo apresenta o projeto artístico interdisciplinar e colaborativo "Monumentos Virtuais", sendo uma pesquisa poética sobre projection art. Tal projeto é uma parceria entre Brasil e África do Sul, realizado a partir de registros em áudio e vídeo do cotidiano das cidades brasileiras de Santa Maria (RS) e Fortaleza (CE), e da cidade sul-africana de Durban. A proposta artística é desenvolvida para projeção em cúpula, tela panorâmica 360o e video mapping. O projeto problematiza noções de memória e monumento, confrontando narrativas oficiais e imponentes em detrimento da vida cotidiana e da efemeridade diária. Neste sentido, práticas em arte e tecnologia tornam-se um espaço e um tempo de resistência e de revitalização de outros sentidos para a vida, sob um olhar contemporâneo.&#x0D; Palavras-chave: Monumentos Virtuais. Memória. Colaboração. Projection Art. Cinema Expandido.

Microsurgical Clipping of an Unruptured Basilar Apex Aneurysm: 2-Dimensional Operative Video.

Aneurysms of the basilar artery apex are generally at an increased risk of rupture compared with aneurysms in other locations, and the risk of rupture increases with increasing aneurysm size. Therefore, these lesions necessitate treatment to decrease the risk of rupture. The location, size, and directionality of dome projection influence the difficulty of microsurgical treatment. The patient presented with an incidental basilar apex aneurysm identified on workup for headaches. The aneurysm projected superoposteriorly into the interpeduncular cistern. The surgical approach involved a wide exposure of the basilar apex complex and meticulous identification and preservation of P1 perforators during clip applications. It was imperative to visualize all perforators on both sides of the clip prior to application, given the severe morbidity associated with a perforator infarct. The patient tolerated the procedure well and remained neurologically intact after the operation. This video is an exemplary demonstration of basilar apex aneurysm clip application for an incidentally discovered aneurysm. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary. Used with permission from Barrow Neurological Institute, Phoenix, Arizona.

Stereo Inverse Brightness Modulation for Guidance in Dynamic Panorama Videos in Virtual Reality

AbstractThe peak of virtual reality offers new exciting possibilities for the creation of media content but also poses new challenges. Some areas of interest might be overlooked because the visual content fills up a large portion of viewers' visual field. Moreover, this content is available in 360° around the viewer, yielding locations completely out of sight, making, for example, recall or storytelling in cinematic Virtual Reality (VR) quite difficult.In this paper, we present an evaluation of Stereo Inverse Brightness Modulation for effective and subtle guidance of participants' attention while navigating dynamic virtual environments. The used technique exploits the binocular rivalry effect from human stereo vision and was previously shown to be effective in static environments. Moreover, we propose an extension of the method for successful guidance towards target locations outside the initial visual field.We conduct three perceptual studies, using 13 distinct panorama videos and two VR systems (a VR head mounted display and a fully immersive dome projection system), to investigate (1) general applicability to dynamic environments, (2) stimulus parameter and VR system influence, and (3) effectiveness of the proposed extension for out‐of‐sight targets. Our results prove the applicability of the method to dynamic environments while maintaining its unobtrusive appearance.

Morphology parameters for rupture in middle cerebral artery mirror aneurysms

ObjectiveTo identify the morphological parameters correlated with the rupture of middle cerebral artery (MCA) aneurysms.MethodsWe retrospectively analyzed the digital subtraction angiography (DSA) data of 48 patients with ruptured mirror MCA...

Exploring neural and peripheral physiological correlates of simulator sickness

AbstractThis article investigates neural and physiological correlates of simulator sickness (SS) through a controlled experiment conducted within a fully immersive dome projection system. Our goal is to establish a reliable, objective, and in situ measurable predictive indicator of SS. SS is a problem common to all types of visual simulators consisting of motion sickness‐like symptoms that may be experienced while and after being exposed to a dynamic, immersive visualization. It leads to ethical concerns and impaired validity of simulator‐based research. Due to the popularity of virtual reality devices, the number of people exposed to this problem is increasing and, therefore, it is crucial to find reliable predictors of this condition before any symptoms appear. Despite its relevance and the several theories about its origins, SS cannot yet be quantitatively modeled and predicted. Our results indicate that, while neural correlates did not materialize, physiological measures may be a solid early indicator of oncoming SS.

Factors determining the best surgical exposure and safe clip positioning in surgical treatment of anterior communicating artery (AComA) aneurysms - particular significance of AComA complex rotation in the axial plane.

The aim of this study was to evaluate whether Anterior Communicating Artery (AComA) complex rotation in axial plane may influence the ease of surgical exploration in this region and safety of clip positioning when left vs right-sided approach is compared. This is a retrospective study based on analysis of patients operated due to AComA aneurysm, both ruptured and unruptured. AComA complex position in relation to coronal plane was evaluated using 3D-CTA VR reconstructions. Next, comparison between surgical approach from the side where A1-A2 junction (angle) was located anterior and posterior to coronal plane was performed in relation to surgical difficulties and intra- and postoperative complications. Subgroup statistical analysis revealed that there is a strong and statistically significant correlation between AComA complex rotation and surgical difficulties expressed by the need of repeated temporary clip application and brain transgression. When anterior vs posterior angle side approach was compared in relation to surgical difficulties and complications, there was a statistically significant difference with strong correlation (p &lt; 0.05) in favour of posterior angle side approach. Interestingly, in 72.7% and 45.5% of patients that were operated from the side where A1-A2 junction was located posterior to coronal plane, the approach was performed form the side of a non-dominant A1 and aneurysm dome projection side, respectively. Despite its limitations, our results suggest that microsurgical clipping strategy of AComA aneurysms should at least include AComA complex rotation in axial plane, besides well acknowledged factors, when deciding from which side these lesions will be approached.

Anatomical triangles defining routes to anterior communicating artery aneurysms: the junctional and precommunicating triangles and the role of dome projection.

Anterior communicating artery (ACoA) aneurysms are common intracranial aneurysms. Despite advances in endovascular therapy, microsurgical clipping remains an important treatment for aneurysms with broad necks, large size, intraluminal thrombus, complex branches, or previous coiling. Anatomical triangles identify safe corridors for aneurysm access. The authors introduce the A1-A2 junctional triangle and the A1-A1 precommunicating triangle and examine relationships between dome projection, triangular corridors of access, and surgical outcomes. Preoperative catheter and CT angiograms were evaluated to characterize aneurysm dome projection. Aneurysm projection was categorized into quadrants and octants. Preoperative, intraoperative, and postoperative factors were correlated to aneurysm dome projection and patient outcomes using univariate and multivariate analyses. A total of 513 patients with microsurgically treated ACoA aneurysms were identified over a 13-year period, and 400 had adequate imaging and follow-up data for inclusion. Surgical clipping was performed on 271 ruptured and 129 unruptured aneurysms. Good outcomes were observed in 91% of patients with unruptured aneurysms and 86% of those with ruptured aneurysms, with a mortality rate < 1% among patients with unruptured aneurysms. Increasing age (p < 0.01), larger aneurysm size (p = 0.03), and worse preoperative modified Rankin Scale score (p < 0.01) affected outcomes adversely. Aneurysms projecting superiorly and posteriorly required dissection in the junctional triangle, and multivariate analysis demonstrated worse clinical outcomes in these patients (p < 0.01). Anteriorly and inferiorly projecting aneurysms involve only the precommunicating triangle, are simpler to treat microsurgically, and have more favorable outcomes. Superior and posterior dome projections make ACoA aneurysms more difficult to visualize and require opening the junctional triangle. Added visualization through the junctional triangle is recommended for these aneurysms in order to facilitate dissection of efferent branch arteries, careful clip application, and perforator preservation. Dome projection can be determined preoperatively from images and can help anticipate dissection routes through the junctional triangle.

Isolated abducens nerve palsy associated with subarachnoid hemorrhage: a localizing sign of ruptured posterior inferior cerebellar artery aneurysms.

OBJECTIVE Compressive cranial nerve syndromes can be useful bedside clues to the diagnosis of an enlarging intracranial aneurysm and can also guide subsequent evaluation, as with an acute oculomotor nerve (cranial nerve [CN] III) palsy that is presumed to be a posterior communicating artery aneurysm and a surgical emergency until proven otherwise. The CN VI has a short cisternal segment from the pontomedullary sulcus to Dorello's canal, remote from most PICA aneurysms but in the hemodynamic pathway of a rupturing PICA aneurysm that projects toward Dorello's canal. The authors describe a cranial nerve syndrome for posterior inferior cerebellar artery (PICA) aneurysms that associates subarachnoid hemorrhage (SAH) and an isolated abducens nerve (CN VI) palsy. METHODS Clinical and radiological data from 106 surgical patients with PICA aneurysms (66 ruptured and 40 unruptured) were retrospectively reviewed. Data from a group of 174 patients with other aneurysmal SAH (aSAH) were analyzed in a similar manner to control for nonspecific effects of SAH. Univariate statistical analysis compared incidence and risk factors associated with CN VI palsy in subarachnoid hemorrhage. RESULTS Overall, 13 (4.6%) of 280 patients had CN VI palsy at presentation, and all of them had ruptured aneurysms (representing 13 [5.4%] of the 240 cases of ruptured aneurysms). CN VI palsies were observed in 12 patients with ruptured PICA aneurysms (12/66 [18.1%]) and 1 patient with other aSAH (1/174 [0.1%], p < 0.0001). PICA aneurysm location in ruptured aneurysms was an independent predictor for CN VI palsy on multivariate analysis (p = 0.001). PICA aneurysm size was not significantly different in patients with or without CN VI palsy (average size 4.4 mm and 5.2 mm, respectively). Within the PICA aneurysm cohort, modified Fisher grade (p = 0.011) and presence of a thick cisternal SAH (modified Fisher Grades 3 and 4) (p = 0.003) were predictors of CN VI palsy. In all patients with ruptured PICA aneurysms and CN VI palsy, dome projection and presumed direction of rupture were directed toward the ipsilateral and/or contralateral Dorello's canal, in agreement with laterality of the CN palsy. In patients with bilateral CN VI palsies, a medial projection with extensive subarachnoid blood was observed near bilateral canals. CONCLUSIONS This study establishes a localizing connection between an isolated CN VI palsy, SAH, and an underlying ruptured PICA aneurysm. CN VI palsy is an important clinical sign in aSAH and when present on initial clinical presentation may be assumed to be due to ruptured PICA aneurysms until proven otherwise. The deficit may be ipsilateral, contralateral, or bilateral and is determined by the direction of the aneurysm dome projection and extent of subarachnoid bleeding toward Dorello's canal, rather than by direct compression.

Effect of Different Display Types on Vection and Its Interaction With Motion Direction and Field Dependence.

Illusory self-motion (vection) can be generated by visual stimulation. The purpose of the present study was to compare behavioral vection measures including intensity ratings, duration, and onset time across different visual display types. Participants were exposed to a pattern of alternating black-and-white horizontal or vertical bars that moved either in vertical or horizontal direction, respectively. Stimuli were presented on four types of displays in randomized order: (a) large field of view dome projection, (b) combination of three computer screens, (c) single computer screen, (d) large field of view flat projection screen. A Computer Rod and Frame Test was used to measure field dependence, a cognitive style indicating the person’s tendency to rely on external cues (i.e., field dependent) or internal cues (i.e., field independent) with respect to the perception of one’s body position in space. Results revealed that all four displays successfully generated at least moderately strong vection. However, shortest vection onset, longest vection duration, and strongest vection intensity showed for the dome projection and the combination of three screens. This effect was further pronounced in field independent participants, indicating that field dependence can alter vection.

Presigmoid Approach to Vertebrobasilar Artery Aneurysms: A Series of 31 Patients and Review of the Literature

The presigmoid approach can be used to treat vertebrobasilar artery aneurysms when circumstances require more operative exposure. High morbidity and mortality in these cases have been reported. In this study, we describe our modified presigmoid approach for vertebrobasilar artery aneurysms and our clinical results. This series includes patients with vertebrobasilar aneurysms clipped via the modified presigmoid approach at the Department of Neurosurgery at Helsinki University Hospital from 1998 to 2014. Data were collected from the operating record books, patients' medical records, and a radiologic database server. Thirty-three presigmoid procedures of 31 patients were performed to treat 34 aneurysms (14 ruptured, 20 unruptured). The aneurysms had a mean distance from the posterior clinoid process to the aneurysm neck of 12.2 mm (range, 0-26.6 mm). A favorable outcome was achieved in 21 patients (64%). A favorable outcome was achieved in 74% of unruptured and good-grade patients, whereas favorable outcome was achieved in only 36% of poor-grade patients. Complete or near-complete occlusion was achieved in 79%. Larger aneurysms, fusiform morphology, and anterior dome projection had lower occlusion rates. We have described our experiences of using the presigmoid approach to treat vertebrobasilar aneurysms. The clinical and radiographic results are acceptable given the complex location and configuration of the treated aneurysms. Unfavorable outcomes are related to the poor admission Hunt and Hess grade, aneurysm morphology, and aneurysm size.

The Implication of Anterior Communicating Complex Rotation and 3-Dimensional Computerized Tomography Angiography Findings in Surgical Approach to Anterior Communicating Artery Aneurysms

To investigate the usefulness of 3-dimensional computerized tomography angiography (3D-CTA) in the microsurgical management of anterior communicating artery (AcomA) aneurysms. Twenty-six consecutive patients with AcomA aneurysms (22 ruptured) underwent microsurgical clipping. Detailed angioanatomic assessment of the AcomA complex and operative approach was based on the 3D-CTA. The 3D-CTA showed a dominant proximal anterior cerebral artery (A1) segment in 61% and symmetric A1s in 39% of aneurysms. Dominant A1 segments presented with rotation of the AcomA complex toward the contralateral side in 63%, toward the ipsilateral side in 25%, and without rotation in 12%. With symmetric A1s, the AcomA was parallel to the coronal plane in 90% and a right-sided approach was carried out in these patients. In rotated AcomA complexes, the virtual 3D views were compared to determine the side of the approach. For superior projecting aneurysms, we determined that the approach from the side in which the A1-distal anterior cerebral artery (posterior communicating) angle was posterior was more favorable. For posterior projecting aneurysms, the approach from the side where the A1-distal anterior cerebral artery (posterior communicating) angle was more anterior was more favorable. For anteroinferior projecting aneurysms, an approach from the dominant A1 side was chosen regardless of AcomA complex rotation. Postoperative 3D-CTA showed complete exclusion of 24 aneurysms (>92%) and 2 small remnants (<2 mm). Outcome was excellent or good (modified Rankin score 0-2) in 88% of patients. Rotation of the AcomA complex and dome projection are important angioanatomic elements in determining the surgical exposure and side of the approach. This study illustrates the role of 3D-CTA in the management of these difficult lesions by individualizing the surgical approach.

Analysis of superiorly projecting anterior communicating artery aneurysms: anatomy, techniques, and outcome. A proposed classification system.

Superiorly projecting (SP) anterior communicating artery (AComA) aneurysms are typically described as a homogenous group. Clinically and microsurgically, these aneurysms vary in multiple important characteristics. We propose a microsurgical classification system for these complex aneurysms and review its implications regarding presentation, microsurgical techniques, and outcome. This retrospective analysis reviews patients undergoing clipping of SP AComA aneurysms (2005-2013). The classification system is based on the virtual plane created by the A2 segments and its relationship to the aneurysm. Aneurysm type was assessed by intraoperative images and videos. Type 1 is defined by bisection of the dome by the virtual plane. Type 2 is defined by dome projection posterior to this plane. Sagittal rotation of the plane defines type 3. We analyzed clinical presentation, morphology, angiographic characteristics, operative technique, and outcome relative to the classification types. There were 44 SP AComA aneurysms. 3D angiographic images predicted classification type in 83%. Type 1 presented more often with SAH (95.5%, p = 0.0046). There was no statistically significant difference between the types regarding patient demographics or aneurysm characteristics. In type 2, fenestrated clips were used frequently (87.5% p= 0.0016), and there was higher rate of intraoperative rupture (37.5%). Although there was no statistically significant difference between the types in respect to HH grade upon presentation, patients with type 2 aneurysms experienced higher rates of poor GOS (50%). The proposed classification system for SP AComA aneurysms has implications regarding surgical planning, micro-dissection, clipping, and outcome. Type 2 aneurysms carry significant surgical risk.