4,520 research outputs found
Implantation of 3D-Printed Patient-Specific Aneurysm Models into Cadaveric Specimens: A New Training Paradigm to Allow for Improvements in Cerebrovascular Surgery and Research.
AimTo evaluate the feasibility of implanting 3D-printed brain aneurysm model in human cadavers and to assess their utility in neurosurgical research, complex case management/planning, and operative training.MethodsTwo 3D-printed aneurysm models, basilar apex and middle cerebral artery, were generated and implanted in four cadaveric specimens. The aneurysms were implanted at the same anatomical region as the modeled patient. Pterional and orbitozygomatic approaches were done on each specimen. The aneurysm implant, manipulation capabilities, and surgical clipping were evaluated.ResultsThe 3D aneurysm models were successfully implanted to the cadaveric specimens' arterial circulation in all cases. The features of the neck in terms of flexibility and its relationship with other arterial branches allowed for the practice of surgical maneuvering characteristic to aneurysm clipping. Furthermore, the relationship of the aneurysm dome with the surrounding structures allowed for better understanding of the aneurysmal local mass effect. Noticeably, all of these observations were done in a realistic environment provided by our customized embalming model for neurosurgical simulation.Conclusion3D aneurysms models implanted in cadaveric specimens may represent an untapped training method for replicating clip technique; for practicing certain approaches to aneurysms specific to a particular patient; and for improving neurosurgical research
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 Ⅰa in 158 sides, type Ⅰb in 11, type Ⅱa in 35, type Ⅱb in 87, type Ⅲ in 171 and absence in 66. The morphology of A-1 segment in 296 patients with other cerebral vascular diseases displayed type Ⅰa in 195 sides, type Ⅰb in 20, type Ⅱa in 47, type Ⅱ b in 74, type Ⅲ 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 (χ2=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 Ⅰa or Type Ⅱa, and was upward when it was Type Ⅰb or Type Ⅱb,and was upward or downward or complicated when it was Type Ⅲ. 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.Keywords: anterior cerebral artery; morphology of A-1 segment; projection of anterior communicating artery aneurysmAfrican Health sciences Vol 14 No. 1 March 201
Hemodynamics in Ruptured Intracranial Aneurysms
Incidental detection of unruptured intracranial aneurysms (UIA) has increased in the recent years. There is a need in the clinical community to identify those that are prone to rupture and would require preventive treatment. Hemodynamics in cerebral blood vessels plays a key role in the lifetime cycle of intracranial aneurysms (IA). Understanding their initiation, growth, and rupture or stabilization may identify those hemodynamic features that lead to aneurysm instability and rupture. Modeling hemodynamics using computational fluid dynamics (CFD) could aid in understanding the processes in the development of IA. The neurosurgical approach during operation of IA allows direct visualization of the aneurysm sac and its sampling in many cases. Detailed analysis of the quality of the aneurysm wall under the microscope, together with histological assessment of the aneurysm wall and CFD modeling, can help in building complex knowledge on the relationship between the biology of the wall and hemodynamics. Detailed CFD analysis of the rupture point can further strengthen the association between hemodynamics and rupture. In this chapter we summarize current knowledge on CFD and intracranial aneurysms
Non-Newtonian and flow pulsatility effects in simulation models of a stented intracranial aneurysm
Permission to redistribute provided by publishers.Three models of different stent designs implanted in a cerebral aneurysm, originating from the Virtual Intracranial Stenting Challenge'07, are meshed and the flow characteristics simulated using commercial computational fluid dynamics (CFD) software in order to investigate the effects of non-Newtonian viscosity and pulsatile flow. Conventional mass inflow and wall shear stress (WSS) output are used as a means of comparing the cfd simulations. In addition, a WSS distribution is presented, which clearly discriminates in favour of the stent design identified by other groups. It is concluded that non-Newtonian and pulsatile effects are important to include in order to avoid underestimating wss, to understand dynamic flow effects, and to discriminate more effectively between stent designs. © Authors 2011
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Posterior Cerebral Artery Angle and the Rupture of Basilar Tip Aneurysms
Since the initial publication of the International Study of Unruptured Intracranial Aneurysms (ISUIA), management of unruptured intracranial aneurysms has been mainly based on the size of the aneurysm. The contribution of morphological characteristics to treatment decisions of unruptured aneurysms has not been well studied in a systematic and location specific manner. We present a large sample of basilar artery tip aneurysms (BTA) that were assessed using a diverse array of morphological variables to determine the parameters associated with ruptured aneurysms. Demographic and clinical risk factors of aneurysm rupture were obtained from chart review. CT angiograms (CTA) were evaluated with Slicer, an open source visualization and image analysis software, to generate 3-D models of the aneurysms and surrounding vascular architecture. Morphological parameters examined in each model included aneurysm volume, aspect ratio, size ratio, aneurysm angle, basilar vessel angle, basilar flow angle, and vessel to vessel angles. Univariate and multivariate analyses were performed to determine statistical significance. From 2008–2013, 54 patients with BTA aneurysms were evaluated in a single institution, and CTAs from 33 patients (15 ruptured, 18 unruptured) were available and analyzed. Aneurysms that underwent reoperation, that were associated with arteriovenous malformations, or that lacked preoperative CTA were excluded. Multivariate logistic regression revealed that a larger angle between the posterior cerebral arteries (P1-P1 angle, p = 0.037) was most strongly associated with aneurysm rupture after adjusting for other morphological variables. In this location specific study of BTA aneurysms, the larger the angle formed between posterior cerebral arteries was found to be a new morphological parameter significantly associated with ruptured BTA aneurysms. This is a physically intuitive parameter that can be measured easily and readily applied in the clinical setting
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Multi-scale interaction of flow and the artery wall
We discuss, from the perspective of basic science, the physical and biological processes which underlie atherosclerotic (plaque) initiation at the vascular endothelium, identifying their widely separated spatial and temporal scales which participate. We draw on current, related models of vessel wall evolution, paying particular attention to the role of flow, and proceed to propose, then validate (in practical, qualitative terms, at least) a multiply coupled, multi-scale modeling strategy, which, eventually, aims at a quantitative, patient-specific understanding of the coupling between the flow and the endothelial state
Hypertension as a Determining Factor in the Rupture of Intracranial Aneurysms, Diagnosed by 64-MDCT Angiography
Background: To determine a correlation between risk factors and the rupture of intracranial aneurysms. Methods: A cross-sectional study of 29 patients with a saccular intracranial aneurysm was obtained using consecutive sampling and examination of 64-MDCT angiography. Bivariate statistical analysis using Fisher's exact test was arranged using cross-tabulation to determine the correlation between each risk factor of age, sex, hypertension, and smoking with the occurrence of ruptured intracranial aneurysms. Results: The highest incidence of ruptured intracranial aneurysms were in patients aged <60 years (70%), male (75%), experienced hypertension (85%), and were smokers (85.7%). Only the risk factor of hypertension had a correlation with the occurrence of a ruptured intracranial aneurysm (p < 0.05). The prevalence ratio of age and sex were 1.0 and 0.9, whereas hypertension and smoking were 2.6 and 1.3. Conclusions: The risk factor of hypertension leading to a ruptured intracranial aneurysm was 2.6 times higher than non-hypertensive patients, and as such hypertension is a risk factor associated with the occurrence of ruptured intracranial aneurysm
Wewnątrznaczyniowe leczenie tętniaków naczyń mózgowych przy użyciu spirali odczepianych hydraulicznie
Background: Authors analysed results of endovascular treatment using platinum hydraulically detachable coils in ruptured and unruptured cerebral aneurysms. The aim of the study was to evaluate the efficacy of the presented method and safety of the treatment for patients with cerebral aneurysms. Material/Methods: Authors describe a clinical analysis in a group of 129 patients with 153 cerebral aneurysms treated with endovascular embolization in Department of Neurosurgery and Neurotraumatology of University of Medical Sciences in Poznań, Poland. 116 patients were hospitalized with a history of subarachnoidal hemorrhage, while 13 patients were without previous onset of bleeding. In bled group the clinical condition was assessed according to Hunt-Hess's scale. All patients were treated using Balt (MDS Pression) hydraulically detachable coils system. Based on angiographic examination results one evaluated the anatomical conditions of the aneurysm, its size, and relationship of the aneurysmal sac to its neck. Considering 116 patients with ruptured aneurysms, endovascular embolization within 72 hours was performed in 70 cases, in case of 46 patients the procedure was delayed. Results: Complete occlusion of the lumen of the aneurysmal sac was achieved in 126 (82.3%) patients, while incomplete occlusion in 27 (17.7%). The efficacy of embolization was connected with the size and morphology of the aneurysm, as well as the relationship of the neck to the aneurysmal sac. Complete embolization was obtained specially in case of small aneurysms and those with a narrow neck. Conclusions: Authors proof justness of transarterial embolisation as a highly effective first choice procedure of aneurismal sack exclusion from cerebral circulation
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