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

Cerebral aneurysm treatment: modern neurovascular techniques.

Endovascular treatment of cerebral aneurysm continues to evolve with the development of new technologies. This review provides an overview of the recent major innovations in the neurointerventional space in recent years

New York State: Comparison of Treatment Outcomes for Unruptured Cerebral Aneurysms Using an Instrumental Variable Analysis

Background: There is wide regional variation in the predominant treatment for unruptured cerebral aneurysms. We investigated the association of elective surgical clipping and endovascular coiling with mortality, readmission rate, length of stay, and discharge to rehabilitation. Methods and Results: We performed a cohort study involving patients with unruptured cerebral aneurysms, who underwent surgical clipping or endovascular coiling from 2009 to 2013 and were registered in the Statewide Planning and Research Cooperative System database. An instrumental variable analysis was used to investigate the association of treatment technique with outcomes. Of the 4643 patients undergoing treatment, 3190 (68.7%) underwent coiling, and 1453 (31.3%) underwent clipping. Using an instrumental variable analysis, we did not identify a difference in inpatient mortality (marginal effect, 0.13; 95% CI, −0.30, 0.57), or the rate of 30‐day readmission (marginal effect, −1.84; 95% CI −4.06, −0.37) between the 2 treatment techniques for patients with unruptured cerebral aneurysms. Clipping was associated with a higher rate of discharge to rehabilitation (marginal effect, 2.31; 95% CI 0.21, 4.41), and longer length of stay (β, 2.01; 95% CI 0.85, 3.04). In sensitivity analysis, mixed‐effect regression, and propensity score, adjusted regression models demonstrated identical results. Conclusions: Using a comprehensive all‐payer cohort of patients in New York State with unruptured cerebral aneurysms, we did not identify an association of treatment method with mortality or 30‐day readmission. Clipping was associated with a higher rate of discharge to rehabilitation and longer length of stay

Pathogenesis of Intracranial Aneurysms

Introduction: Intracranial aneurysms (IA) are a common neurological problem, the rupture of which frequently constitutes a catastrophic neurological event. While the pathogenesis is largely unknown, it is believed that both genetic and environmental factors work in concert to some degree within patients. Our goal was to take a comprehensive approach to understanding the pathogenesis of IA by identifying factors leading to the formation, growth and rupture of IA. Methods: Since 1994, we have recruited patients and families with IA into the Yale Brain Aneurysm Database. Information regarding aneurysm characteristics (size, location, number), patient characteristics (age, medical, and social history), and family history were recorded. We analyzed this database for environmental factors associated with aneurysmal rupture. Within the same database, we identified and analyzed kindreds with a high IA incidence and penetrance using genome-wide linkage analysis. Collaborations with other centers provided additional kindreds to analyze and confirm our results. Results: Analysis of our database revealed hypertensive patients with IA ≤ 7mm were 2.6 times more likely to rupture (p = .01, 95% CI: 1.21, 5.53) than normotensive patients. Posterior circulation aneurysms were 3.5 times more likely to rupture than anterior circulation aneurysms (p = .048, 95% CI: 0.95, 19.4). Further, genome-wide linkage analysis revealed significant linkage to a single locus, with a lod score of 4.2 at 1p34-36. Conclusions: We identified hypertension, young age, and posterior circulation as significant risk factors for rupture among patients with small aneurysms (≤ 7mm). Additionally, we are the first to map the gene responsible for IA to chromosome 1p34-26

Primary and Secondary Flow Structures in a Model Cerebral Aneurysm

Cerebral aneurysms affect 5% of western populations and can cause morbidity and mortality if they rupture. Various treatments can be used to minimize the risk of rupture, with new diagnostics and treatments under development that require information from non-invasive techniques such as Particle Imaging Velocimetery (PIV). The current study focused on developing a setup as a basis for future experiments and work on intracranial aneurysms involving PIV. PIV experimentation and data collection were carried out during the summer of 2010 at Ohta Labs of Tohoku University in Sendai, Japan. The experimental setup consisted of a pulsatile flow system, which was configured to realistically reproduce conditions found in cerebral aneurysms. PIV is often used as a validation measure in tandem with Computational Fluid Dynamic (CFD) research, and it is important that experimental setups in PIV produce realistic hemodynamics. A PIV system was used to record velocity field data in select planes through a silicone model of a curved artery with a saccular aneurysm attached at a 90 degree angle to the bend. Hemodynamics throughout the aneurysm and near aneurysm region of the parent artery were successfully recorded for future reference with CFD. Focal attributes to confirm experimental success were: 1) creation of laminar flow before the aneurysm; 2) development of Dean Vortices that interacted predictably with the aneurysm; and 3) aneurysmal inflow consistent with physiological data

Comparison of existing aneurysm models and their path forward

The two most important aneurysm types are cerebral aneurysms (CA) and abdominal aortic aneurysms (AAA), accounting together for over 80\% of all fatal aneurysm incidences. To minimise aneurysm related deaths, clinicians require various tools to accurately estimate its rupture risk. For both aneurysm types, the current state-of-the-art tools to evaluate rupture risk are identified and evaluated in terms of clinical applicability. We perform a comprehensive literature review, using the Web of Science database. Identified records (3127) are clustered by modelling approach and aneurysm location in a meta-analysis to quantify scientific relevance and to extract modelling patterns and further assessed according to PRISMA guidelines (179 full text screens). Beside general differences and similarities of CA and AAA, we identify and systematically evaluate four major modelling approaches on aneurysm rupture risk: finite element analysis and computational fluid dynamics as deterministic approaches and machine learning and assessment-tools and dimensionless parameters as stochastic approaches. The latter score highest in the evaluation for their potential as clinical applications for rupture prediction, due to readiness level and user friendliness. Deterministic approaches are less likely to be applied in a clinical environment because of their high model complexity. Because deterministic approaches consider underlying mechanism for aneurysm rupture, they have improved capability to account for unusual patient-specific characteristics, compared to stochastic approaches. We show that an increased interdisciplinary exchange between specialists can boost comprehension of this disease to design tools for a clinical environment. By combining deterministic and stochastic models, advantages of both approaches can improve accessibility for clinicians and prediction quality for rupture risk.Comment: 46 pages, 5 figure

European Stroke Organization Guidelines for the Management of Intracranial Aneurysms and Subarachnoid Haemorrhage

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