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Description
Background: Rupture of giant intracranial aneurysm (GIA, aneurysm larger than 25 mm) can result with either serious brain damage or death. Bypassing is one of the available methods to prevent the aneurysm from rupture. This involves neurosurgeons carefully cutting off the blood inflow to the aneurysm sac, while also creating an additional connection to the distal arteries. It is thought that such a connection may help to preserve the proper blood supply to all efferent arteries. However, up to date there is no information which cerebral perforator should be selected as the ‘anchoring’ vessel. It is challenging to predict the outcomes of each possibility in clinical practice, however, it is possible with the use of computational fluid dynamics (CFD). Thus, the main objective of this study was to perform virtual bypass procedures and observe which configuration was optimal for the given patient.
Methods: The geometry of the arterial system, including the giant aneurysm, was reconstructed from biomedical imaging scans using custom software. Two bypass options were then proposed. Afterwards, a series of fluid-structure interaction (FSI) simulations were performed assuming physiological vasomotion of the walls. This allowed us to assess the flow-haemodynamics in the cerebral region, including shear stress, blood distribution, pressure distribution and aneurysm volume.
Results: Comparative analysis of the results from three case studies indicated that the configuration of the bypass may have a significant impact on the internal flow conditions within the aneurysmal region. Notable differences were observed in the shear-related parameters as well as in viscosity. A notable decrease in pressure was observed, which may have contributed to the observed aneurysm shrinkage. Additionally, areas that may be susceptible to thrombosis were identified.
Conclusions: In-silico analyses show that bypassing surgeries reduce mechanical stress on vessel walls and that the risk of thrombus formation varies depending on the bypass location.
