Contact-resolved deployment of the Contour Neurovascular System in patient-specific intracranial aneurysms

Abstract

While intrasaccular flow disruptors are widely used to treat wide-neck intracranial aneurysms, state-of-the-art patient-specific computational models routinely neglect the deployment mechanics by prescribing a pre-seated geometry. This shortcut oversimplifies the true physics and misrepresents the Contour Neurovascular System (CNS), whose critical biomechanical features, such as neck coverage, wall apposition, and migration resistance, are highly path-dependent. To resolve this limitation, we present a contact-resolved finite-element framework that explicitly computes the structural mechanics of implant deployment within patient-specific vascular environments. The device is discretized as a dual-layer interwoven Nitinol braid using geometrically exact beams, while the vascular wall is represented as a deformable hyperelastic shell. Non-linear frictional contact formulations govern complex wire-wire and wire-wall interactions under a staged release protocol. Evaluating three anatomical phenotypes reveals that the final equilibrium morphology is highly sensitive to tangential slip resistance and vertical release depth. Frictionless assumptions permit excessive post-contact sliding, whereas near-stick conditions enhance anchoring but restrict local compliance. Crucially, conventional geometric fast placement fails to capture these critical contact interactions and wall-supported mechanical equilibrium. This deployment-resolved framework establishes a biomechanically grounded foundation for downstream hemodynamics, fluid-structure interaction, and mechanobiological thrombus-formation modeling.