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

Abstract

While intrasaccular flow disruptors are increasingly used to treat wide-necked intracranial aneurysms (IAs), many patient-specific computational workflows prescribe a pre-seated device geometry and omit deployment mechanics. This simplification is particularly restrictive for the Contour Neurovascular System (CNS), for which neck coverage, wall apposition, and post-contact motion depend on the deployment process. To address this, we present a contact-resolved finite-element framework that models CNS deployment within patient-specific IAs. We represent the device as a dual-layer interwoven Nitinol braid using geometrically exact beam models, and the aneurysm wall as a deformable hyperelastic shell. Frictional contact governs wire-wire and wire-wall interactions during staged release. The framework is demonstrated across three patient-specific anatomies. In the reference anatomy, the seated configuration is sensitive to the assumed device-wall tangential friction and to release depth relative to the aneurysm neck plane. Frictionless wall contact permits pronounced post-contact sliding, whereas finite tangential friction strongly suppresses residual pole motion. Release depth alters both the onset of wall engagement and the subsequent deployment path. Geometric placement approaches that prescribe the implanted configuration cannot recover this contact history or the associated wall-supported state. Our framework provides a mechanics-based route to deployed geometries for downstream hemodynamic, fluid-structure interaction, and mechanobiological analyses.

Revised version with updated computational workflow and structural parameters