PhonoSim: a subject-specific modeling tool for pre-surgical planning of type I thyroplasty procedure

Type I thyroplasty procedure (TP) is widely used for the patients with unilateral vocal fold paralysis (UVFP) by inserting the implant into the paralyzed side of the vocal fold (VF). To improve the outcomes of TP, a suite of computational tool "PhonoSim" has been developed to simulate the fluid-structure interaction (FSI) of VF vibration under different configurations for pre-surgery planning. This suite includes different fidelity models for various purposes: an FEM model to reconstruct the subject-specific model based on MRI scan and conduct initial implant designs; a 1D flow model improved by machine learning coupled with 3D tissue model to adjust the tissue properties and further improve the implant design; a 3D FSI model to finalize the implant design. Our cross-disciplinary team has performed both numerical and experimental investigations on VF vibration in four configurations: rest configuration, two-side suture to mimic healthy phonation, one-side suture for UVFP, and one-side suture/one-side implant for TP surgery. Subject-specific model reconstruction is based on the rest configuration, while the other configurations are achieved by modeling the adduction process, which provides the pre-stress field within the tissue before FSI simulations. Larynges from rabbits were randomized to two groups: PhonoSim informed (n=6), and control (non-model informed, n=5) to perform TP. All six model-informed TP tests are successful while only one in control group is successful. Details of these computational components and their combination with the experiment study will be presented.