Computational modeling and experiment validation of vocal fold vibration for type-1 thyroplasty*

We present an integrated computational and experiment study of type-1 thyroplasty (TP) and its impact on vocal fold (VF) vibration. TP is a common intervention for unilateral VF paralysis (UVFP), involving medialization of the paralyzed VF via an implant. In the ex vivo experiment, a rabbit larynx was used to for the study, where “healthy” side of VF was medialized via trans-muscular suture and the “paralyzed size” was medialized by implant insertion. Flow experiment was then done to induce the VF vibration. The computational model was based on the pre-operative MRI scan, and the FEM model of the VF was numerically implanted to achieve the medialized configuration. This configuration was then used to perform fluid-structure interaction (FSI) simulation of the VF vibration to assess the effect of the implant. The FEM simulation of the medialization was validated against the post-operative MRI scan by comparing the VF displacement; and the FSI simulation was validated against the phonation experiment by comparing the vibratory characteristics of the VF against the high-speed video. Furthermore, the flow characteristics showed evidence of restored pulsatile glottal airflow. These results support the use of current computational model for pre-surgical planning of type-1 thyroplasty.