## 1 Introduction
reported that cricothyroid suture approximation alone was sufficient to improve multiple measures including glottic closure, frequency (fundamental, falsetto, basal), maximum phonatory time, and patient-reported perception [28] Subsequent investigation of cricothyroid suture approximation by our group in a rabbit model allowed for the development of a non-stimulatory method for medialization which achieved fundamental frequencies, vocal intensities, and aerodynamic measures consistent with modal phonation elicited through electrical stimulation [29]. The cricothyroid suture approximation model described by [PERSON] et al. has the specific advantage of retaining vocal fold approximation ex vivo for imaging studies, something that cannot be achieved by electrical stimulation, such that high-speed videoendoscopy (HSV) and imaging from the same subject can be used to inform computational models of vocal fold vibration [30]. Besides experimental efforts, many numerical investigations using computational mechanics models have been conducted to study vocal fold vibration. Complementary to the physical models in experimental studies, computational models have the advantage of providing insight into the phonation process and predicting the vibration through mathematical modeling and computer simulation of the physical system. Such computational models usually include governing equations for the vocal fold biomechanics, the glottal aerodynamics, or a combination of both for fluid-structure interaction (FSI) simulations. Depending on the realism of vocal fold representation, there were lumped-mass models, two-dimensional, and three-dimensional finite-element models of the vocal fold tissues [30; 31; 32; 33; 34; 35; 36]. With the fast growth of computational power and medical imaging technologies, e.g., computed tomography (CT) and magnetic resonance imaging (MRI), patient-specific geometries have been incorporated into the FEM model of the vocal fold to represent the anatomy of individual patients or subjects [37; 38; 39]. Such models have potential applications in the surgical treatment of voice disorders like UVFP. More details about the development of computational models can be found in recent review papers [38; 40]. While simulating vocal fold vibration, many FEM models have ignored the vocal fold addduction process and assumed equivalent stiffness properties for the vocal fold tissue to produce a suitable fundamental frequency. This ad hoc assumption may include asymmetric vibration, where two sides were assigned with different stiffness properties [41]. To study the effect of the approximation on vibration, the large tissue deformation due to adduction should be part of the FEM model to account for the effect of the structural stiffening (as opposed to material stiffening) on the dynamic behavior of the vocal fold. In the past, quite a few FEM models have been developed in combination with experimental testing to investigate vocal fold addduction, including both in vivo and ex vivo conditions [42; 43; 44; 45; 46; 47; 48], while the main interests of these studies were to determine the material properties of the vocal fold tissue. Some studies have looked at the effect of addduction or lengthening on the vocal fold structure [42; 45; 46]. However, those models only have simple vocal fold geometries and have not included details of cartilage movement. To accurately simulate vocal fold approximation, it is necessary to obtain quantitative information of cartilage displacement in the process. There have been efforts to segment and reconstruct laryngeal cartilages based on 3D image data [49; 50]; however, this approach has not been used in FEM modeling of the vocal fold. In this study, we constructed a subject-specific rabbit vocal fold model based on the excised MRI scans at different surgical vocal fold approximation conditions.