Hai ZiFollow

Date of Award

Summer 8-15-2018

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)


Mechanical Engineering


Qian Xue

Second Committee Member

Xudong Zheng

Third Committee Member

Mohsen Shahinpoor


Unilateral vocal fold paralysis (UVFP) is one of the most common laryngeal diseases that affect human voice and speech production. It often causes incomplete glottal closure, resulting in voice symptoms including hoarseness, voice fatigue and increased voice effort. One common treatment of UVFP is Thyroplasty Type I, which uses a thyroplasty implant to medialize the paralyzed vocal fold and restore the normal vibration of the vocal fold. However, the surgical outcome is extremely sensitive to the size and shape of the implant. Currently, modifications in the implant size and shape rely upon surgical intuition and experience. The level of voice production restored and satisfaction from patient are variable. Furthermore, the surgical outcome also changes with time as the morphology of the vocal fold changes. In the United States, up to 25% of patients need a revision of the surgery. Therefore, it is desired to have an adjustable implant whose shape and size can be adjusted externally. In this way, the need of reopening the voice box can be permanently removed. This thesis explores employing external forces to control the penetration and shape of the implant. In this way, the contact between the implant and the paralyzed vocal fold can be adjusted as needed. The relationship between the external force, displacement of the implant penetration, and deformation and mechanical stress of the vocal fold was systematically studied in both numerical and experimental ways. Such relationship will inform series of reliably loadings on the device without intensive stress inside the vocal fold. The device is the first step toward a magnetically adjustable implant for Thyroplasty Type I surgery.