A synthetic, self-oscillating vocal fold model platform for studying augmentation injection.
OBJECTIVE
To design and evaluate a platform for studying the mechanical effects of augmentation injections using synthetic, self-oscillating vocal fold models.


METHODS
Basic science.


METHODS
Life-sized, synthetic, multilayer, self-oscillating vocal fold models were created that simulated bowing via volumetric reduction of the body layer relative to that of a normal, unbowed model. Material properties of the layers were unchanged. Models with varying degrees of bowing were created and paired with normal models. Following initial acquisition of data (onset pressure, vibration frequency, flow rate, and high-speed image sequences), bowed models were injected with silicone that had material properties similar to those used in augmentation procedures. Three different silicone injection quantities were tested: sufficient to close the glottal gap, insufficient to close the glottal gap, and excess silicone to create convex bowing of the bowed model. The above-mentioned metrics were again taken and compared. Pre- and post-injection high-speed image sequences were acquired using a hemilarynx setup, from which medial surface dynamics were quantified.


RESULTS
The models vibrated with mucosal wave-like motion and at onset pressures and frequencies typical of human phonation. The models successfully exhibited various degrees of bowing which were then mitigated by injecting filler material. The models showed general pre- to post-injection decreases in onset pressure, flow rate, and open quotient and a corresponding increase in vibration frequency.


CONCLUSIONS
The model may be useful in further explorations of the mechanical consequences of augmentation injections.
Department of Mechanical Engineering, Brigham Young University, Provo, Utah.
Preston R
PR
Murray
Department of Mechanical Engineering, Brigham Young University, Provo, Utah. Electronic address: thomson@byu.edu.
Scott L
SL
Thomson
Division of Otolaryngology-Head Neck Surgery, University of Utah, Salt Lake City, Utah.
Marshall E
ME
Smith
D001696:Biomechanical Phenomena; D055119:Elastic Modulus; D006801:Humans; D007267:Injections; D008953:Models, Anatomic; D009991:Oscillometry; D010699:Phonation; D011312:Pressure; D012212:Rheology; D012828:Silicones; D014732:Vibration; D014827:Vocal Cords / Q000033:anatomy & histology* / Q000502:physiology*
D012828:Silicones
Bowing; Direct linear transformation; Injection; Medial surface dynamics; Synthetic vocal fold models; Vocal fold medialization