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Effect of Vocal Fold Implant Placement on Depth of Vibration and Vocal Output
Author(s) -
Smith Simeon L.,
Titze Ingo R.,
Storck Claudio,
Mau Ted
Publication year - 2020
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1002/lary.28365
Subject(s) - phonation , medicine , implant , lamina propria , vocal folds , vibration , fold (higher order function) , anatomy , biomedical engineering , larynx , surgery , audiology , acoustics , pathology , epithelium , computer science , physics , programming language
Objective Most type 1 thyroplasty implants and some common injectable materials are mechanically stiff. Placing them close to the supple vocal fold mucosa can potentially dampen vibration and adversely impact phonation, yet this effect has not been systematically investigated. This study aims to examine the effect of implant depth on vocal fold vibration and vocal output. Study Design Computational simulation. Methods Voice production was simulated with a fiber‐gel finite element computational model that incorporates a three‐layer vocal fold composition (superficial lamina propria, vocal ligament, thyroarytenoid muscle). Implants of various depths were simulated, with a “deeper” or more medial implant positioned closer to the vocal fold mucosa and replacing more muscle elements. Trajectories of surface and within‐tissue nodal points during vibration were produced. Outcome measures were the trajectory radii, fundamental frequency ( F 0 ), sound pressure level (SPL), and smoothed cepstral peak prominence (CPPS) as a function of implant depth. Results Amplitude of vibration at the vocal fold medial surface was reduced by an implant depth of as little as 14% of the total transverse vocal fold depth. Increase in F 0 and decrease in CPPS were noted beyond 30% to 40% implant depth, and SPL decreased beyond 40% to 60% implant depth. Conclusions Commonly used implants can dampen vibration “from a distance,” ie, even without being immediately adjacent to vocal fold mucosa. Since implants are typically placed at depths examined in this study, stiff implants likely have a negative vocal impact in a subset of patients. Softer materials may be preferable, especially in bilateral medialization procedures. Level of Evidence N/A Laryngoscope , 130:2192–2198, 2020