Infraglottal Medialization: Increasing Vocal Fold Stiffness Gradient for Improved Vocal Efficiency

Area of Science:

• Laryngology and Voice Science
• Biomechanical Engineering
• Acoustic Analysis

Background:

• Vocal fold medialization aims to restore voice function by improving glottal closure.
• Understanding the biomechanical properties of the vocal fold, such as stiffness, is crucial for effective medialization.
• The vertical stiffness gradient of the vocal fold influences vibratory patterns and acoustic output.

Purpose of the Study:

• To evaluate the impact of an infraglottal medialization technique on vocal fold acoustics and vertical stiffness gradient.
• To compare the effects of infraglottal medialization with glottal medialization using excised canine larynges.

Main Methods:

• Seven ex vivo canine larynges were analyzed in three conditions: no implant, glottal implant, and infraglottal implant.
• Vocal efficiency was measured as an acoustic outcome.
• Vocal fold stiffness was assessed using an indentation technique at three height levels to determine the vertical stiffness gradient.

Main Results:

• Infraglottal medialization significantly improved vocal efficiency in all tested larynges, outperforming glottal medialization.
• The infraglottal technique increased the vertical stiffness gradient of the vocal fold.
• Glottal medialization increased overall vocal fold stiffness but did not significantly alter the vertical stiffness gradient.

Conclusions:

• Infraglottal medialization is effective in enhancing both vocal efficiency and the vertical stiffness gradient.
• The increased stiffness gradient may explain the glottal divergent angle observed with infraglottal medialization.
• These findings provide valuable insights for clinicians regarding implant placement and medialization strategies to improve vocal outcomes and vocal fold vibration mechanics.