Evaluation of True Vocal Fold Growth as a Function of Age

Abstract

Objectives: Evaluate change in true vocal fold length as function of age. Methods: Prospective study at tertiary aerodigestive center between 2011 and 2013. A total of 205 patients (ages 1 month to 20 years), of which 87 (42.4%) were female and 118 (57.6%) male, were included. Lengths of total vocal fold (TVFL), membranous vocal fold (MVFL), and cartilaginous vocal fold (CVFL) were measured during direct laryngoscopy. Membranous-to-cartilaginous ratios (M/C) were calculated. Results: Mean MVFL under age 1 year for females was 4.4 ± 1.3 mm and for males 4.9 ± 1.8 mm. At age 17 years, mean MVFL was 12.3 ± 2.1 mm for females and 14.0 ± 1.4 mm for males. Mean TVFL, MVFL, and CVFL increased 0.7 mm, 0.5 mm, and 0.2 mm per year in linear fashion, respectively (linear regression, P < .0001). M/C ratio did not significantly change with age ( P = .78). Mean TVFL, MVFL, and CVFL showed trend of being longer in males than females, but these did not reach statistical significance ( P = .27; .11; .75, respectively). Conclusions: This is the largest longitudinal pediatric study specifically examining vocal fold length as function of age. Each length of true vocal fold appears to linearly increase for both females and males. M/C ratio remained relatively constant unlike previously reported data, possibly due to in vivo versus cadaveric measurements. These findings suggest critical periods of development in females and males are not explainable by changes in vocal fold length alone, and other factors such as vocal fold layers (linear density) need further exploration.