Influence of gender and injection site on vocal fold augmentation

Objective: To determine the influence of gender and injection site on the amount of injectate needed to medialize an immobile vocal fold, and to describe the distribution patterns of the injected bolus. Study Design: Surgical intervention in human cadaveric larynges in experimental setting. Subjects and Methods: Cadaveric larynges were injected with calcium hydroxylapatite into the lateral or medial aspect of the vocal fold. High-resolution CT scans were obtained before and after injection. Results: Males required 50% to 60% more material than females (P = 0.03). For both genders, lateral injections required more than medial injections (P < 0.001). Laterally injected boluses tended to distribute toward the cricothyroid space, with frank extrusions more common in females. Conclusion: The amount of injectate required to medialize male and female vocal folds is significantly different. The smaller size of the female larynx likely accounts for a higher incidence of extrusion through the cricothyroid space. These gender differences should be taken into consideration when performing injection laryngoplasty.