The Vertical Level of the Paralyzed Vocal Fold in Unilateral Vocal Fold Paralysis

Hong, Ki Hwan; Youn, Hee Wan; Kim, Chang Hyun

Abstract

BACKGROUND AND OBJECTIVES: ln the unilateral vocal fold paralysis, it has been generally accepted that the level of the paralyzed vocal fold is higher than that of a normally innervated vocal fold. In this study, we introduce methods to detect the level difference between the paralyzed and innervated vocal folds, and observe the vertical levels of paralyzed vocal fold. MATERIALS AND METHOD: We conducted a retrospective review using video recorded images of the larynx. A total of 38 patients selected for this study complained of voice change due to a unilaterally paralyzed vocal fold. Video-recordings were obtained using a laryngeal telescope. The height was assessed according to the paralyzed positions, status (inspiration or phonation) and shapes of the paralyzed arytenoid. The shapes of paralyzed arytenoid during inspiration were classified as a body type, process type, tip type and no type.
RESULTS
In the medial paralysis, a paralyzed vocal fold showed same horizontal level as does a normal vocal fold during phonation. But in some cases of medial paralysis, the vertical level was either lower or higher than the normal vocal fold depending on the types of paralyzed arytenoid during phonation. In the lateral paralysis, interestingly, most of the paralyzed vocal fold is not vertically higher than an innervated vocal fold during phonation.
CONCLUSIONS
The height of paralyzed vocal fold depends on the paralyzed positions, inspiration or phonation, and shapes of the paralyzed atytenoid. The fact that a paralyzed vocal fold is placed vertically higher than a normal vocal fold should be reconsidered from now.