Three-dimensional characteristics of the larynx with immobile vocal fold.

OBJECTIVES

To evaluate the 3-dimensional (3-D) characteristics of the laryngeal lumen in patients with unilateral vocal fold immobility (UVFI) during phonation with the aid of multislice helical computed tomography (MSHCT).

DESIGN

A retrospective study.

SETTING

University hospital. Subjects Thirty-seven patients with UVFI.

INTERVENTIONS

Each subject was asked to sustain the vowel /a/ and then to inhale slowly. The region over the larynx was scanned using MSHCT during each maneuver for 5 seconds; 3-D endoscopic images and coronal multiplanar reconstruction images were produced and evaluated. Thirty-two subjects underwent videostroboscopy within 2 weeks of the MSHCT.

MAIN OUTCOME MEASURES

Presence of thinning and paradoxical movement of the affected vocal fold, overadduction of the healthy fold, and vertical positional difference between the vocal folds during phonation were assessed based on 3-D and multiplanar reconstruction images.

RESULTS

During phonation, the affected vocal fold was thinner in 31 subjects and was situated in a higher position in 21 subjects than the healthy fold. In 4 subjects, the affected vocal fold showed paradoxical movement and 3 other subjects had probable paradoxical movement. Overadduction of the healthy vocal fold occurred during phonation in 15 subjects. Videostroboscopy detected paradoxical movement in 2 of the 3 subjects with abduction of the affected vocal fold during phonation based on 3-D images, and overadduction in all 13 subjects examined.

CONCLUSIONS

The combination of 3-D endoscopy with coronal multiplanar reconstruction images enables description of the 3-D characteristics of the unilaterally immobile larynx and supplements videostroboscopic findings exemplified by differences in vertical position and thickness between the vocal folds.