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.