Detection of passive movement of the arytenoid cartilage in unilateral vocal-fold paralysis by laryngoscopic observation: useful diagnostic findings.

In a previous study of patients with unilateral vocal-fold paralysis (UVFP), three-dimensional computed tomography (3DCT) revealed passive movement during phonation, with the arytenoid cartilage on the paralyzed side pushed to the unaffected side and deviated upwards. The present work compares the 3DCT findings with those obtained by 2-dimensional endoscopy to visualize the vertical passive movement of the arytenoid cartilage. The study population consisted of 23 patients with UVFP and two with laryngeal deviation but normal movement of the vocal folds. Two endoscopic findings represented cranial deviation during phonation: posterior deviation of the arytenoid hump and lateral deviation of the muscular process. These two findings were classified into four grades, ranging from 0 (normal) to 3 (severe). Cranial displacement detected by 3DCT was also classified into four grades. Significant correlations were found between the 3DCT-determined grade of cranial displacement of the arytenoid cartilage and the grade assigned based on the two endoscopic findings. Moreover, lateral deviation of the muscular process was more significantly correlated with 3DCT grade than with endoscopic grade. Thus, endoscopic findings may be useful in the diagnosis of vocal-fold paralysis, and passive lateral deviation of the muscular process as an indicator of UVFP.