The diagnostic value of laryngeal electromyography in vocal fold paralysis and arytenoid dislocation

OBJECTIVES: To identify diagnostic value of laryngeal electromyography (LEMG) in differentiating vocal fold paralysis (VFP) from arytenoid dislocation. METHODS: The history, laryngeal morphologic characteristics and LEMG of 36 patients with VFP and 10 patients with arytenoid dislocation were compared and analyzed. RESULTS: The most common cause of 36 VFP patients was surgical damage (24 cases), and the most common cause of 10 arytenoid dislocation patients was history of endotracheal intubation (9 cases). There was no statistical difference between the vocal fold and the fixed position of the vocal fold between the group of VFP patients and arytenoid dislocation patients. In the patients with VFP, 33 VFP patients (91.67%) had decreased recruitment; 9 cases (9/13) of denervation potential and 8 cases (8/9) of regeneration potential occurred within 1-6 months of the course of disease; 3 cases (3/4) of synkinesis occurred in the course of disease more than 6 months. In the patients with VFP, the amplitude (P<0.01) and turns (P<0.05) of thyroarytenoid muscles significantly decreased in the lesioned side comparing to the normal one, but the turns/amplitude ratio showed no statistical difference. In the patients with superior laryngeal nerve injury, the turns and amplitude analysis of cricothyroid muscles showed no statistical difference. All of 10 patients with arytenoid dislocation showed normal LEMG patterns. CONCLUSIONS: LEMG can be used to differentiate the patients with vocal cord paralysis from arthrodesis dislocation, and can also carry out quantitative analysis to provide valuable help for the diagnosis.