THE CRICOTHYROID MUSCLE DOES NOT INFLUENCE VOCAL FOLD POSITION IN LARYNGEAL PARALYSIS

The status of the cricothyroid muscle, which is innervated by the supe rior laryngeal nerve, is believed to influence the vocal fold position in laryngeal paralysis, It is believed that isolated lesions of the r ecurrent laryngeal nerve generally result in the paralyzed vocal fold assuming a paramedian position but that with lesions of both the super ior and recurrent laryngeal nerves, a more lateral (intermediate or ca daveric) vocal fold position can be expected. Twenty-six consecutive p atients with unilateral vocal fold paralysis underwent transnasal fibe roptic laryngoscopy (TFL) and laryngeal electromyography (LEMG). By TF L, the vocal fold positions were paramedian in 8 patients, intermediat e in 7, and lateral in 11, By LEMG, 13 patients had isolated recurrent laryngeal nerve lesions and 13 patients had combined (superior and re current laryngeal nerve) lesions. There was no correlation between the vocal fold position and the status of the cricothyroid muscle, i,e., the status of the cricothyroid muscle by LEMG did not predict the voca l fold position nor did the vocal fold position by TFL predict the sit e of lesion. In addition, we investigated the possibility that the deg ree of thyroarytenoid muscle recruitment (tone) might correlate with v ocal fold position, but no relation was found, We conclude that 1, the cricothyroid muscle does not predictably influence the position of th e vocal fold in unilateral paralysis; 2, thyroarytenoid muscle recruit ment (tone) does not appear to influence vocal fold position; and 3, s till unidentified and unknown factors may be responsible for determini ng vocal fold position in laryngeal paralysis.