Eight cases of bilateral immobilization of the vocal cords in median position were reported. This condition is also known as bilateral abductor or posticus paralysis.
However, it should be noted that the term of median immobilization is most preferable, because it describes laryngoscopic findings fully.
The cords may be immobilized by various factors; paralysis of the laryngeal nerves, arthritic fixation of the cricoarytenoid joints and so on. No information on the cause of immobilization can be obtaind by mere inspection of the larynx. The differential diagnosis must be made by palpation of the arytenoids (passive mobility test) and by electromyographic examination of the intrinsic laryngeal muscles.
It is usually said that operation for goiter is the most frequent cause. However, seven of the eight cases are etiologically unknown and the other one was caused by laryngeal trauma.
Of 44 cases of the bilateral immobilization reported in this country (including our cases), twelve are etiologically unknown. Next to this, comes laryngeal trauma.
In three of our cases, respiratory function test and phonetical test were made before and after the extralaryngeal laterofixation of the vocal cords. These tests were found to be very important for evaluating the patient's ability of breathing and speech.
