[Glottal configuration and histological findings in vocal muscles following trauma to cricoarytenoid joint].

OBJECTIVE

The unilateral cricoarytenoid joints of the rabbits were traumatized bluntly to investigate the changes of glottal configuration and histology of the vocal muscles.

METHOD: 10 New Zealand white rabbits divided into 4 groups were studied. Under direct laryngoscope, the unilateral cricoarytenoid joint of each rabbit was traumatized bluntly. The glottal configuration and histology of the true cords demonstrated atrophy of the vocal muscles. The remarkable atrophy of the vocal muscles was evaluated after 1, 3, 6 and 9 months.

RESULT: In 1 and 3 months after trauma, the glottal configuration of the rabbits showed no difference from that in the period of trauma. The histology of the vocal muscles was approximately normal. The lateral drift and deformity of the fixed vocal cord and wider glottal gap were seen 6 months after trauma. The histological sections of the vocal muscles were noted 9 months after trauma.

CONCLUSION

The atrophy of the vocal muscles may occur 6 months after trauma to cricoarytenoid jonint. This pathologic change may cause the lateral displacement and deformity of the vocal cord, which increases the glottal incompetence and affects voice recovery. The laryngeal electromyography may be influenced by the pathologic changes of the vocal muscles.