A New Classification of Laryngeal Synkinesis

Abstract

Objective: 1) Develop a new classification of laryngeal synkinesis in patients with unilateral vocal fold paralysis (UVFP) based on images of the vocal fold using 3-dimensional computed tomography (3DCT) 2) Compare synkinesis type based on 3DCT image analysis with recruitment in electromyography during phonation.

Method: Retrospective. Subjects included 50 patients with UVFP who underwent framework surgeries between 2000 and 2010. Three-dimensional images during phonation and inhalation preoperatively were assessed focusing on thickness of the affected fold to classify synkinesis. Recruitment of thyroarytenoid muscle was rated and compared with synkinesis type.

Results: Two subjects were excluded because of poor performance during scanning. Three synkinesis types were identified. The affected fold in 12 subjects showed some degree of thickening during phonation. The affected fold of the remaining 36 was thin during phonation. Thickening of the affected fold was evident during inhalation in 20 of the 36 subjects, while the affected fold in the rest (16 subjects) remained to be thin. Thirty-one subjects underwent electromyography. Those with the latter 2 types of synkinesis had a tendency of less recruitment compared with those with the former type of synkinesis.

Conclusion: The use of the new classification of laryngeal synkinesis facilitates understanding of behavior of the affected vocal fold in patients with UVFP. The number of subjects who underwent electromyography was not sufficient to draw a conclusion about the relation between synkinesis classification and recruitment.