2025 Volume 71 Issue 4 Pages 151-156
This study retrospectively examined the effects of type IV thyroplasty (cricothyroid approximation) in patients with high-frequency pitch disorder. The cases consisted of 8 patients who underwent surgery at our department between April 2014 and August 2021. The causes of pitch disorders were post-thyroidectomy in 4 cases, trauma in 1, and idiopathic in 3. The speaking pitch, highest pitch, and vocal range increased significantly after surgery (p < 0.05), and the average voice handicap index (VHI) showed significant improvement (p < 0.05). However, the lowest pitch did not increase significantly (p=0.363). Among the cases, some patients maintained the lowest pitch even though the speaking pitch and vocal range were increased. Type IV thyroplasty may especially improve high-frequency voice disorders. In pitch control, both tension of the vocal cords due to the cricothyroid muscle, and modification of stiffness doe to the thyroarytenoid muscle are related to each other.
