Abstract
Thyroplasty type IV (Isshiki) was performed in 6 patients with sulcus vocalis to improve hoarseness of voice. Improvement of their hoarseness by an approximation of the cricoid and thyroid cartilage with a manual maneuver was considered a good indication for the surgery. Voice was improved in all the patients operated on. The patients reported that their voice became louder and that it was easier for them to phonate after surgery. An objective voice evaluation showed a marked improvement in terms of auditory perception and acoustic analysis, though the amount of improvement was generally not so remarkable in the aerodynamic voice evaluation. In sound spectrogram, increase of harmonics in the middle to high voice range and the decrease of noise component were also noted after the surgery.
