Type IV Thyroplasty

Isshiki invented this surgery for the people who cannot produce the high pitched voice because of estrogen / androgen hormone secretion disorder, inappropriate intake of anabolic steroids, superior laryngeal nerve paralysis, etc. This surgery was originally named 'cricothyroid approximation'.

The higher tension of vocal folds produces higher pitched voice. Cricothyroid muscle which is connecting the cricoid and thyroid cartilages contracts when we phonate in high pitch, to increase the tension of vocal folds. The surgery substitutes the contraction of the muscle by approximating cricoid and thyroid cartilage.

Following local anesthesia, a 4 to 5 cm of skin incision is made on the neck to expose the larynx. The four sutures which connect the cricoid cartilage and the lower edge of thyroid cartilage are made. Listening to the voice of patients, the voice pitch is tuned by pulling the sutures. The sutures are tightened at the point that patients feel comfortable with their voice pitch. 

Patients are allowed to speak after three days voice rest.