This surgery is sometimes called ‘voice deepening surgery’ or ‘voice muscularization surgery’. The concept of the surgery is to lose the tension of vocal folds to get a low frequency voice. Isshiki invented this method for mutational voice disorder patients whose voice was high as matured male person or spastic dysphonia patients whose voice was broken due to over adduction of vocal folds. At present, this method has been performed for the people who want their voice pitch gets lower or some abductor type spasmodic dysphonia patients.
The surgical procedure is as follows. Following local anesthesia using xylocaine, a 4 to 5cm incision is made at the front neck to expose the thyroid cartilage. 2 to 3mm of stripes are made at the 10 to 15mm lateral part from the midline on the both sides of thyroid cartilage and carefully removed. Middle and both sides of thyroid cartilages are sutured. Patients are asked to phonate during the surgery to ensure that their voice pitch gets lower. Speaking is possible following one week of voice rest.