The case consisted of a young male with mutational dysphonia, who aged 25years. The speaking fundamental frequencies (SFFs) at the time of the initial diagnosis was174.6. In this patient, voice therapy proved ineffective; therefore, surgery was considered. In the anterior-posterior compression test performed preoperatively in this patient, the voice became low-pitched. The SFFs decreased postoperatively to 106.9, Hz, in this patient. Type 3 thyroplasty (TP3) is effective for the treatment of patients with mutational dysphonia in whom voice therapy proved unsuccessful. The SFF of men is high in childhood. At the time of the second pubescent sexual orientation, the frequency usually decreases. However, in some cases, the high-pitched voice of childhood may persist without successful switch to a low-pitched voice during puberty. Thus, there are rare cases of adults with a high-pitched boyish voice. Voice therapy is usually effective for the treatment; however, it may fail in some cases. We performed TP3 for subjects in whom voice therapy proved ineffective. With TP3, the tension of the vocal folds decreases and the voice becomes low-pitched.
