Key Points for Successful Surgery to Improve Symptoms of Adductor Spasmodic Dysphonia

PROGRAM DESCRIPTION: Spasmodic dysphonia（SD）is thought to be a focal dystonia, although the cause is still unknown. Symptoms are characterized by a loss of voice during conversation. Symptoms appear in a task-specific manner. However, it is also characterized by the absence of symptoms during coughing, laughing, or crying. We currently have two methods of treatment for adductor spasmodic dysphonia (AdSD). One treatment is pharmacotherapy, such as botulinum toxin injections. Botulinum toxin injections have been used to treat SD with good temporary results and minimal morbidity. However, injections are usually required once every 3-4 months and can result in initial temporary dysphonia, caused by incomplete glottic closure. The second method involves surgical treatments, including RLN denervation and reinnervation, thyroarytenoid muscle myectomy, and type 2 thyroplasty, the last of which has been shown to provide permanent relief from voice symptoms.　botulinum toxin injection, RLN denervation, and thyroarytenoid myectomy are intended to reduce spasmodic glottis closure. Type 2 thyroplasty is based on the hypothesis that the voice symptoms in AdSD are a consequence of excessively tight glottal closure. This surgery differs from previous treatments in that it does not involve any surgical intervention into the laryngeal muscle nerve or vocal fold. At present, type 2 thyroplasty has yet to gain acceptance outside of Japan; however, this surgery has demonstrated superior long-term outcomes compared with traditional treatments. This presentation will focus mainly on the key points for successful type 2 thyroplasty to improve symptoms of AdSD.