Vocal outcome after endoscopic thyroarytenoid myoneurectomy in patients with adductor spasmodic dysphonia

Spasmodic dysphonia (SD) remains one of the most difficult of laryngeal pathologies to treat. With limited role for speech therapy, various surgical modalities have been tried with various success rates. The objective of the study is to report the results of vocal outcome after thyroarytenoid myoneurectomy in patients of adductor spasmodic dysphonia (ASD). 15 patients of ASD were selected. GRBAS, and voice handicap index (VHI) were used for perceptual evaluation of voice. Thyroarytenoid myoneurectomy was performed by vaporizing the muscular layer of the vocal fold with CO2 laser, at an intensity of 6 W with 1.2 mm diameter in scanner mode. Voice analysis was repeated at 12, 24 and 48 months follow-up. Preoperative GRBAS scores and VHI score of all the patients were poor. At 12 months 12/15 (80 %) patients having strain score of 0. There was marked improvement in VHI scores at 6 months. 10/15 (67 %) patients have been followed up for 24 months. 5/10 (50 %) patients have strain (S) value of 0. VHI scoring of 5/10 (50 %) patients was <30. Two of the four patients completed 48 months follow-up had a strain (S) value of 0, one patient has strain value of 1 and one patient had strain value of 2. 2/4 patients had VHI score of <30; one patient had that of 40. Trans-oral CO2 laser thyroarytenoid myoneurectomy shows significant long-term improvement in voice quality in terms of reduced speech brakes, effort and strain in voice.