Abdul-Latif Hamdan - Department of Otorhinolaryngology – Head and Neck Surgery, American University of Beirut Medical Center, Beirut, Lebanon.
Jad Hosri - Department of Otorhinolaryngology – Head and Neck Surgery, American University of Beirut Medical Center, Beirut, Lebanon.
Vanessa Helou - Faculty of Medicine, American University of Beirut, Beirut, Lebanon.
Marc Mourad - Department of Otorhinolaryngology – Head and Neck Surgery, American University of Beirut Medical Center, Beirut, Lebanon.

Introduction:Adductor Spasmodic Dysphonia (ADSD) is the most common form of spasmodic dysphonia. It encompasses various symptoms affecting voice and speech. The objective of this study is to report the management of patients with ADSD using the transnasal endoscopic approach for laryngeal Botulinum Toxin (Botox) injection.Materials and Methods:A retrospective chart review of patients with ADSD who underwent transnasal endoscopic laryngeal Botox injection was conducted. Voice outcome measures included the Voice Handicap Index-۱۰ (VHI-۱۰) score and the degree of speech fluency.Results:Eight patients with ADSD who underwent ۲۰ office-based transnasal endoscopic laryngeal Botox injections were included. The most commonly injected sites were the thyroarytenoid muscle (TA) and the false vocal fold in ۹۵% and ۵۵% of the cases, respectively. The mean dose of injected Botox was ۲.۴۸ ± ۰.۵۵ IU in the TA muscle, and ۲.۱۴ ± ۰.۵۳ IU in the false vocal fold. The mean amount of Botox injected in the larynx was ۷.۱۶ ± ۲.۴۲ IU. The mean follow-up period was ۱۷.۷ ± ۱۳.۳ months. There was marked improvement in speech fluency in ۶۴.۷% of the cases and mild improvement in one third of the cases. Marked improvement in speech fluency was recorded in ۶۴.۷% of the cases and mild improvement in one third of the cases. The mean VHI-۱۰ score of patients dropped significantly from ۲۲.۴۷±۴.۰۸ to ۱۵±۴.۶۹ following treatment (p<۰.۰۰۱).Conclusions:The transnasal endoscopic approach is an effective and well-tolerated approach for laryngeal Botox injection in patients with ADSD.

Botox, Botulinum toxin, Hyperkinetic dysphonia, Spastic dysphonia