What substance is typically injected into the thyroarytenoid muscle to treat adductor spasmodic dysphonia?

The substance typically injected into the thyroarytenoid muscle to treat adductor spasmodic dysphonia is botulinum toxin. This treatment works by temporarily paralyzing the muscle to reduce its over-activity, which helps alleviate the characteristic voice breaks and strain experienced in this condition. Botulinum toxin acts at the neuromuscular junction to prevent the release of acetylcholine, leading to muscle relaxation and allowing for smoother vocal cord function.

In the context of adductor spasmodic dysphonia, effective voice therapy and other less invasive treatments may sometimes help, but botulinum toxin injections are generally considered the most effective and evidence-based intervention for this disorder. The option of Gelfoam, collagen, or autologous fat would not provide the targeted neuromuscular modulation needed to address the specific spasms associated with adductor spasmodic dysphonia.