Botulinum toxin treatment for spasmodic dysphonia.

Effective treatment of adductor type spasmodic dysphonia with botulinum toxin injection is presented. Patients showed objective and/or subjective improvement in phonation. The beneficial effect lasted for approximately 3 months. An immediate complication is temporary hoarseness or aphonia, mainly due to diffusion of BT into the adjacent muscles. This is avoided by limiting the injection to one vocal fold only and by keeping the dose at less than 5 units. Insertion technique of the needles, such as percutaneous and laryngoscopically controlled techniques, are discussed.