UNILATERAL VERSUS BILATERAL BOTULINUM TOXIN INJECTIONS IN ADDUCTOR SPASMODIC DYSPHONIA

Thyroarytenoid injection of botulinum toxin is the therapy of choice i n spasmodic dysphonia. However, there is no convincing evidence as to whether unilateral or bilateral injections are to be preferred. For th is reason, a prospective study was designed in which voice quality, du ration of effect, and side effects were assessed. Twenty-seven patient s with adductor spasmodic dysphonia were treated with percutaneous inj ections of botulinum toxin. The first treatment consisted of injection of 5 units in the left thyroarytenoid muscle. The second treatment, 2 .5 units in both sides, took place when the effect of the first proced ure had completely ceased. All patients underwent both procedures. By means of self-rating scales, effects and side effects were assessed ov er at least 3 months. There was no difference between the procedures i n duration of voice improvement, nor in the occurrence of breathy dysp honia. After a bilateral injection, statistically more patients report ed swallowing problems. However, most patients preferred the bilateral injection, in spite of more and longer-lasting side effects.