Safety of simultaneous bilateral botulinum toxin injections for abductor spasmodic dysphonia.

OBJECTIVE To review the safety of simultaneous bilateral posterior cricoarytenoid muscle botulinum toxin injections. DESIGN Retrospective case series review. SETTING Tertiary care academic clinic. PATIENTS Twenty-one patients with abductor spasmodic dysphonia. INTERVENTIONS Patients received 100 simultaneous bilateral posterior cricoarytenoid muscle botulinum toxin injections for isolated abductor spasmodic dysphonia over a 6-year period. MAIN OUTCOME MEASURES Major and minor complications, injection dosing, and demographics. RESULTS The total bilateral botulinum toxin injection dose per session ranged from 2.50 to 7.50 U, and the average total bilateral dose per patient was 4.70 U. There were no major complications, and minor complications were self-limited. There was a 5% incidence of significant dyspnea and a 2% incidence of dysphagia, and all patients were treated conservatively. The average doses at which dyspnea and dysphagia occurred were 4.97 and 5.56 U, respectively. CONCLUSIONS This case series demonstrates that simultaneous bilateral posterior cricoarytenoid muscle botulinum toxin injection is safe up to the highest doses reported. Complications with this approach are consistent with those previously reported using other methods. Prospective studies on vocal outcome measures are needed for simultaneous bilateral posterior cricoarytenoid muscle botulinum toxin injections to evaluate the efficacy of this technique.