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Head & Neck Oncology

Open Access

Unilateral versus bilateral thyroarytenoid Botulinum toxin injections of in adductor spasmodic dysphonia

  • Jesuloba Abiola1,
  • Waseem Jerjes1,
  • Ruth Epstein1,
  • John Rubin1 and
  • Tahwinder Upile1
Head & Neck Oncology20091(Suppl 1):P25

Published: 28 July 2009


In this prospective study, we compared unilateral and bilateral thyroarytenoid muscle injections of Botulinum toxin (Dysport®) in 31 patients with adductor spasmodic dysphonia, who had undergone more than 5 consecutive Dysport® injections (either unilateral or bilateral) and had completed 5 concomitant self-rated efficacy and complication scores questionnaires related to the previous injections. We also developed a Neurophysiological Scoring (NPS) system which has utility in the treatment administration.

Materials and methods

Data were gathered prospectively on voice improvement (self-rated 6 point scale), length of response and duration of complications (breathiness, cough, dysphagia and total voice loss). Injections were performed under electromyography (EMG) guidance. NPS scale was used to describe the EMG response. Dose and unilateral/bilateral injections were determined by clinical judgment based on previous response. Time intervals between injections were patient driven.


Low dose unilateral Dysport® injection was associated with no significant difference in the patient's outcome in terms of duration of action, voice score and complication rate when compared to bilateral injections. Unilateral injections were not associated with any post treatment total voice loss unlike the bilateral injections.


Unilateral low dose Dysport® injections are recommended in the treatment of Adductor Spasmodic Dysphonia.

Authors’ Affiliations

Head & Neck Centre, University College London Hospitals


© Abiola et al; licensee BioMed Central Ltd. 2009

This article is published under license to BioMed Central Ltd.