Unilateral versus bilateral thyroarytenoid Botulinum toxin injections in adductor spasmodic dysphonia: a prospective study

Abstract

ObjectivesIn this preliminary 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.Method and materialsData 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.ResultsLow dose unilateral Dysport injection was associated with no significant difference in the patient's outcome in terms of duration of action, voice score (VS) and complication rate when compared to bilateral injections. Unilateral injections were not associated with any post treatment total voice loss unlike the bilateral injections.ConclusionUnilateral low dose Dysport injections are recommended in the treatment of adductor spasmodic dysphonia.

Botulinum toxin A, brain and pain

“…Effective therapeutic doses in different clinical conditions are much lower-in some conditions like spasmodic dysphonia in order of picograms (Upile et al, 2009). Main pharmacokinetic and pharmacodynamic factors which summate and result in high BoNT/A potency are summarized in sections 3.…”

An Update on the Neurologic Applications of Botulinum Toxins

“…A large retrospective study of 901 patients demonstrated the safety and efficacy of Botox [30]. In a retrospective study of 31 patients who had undergone five consecutive Dysport injections for ADSD, unilateral injections to the thyroarytenoids were just as effective as bilateral injections in terms of voice improvement and duration of action, with no posttreatment total voice loss observed with unilateral injections [31,32]. BoNT-B (Myobloc) was found to be safe and effective for ADSD in a class IV single-site, open-label study in 13 patients [33].…”

Die Behandlung der laryngealen Dystonie mit Botulinumtoxin

“…Allgemein ist zu sagen, dass sich bezüglich erwünschter und unerwünschter Wirkungen keine Unterschiede zwischen uni- und bilateralen Injektionsschemata nachweisen lassen und intiale Heiserkeiten für wenige Tage bis Wochen bei endolaryngealen Behandlungen mit Botulinumtoxin nicht vermeidbar erscheinen [129][130][131][132][133][134][135][136]. Diese sind jedoch passager und werden bei überwiegend positivem Behandlungseffekt von den Patienten akzeptiert [5,124].…”