Alternating Unilateral Versus Bilateral Injections of Botulinum Toxin for the Treatment of Adductor Spasmodic Dysphonia

Abstract

Objective This study aimed to compare the long-term efficacy, durability, and dose and interval stability between alternating unilateral and bilateral injections of botulinum neurotoxin type A for the treatment of adductor spasmodic dysphonia. Study Design Retrospective cohort study. Setting Academic tertiary medical center. Methods A total of 137 patients (105 alternating unilateral and 32 bilateral injections) who were administered ≥5 injections of botulinum neurotoxin type A were included in this study. The mean dosage change, dose adjustment ratio (number of dose increases/total number of injections), and stability of treatment responses were compared between the alternating unilateral and bilateral injection groups. Results Long-term changes in the mean dosages for alternating unilateral (mean ± SD, –0.010 ± 0.048 IU) and bilateral (–0.042 ± 0.142 IU) injections did not differ between groups ( P = .225), suggesting that both methods follow a decreasing dosing trend over time. The dose adjustment ratio also did not differ between groups ( P = .077), although a longer average treatment interval ( P < .001) and duration of hoarse voice ( P = .045) were found in the bilateral injection group. The proportion of stable patients who did not increase injection dose and had regular follow-up did not differ between the groups. Conclusion Both alternating unilateral and bilateral injection methods showed a long-term decreasing dosing trend, with comparable levels of efficacy, durability, and stability for treating adductor spasmodic dysphonia. Our findings indicate that alternating unilateral injections can be routinely performed with fewer side effects, albeit at shorter treatment intervals, than bilateral injections.

Optimizing Botox regimens in patients with adductor spasmodic dysphonia and essential tremor of voice: A 31‐year experience

“…These findings suggest that a UL injection regimen may be beneficial specifically for patients with suboptimal outcomes resulting from increased weak and breathy periods and/or swallowing complaints. Findings in the current study are consistent with previous retrospective 4 , 13 and crossover 3 studies which report UL injections provide a shorter length of improved voice compared to BL injections but effectively reduce extended durations of weak and breathy voice.…”

“…Findings in the current study are consistent with previous retrospective 4,13 and crossover 3 studies which report UL injections provide a shorter length of improved voice compared to BL injections but effectively reduce extended durations of weak and breathy voice.…”

“…4 Multiple studies have compared the benefit/side effect profile of bilateral and unilateral BTX-A injections of variable doses ranges for patients with ADSD with and without ETV. [3][4][5][6][7][8][9][10][11][12][13] However, ongoing management of these disorders is dynamic, and each injection is titrated based on the physician experience with injections and the patient's report of the previous injection's effectiveness in managing symptoms without causing excessive adverse side effects. The patient's unique communication needs over the course of the next dose cycle must also be considered, and to this end, multiple treatment regimens including bilateral injections, unilateral injections, and mini-doses may be used to optimize a patient's treatment outcomes.…”

“…Multiple studies have compared the benefit/side effect profile of bilateral and unilateral BTX‐A injections of variable doses ranges for patients with ADSD with and without ETV 3–13 . However, ongoing management of these disorders is dynamic, and each injection is titrated based on the physician experience with injections and the patient's report of the previous injection's effectiveness in managing symptoms without causing excessive adverse side effects.…”

Botulinum Neurotoxin Therapy in the Clinical Management of Laryngeal Dystonia

“…Unilateral botulinum toxin injections have also been reported as an effective primary treatment for ADLD. Lee et al [97] have observed that both alternating unilateral and bilateral injection regimes demonstrated comparable levels of efficacy, durability, and stability for the treatment of ADLD. The group concluded that alternating unilateral injections could be routinely performed at shorter intervals, with fewer side-effects compared to bilateral injections.…”