Long-term Dose Stability of OnabotulinumtoxinA Injection for Adductor Spasmodic Dysphonia: A 19-Year Single Institution Experience

The Long-term Efficacy of Botulinum Toxin Injection to Treat Retrograde Cricopharyngeus Dysfunction

Objectives

To report the percentage of patients with symptom relief 6 or more months after botulinum toxin injection into the cricopharyngeus muscle for retrograde cricopharyngeus dysfunction (R-CPD).

Study Design

Retrospective case series of consecutively treated patients.

Setting

Tertiary care laryngology clinic.

Subjects and Methods

A review was performed of the first 200 patients who were diagnosed with R-CPD and treated with botulinum toxin injection into the cricopharyngeus muscle by a single surgeon. The study group was limited to those for whom a minimum of 6 months has elapsed since the injection. Items assessed were efficacy, safety, complications, and duration of benefit.

Results

Of 200 patients treated, (99.5%) gained the ability to burp and 95% experienced relief of the cardinal symptoms of R-CPD: inability to belch, socially awkward gurgling noises, abdominal/chest pressure and bloating, and excessive flatulence. For those who experienced relief, 159 (79.9%) maintained a satisfactory ability to burp after 6 months. Of those who did not maintain the ability, 12 underwent a second injection, 1 patient underwent 3 subsequent injections, and 3 patients underwent partial myotomy. No patients experienced complications of botulinum toxin injection itself, and 4 patients had complications from esophagoscopy or anesthesia.

Conclusion

In a case series of 200 patients with retrograde cricopharyngeus dysfunction, 99% experienced relief of the cardinal symptoms and 79.9% experienced lasting relief of their symptoms beyond pharmacologic duration of action after a single injection of botulinum toxin into the cricopharyngeus muscle. Relief can be reestablished in the remainder via additional injection or cricopharyngeus myotomy.

Unilateral versus bilateral botulinum toxin injections in adductor spasmodic dysphonia in a large cohort

OBJECTIVES/HYPOTHESIS

The primary treatment of adductor spasmodic dysphonia is repeated injections of botulinum toxin type A (Botox) into the thyroarytenoid muscles. Dosing can be performed into either one or both thyroarytenoid muscles. The objective of this study was to evaluate the treatment effect and side effect profile across a large number of injections. This study was performed previously in 2002 on 45 patients.

STUDY DESIGN

Individual cohort study.

METHODS

This is retrospective study of all patients with adductor spasmodic dysphonia with and without tremor treated by the senior laryngologist at George Washington University. In the current study, 272 patients (214 females and 58 males) were included in the current analysis. Duration of effects and side effects (vocal weakness and liquid dysphagia) were recorded into a database for each patient after each injection. These data were analyzed using χ² analysis.

RESULTS

A total of 4,023 injections (2,708 bilateral and 1,315 unilateral) were evaluated in this study. Optimal effect duration (≥3 months) was more commonly seen in the bilaterally injected patients (55%) compared to the unilaterally injected patients (47%) (P = .0001). Optimal side effect duration (≤2 weeks) was better for the unilaterally injected patients (77%) compared to the bilaterally injected patients (73%) (P = .023). Having both optimal effect and side effect in the same injection was more commonly seen in the bilaterally injected patients (36%) compared to the unilaterally injected patients (33%) (P = .0228).

CONCLUSIONS

This study shows that bilateral injections of Botox are more effective in producing optimal effect/side effect profiles.

LEVEL OF EVIDENCE

2b Laryngoscope, 130:2659-2662, 2020.