Botulinum toxin treatment of false vocal folds in adductor spasmodic dysphonia: Functional outcomes

Patient-Reported Outcomes after False Vocal Folds Injections for Adductor Spasmodic Dysphonia

OBJECTIVES

The primary objective of this study is to investigate if false vocal folds (FVF) or simultaneous FVF with thyroarytenoid (FVF+TA) Botox® injections achieve comparable treatment effects to standard TA injections. This study also aims to determine how patient-reported outcomes contribute to the transition to, and continuation of, FVF or FVF+TA injections.

METHODS

Retrospective chart review was performed for all patients receiving Botox® for adductor spasmodic dysphonia at a laryngology practice between 2005 and 2018. Twenty out of 103 patients met the study's inclusion criteria. All subjects began standard treatment with TA injections. Based on response to injection, patients either continued to receive TA injections (group TA; n = 7), switched to FVF injections (group FVF; n = 7), or switched to FVF+TA injections (group FVF+TA; n = 6). A comparison of group means before and after initiation of FVF±TA injections was performed between groups FVF and FVF+TA to group TA for the injection dosage, the duration of injection cycles, the patient-reported duration of best voice, and the presence and duration of breathiness and choking. Within-group observations were also compared before and after FVF±TA injections.

RESULTS

There were no significant findings for the variables between group FVF and group TA before FVF injections. The duration of injection cycles was significantly shorter for group FVF than group TA after FVF injections (95% CI: -66.05, -0.34; P = 0.05). However, duration of best voice quality, breathiness, and choking were similar (P > 0.05) for group FVF to group TA after FVF injections. Group FVF+TA had a significantly shorter duration of injection cycles (95% CI: -66.97, -3.22; P = 0.03), best voice (95% CI: -0.76, -0.03; P = 0.04), and choking (95% CI: -2.68, 0.02; P = 0.05) than group TA before FVF+TA injections. Group FVF+TA displayed a similar duration (P > 0.05) of injection cycles, best voice quality, breathiness, and choking to group TA after FVF+TA injections. Within-group, increased duration of injection cycles and best voice were observed after FVF±TA injections for both group FVF and FVF+TA. Acute adverse events were variable within groups after FVF±TA injections.

CONCLUSION

This study compared outcomes of FVF or FVF+TA injections to successive TA injections among patients. FVF injections displayed similar duration of best voice quality, breathiness, and choking to TA injections. FVF+TA injections achieved similar duration of injection cycles, best voice quality, breathiness, and choking to TA injections. This study demonstrates that patients guided by a reduced duration of adverse events, while tolerating a shorter injection cycle, may benefit from initiation and continuation of FVF injections. Patients guided by increased duration of injection cycle and best voice, while tolerating the duration of adverse events, may benefit from initiation and continuation of FVF+TA injections.

Efficacy of Botulinum A Injection to the Laryngeal Adductor Compartment for Treatment of Cough

OBJECTIVES

Studies examining electromyography (EMG)-guided laryngeal onobotulinumtoxinA (BTxA) injection for chronic cough reveal promising efficacy, however, are limited by small cohorts and absent quantifiable outcomes. It further remains unclear if pulmonary disease limits efficacy, or if vagal motor neuropathy prognosticates response. We hypothesize BTxA injection results in qualitative improvement in cough, decrease in Cough Severity Index (CSI), no change in Voice Handicap Index-10 (VHI-10), and complication rates comparable to historical data. We also examine the correlation of pulmonary comorbidities and vocal fold hypomobility with treatment efficacy.

STUDY DESIGN

Retrospective review.

METHODS

Charts for patients receiving percutaneous adductor compartment BTxA injection for cough were reviewed for the binary outcome of patient-reported presence or absence of improvement. Generalized estimating equations regression models were used to analyze the change in CSI (ΔCSI) and the correlation of ΔCSI with qualitative outcomes. Multivariable analyses were used to examine correlation of vocal fold hypomobility and pulmonary disease with qualitative outcomes and ΔCSI.

RESULTS

Forty-seven patients underwent 197 BTxA injections from June 2012 to June 2022. A statistical proportion of 0.698 (0.599-0.813, p < 0.0001) or 69.8% of injections resulted in subjective improvement. Mean ΔCSI was -2.12 (0.22-4.02, p < 0.05), indicating overall improvement. With and without subjective improvement, estimated ΔCSI was -4.43 and +2.68, respectively (p < 0.0001). VHI-10 did not change (0.69, p = 0.483). Neither pulmonary disease nor vocal fold hypomobility correlated with subjective improvement or ΔCSI. Dysphagia occurred following 15 (7.6%) injections with no aspiration pneumonia or hospitalization.

CONCLUSIONS

BTxA injection to the laryngeal adductors may effectively treat cough with limited risk for serious complications.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1749-1756, 2024.

Hemodynamic Changes Associated With Transcervical Laryngeal Injection of Botulinum Toxin

PURPOSE

Laryngeal dystonia is a chronic neurologic disorder characterized by intention-induced spasms of the vocal folds driven by aberrant central motor processing. The use of in-office transcervical botulinum toxin injection for the treatment of laryngeal disorders, such as laryngeal dystonia, has been deemed safe and efficacious. There is, however, no available data outlining the hemodynamic changes experienced by patients undergoing this frequently performed procedure.

METHODS

One hundred and one patients diagnosed with laryngeal dystonia were enrolled in this prospective study. These patients underwent transcervical laryngeal botulinum toxin injection to address their dysphonia. Vital signs where acquired prior to, and at the time of injection. Alterations in these parameters were then evaluated for statistical significance.

RESULTS

Statistically significant increases in mean heart rate (5.8 ± 10.8 bpm, P < 0.0001), systolic blood pressure and diastolic blood pressure (7.0 ± 9.5 mm Hg, P < 0.0001; 8.7 ± 14.7 mm Hg, P < 0.0001) were discovered. No statistically significant difference in oxygen saturation was noted and no patients in the study faced major adverse outcomes.

CONCLUSIONS

Though these findings may not have related to clinically significant complication, our study demonstrates the importance of understanding potential stressors in a procedure routinely performed by laryngologists. This may result in more careful patient selection, alterations in procedure, and improved safety by acting in a timely fashion if alarming changes in hemodynamic parameters are noted.

Botulinum Neurotoxin Therapy in the Clinical Management of Laryngeal Dystonia

Laryngeal dystonia (LD), or spasmodic dysphonia (SD), is a chronic, task-specific, focal movement disorder affecting the larynx. It interferes primarily with the essential functions of phonation and speech. LD affects patients' ability to communicate effectively and significantly diminishes their quality of life. Botulinum neurotoxin was first used as a therapeutic agent in the treatment of LD four decades ago and remains the standard of care for the treatment of LD. This article provides an overview of the clinical application of botulinum neurotoxin in the management of LD, focusing on the classification for this disorder, its pathophysiology, clinical assessment and diagnosis, the role of laryngeal electromyography and a summary of therapeutic injection techniques, including a comprehensive description of various procedural approaches, recommendations for injection sites and dosage considerations.

Supraglottic Botulinum Toxin Improves Symptoms in Patients with Laryngeal Sensory Dysfunction Manifesting as Abnormal Throat Sensation and/or Chronic Refractory Cough

Laryngeal sensory dysfunction (LSD) encompasses disorders of the vagal sensory pathways. Common manifestations include chronic refractory cough (CRC) and abnormal throat sensation (ATS). This study examined clinical characteristics and treatment outcomes of LSD using a novel approach of laryngeal supraglottic Onabotulinum toxin Type A injection (BTX). This was a retrospective review of clinical data and treatment outcomes of supraglottic BTX in patients with LSD. Between November 2019 and May 2021, 14 patients underwent 25 injection cycles of supraglottic BTX for treatment of symptoms related to LSD, including ATS and CRC. Primary outcome measures included the Newcastle Laryngeal Hypersensitivity Questionnaire (LHQ), Cough Severity Index (CSI), Reflux Symptom Index (RSI), and Voice Handicap Index-10 (VHI-10) at baseline and within three months of treatment. Pre- and post-treatment data were compared using a linear mixed model. After supraglottic BTX, LHQ scores improved by 2.6. RSI and CSI improved by 8.0 and 5.0, respectively. VHI-10 did not change as a result of treatment. Short-term response to SLN block was significantly associated with longer term response to BTX treatment. These findings suggest that LSD presents clinically as ATS and CRC along with other upper airway symptoms. Supraglottic BTX injection is a safe and effective technique in the treatment of symptoms of LSD.

Life Threatening Delayed Complication of Botulinum Toxin Injection for Treatment of Spasmodic Dysphonia

Spasmodic dysphonia is a primary task specific focal dystonia affecting the laryngeal muscles during speech. Most medical and surgical approaches to treatment of spasmodic dysphonia are aimed at the denervation of the laryngeal muscles to block symptom expression in the voice. The standard of care for the adductor form of spasmodic dysphonia is botulinum toxin chemodenervation. The common side effects of treatment with Botox are excessive breathiness and aspiration of fluids. We present the report of a delayed presentation of upper airway obstruction due to a complete vocal cords adduction requiring intubation ten days post Botox injection for the adductor form of spasmodic dysphonia. This presentation may be preceded by a change in voice, productive cough, shortness of breath, or odynophagia. We would recommend supportive treatment in an Intensive Care Unit and close liaison with the otolaryngology team for the management of this complication. Acute upper airway obstruction requiring tracheal intubation is a delayed complication of botulinum toxin administration in the adductor form of spasmodic dysphonia.

Office-based endoscopic botulinum toxin injection in laryngeal movement disorders

INTRODUCTION

Botulinum toxin injection is widely used for the treatment of laryngeal movement disorders. Electromyography-guided percutaneous injection is the technique most commonly used to perform intralaryngeal botulinum toxin injection.

OBJECTIVE

We describe an endoscopic approach for intralaryngeal botulinum toxin injection under local anaesthesia without using electromyography.

TECHNIQUE

A flexible video-endoscope with an operating channel is used. After local anaesthesia of the larynx by instillation of lidocaine, a flexible needle is inserted into the operating channel in order to inject the desired dose of botulinum toxin into the vocal and/or vestibular folds.

CONCLUSION

Endoscopic botulinum toxin injection under local anaesthesia is a reliable technique for the treatment of laryngeal movement disorders. It can be performed by any laryngologist without the need for electromyography. It is easy to perform for the operator and comfortable for the patient.

Chemodenervation of the Larynx

Botulinum neurotoxin (BoNT) has existed for thousands of years; however, it was not medically utilized until investigations into its therapeutic use began in sincerity during the late 1970s and 1980s. This, coupled with the reclassification of spasmodic dysphonia as a focal dystonia, led to the use of chemodenervation for this disorder, which has since become a refined technique. Indeed, due to its safety and efficacy, BoNT has been investigated in multiple neurolaryngology disorders, including spasmodic dysphonia, vocal tremor, and muscle tension dysphonia. BoNT has been shown to be a useful and safe adjunct in the treatment for these disorders and may reduce or eliminate oral pharmacotherapy and/or prevent the need for a surgical intervention. We present the historical background, development, proposed mechanisms of action, uses, and techniques for administering BoNT for laryngeal disorders, with a particular focus on spasmodic dysphonia.

Liquid-type Botulinum Toxin Type A in Adductor Spasmodic Dysphonia: A Prospective Pilot Study

OBJECTIVES

Botulinum toxin (BTX) has been widely used to treat adductor spasmodic dysphonia (ADSD). Most commercially available forms of BTX require reconstitution before use, which may increase the risk of contamination and requires careful titration. Recently, a liquid-type BTX type A (BTX-A) has been developed, which should simplify the procedure and enhance its efficacy. Herein, we present a prospective pilot study to investigate the efficacy and safety of liquid-type BTX-A in the treatment of ADSD.

METHODS

Twenty-six consecutive liquid-type BTX-A injections were performed in 12 patients with ADSD. We included as a control group 34 consecutive patients with ADSD who had previously undergone 52 vocal fold injection procedures with freeze-dried-type BTX-A.

RESULTS

All patients in both groups had improvement of symptoms related to ADSD and period of normal voice. Most patients experienced breathiness, and the onset time, the peak response time, and the duration of breathiness were similar in both groups. The duration of effect (days) was 96.96 ± 18.91 and 77.38 ± 18.97 in the freeze-dried-type and the liquid-type groups, and the duration of benefit (days) was 80.02 ± 18.24 and 62.69 ± 19.73 in the freeze-dried-type and the liquid-type groups. To compare the efficacy between the freeze-dried-type and the liquid-type BTX-A, the sessions of the unilateral vocal fold injection were included and were categorized as group A (1 ~ 2 units BTX-A) and group B (2 ~ 3 units BTX-A), according to the dose per vocal fold. There was no significant difference of effect time between freeze-dried-type and liquid-type BTX-A groups. No adverse events related to BTX or vocal fold injection were reported.

CONCLUSIONS

Liquid-type BTX-A is safe and effective for the treatment of spasmodic dysphonia. With the advantages of simple preparation, storage, and reuse and animal protein-free constituents, liquid-type BTX-A may be a good option in the treatment of spasmodic dysphonia.