Chemodenervation of the Larynx

Guidelines for the Use of Botulinum Toxin in Otolaryngology From the Korean Society of Laryngology, Phoniatrics and Logopedics Guideline Task Force

The Korean Society of Laryngology, Phoniatrics and Logopedics created a task force to establish clinical practice guidelines for the use of botulinum toxin (BT) in otolaryngology. We selected 10 disease categories: spasmodic dysphonia, essential vocal tremor, vocal fold granuloma, bilateral vocal fold paralysis, Frey's syndrome, sialocele, sialorrhea, cricopharyngeal dysfunction, chronic sialadenitis, and first bite syndrome. To retrieve all relevant papers, we searched the CORE databases with predefined search strategies, including Medline (PubMed), Embase, the Cochrane Library, and KoreaMed. The committee reported 13 final recommendations with detailed evidence profiles. The guidelines are primarily aimed at all clinicians applying BT to the head and neck area. In addition, the guidelines aim to promote an improved understanding of the safe and effective use of BT by policymakers and counselors, as well as in patients scheduled to receive BT injections.

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.

Intraductal Salivary Gland Infusion With Botulinum Toxin

Background

Administration of botulinum toxin through intraductal salivary infusion may decrease the risks of percutaneous needle injection and improve delivery to permeate the entire gland parenchyma.

Methods

The safety of intraductal salivary gland infusion was tested with prospective evaluation of two patients using interviews, clinical examination, and pressure measurement during infusion. Retrospective chart review of two subsequently treated patients assessed treatment of a parotid-cutaneous fistula and sialorrhea.

Results

No complications were identified in the safety study. Pressure changes during infusion supported the concept of botulinum neurotoxin delivery to permeate the gland. Patient-assessed success was subjectively reported as a reduction in the parotid-cutaneous output "by 95%" and the sialorrhea "by 90%" at 2-week follow-up.

Conclusions

The intraductal route of botulinum toxin delivery to salivary glands was without complication and was effective in two patients treated therapeutically. Pressure measurements during infusion may be helpful to direct treatment.

Level of Evidence

4.

Quality of Life After Botulinum Toxin Injection in Patients With Adductor Spasmodic Dysphonia; a Systematic Review and Meta-analysis

INTRODUCTION

Adductor spasmodic dysphonia is an extremely disabling voice disorder that negatively impacts a patient's quality of life (QOL). We performed a systematic review to determine if Botulinum Toxin (BT) injections improved voice related QOL in patients with this disorder.

METHODS

PubMed, EMBASE, Web of Science, Cochrane Library, ProQuest, and Scopus from 2000, to and including November 1st, 2018, were searched. We identified randomized controlled trials, controlled trials, and observational studies of the effects of BT injections on the QOL in patients with adductor spasmodic dysphonia. The two authors, separately and individually chose the studies based on inclusion criteria, assessed study quality, and relevant extracted data.

RESULTS

Nine studies used the Voice Handicap Index (VHI). The results showed significant changes pre- to post-BT injection (SMD = -0.357; 95% CI: -0.579, -0.136; z = 3.16; P = 0.002; I-squared = 0.000%). Five studies used the Voice-Related QOL; their results also showed a significant improvement pre- to postinjection (SMD = -2.99; 95% CI: -3.27, -1.32; z = 4.61; P < 0.001; I-squared = 87%). Three other studies used other, shortened versions of the VHI, VHI-10. They also showed significant results (SMD = -0.145; 95% CI: -0.349, 0.06; z = 1.38; P = 0.17; I-squared = 0.000).

CONCLUSION

BT injections positively affect patients' QOL. However, patients' QOL scores may never be normalized, in line with perceptual voice quality and acoustic parameters.

Laryngeal Botulinum Toxin Injection for Vocal Tremor: Utility of Concurrent Strap Muscle Injection

OBJECTIVES/HYPOTHESIS

Vocal tremor is a neurologic disorder that can be treated with laryngeal botulinum toxin injections (LBTX). We sought to describe our experience with thyroarytenoid and concurrent strap muscle injection.

STUDY DESIGN

Retrospective chart review.

METHODS

A chart review was performed of all patients with a primary diagnosis of vocal tremor treated with LBTX from 2012 through 2017.

RESULTS

Twenty-one patients were included (mean age 69 years, 100% female). Thirteen patients (62%) had a minor component of spasmodic dysphonia in addition to their tremor. Fourteen patients had vertical and horizontal components to their tremor, and two had horizontal tremor alone. The remaining five patients did not have clear characterization of their tremor. A total of 49 injections were reviewed (25 thyroarytenoid [TA], 24 thyroarytenoid and strap muscle [TA+S]), and patients reported subjective voice benefit with 48 (96%) of these (92% TA, 100% TA+S). When available, the postprocedural change from baseline Voice Handicap Index-10 and Consensus Auditory Perceptual Evaluation of Voice scores were calculated (mean overall: -1.9, -7.8; TA: -2.7, -3.5; TA+S: -1.4, -10.3, respectively). Subjective patient improvement ratings (scale 0%-100%) were obtained for 46 injections, with a mean of 70% improvement per injection. Of patients with both horizontal and vertical tremor, outcomes were improved with TA+S injection versus TA alone (mean improvement 74% vs. 35%, P < .005).

CONCLUSIONS

There is utility in the characterization of vertical and horizontal components of vocal tremor. Patients with both appear to have increased benefit with injection of strap muscles in addition to thyroarytenoid muscles.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:1433-1437, 2019.