Chemodenervation of the Larynx

Abstract

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.

Intraductal Salivary Gland Infusion With Botulinum Toxin

“…Intraglandular injection of botulinum neurotoxin (BTX) is designed to decrease the cholinergic neural stimulus to salivary glands through the process of “chemical denervation.”…”

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

“…Additionally, VT is not always limited to the intrinsic muscles of the larynx, but may also involve extrinsic laryngeal, pharyngeal, and palatal musculature . There are two well‐described subtypes of VT: horizontal vocal tremor and vertical vocal tremor . The former describes oscillatory movements in the horizontal plane, which are predominantly mediated by the thyroarytenoid and lateral cricoarytenoid muscles.…”

“…Vertical tremor describes vertical plane oscillation of the laryngopharynx, which can be mediated by a variety of extrinsic laryngeal muscles including strap musculature . The therapeutic decision tree for VT is complex, with options that include voice therapy, medical therapy, vocal fold augmentation, or laryngeal botulinum toxin injection (LBTX), with roles for speech pathologists, neurologists, and laryngologists . There is, however, a growing body of evidence for the role of LBTX therapy .…”

“…The therapeutic decision tree for VT is complex, with options that include voice therapy, medical therapy, vocal fold augmentation, or laryngeal botulinum toxin injection (LBTX), with roles for speech pathologists, neurologists, and laryngologists . There is, however, a growing body of evidence for the role of LBTX therapy . Although treatment paradigms exist describing differing injection sites for both horizontal and vertical tremor, namely thyroarytenoid muscle injections for horizontal tremor and strap muscle injections for vertical tremor, there is little published on the outcomes of these injection sites based on these characteristics of vocal tremor .…”

“…There is, however, a growing body of evidence for the role of LBTX therapy . Although treatment paradigms exist describing differing injection sites for both horizontal and vertical tremor, namely thyroarytenoid muscle injections for horizontal tremor and strap muscle injections for vertical tremor, there is little published on the outcomes of these injection sites based on these characteristics of vocal tremor . Our study aimed to measure outcome differences when different sites of injection are chosen based on a horizontal or vertical tremor profile.…”