Office-Based Laryngeal Botulinum Toxin Injection

Botulinum toxin (BT) is a neurotoxin produced by fermentation of Clostridium botulinum. There are eight serotypes of botulinum toxin (A to G), the most common of which is type A in clinical settings. Botulinum toxin acts by inhibiting the release of acetylcholine at the neuromuscular junction of the targeted muscle, leading to temporary chemical denervation and reduction in excessive and/or uncontrolled muscle activity. The success of BT in the treatment of various forms of focal dystonia such as blepharospasm, oromandibular dystonia, torticollis, hemifacial spasm, and focal limb dystonia has fostered its use in the treatment of laryngeal movement disorders. These include spasmodic dysphonia, essential voice tremor, paradoxical vocal fold movement disorders or “induced laryngeal obstruction,” laryngeal tics, occasionally muscle tension dysphonia, and others. Various intrinsic and extrinsic laryngeal muscle groups may be injected, and targeting the affected muscle under electromyographic (EMG) guidance is valuable to optimize the treatment outcome. History of prior treatment and dose of BT used are also important determinants of the success of injection. Patient counseling and individualized treatment plans are crucial to minimize adverse events.

This chapter reviews the application of BT injections in the management of laryngeal movement disorders. The surgical technique and use of EMG guidance are described thoroughly described. The site and dose of injection, as well as associated adverse effects, are discussed also.