The Role of Botulinum Toxin Injections in the Treatment of Facial Nerve Palsy

Editorial

Austin J Otolaryngol. 2014;1(4): 3.

The Role of Botulinum Toxin Injections in the Treatment of Facial Nerve Palsy

Spataro E, Desai SC and Branham G*

Department of Otolaryngology-Head and Neck Surgery, Washington University, USA

*Corresponding author: Branham G, Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, 660 S. Euclid Ave., Campus Box 8115, St. Louis, MO 63110, USA

Received: October 01, 2014; Accepted: November 16, 2014; Published: November 19, 2014

Introduction

The treatment of facial nerve palsy is complex and often requires multiple interventions to restore function and symmetry to the face. Botulinum toxin injections treat complications of facial nerve palsy such as synkinesis, facial asymmetry and contralateral hyperkinesis. The use of botulinum toxin to treat facial asymmetry began in the 1980s and expanded to treat synkinesis in the early 1990s. Since this time many studies have shown its effectiveness to improve facial symmetry as well as function of the paralyzed face [1-8].

Botulinum toxin type A produces chemodenervation of the injected muscle by inhibiting presynaptic acetylcholine release from nerve terminals. Specifically, once the toxin is internalized by endocytosis into the nerve axon, inhibition of SNAP-25 (synaptosomal associated protein-25) on the cell membrane blocks acetylcholine release, in turn preventing muscle contraction (Figure 1). The onset takes 2-3 days with maximum effect occurring at 2 weeks. Binding of the toxin to the nerve is irreversible, and recovery of muscle function is due to collateral axonal growth to restore the motor synapse. The chemodenervation effect of botulinum toxin reverses in 3-5 months, depending on site of injection, often requiring repeat injections to maintain results [9]. Two commercial formulations of botulinum toxin type A are available: Dysport and Botox, generically known as AbobotulinumtoxinA (ABO) and OnabotulinumtoxinA (ONA), respectively. Comparison of these two preparations in frontalis injections have shown earlier onset and longer duration of improvement using ABO (Dysport) compared to ONA (Botox). However, the two preparations have similar effectiveness. A dose ratio of ONA to ABO for frontalis injections of 2.5:1 has been effectively used [10-11].

Citation: Spataro E, Desai SC and Branham G. The Role of Botulinum Toxin Injections in the Treatment of Facial Nerve Palsy. Austin J Otolaryngol. 2014;1(4): 3. ISSN :2473-0645