Chemodenervation (Botox injection) for facial spasm

Background:

Hemifacial spasm (HFS) is a neurological disorder in which muscles of one side of the face intermittently and/or continually involuntarily contract, causing uncontrollable spasm/contortion of the face. The most common cause of hemifacial spasm is post-paralytic neve dysfunction following incomplete recovery after sudden facial paralysis (i.e., Bell’s Palsy). HFS is caused by hyperactivity of cranial nerve VII (the facial nerve), which originates in the brainstem and controls muscles of facial expression. The 2nd most common cause of HFS is irritation of the facial nerve from compression by an adjacent artery or vein.

Medications are ineffective for treatment of HFS, but Botulinum toxin (Botox®) injections can provide a temporary treatment of the symptoms of spasm associated with HFS. While Botox® does not treat the cause of HFS, it can help quiet down the undesirable pathways that have formed from improper nerve regeneration after facial paralysis.

Botox® is a bacterial toxin injected by needle into facial muscles that paralyzes the muscles in the area where it is injected. While this prevents the spasms seen in HFS, it also prevents normal movement at the sites of injection. A small amount of Botox® is injected into each of the desired areas using a 30 gauge (very tiny) needle. Each injection site will receive a small amount of the solution, which will leave a pinpoint needlestick and small lump from the fluid itself, which usually resolves in about 15-20 minutes.

The Botox® takes effect within 3-7 days, which should result in less sensation of tightness and improved symmetry. If a bruise does occur (approximately 3-5%), icing for the first 24 hours and topical arnica gel/ointment can help expedite healing. These injections are temporary, with median length of effect lasting 11 weeks, and can be repeated. Botox injections may have lessening effect on treating hemifacial spasm in certain cases over time. However, overall this treatment shows excellent promise for not only treating the discomfort and visible asymmetries associated with incomplete recovery of facial paralysis, but also as an adjunct to neuromuscular physical therapy and rehabilitation.