[Hemifacial spasm].

Hemifacial spasm is one of the two most common craniofacial movement disorders (blepharospasm is the second one). It is characterised by unilateral involuntary contractions of muscles involved in facial expression that are innervated by the facial nerve. Most of the time, hemifacial spasm is a peripherally-induced movement disorder caused by vascular compression of the facial nerve near its origin from the brainstem. Although it is a benign condition, it can cause significant cosmetic and functional disability. It is a chronic disease and spontaneous recovery is very rare. The two treatments that are really efficient and routinely available are microvascular decompression and botulinum toxin muscular injections.