Hemifacial Spasm

This syndrome results from vascular compression and distortion of the 7th cranial or facial nerve resulting in painless twitching of the muscles of the face (figure 1,2). Medical management is the first course of action together with chemodenvervation achieved by Botulinum Toxin injections. Microvascular decompression is reserved for patients with persistent symptoms despite these treatments. See videos below.

Figure 1
MR image demonstrating the posterior inferior cerebellar artery (red arrow) passing under and in close proximity of the facial nerve at its entry zone into the brainstem (white arrow).

Figure 2
Intraoperative image demonstrating artery (PICA) in apposition of the facial nerve (CN VII).