[Hemifacial spasms and vertebral dolichoectasias]

Hemifacial spasm (HFS) is characterized by chronic twitching or spasm of one side of the face. It affects muscles activated by the facial nerve. HFS is believed to result from irritation of the facial nerve at its exit from the brainstem and most cases are associated with a small vascular loop compression. Rarely it is associated with a vertebral artery dolichoectasia.

We report three cases of HFS whose magnetic resonance imaging and magnetic resonance angiography revealed vertebral dolichoectatic arteries compressing the facial nerve and causing HFS. These cases were selected from the group of patients of the dystonic outpatient clinics, Neurology Department, between April 1st 1998 and December 30th 2007.

Magnetic resonance imaging and magnetic resonance angiography are essential for the diagnosis of a vertebral dolichoectasia and should be considered the initial screening procedures in the assessment of patients with HFS. The role of these neuroradiologic studies in the diagnosis of HFS is not only to detect the vascular structures running adjacent to the root exit zone that might distort the facial nerve and compress the brain stem around the root exit zone, but also to exclude other causes in a single non-invasive examination.