Hemifacial spasm in vertebrobasilar dolichoectasia.

Vascular compression of the facial nerve is a well recognized cause of hemifacial spasm (HFS). Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) provide vascular and brain tissue diagnosis in a single non-invasive examination and should be recommended as primary neuroradiological procedure in HFS. We report a rare case of symptomatic HFS caused by a vertebrobasilar dolichoectasia. A 49-year-old women experienced left hemifacial spasm for 10 months. MRI showed an enlarged vertebrobasilar dolichoectasia of the left vertebral artery which compressed the seventh cranial nerve at its exit from the caude pons. MRI is essential in establishing the cause of HFS. Together with MR angiography it shows the correlation among the seventh cranial nerve, blood vessels and the structures of mid-brain. Vertebrobasilar delichoestasia is just one of the blood vessel anomalies which causes HFS and which can be shown by MRI. HFS caused by vertebrobasilar dolichoectasia is quite rare.