MAGNETIC-RESONANCE-IMAGING OF VERTEBROBASILAR ECTASIA IN TRIGEMINAL NEURALGIA

Vertebrobasilar ectasia is a rare cause of typical trigeminal neualgia . In a recently published large series only thirty-one (2%) of 1404 co nsecutive patients with vascularly determined neuralgia were found to have vertebrobasilar compression. We present three patients with trige minal neuralgia caused by vertebrobasilar ectasia, who were evaluated with high resolution magnetic resonance imaging (MRI). MRI studies pro vided accurate information on the anatomical location and course of th e ectatic vessel in the cerebellopontine angle and the caused mass eff ect on the brainstem. With gadolinium-enhancement vascular compression of the trigeminal nerve was demonstrated clearly. Surgery confirmed c ompression of the fifth nerve by an ectatic and tortuous vertebrobasil ar artery in two cases. Following microvascular decompression neither patient experienced further pain. The third patient was treated with a ventriculoperitoneal shunt, as he developed occlusive hydrocephalus c aused by the vertebrobasilar dolicho-ectasia, MRI is useful in the eva luation of trigeminal neuralgia as it excludes other aetiologies such as tumour or arteriovenous malformation, but also demon strates crania l nerve compression by ectatic vertebral arteries.