Size of the internal carotid and middle cerebral arteries in patients with trigeminal neuralgia.

Internal carotid angiography was performed in 38 patients with trigeminal neuralgia. The diameters of the middle cerebral and internal carotid arteries were measured and compared with the expected normal values obtained from a previously published study of a reference group of patients. The internal carotid artery was narrower than expected in the region close to the Gasserian ganglion and wider proximal and distal to this region. The differences were statistically significant. In 45 per cent of the patients, tortuosity and kinking of the internal carotid artery was found, indicating ectasia. Thus, in spite of signs of ectasia of the internal carotid artery, a significant reduction of the vessel size was seen close to the Gasserian ganglion, suggesting an etiologic relationship between the vascular changes and trigeminal neuralgia.