Angiographic observations in idiopathic trigeminal neuralgia.

Twenty-four patients with idiopathic trigeminal neuralgia were treated by neurovascular decompression surgery. All patients underwent preoperative vertebral angiography. After surgery, the vertebral angiograms of these patients were retrospectively reviewed. In 23 of the 24 patients, the superior cerebellar artery (SCA) and/or the anterior inferior cerebellar artery (AICA) compressed the trigeminal nerve. In the remaining case, no such compression by vessels was observed. On review of the angiograms, most of the compressing arteries, and the sites and numbers of compression points could be identified. Most of the caudal points of the SCAs which did not compress the trigeminal nerve were located higher than the compression points of the SCAs. It was therefore concluded that vertebral angiography is useful in the preoperative evaluation of compressing arteries. Since superimposition of arteries could be avoided, the straight AP projection was the most valuable of the three projections employed.