Arterial compression of the fifth cranial nerve causing trigeminal neuralgia: angiographic findings.

A common cause of trigeminal neuralgia (TN) is compression of the root of the fifth cranial nerve by a tortuous basilar artery or one of its branches. Microvascular decompression surgery has proved valuable in relieving the symptoms of these patients with nerve compression. We performed vertebral angiography on 22 patients with TN. The angiographic appearances were compared with the findings obtained from an anatomic study in which the positions of 20 trigeminal nerves in the skull were determined radiographically in 12 cadavers. By using this information, we were able to predict the presence of arterial-nerve compression in 20 of the 22 patients, and these positions were later confirmed at surgery. We describe the angiographic findings in patients with TN as well as the findings in a control group of 159 individuals with no history of TN. From these preliminary results, angiography appears to be valuable in the preoperative evaluation of patients with TN.