Trigeminal neuralgia caused by venous compression

The purpose of this study is to clarify whether venous compression on the trigeminal nerve really causes trigeminal neuralgia or not, and to identify which veins are the offending veins. We used microvascular decompression in operations on 121 patients with typical trigeminal neuralgia. We analyzed the intraoperative findings and surgical results in these 121 cases. In 7 of the 121 cases, only the vein was identified as a compressive factor on the trigeminal nerve. In 6 of these 7 cases, single venous compression was found, whereas the remaining case had two offending veins. The transverse pontine vein was most frequently found as the offending vein near Meckel's cave. All patients showed complete relief of trigeminal pain after decompression of the veins, but four of them developed facial numbness after surgery, which tended to be slight and did not require any treatment. Our surgical experiences showed that venous compression could cause trigeminal neuralgia by itself and that the transverse pontine vein should be carefully observed because it is most frequently the offending vein.