[Trigeminal neuralgia associated with primitive trigeminal artery: report of two cases].

Two cases of trigeminal neuralgia associated with the primitive trigeminal artery are reported. From 1981, the authors have treated 131 trigeminal neuralgia patients with microvascular decompression. Among them, we encountered two rare cases of trigeminal neuralgia associated with the primitive trigeminal artery (PTA) and its variant (PTAV). Case 1 is a 74-year-old woman who was admitted to our hospital due to pain of maxilla and mandible. We diagnosed her pain as trigeminal neuralgia. Preoperative angiogram showed the primitive trigeminal artery arising from the cavernous portion of the right internal carotid artery (ICA). She underwent a microvascular decompression operation. We found that her right trigeminal nerve was compressed by the right superior cerebellar artery (SCA) and the right anterior inferior cerebellar artery (AICA). We transferred the offending arteries, and her pain disappeared. Case 2 is a 48-year-old man who was admitted to our hospital due to severe mandibular pain. We diagnosed his pain as trigeminal neuralgia, and he underwent a microvascular decompression operation. His left trigeminal nerve was found compressed by the left SCA and the AICA, and the AICA was arising from the direction of Meckel's cave. His severe pain disappeared completely after operation. Postoperative angiogram of his left ICA showed an aberrant artery arising from the cavernous portion of the ICA, to the region of the left AICA. This aberrant artery is a variant of PTA (PTAV). PTA and PTAV, the so called persistent congenital arteries, are said to accompany aneurysms and other vascular lesions, and affect hemodynamic stress.(ABSTRACT TRUNCATED AT 250 WORDS)