[Microvascular decompression of trigeminal neuralgia caused by vascular compression which penetrated the trigeminal nerve: a case report].

A rare case of trigeminal neuralgia, caused by a branch of the superior cerebral artery running through the trigeminal nerve, was successfully treated by microvascular decompression. The nerve gap at the arterial penetration point was widened by the dissection of the epineurium to obtain sufficient mobilization of the artery and decompression of the nerve. This technique would be useful for securing neurovascular decompression, as well as for avoiding postoperative hypesthesia owing to the neurotomy described in previous reports. Preparing for such a rare case is important as preoperative magnetic resonance imaging (MRI) often fails to disclose precise diagnoses.