責任血管が三叉神経を貫通する特発性三叉神経痛の微小血管減圧術

Microvascular Decompression of Trigeminal Neuralgia Caused by Vascular Compression Which Penetrated the Trigeminal Nerve: A Case Report

I．はじめに

　特発性三叉神経痛は，三叉神経根進入部（root entry zone：REZ）への血管圧迫により生じ，治療として微小血管減圧術（mircrovascular decompression：MVD）が行われている^1,3,5)．通常，血管は外側から神経組織を圧迫しており，血管移動法など減圧手技についておおむねコンセンサスが得られている^2,3,5)．しかし，責任血管が三叉神経を貫通することが0.8％と稀にあり¹¹⁾，このような症例に対する減圧手技についての報告はほとんどない．今回，責任血管が三叉神経を貫通し圧迫していた特発性三叉神経痛の1例を経験したので手術手技の工夫について報告する．

　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.