頭位変換による環椎軸椎関節部での椎骨動脈狭窄

Rotational Stenosis of the Vertebral Artery at the Atlantoaxial Joint: Report of three cases

I．はじめに

　頭位変換により頭蓋外椎骨動脈がfirst portion，second portion，環椎軸椎関節（atlantoaxial joint：AAJ）部，後頭環椎関節部で閉塞され椎骨脳底動脈循環不全症をきたすことが稀にある^3）．最近椎骨脳底動脈循環不全症を主訴として来院し，両側椎骨動脈撮影で正中位では異常がないが頭部回転により回転と反対側の椎骨動脈が，AAJ部で狭窄あるいは閉塞をきたした3症例を経験したので症例を呈示するとともに，頭位変換によるAAJ部での椎骨動脈閉塞の病態とその治療法について文献的考察を加え報告する．

Three cases of vertebral artery stenosis or occlusion at the level of the atlantoaxial joint during head rota-tion were reported. The vertebral artery was mechani-cally compressed on the side of the head opposite to the direction in which the heads was turned. One case was associated with atlantoaxial dislocation due to rheumatoid arthritis. Posterior fixations of C1-C2 or C1-C3 using iliac bone and wire were performed in two cases, and a neck collar was applied in another case. All of the three cases have been free from verteb-robasilar insufficiency since the treatment.