椎骨動脈循環不全の病態生理に関する研究—とくに一側椎骨動脈血流遮断ならびに椎骨動脈周囲神経組織の電気刺激について

OBSERVATIONS UPON THE PHYSIOLOGICAL MECHANISM OF THE SYNDROME OF VERTEBRAL ARTERY INSUFFICIENCY DUE TO COMPRESSION OF THE VERTEBRAL ARTERY

I．緒言

　虚血性の脳血管障害の原因として頸部血管の病変が問題にされるようになつたのは古くRamsy Hunt （1914）^1）の頃からである。当初はもつぱら頸動脈系の病変が注目され，椎骨動脈系に対してはあまり注意がはらわれなかつた。その理由の一つに，椎骨動脈の大部分が骨および靱帯で囲まれた管のなかを通つており，このことが椎骨動脈の検索を困難なものとしてきた。

　これに反して頸動脈系については，閉塞性血管病変のみならずbaroreceptor, chemoreceptor, osmoreceptorの存在など脳の循環調整に貢献するさまざまな機構が明らかになり，頸動脈系に基因する循環不全の病態生理はほとんどあますところなく究明された感がある。

The present investigation dealed with the respon-ses produced by (1) electrical stimulation of periar-terial nerve tissue of proximal area of the vertebral artery (2) electrical stimulation of well-exposed stel-late ganglion (3) temporally sudden obstruction of the unilateral vertebral artery by digital compres-sion against the underlying vertebrae for 30 seconds to 2 minutes. These studies were done during operative treatment of 37 cases of Powers' intermit-tent vertebral artery compression syndrome under local anesthesia utilizing Zeiss biocular dissecting microscope to see periarterial fine structures.

Results as follows ; (1) Stellate ganglion stimula-tion showed ipsilateral, prompt and full mydriasis alone. No nystagmus, no subjective symptoms ensued. (2) Stimulation of periarterial nerve (N. vertebralis) showed various manifestations on pupil-lary change, nystagmus, eye ball movement and subjective complain as well. Slow and mild mydri-asis or miosis were noted both ipsilateral or contra-lateral pupils, case by case. However, individual response had definite and reproductive pattern. Vertical or horizontal nystagmus, conjugate or dis-conjugate eye movement, nausea, occipito-nuchal ache, retroauricular and shoulder ache, bradycardia and mild hypotension were also noted. After the periarterial denervation, no such responses was ob-tained. (3) Sudden obstruction of unilateral verte-bral artery showed no pupillary change whatever. Vertical, horizontal or vertical with occasional hori-zontal nystagmus, conjugate or disconjugate eye movements were noted. Subjectively, sudden dizzi-ness, sensation of impending fainting, blurred vision, oscillopsia, nausea and vomiting were noted over one half of the cases.

The results indicate importance of neurogenic mechanism arising from the vertebral nerve and reduced blood flow of the vertebral artery to produce the syndrome of vertebral artery insufficiency due to vertebral artery compression (Powers). The role of the stellate ganglion has little importance.