Rete Mirabile Anastomoses—脳側副循環の血管造影による研究 第2報

CEREBRAL RETE MIRABILE ANASTOMOSES

Ｉ．はじめに

　主要脳動脈の閉塞症においては，ウイリス動脈輪，軟膜動脈間吻合（leptomeningeal anastomoses）および眼動脈を介する外頸動脈—内頸動脈吻合などを介して脳側副循環が形成されることは周知の事実であり，これらの脳側副血行路に関する報告は多い^{3）5）9）11）〜14）16）〜19）22）}。しかし一方外頸動脈分枝である中硬膜動脈が異常に発達し，その末梢部が網状細動脈叢を介して直接大脳表面の軟膜動脈と吻合して，閉塞血管の栄養領域に供血が行なわれるきわめてまれな脳側副循環路がある。この網状細動脈叢を介して形成される中硬膜動脈と脳動脈との直接吻合はrete mirabile anastomosesといわれている^{1）8）11）21）}。著者らは頸部内頸動脈閉塞症1例および大脳基底核に異常血管網を伴う両側内頸動脈サイフォン末端部閉塞症2例をもとに，経大腿動脈カテーテル法および逆行性浅側頭動脈造影による選択的外頸動脈造影法によつてrete mirabile anastomosesを追求し，自験例および報告例をもとに，その発生要因に関して検討し考察を加えた。

1. We have studied and demonstrated the cere-bral collateral circulation via the middle meningeal rete mirabile anastomoses by selective external carotid angiography.

2. A 51-year-old female had often attacks of loss of consciousness, followed by a general convulsion and was admitted to this hospital on January 15, 1967. Carotid angiography revealed an occlusion of the left internal carotid artery just distal to thebifurcation of the common carotid artery and direct communication between the enlarged, posterior branch of the middle meningeal artery and the peripheral branches of the middle cerebral artery via rete mirabile collaterals.

A 18-year-old girl was admitted to our hospital on August 21, 1968, because of an involuntary movements of the right upper extremity of several years duration.

Another 3-year-old girl had a sudden onset of the right hemiparesis. She was hospitalized at the University Hospital on January, 1969.

Carotid angiography of the both patients showed the bilateral occlusion of the end portion of the carotid syphon and the abnormal hypervascularity network in the basal ganglion and its neighbor-hood.

Selective external carotid angiography of the both patients demonstrated collateral filling of the frontal peripheral branches of the anterior cerebral artery from the enlarged anterior branch of the middle meningeal artery via rete mirabile.

3. Anastomoses between the external and the internal carotid arteries, especially direct communi-cation between the middle meningeal artery and the cerebral arteries on the surface of the brain were rarely demonstrated angiographically in the literatures.

4. Pathogenesis and clinical significance of the middle meningeal rete mirabile anastomoses in the cerebro-vascular occlusive diseases were discussed and described, reviewing our 3 cases and 3 cases in the literatures.

5. Selective external carotid angiography is man-datory in order to study and demonstrate the cerebral collateral circulation from the middle meningeal artery to the cerebral arteries via rete mirabile ar-terial anastomoses.

And our technique and method of the selective external carotid angiography were discussed.

6. The middle meningeal rete mirabile anasto-moses were thought to be formed under special conditions that the blood pressure of the pial arteries of the brain were reduced less than that of the middle meningeal artery in such a severe cerebrovascular occlusion which failed to form the major important collaterals such as Willis circle and/or leptomenin-geal anastomoses.