Bypassing the blood vessels outside the head to the blood vessels inside the head has the effect of preventing subsequent cerebral infarction if performed in areas with no cerebral blood flow reserve, according to a cerebral blood flow test, according to a Japanese collaboration.
Please refer to "self-introduction" for actual surgery examples.Self introduction
On this page, we will briefly explain the circumstances leading up to the fact that superficial temporal artery-middle cerebral artery anastomosis has a preventive effect on cerebral infarction in joint research in Japan.


The internal carotid and middle cerebral arteries, which supply blood to the front half of the brain, can become completely blocked as arteriosclerosis progresses. If a blood vessel becomes clogged and a complete stroke occurs, then it will be too late, but before the blood vessel is completely clogged, symptoms may appear, and if treatment is given at that stage, a large stroke can be prevented. A transient ischemic attack (TIA) is a condition in which neurological symptoms due to cerebral ischemia appear and are completely cured within a day. Cerebral infarction can be prevented by removing an artery in the skin and connecting it to the middle cerebral artery in the head (superficial temporal artery-middle cerebral artery anastomosis). This surgery was started in 1967 by Professor Yasajir of the University of Zurich in Switzerland and spread all over the world.
However, in 1985, Barnett et al. published the results of a multi-center joint study in the United Kingdom, the United States, Canada, Japan, West Germany, Italy, and Spain (Ref. 1), which shocked the neurosurgeons who were performing this surgery at the time. gave. For stenosis or occlusion of the internal carotid artery and middle cerebral artery, superficial temporal artery-middle cerebral artery anastomosis did not reduce stroke mortality compared with best medical treatment. The operation was discontinued after severe criticism was heard that it was irresponsible and fraudulent.
However, Burnett et al.'s study did not investigate whether it prevents hemodynamic cerebral ischemia (a stroke occurring in a region with no cerebral blood flow reserve). Bypass surgery prevents recurrence of cerebral infarction due to hemodynamic cerebral ischemia, and does not prevent cerebral infarction due to other mechanisms.
Cerebral blood flow examination (SPECT: single photon emission CT) can diagnose hemodynamic cerebral ischemia by observing how much cerebral blood flow increases before and after injection of acetazolamide (Diamox), a vasodilator. Therefore, it is thought that cerebral infarction can be prevented by judging the part of the brain where there is no extra blood flow and performing superficial temporal artery-middle cerebral artery anastomosis there.
Based on this idea, the Japan Neurosurgical Society conducted a prospective randomized sampling study as a multi-center joint study (Japanese EC-IC bypass trial: JET). In patients with occlusion or severe stenosis of the internal carotid artery or middle cerebral artery, (1) quantitative measurement of cerebral circulation with high accuracy, targeting only patients with hemodynamic cerebral ischemia, (2) subject Patients were randomly assigned to either the drug therapy alone group or the drug therapy + bypass surgery group, followed for 2 years, and investigated which group had more ischemic stroke. The study started in 1998 and ended in 2004 with final results. In conclusion, among patients with occlusion or severe stenosis of the internal carotid artery or middle cerebral artery but no or mild neurological symptoms, cerebral perfusion testing revealed that the resting cerebral blood flow was less than 80% of the reference value and cerebral circulation reserve. In patients with a brain of less than 10%, superficial temporal artery-middle cerebral artery anastomosis was associated with a significantly lower incidence of cerebral infarction than the medical treatment alone group. As a result of these results, superficial temporal artery-middle cerebral artery anastomosis is performed again in Japan when it is considered to be an indication for surgery (see document 2).
However, these results have not been accepted by authoritative medical journals to date, and it seems that bypass surgery is not performed as a preventive method for cerebral ischemia outside of Japan. At Mitsui Memorial Hospital, bypass ( Superficial temporal artery-middle cerebral artery anastomosis).


(Document 1) EC/IC Bypass Study Group: Failure of extracranial-intracranial arterial bypass to reduce the risk of ischemic stroke: results of an international randomized study. N. Eng. J. Med., 313: 1191-1200, 1985
(Document 2) JET Study Group. Japanese EC-IC Bypass Trial (JET Study) Interim Analysis Results (Second Report). Stroke Surgery 2002;30:434-437