The disease is mostly caused by localized congenital defects in the walls of cerebral arteries and on the basis of increased intraluminal pressure. Hypertension, cerebral atherosclerosis, and vasculitis are associated with the development of aneurysms. Etiology Cerebral aneurysms are most often seen at the bifurcation of the arteries at the base of the brain. According to the site of origin, 4/5 of them are located in the anterior half of the cerebral artery ring, mostly in the internal carotid artery, posterior communicating artery, anterior communicating artery, and also in the middle cerebral artery or branches of the anterior cerebral artery; about 1/5 of them are in the posterior half of the cerebral artery ring, occurring in the vertebrobasilar artery, posterior cerebral artery and its branches. Saccular aneurysms are common and vary in size, with those less than 14 mm in diameter being small, those between 15 and 24 mm being large, and those over 25 mm being giant. Trauma can also cause aneurysms, but they are less common. Symptoms 80% of spontaneous subarachnoid hemorrhages are caused by ruptured aneurysms. When an aneurysm ruptures, there are often prodromal symptoms such as headache, followed by hemorrhagic symptoms in the form of severe headache, irritability, nausea and vomiting and other signs of meningeal irritation, followed by an increase in intracranial pressure. This may be accompanied by impaired consciousness and neurological localization of the corresponding site. In cases where the aneurysm bleeds and forms a large hematoma, the condition often deteriorates sharply and brain herniation crisis occurs. According to statistics, after the first rupture of an aneurysm, the mortality rate is as high as 30-40%, half of them die within 48 hours after the onset of the disease, and in 1/3 of the surviving cases, rebleeding may occur. CT scan can sometimes reveal aneurysmal lesions. New examination means are 3D-CTA, which can not only find smaller aneurysms, but also see the relationship with surrounding blood vessels and skull, which provides a good visual aid for surgery. Treatment 1. Currently, the surgical method of directly dealing with aneurysm by craniotomy is used. A special aneurysm clip is used to clamp the neck of the aneurysm and to protect the patency of the aneurysm-carrying artery. If the base of the aneurysm is too large or shuttle-shaped to be clamped, and its collateral circulation is good, the aneurysm-carrying artery can be ligated and aneurysm isolation surgery can be performed, or only the muscle piece and biological adhesive can be used to reinforce the aneurysm wall. 2.Treatment by intra-arterial embolization, which is performed by inserting a tube from the artery to the opening of the aneurysm and occluding the aneurysm with a balloon or spring bolus, etc. to achieve the treatment purpose.