What is an aneurysm and what are its risks? The term “aneurysm” is often misunderstood and confused with “tumor”, but it is actually a different thing. The medical definition of an aneurysm is an abnormal localized enlargement of an artery in the brain. In layman’s terms, the arterial wall is like the inner tube of a bicycle, except that the artery is filled with blood and the inner tube is filled with gas. If there is localized wear on the inner tube, a packet will bulge out of the worn area when it is inflated, forming an “aneurysm”, where the wall of the inner tube becomes weak, and if it ruptures, an “aneurysm rupture and bleeding” is formed. According to statistics, once an aneurysm ruptures (subarachnoid hemorrhage), the mortality rate for the first hemorrhage is 40% and for the second hemorrhage is 60%. Thirty-five percent of patients who survive the first bleed with conservative treatment will die within a year from another bleed, and 51% will die within 5 years. Severe disability or death after bleeding from unruptured aneurysms occurs in more than 60% of patients. Therefore, cerebral angiography should be performed promptly for such patients to clarify the diagnosis and provide timely treatment in order to obtain satisfactory results. How to treat aneurysm? Aneurysm is a disease with a very high mortality and disability rate among young and middle-aged patients. Once an aneurysm is diagnosed, it must be given the necessary treatment. Firstly, during the acute stage, the blood irritates the blood vessels at the base of the brain or on the surface of the brain, causing cerebral vasospasm leading to cerebral infarction and brain damage manifestations such as increased impairment of consciousness, hemiparesis and aphasia; secondly, because such patients are most likely to relapse at 2-4 weeks, worsening their condition and leading to death. Therefore, even if the patient’s self-perceived symptoms disappear after medical treatment and is considered cured, the corresponding surgical treatment should be given. The aim of surgical treatment is to remove the cause of the disease, i.e., to eliminate the break in the arterial wall, and to try to prevent the aneurysm from rupture again. It includes direct cranial clamping of the aneurysm neck in microneurosurgery and endovascular embolization of the aneurysm within the sac in endovascular neurosurgery, i.e., endovascular treatment or a combination of the two. Endovascular treatment of aneurysms involves delivering a microcatheter into the aneurysm and occluding the aneurysm with materials such as spring coils and medical adhesive, thereby preventing bleeding and recurrence of the aneurysm and allowing the patient to heal. Endovascular treatment has been adopted as the preferred method of treating aneurysms in Europe and the United States. Endovascular treatment can also be effective for aneurysms that are difficult to reach by opening the skull, for patients who are in poor general condition and cannot tolerate surgery, or for patients in the acute phase of bleeding. Endovascular treatment for cerebrovascular disease reflects the development trend from inoperable to operable, from less invasive surgery to minimally invasive surgery, and from minimally invasive to non-invasive, with the outstanding advantages of less trauma, less pain, less danger, and higher success rate, which is widely accepted by patients.