How should I treat a brain aneurysm when it is detected? Two words: surgery. Simply put, surgery is performed to close the bulge in the wall of this artery and stop the blood flow from entering the bulge, thus preventing the aneurysm from rupture. There are two types of surgery. The first one is craniotomy. Depending on the location of the cerebral aneurysm, the neurosurgeon selects the appropriate craniotomy approach, exposes the aneurysm under the microscope, and clamps the neck of the aneurysm with a special titanium aneurysm clip (shown in Figure 3). Figure 3: Schematic diagram of craniotomy for cerebral aneurysm This treatment method is mainly suitable for: (1) patients who are in good physical condition and can withstand craniotomy, with Hunt-Hess grading (Hunt-Hess grading method as shown in Figure 4) I~III; (2) patients who have intracranial hematoma with occupying effect on CT examination, or who have formed brain herniation and need craniotomy for decompression; (3) aneurysms that can be easily exposed by craniotomy. (3) Aneurysms that are easily exposed by craniotomy, especially those with large aneurysms and compression symptoms; (4) Those who have failed interventional treatment. The advantages of craniotomy are the low recurrence rate and the possibility of simultaneous hematoma removal in patients with combined intracranial hematomas. The disadvantage is that it requires opening of the cranial cavity, which is relatively more traumatic and results in a longer postoperative recovery time, and is more risky in older, less fit patients. The second surgical procedure is interventional embolization. This is an intracranial catheter technique, the details of which will be described in a separate topic. At present, most patients are suitable for interventional embolization, especially those with the following characteristics: (1) patients who are older, or who are in poor health and cannot tolerate craniotomy, or critical patients with Hunt-Hess class IV-V; (2) aneurysms located at the base of the skull or in the posterior circulation, which are difficult to be exposed by craniotomy; (3) multiple aneurysms; (4) aneurysms that are incompletely clamped by craniotomy. The advantages of interventional surgery are that it does not require craniotomy, less damage, and faster postoperative recovery. The disadvantages are the high cost and the relatively high recurrence rate of large aneurysms after surgery. In economically advanced Europe, most patients choose this more minimally invasive and safer interventional treatment. Most cerebral aneurysms can be treated well with both procedures, but the choice depends on a variety of factors, including the location and anatomical features of the aneurysm, the patient’s age and physical condition, as well as the clinical experience of the surgeon and the equipment of the hospital.