Smog is an abnormal network of blood vessels at the base of the brain that appears like smoke during cerebral angiography, hence the name smog. Smog is divided into unilateral smog and bilateral smog, and according to clinical research, bilateral smog accounts for a larger proportion of cases. How long does it take for bilateral smog to develop? In fact, there is no uniform standard for the specific formation time of smog, but generally patients will have symptoms such as dizziness, headache, aphasia, hemiparesis, etc. When the cerebral blood vessels are narrowed or even occluded, patients will also face the risk of large cerebral infarction and cerebral ischemia, and there are a few patients who basically do not have any particularly obvious symptoms at the time of the disease. As a progressive disease, smog should be treated as soon as it is detected. Drug treatment has been proven to be largely ineffective in a large number of cases. Many medical experts at home and abroad have found that surgery is the new mode of treatment for smog, but some hospitals in China have found many drawbacks when treating patients with traditional bypass surgery and patching, such as the limited blood supply range of bypass surgery and the difficulty of surgery. The patching procedure has limited treatment groups and is not effective for adults. The combined vascular bypass surgery, which is better than the traditional surgery in China, is a combination of traditional bypass surgery and patching surgery, avoiding the defects of each, which can quickly establish a good blood flow side channel, and better improve the brain blood supply.