Concept of Moyamoya Disease Moyamoya Disease (MMD) is named after the stenosis or occlusion of the terminal branches of the internal carotid artery, with neovascularization that looks like smoke on cerebral angiography (DSA). Epidemiology The cause of the disease is unknown, and it is most common in children and young adults. There is a genetic predisposition to smog disease, and genetic and family screening is recommended. Classification and Clinical Presentation Smoke disorders can be classified into hemorrhagic (intracranial hemorrhage) and ischemic (cerebral infarction). Patients often present with symptoms such as dizziness, headache, numbness and weakness of limbs, decreased memory and reaction time. Early diagnostic evaluation and prompt treatment are recommended, otherwise the disability rate is extremely high. Treatment Currently, only surgical treatments are effective for smog disease, aiming to improve cerebral blood perfusion. Common surgical methods include intracranial-extracranial vascular anastomosis and temporalis muscle plication, with some patients requiring bilateral staged surgery; in addition to surgery, adjunctive treatments include anti-inflammatory and anti-polymerization (aspirin), neuroprotection (donepezil), and neurorehabilitation (hyperbaric oxygen, functional training). Surgical efficacy There is a certain possibility of postoperative complications in smokers’ disease. In order to achieve the best therapeutic effect, it is recommended that adequate assessment of the disease be performed before surgery and during postoperative follow-up. The evaluation includes cognitive function, perfusion and metabolism of the lesion area, brain function and electrical activity; the recovery of smog disease is a long and uncertain process, and it is recommended to follow the doctor’s instructions closely for 2 years. Question and Answer (Q&A) Q: How do I know if I and my family members have smog disease? A: Screening can be done on an outpatient basis through angiography with MR and CT of the head. Q: Do I have to have surgery for smog disease? A: If your condition is still considered stable with good self-compensation of brain function through a complete evaluation by your doctor, surgery can be deferred, but close observation is needed to prevent disease progression. However, most patients need surgery because there is no effective drug treatment. Q: What are the surgical methods? A: Currently, the commonly used surgical methods are intracranial-extracranial vascular anastomosis + temporalis muscle patch. If there is no suitable recipient vessel in your brain, then only temporal muscle plication will be performed. Q: What are the results of temporalis only? A: In children, the effect of temporalis only has been shown to be significant; in adults, temporalis only has a slow onset but good long-term effect, with no evidence of short-term effect. Q：What happened when I had a good result after the surgery, but my condition worsened again in a few days? A: This is very common and is generally one of two possibilities: ① High perfusion pressure syndrome. It may be due to the redistribution of cerebral blood flow after bypass, and the long-term ischemic brain tissue cannot adapt to the large amount of blood perfusion in the short term. It can be clarified by imaging. ② Cerebral infarction or cerebral hemorrhage. Most of them are caused by reperfusion injury of long-term ischemic brain tissue. Q：Why do I need to do so many tests before surgery if I can just have the surgery? A: Surgery for smog disease has a high success rate, but there are a lot of postoperative complications, and many of them cannot be fully recovered, which has a greater impact on the patient’s quality of life. Adequate preoperative evaluation can effectively predict and reduce the incidence of postoperative complications and reduce the suffering of patients and families. Q：Why do I have to come back to the hospital repeatedly for review if I recovered quite well after surgery? A: Smoke disease is a chronic progressive cerebrovascular disease. The reason for long-term review is, on the one hand, because some patients have bad blood vessels on the other side, which requires staged surgery; on the other hand, because recovery from smoke disease is also very slow, and the condition may recur in a short period of time, which requires timely treatment and guidance from the doctor.