Chronic subdural hematoma is a hematoma between the brain and the dura mater that occurs more than 3 weeks after trauma, because most patients are older than 50 years and 1/4-1/2 of them have no clear history of trauma and in fact cannot remember a history of trauma. Because most definite trauma is also minor, for example, remembering an occasional injury by a tree branch or door corner. There are also post-traumatic subdural effusions that evolve from trauma. Chronic subdural hematomas arise mainly from injuries to small cortical vessels or pontine veins, and small amounts of continuous bleeding accumulate in the subdural space to form and expand. The simultaneous occurrence of bilateral hematomas is not uncommon. Clinical manifestations Clinical symptoms and signs are varied, with headache and mild hemiparesis as well as dementia mental abnormalities, and dementia mental abnormalities are common in the elderly, even mistaken for psychiatric patients. Diagnosis CT, MRI can be clear, CT can show hypodensity or isodensity or mixed density. MRI shows high signal in T1 and T2. Treatment Once the diagnosis is clear, timely borehole irrigation and drainage surgery is performed, and the results are mostly satisfactory. For elderly people with more underlying diseases, try to operate under local anesthesia, drill a single hole, try to drain the accumulated gas, and strive to complete the operation in the shortest time. I have successfully cured a 92-year-old man.