In reality, many elderly people do not pay attention to minor head injuries, especially those to the forehead or occipital area, because there are no obvious clinical symptoms at the time. However, about a month after the injury, a series of symptoms will appear, and it is important to be alert to the occurrence of chronic subdural hematoma. Chronic subdural hematoma is a late onset intracranial hematoma that develops more than 3 weeks after head trauma. It occurs in the elderly and is generally more common on one side, but bilateral hematomas can occur in up to 14% of cases. The volume of accumulated blood is sometimes as high as about 100 ml. Most hematomas are caused by bleeding from blood vessels on the surface of the brain, or by bleeding from damaged subdural fluid. The exact cause of how a subdural hematoma expands is unknown, but most mathematicians believe that its occurrence is related to the following factors: cranial trauma, patient brain atrophy, decreased intracranial pressure, increased venous tone, and abnormal coagulation. The main symptoms and signs of chronic subdural hematoma are: headache mainly, mental disorders: dementia, disorientation, memory loss, mental retardation, etc.; weakness of limbs, unstable gait, coma in severe cases, hemiparesis; inability to speak; seizures, etc. Therefore, elderly people with a history of head trauma and gradual appearance of the above clinical manifestations should be alert to the possibility of intracranial chronic hematoma formation. To make a clear diagnosis, ancillary examinations such as cranial CT should be done as early as possible. however, for cranial CT into isodensity, or bilateral chronic subdural hematoma, or accumulation of blood or fluid without intracranial occupying effect, cranial MRI examination has certain differential diagnostic significance. The main hazards of chronic subdural hematoma are slowly increasing intracranial pressure, localized compression of brain tissue, and impaired cerebral blood circulation. As the clinical manifestation of this disease is a chronic process, if it can be diagnosed and operated in time, the result is satisfactory, but if it cannot be diagnosed and treated in time, it is very easy to cause disability or even death. At present, minimally invasive borehole surgery is advocated, which is not only less traumatic, but also has faster patient recovery, fewer complications, shorter treatment course and lower cost. The indications for surgery are: those who have obvious symptoms of increased intracranial pressure after diagnosis should be actively treated by surgery. For the following cases, surgery should be cautious: the amount of hematoma is too small, the patient has no obvious clinical symptoms; the hematoma has formed a thick wall or even calcification, and the general condition of the patient is not good. 2. Bone flap craniotomy for subdural hematoma removal The indications for surgery are: blood clots in the hematoma cavity; recurrence of drilling and drainage; no improvement or aggravation after drilling; no significant reduction or significant increase in the hematoma cavity on review of CT; obvious thickening or calcification of the envelope. At present, the vast majority of patients with chronic subdural hematoma choose minimally invasive treatment.