Can skull bone be left unrepaired? Cranial defects are more dangerous. Cranial defects can produce a large number of sequelae, and this is related to the degree of injury, and the symptoms vary from person to person. In less severe cases, the symptoms may include headache, anxiety, depression, dizziness, panic, chest tightness, loss of appetite, sleep disturbance or neurological disorders. Those with severe injuries have more sequelae, such as paralysis of limb functions, urinary and fecal incontinence, memory impairment, dementia, etc. Therefore, timely surgical treatment must be performed. Peek material is the most advanced material for skull defect treatment. It is also one of the materials that are suitable to be selected for skull repair surgery. Peek is a polymer material that is comparable to the body’s own cranial bone. It is more biocompatible. It is strong but very elastic and tough, more resistant to impact and better protection. It is also more comfortable. It has strong insulation properties. There is no sensitivity to hot or cold reactions. There is also no post-operative infection and no rejection. Rays can be transmitted without forming artifacts. The more important point is that polyetheretherketone is a material that can be plasticized in three dimensions and can be customized for three-dimensional reconstruction according to the different needs of patients. Based on the patient’s brain CT data, the design is made according to the 3D printing technology to produce a cranial bone that perfectly matches the bone window after the repair is basically indistinguishable from the own cranial bone. Patients with cranial defects are recommended to go to the hospital early to choose the appropriate repair material and regain their health as soon as possible.