Can a skull defect be left unrepaired? Some patients may ask this question. It is normal to have this question until you know what the effects of a skull defect are. Many patients feel that cranial defects will only cause damage to their image and will not affect their health. In fact, this view is wrong. The dangers of cranial defects Cranial defects can cause a large number of sequelae, which are 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. What is the best material to use for skull repair? Peek is the most advanced material for the treatment of cranial defects. It is also one of the most suitable materials for skull repair surgery. Peek is a polymer material that is comparable to the body’s own skull 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 matches the bone window perfectly after the repair and is basically indistinguishable from the own cranial bone. However, there are not many hospitals that do skull repair by peek at present. It also requires a high level of skill and professionalism from the doctors who do peek skull repair in China. Therefore, it is recommended to choose a more authoritative hospital if there is a patient who needs this treatment. To sum up, if the skull defect must be repaired in time to avoid the occurrence of health risks. The most suitable material for the surgery is peek material. Patients must find a more authoritative hospital and a more experienced surgeon before the surgery to ensure the completion rate and safety of the surgery.