Is it okay to not repair a skull defect? Cranial repair is required and skull repair is generally not possible without repair. Why is cranial repair necessary? The skull is one of the hardest bones in the human body and has considerable strength to provide strong protection to the brain and other head organs. However, there are still some irresistible factors that may cause damage to the skull, such as cranial trauma caused by falling objects, fights, traffic accidents, production safety accidents, etc., or the removal of part of the skull flap due to illness, which can lead to cranial defects. If a cranial defect occurs, the cranial bone will be repaired. If the skull is not repaired, it can cause damage to the body. The intracranial pressure is unstable and the various vital activities in the skull may be disturbed, which may manifest as headache and dizziness, in addition to the patient’s fear of pulsation, expansion, and collapse of the defect area, as well as fear of sunlight, vibration, and even loud noises. It may also cause lack of concentration and memory loss, and some patients may be depressed, tired, reticent and have low self-esteem. Therefore, it is still necessary to have a cranial repair. The repair material used in cranial repair surgery is very important. A new polymer material, polyether ether ketone (PEEK), is currently being used for skull repair to achieve ideal results. It is the ideal material for three-dimensional shaping, precise matching, high biocompatibility, and does not interfere with medical examinations. Experts say that PEEK material is ideal as a material for cranial bone repair because, PEEK material has very good tissue compatibility and basically does not produce rejection, and PEEK material has good radiolucency and does not interfere with various postoperative medical examinations. In addition, the performance of PEEK material in terms of elasticity, strength, thermal insulation, and stability is comparable to that of human cranial bone, making it a very ideal material for cranial repair.