Cranial defects are very common in our lives. Although our body’s skull is very strong and provides strong protection for the brain and other soft tissues. However, the skull is not indestructible and unbreakable, and there are many uncertainties in life that can lead to cranial defects. The common causes of cranial defects are: open cranial trauma or firearm penetrating injury; after reopening of crushed or depressed cranial fractures that cannot be repositioned; severe cranial injury or other types of cranial surgery for debridement and decompression as required by the condition; pediatric growth fracture of the skull; cranial osteomyelitis and other lesions of the skull itself caused by penetrating cranial destruction or surgery for removal of cranial lesions. Specifically, there are causes such as traffic accidents, production safety accidents, and neurosurgery. Among all causes of cranial defects, cranial trauma accounts for a large proportion, and among patients with cranial trauma, traffic accidents are more common. For example, one patient had a serious cranial trauma caused by a car accident, and was left with a cranial defect after emergency rescue, and has been in discomfort for two years. So can skull repair be performed two years after a car accident like this? Of course it is possible, although it is a little late, because the best time for skull repair is about 2-3 months after the injury. And now it has been two years, all the more reason to have the repair as early as possible to improve the corresponding symptoms. Patients can go to Beijing to choose some expert team with strong technical strength and rich clinical experience to perform cranial bone repair surgery. The use of cranial repair materials should also be carefully selected, and the use of polyether ether ketone PEEK material, which has excellent performance, is recommended to achieve very satisfactory repair results, and this material has also been unanimously recognized and praised by the majority of patients.