Cranial defects are a relatively common condition, and we face a variety of dangers in our lives, such as traffic accidents, workplace accidents, falling objects, or cranio-cerebral surgeries, all of which may eventually lead to cranial defects. Cranial defects need to be repaired in a timely manner, but sometimes the shape of the defect is irregular, and some patients may have bilateral defects. Are bilateral skull defects repaired at the same time? Yes, if there are defects on both the left and right sides of the skull, it is possible to repair both sides in a single operation, and there are many cases of this in the clinic. In such cases, a CT scan of both sides of the skull is performed to identify the shape, area, and curvature of the defects, and then a 3D reconstruction is performed to create a three-dimensional polyether ether ketone (PEEK) patch for both sides of the skull. Then the defects on both sides were successively repaired during the operation, the flap was cut, the bone window was fully exposed, the material was placed, and fixed after adjusting and resetting well. Simultaneous repair can save the patient from the trauma of secondary surgery, and at the same time shorten the treatment period and save the cost of treatment. In addition, the material used for cranial bone repair should also be carefully selected, the above mentioned PEEK material is currently the ideal cranial bone repair material, its excellent performance has been gradually favored by neurosurgeons, the clinical effect has been recognized by the majority of patients and their families. It is understood that the PEEK material can be three-dimensional shaping, 3D printing, highly restore the skull structure, while it is in the hardness, elasticity, thermal insulation, insulation, stability and other aspects are very excellent, almost comparable to the autologous skull, whether in the unilateral cranial defects or in the bilateral cranial defects in the repair of the skull can obtain satisfactory results.