Skull defects are mostly caused by open cranial injury or firearm penetrating injury, and some patients have residual bone defects due to surgical decompression or diseased skull removal. After skull defect, cranial bone repair should be carried out in regular hospital in time. What are the dangers of cranial defects? Defects with a diameter of more than 3cm, especially those located in the frontal area, which are aesthetic and safe, often have one or another symptoms, such as dizziness, headache, local tenderness, irritability, restlessness, etc.; or patients have fear of pulsation, expansion, collapse of the defect area, fear of sunlight, fear of vibration and even fear of noisy sound, often have poor self-control, concentration and memory loss; or have depression, fatigue, low speech and low self-esteem, The patient’s skull is severely deformed due to large skull loss, which directly affects the physiological balance of intracranial pressure, collapsing when upright, expanding when lying down, concave in the morning and convex at night; or the atmospheric pressure acts directly on the brain tissue through the defect area, which inevitably leads to local brain atrophy over time and aggravates the symptoms of brain wasting, and at the same time, the affected ventricle gradually expands and expands or deforms to the defect area. Therefore, cranial bone repair should be performed as soon as possible. The material chosen for cranial bone repair in our hospital neurosurgery is polyetheretherketone peek material, which has been recognized by many patients with cranial bone defects and is the preferred material for cranial bone repair for patients with cranial bone defects. Cranial bone repair experts said, in order to restore the cranial cavity confinement, maintain the physiological intracranial pressure stability, reduce the cranial defect syndrome, the cranial bone defect diameter of more than 3 cm, no muscle coverage, no contraindications should be cranial bone repair, surgery time is generally selected after three months after craniotomy. The choice of material for cranial repair is also very important to reduce infection. Neurosurgery experts use new PEEK material for cranial repair. PEEK (polyether ether ketone) has many advantages such as high temperature resistance, corrosion resistance, sturdiness, and good toughness at the same time, and does not interfere with postoperative review. PEEK material is generally shaped using 3D printing technology for overall shaping and fusion casting, so it can be personalized and perfectly shaped according to the patient’s cranial defect site. Furthermore, PEEK significantly reduces the rate of subcutaneous fluid accumulation and subcutaneous infection after surgery.