Open craniocerebral injuries or firearm penetrating injuries, comminuted or depressed fractures that cannot be reset after dilatation, severe craniocerebral trauma patients after debridement and decompression, and pediatric skull fractures can lead to large cranial defects. Usually, those with skull defects less than 3cm are mostly asymptomatic, and after temporalis muscle decompression or suboccipital decompression, there are hypertrophied muscles and fascia covering and forming a tough fibrous healing layer in the defect area, which plays the role of protection of the original skull to the brain, and clinically there are no symptoms. Defects with a diameter of more than 3cm, especially those located in the frontal area that hinder the aesthetics and safety, often have this or that kind of symptom, such as dizziness, headache, localized tenderness, irritability, restlessness and other manifestations, or the patient’s fear of the defect area’s throbbing, bulging, collapsing, fear of the sun, fear of vibration and even fear of noisy sounds, often have poor self-control, poor concentration and memory loss, or have depression, fatigue, Or there are depression, fatigue, reticence and low self-esteem, or the patient’s skull is severely deformed due to the large cranial defect, which directly affects the physiological balance of intracranial pressure, collapses when standing upright, expands when lying down, and is concave in the morning and convex at night, or the atmospheric pressure directly acts on the brain tissue through the defective area, which will inevitably lead to local cerebral atrophy and aggravate the symptom of cerebral wastage in the long run, and at the same time, the ventricles on the affected side will gradually expand and dilate or deform to the defective area. Differential diagnosis of huge cranial defect: Typical local clinical manifestations of the defect, combined with X-ray film and CT scan, can be clearly diagnosed. The main points of diagnosis are cranial defects and the contents herniated out of the cranial cavity through the defects, and the diagnosis is not difficult. For meningoencephalocele or meningoencephalocele at the base of the skull, it should be considered to differentiate from nasal polyps or pharyngeal tumors, but the diagnosis can still be clearly made under the three-dimensional observation of MRI. Nasal polyp: It is a common disease of the nose and is also associated with certain systemic diseases. It is the result of tissue edema caused by long-term inflammatory reaction of nasal mucosa. Pharyngeal tumors: the pharynx is divided into nasopharynx, oropharynx, hypopharynx, and tonsils are listed as another part. Squamous cell carcinoma has the highest incidence rate among the pharyngeal tumors, and the incidence rate of squamous cell carcinoma is still the highest among the incidence types of tumors in the nasopharynx, oropharynx, and hypopharynx, while the incidence rate of malignant lymphoma is higher than that of squamous cell carcinoma in the tonsil tissues, and squamous cell carcinoma is in the second place. Squamous cell carcinoma, malignant lymphoma, fibrovascular tumors, and pleomorphic adenomas are the major tumor types, and the vast majority of pharyngeal tumors occur in the nasopharynx. Malignant lymphomas are mainly concentrated in the tonsils.