Decreased cerebral blood flow to the brain tissue in the vicinity of the cranial defect. The rationale for the formation of various complications after cranial defects. In this classic review tell on debridement decompression, it is mentioned that after debridement decompression, disturbance of cerebrospinal fluid dynamics occurs, which can cause subdural fluid and hydrocephalus. If combined with excessive loss of cerebrospinal fluid, paradoxical brain herniation occurs. Severe subdural effusion The above graph shows the various adverse effects of decompression with a large bone flap. This study found that a smaller bone window did not affect decompression and demonstrated a trend toward higher GOS scores at three months. No cranial repair with a VP shunt, especially a nonadjustable pressure shunt, may result in paradoxical brain herniation or intractable subdural effusion, or chronic subdural hematoma. Traumatic craniocerebral injury accounts for the second highest incidence of systemic trauma, but the rate of death and disability is in the first place; the direct and indirect economic losses caused each year are up to more than 10 billion yuan. The causes of injury include traffic accidents, falls from height, violent blows, etc. [1]. The national guidelines for craniocerebral trauma treatment generally recommend debridement decompression as the first choice among the second-line methods for the treatment of malignant high cranial pressure, and debridement decompression can effectively reduce the intracranial pressure and the compression of the brainstem vital center. With the promotion and application of standardized large bone flap decompression for the treatment of heavy craniocerebral injury, more and more cases of large cranial defects are bound to occur in the clinic, and in recent years, it has been proposed that large bone flap decompression may alter the hydrodynamic parameters of cerebrospinal fluid, which in turn promotes the formation and development of hydrocephalus after trauma [2-3], which can result in decreased intelligence, abnormal gait, urinary incontinence, etc., and even cause cranial high pressure and brain herniation, which can be life-threatening. Therefore, timely repair of cranial defects is essential. The volume of the skull is fixed, and when the protection of the bone flap is lost, the restriction disappears, the cerebral venous return and the external pressure on the dural sinus decrease, and the brain parenchyma can expand outward, resulting in increased venous return of the cerebral hemispheres, increased absorption of plasma, tissue fluid and other extracellular fluids, thus causing a decrease in the volume of brain parenchymal cells, an increase in the brain space and thus the enlargement of the ventricles This leads to the development of hydrocephalus [4]. If this hypothesis is valid and reversible, then cranioplasty can restore the integrity of the skull and meninges and re-form the cranial closed space, so that cerebrospinal fluid circulation can be restored and hydrocephalus can be relieved, although such cases have been reported, i.e., hydrocephalus dissipates on its own after cranioplasty [5]. However, this has not been universally confirmed. Most scholars believe that the enlargement of the ventricles after decompression with debridement is irreversible. If cranioplasty alone is performed, the enlarged ventricle will compress the cerebral cortex and obstruct the subarachnoid space, further increasing the resistance to cerebrospinal fluid absorption in the convex surface of the brain and aggravating hydrocephalus, which may further deteriorate neurological function, so more clinicians choose to perform both cranioplasty and ventriculo-abdominal shunt to treat hydrocephalus, and this method has been proven to be effective. The traditional treatment method is to perform ventriculo-abdominal shunt first and then perform cranial repair after 3-6 months, which is easy to miss the best treatment period. The patient’s consciousness and neurological dysfunction have been significantly reduced. Currently, there are many reports on early cranial repair, and studies have shown that patients with early cranial repair (<2 months) have a better prognosis than those with delayed repair (>3 months). In this paper, we believe that patients undergoing early cranial repair should exclude increased intracranial pressure, intracranial masses, brain swelling and abnormal cerebrospinal fluid, and once intracranial pressure and other contraindications to cranial repair are excluded, early cranial repair should be performed. 4.Repair and shunt material The most used artificial material is titanium mesh plate, because titanium alloy material is non-toxic, low inflammatory and allergenic, good histocompatibility, after implantation, fibroblasts can grow into the micro-pores of titanium mesh, so that titanium mesh and tissue fuse into one, and there is a trend of calcification and ossification, which is a more ideal artificial repair material. As for the abdominal shunt, we use an adjustable pressure shunt, which has the advantage that the adjustable pressure shunt can be adjusted non-invasively to set the pressure after the problem of the shunt system, thus avoiding the shunt revision. Studies have shown that patients with adjustable shunts are less likely to undergo shunt revision, making it more cost-effective. In addition, the shunt adjustments made in patients with adjustable shunts also resulted in better neurological outcomes. The Department of Transcranial Surgery has accumulated a wealth of experience in the treatment of craniocerebral trauma, and is currently the National Center for Craniocerebral Injury Treatment, the National Center for Standardized Treatment of Craniocerebral Injury, and the Wuxi Collaborating Center of Shanghai Institute of Craniocerebral Trauma, and routinely cooperates and exchanges with large research units at home and abroad. At present, the center has PET-CT, 3.0 TMRI and other high-tech equipment, which can provide standardized treatment for skull defects and hydrocephalus caused by craniocerebral trauma.