Subarachnoid hemorrhage is more common after cerebral contusion, and the large amount of bloody cerebrospinal fluid will produce a strong irritation to the meninges, which can cause a sterile inflammatory response and, therefore, can cause adhesions between the soft membranes and the arachnoid and even block the arachnoid villi, thus causing impaired circulation and absorption of cerebrospinal fluid. This is similar to hydrocephalus caused by subarachnoid obstruction due to septic meningitis, i.e., although cerebrospinal fluid produced by the choroid plexus can flow out of the ventricles, it is obstructed in the subarachnoid space and prevents cerebrospinal fluid from circulating through the cerebral convexity to the arachnoid granules for absorption in the basal pool, cricoid pool, and lateral fissure pool. As a result, patients often present with symptoms of increased intracranial pressure and an enlarged ventricular system, and their condition will worsen if they do not receive timely and reasonable treatment. Occasionally, cerebrospinal fluid circulation obstruction occurs within the ventricular system, causing fluid accumulation in one or both ventricles. This is usually due to ventricular penetrating injury or intramedullary hematoma breaking into the ventricles, often with obstruction at the interventricular foramen, aqueduct, or exit of the four ventricles. Occasionally, hydrocephalus can be caused by herniation of the cerebellar curtain, occlusion of the cricoid pool due to brainstem displacement, or compression of the aqueduct; or hydrocephalus can also occur due to inappropriate decompression of the greater trochanter and severe brain bulging and displacement, resulting in obstruction of cerebrospinal fluid circulation. Acute hydrocephalus refers to hydrocephalus that occurs within 2 weeks after injury. The possible mechanisms are: 1. Direct blockage of cerebrospinal fluid circulation by blood clots or blockage of arachnoid villi by red blood cells, which affects cerebrospinal fluid absorption. 2. 2. Cerebral edema, intracranial hematoma, brain herniation, brain bulge or protrusion may also compress the cerebral pool and the subarachnoid space on the brain surface, affecting the circulation and absorption of cerebrospinal fluid. 3, intraventricular hemorrhage, ventricular penetrating injury, blood accumulation can block the interventricular foramen, aqueduct, and median foramen of the fourth ventricle, so that the cerebrospinal fluid cannot flow back to the subarachnoid space. In most patients with severe traumatic brain injury, after timely and reasonable management, if the condition is stable but the recovery of consciousness is poor or new signs of neurological damage appear, imaging should be performed promptly to determine the presence of acute hydrocephalus. In addition, CT or MRI examination should be performed in cases of dementia, impaired mobility, and urinary incontinence for a long time after traumatic brain injury. If enlargement of the ventricular system is found, lumbar puncture with normal pressure and radionuclide cerebrospinal fluid imaging are also valuable for the diagnosis of hydrocephalus, and the duration of retention of the nuclide in the ventricles can help to estimate the severity of hydrocephalus. Treatment of traumatic hydrocephalus, either intracranial hypertensive hydrocephalus or normal pressure hydrocephalus, should be treated by shunting with a one-way valve shunt. However, it is sometimes possible to reduce the incidence of later hydrocephalus in patients with acute hydrocephalus if intracranial pressure monitoring is performed early after head trauma and blood cerebrospinal fluid is drained promptly (Kollusi et al., 1984). In any case, when traumatic hydrocephalus is suspected, early imaging should be performed to clarify the diagnosis and shunt surgery should be performed as soon as possible to relieve progressive brain tissue atrophy caused by hydrocephalus. There are two types of shunts: ventriculo-peritoneal and ventriculo-atrial, as the latter is not suitable for shunting patients with cerebrospinal fluid containing air, contaminated tissue, or blood clots and/or with newly performed extraventricular drainage. Therefore, ventriculo-ventricular shunts are more commonly used for post-traumatic hydrocephalus. This procedure is indicated for obstructive hydrocephalus, communicating hydrocephalus, and normal cranial pressure hydrocephalus. The purpose is to place the end of the shunt into the pelvic cavity to prevent closure of the greater omentum. The pressure of the patient’s cerebrospinal fluid should also be measured, and a medium-pressure shunt device (55-85 mmH20) should be used for those above 140 mmH2O; a low-pressure shunt device should be used for those below 140 mmH2O (McQuarrie et al., 1984). Chhabra et al. (1993) also developed a “Z” flow shunt device to avoid excessive drainage due to posture. The procedure is performed under local or general anesthesia with the patient lying supine with the head to the left and the right shoulder slightly elevated to allow lateral extension of the neck. The cranial hole is first drilled in the right posterior temporal part (4 cm behind and above the external auditory canal), and the ventricular triangle is reached by vertical puncture with a cerebral needle 3-4 cm deep, which confirms that there is cerebrospinal fluid outflow without excessive discharge, and then the ventricular end of the shunt is inserted into the ventricle in the direction and depth of the cerebral needle, and then the one-way valve is fixed slightly below the bone hole. Then a tunnel is made through the subcapsular tendon layer of the scalp from behind the ear to the subcutaneous side of the neck, and the ventral end of the shunt is introduced to meet the valve outlet, and the scalp incision is then sutured. The distal end of the shunt was continued subcutaneously through the neck and chest to the right lower abdomen. Then an appendicitis maix incision is made, and the end of the shunt is carefully fed into the recto-vesical crypt or utero-rectal crypt along the right side of the pelvic wall with a ring forceps after cutting the peritoneum. After surgery, the abdominal wall incision and segmental skin incision were closed as usual without drainage. Postoperatively, antibiotics were administered to prevent infection, and the valve was pressed 2 to 3 times daily to avoid obstruction of the one-way valve shunt.