Excess cerebrospinal fluid accumulates in the enlarged ventricular system, and/or subarachnoid space, called hydrocephalus. In children, hydrocephalus often coexists with elevated intracranial pressure. In most patients, the accumulation of excess cerebrospinal fluid in the ventricles is due to a disturbance in cerebrospinal fluid circulation. Rarely, cerebrospinal fluid accumulation occurs due to impaired absorption of cerebrospinal fluid. In addition, in patients with normal pressure hydrocephalus, the ventricles are enlarged, but the intracranial pressure is normal. This condition is usually due to impaired absorption of cerebrospinal fluid and is most often seen in adults. Hydrocephalus ex-vacuo refers to the enlargement of the ventricles secondary to brain atrophy or loss of brain tissue after injury. Extrinsic hydrocephalus (external hydrocephalus) or benign enlargement of the extra-axial space refers to the presence of excess fluid, especially cerebrospinal fluid, in the subarachnoid space with familial macrosomia. Congenital and infantile hydrocephalus is approximately 0.5 to 0.8 per thousand in European and American societies. Approximately 15-25% of these cases are associated with spondylolisthesis (spina bifida). The following factors increase the likelihood of hydrocephalus in infants: 1. birth weight <1500 g 2. gestational age ≤30 weeks 3. mother with diabetes 4. low socioeconomic status 5. male child with the disease 6. racial predilection (risk is decreased in Asians) Untreated hydrocephalus that begins in infancy with unclosed cranial sutures Hydrocephalus leads to the typical enlargement of the skull. Compared to those with acute hydrocephalus, such hydrocephalus causes relatively little damage to brain tissue. This is due to the expansion of the skull, which results in a partial reduction of intracranial pressure. As hydrocephalus progresses, edema and cerebral ischemia develop, leading to atrophy of the white matter of the brain. Common causes of congenital hydrocephalus include intraventricular hemorrhage and neural tube defects, including spinal cord spondylolisthesis. Other causes include infections, genetic defects (X-linked hydrocephalus), trauma, tumors, and teratogenic agents... Symptoms of hydrocephalus arise from elevated intracranial pressure and an enlarged ventricular system. The timing of the onset of symptoms depends on the acuity of the pathogenic process. Symptoms are usually nonspecific and independent of the cause. Headache is a prominent symptom, tends to occur in the morning, and may be accompanied by nausea and vomiting. Patients with hydrocephalus often have altered personality and behavior. The possibility of hydrocephalus is suggested if the child's head circumference is significantly larger at birth or exceeds the standard size in consecutive measurements . Diagnosis can be made by cranial ultrasound in infants, or by cranial CT or MRI in older children or children. Brain imaging can help distinguish between obstructive or traffic hydrocephalus. Most hydrocephalus is progressively worse. Usually, a triple ventriculotomy is the treatment for simple obstructive hydrocephalus. Shunt surgery is used for traffic hydrocephalus or in those cases where a triculostomy does not work. However, many forms of hydrocephalus have both obstructive and resorptive causes, so the effectiveness of triculotomy is difficult to evaluate consistently. The major complication of hydrocephalus treatment is shunt dysfunction. Approximately 40% of shunt dysfunction occurs in the first postoperative year.