**1. Introduction**

Hydrocephalus has always been and remains one of the most complicated problems of pediatric neurosurgery. The progressive course of hydrocephalus leads to

severe neurological and mental disorders with a lag in intellectual and physical development, significantly affecting the incidence of disability and mortality of the child population.

The term "hydrocephalus" (from others-Greek υ῞δωρ "water" + κεφαλή "head"), synonymous with "dropsy of the brain," is an excessive accumulation of cerebrospinal fluid (CSF) in the ventricles of the brain and/or external cerebrospinal spaces, accompanied by their expansion [1].

The problems of hydrocephalus pathogenesis, diagnosis, and treatment have always been relevant at all stages of neurology and neurosurgery development. Hydrocephalus affects an average of five children out of every thousand newborns. In neurosurgical patients, hydrocephalus syndrome is detected in every fourth patient. In one-third of children with hydrocephalus, the development of hydrocephalic hypertension syndrome is one of the causes of decompensation of the patient's condition [2–4].

Among central nervous system (CNS) injury cases of 25–80% lead to hydrocephalus as a complication at the late stages of the disease, while only 5–10% of cases develop in the acute period. In most patients with pathology of cerebral vessels (mainly ruptured cerebral aneurysms), persistent hydrocephalus, which needs correction, is observed in 5–7% of cases, and it is often found in strokes (up to 60%).

According to the data, the prevalence of congenital hydrocephalus ranges from 2.5 to 8.2 cases per 10,000 newborns, and in patients with malformations of the brain or spinal cord hydrocephalus is observed in up to 78% of cases. In patients with brain tumors, hydrocephalus occurs in 20–94%, with cerebrovascular pathology—in 6–67% of cases, with inflammatory diseases of the CNS—up to 5–60% of cases [5–7], with the indicators increasing every year. The mortality rate in hydrocephalus used to be more than 50% before the valvular fluid bypass operations were introduced. Since these operations became regular practice the mortality rate decreased to 2–5% [8].

State-of-the-art research considers hydrocephalus to be the result of persistent disorders of the CSF circulation.
