Surgery is the only known treatment for congenital hydrocephalus. Most often, a surgeon inserts a device called a shunt into a ventricle in the brain. The brain has four interconnected ventricles, which are the spaces that the cerebrospinal fluid (CSF) flows through. The CSF is a fluid that is necessary for the normal functioning of the brain and spinal cord. Made up of a valve and a thin plastic tube called a catheter, the shunt controls the flow of the CSF and allows excess CSF to be siphoned off through the catheter into another part of the body, such as the abdomen, the heart, or near a lung. The excess CSF is then absorbed back into the body so it does not accumulate in the brain's ventricles and cause the swelling associated with hydrocephalus. A less common surgical procedure called a ventriculostomy is sometimes used to treat hydrocephalus if there is a blockage that is restricting the flow of CSF in the ventricles. A surgeon drills a small hole in one of the ventricles to bypass the blockage. As they get older, some children living with hydrocephalus may need ongoing treatment, such as physical rehabilitation therapy and special education, to counteract the effects of brain damage.