Normally, the brain is bathed in a liquid called cerebrospinal fluid. This fluid cushions and nurtures the brain cells as it flows around and through the brain. Sometimes, cerebrospinal fluid does not get reabsorbed into the body properly, or a blockage in the brain can stop it from flowing. This causes a buildup of pressure called hydrocephalus. This condition affects a wide range of people, but it is much more prevalent among infants and older adults. Left untreated, hydrocephalus can cause uncomfortable symptoms, such as headaches and blurred vision, and eventually may cause brain damage.
Hydrocephalus is most often treated with an implanted device called a shunt. A shunt is a long, thin tube that is used to drain excess fluid. One end is placed within the brain. The tube runs under the skin, along the neck behind the ear, and to another part of the body where the fluid can be reabsorbed. Most often this is the abdomen, but the chest or other areas can also be used. Shunts have a valve that allows doctors to monitor and control the pressure within the brain. Insertion of a shunt is a surgical procedure that takes one to two hours. Incisions are made in the head and the abdomen, and the shunt is threaded into place before the openings are stitched closed.
In cases where hydrocephalus is caused by a blockage, a procedure called endoscopic third ventriculostomy, or ETV, may be performed. During this procedure, a surgeon makes a dime-sized hole in the skull and uses a thin tube with a camera on the end (called an endoscope) to see inside the brain. The surgeon punctures a hole in the floor of the third ventricle, a fluid-filled space within the brain. The hole provides an opening for cerebrospinal fluid to flow around the blockage, normalizing pressure. The entire procedure usually takes less than an hour and patients can often go home the following day. ETV can provide a permanent and safe alternative to a shunt, but it is only useful for patients whose hydrocephalus is caused by a blockage.