A shunt in the brain is a hollow tube surgically placed in the brain to help drain cerebrospinal fluid and redirect it to another location in the body where it can be reabsorbed. Shunt procedures can address pressure on the brain caused by hydrocephalus and relieve its symptoms such as gait difficulty, mild dementia, and lack of bladder control. Most shunts have two catheters connected by a valve, with one end of the upstream catheter in a ventricle and the other end of the downstream catheter in the peritoneal cavity. Shunts can be placed in different parts of the body, including the abdomen, chest, heart, or lungs. Shunt systems can be programmable or non-programmable, and different shunt systems re-route the excess fluid to different parts of the body.

Shunt surgery is done by a specialist in brain and nervous system surgery (neurosurgeon) and is usually done under general anesthesia. The surgeon will make a small incision in the scalp, make a small hole in the skull, and place the catheter into the ventricle. The other end of the catheter will be tunneled under the skin into the abdomen, chest, or heart, depending on where the neurosurgeon has decided. Shunt placement is usually successful in reducing pressure in the brain, but there are risks associated with the surgery, including bleeding, infection, and damage to brain tissue.