What is a ventriculoperitoneal shunt?
A ventriculoperitoneal (VP) shunt is a medical device that relieves pressure on the brain caused by fluid accumulation.
VP shunting is a surgical procedure that primarily treats a condition called hydrocephalus. This condition occurs when excess cerebrospinal fluid (CSF) collects in the brain’s ventricles. CSF cushions your brain and protects it from injury inside your skull. The fluid acts as a delivery system for nutrients that your brain needs, and it also takes away waste products. Normally, CSF flows through these ventricles to the base of the brain. The fluid then bathes the brain and spinal cord before it’s reabsorbed into the blood.
When this normal flow is disrupted, the buildup of fluid can create harmful pressure on the brain’s tissues, which can damage the brain. Doctors surgically place VP shunts inside one of the brain’s ventricles to divert fluid away from the brain and restore normal flow and absorption of CSF.
People of any age can develop hydrocephalus and therefore require a VP shunt. However, according to the Mayo Clinic, hydrocephalus is more likely to occur in babies and older adults. The National Institute for Neurological Disorders and Stroke (NINDS) estimates that 1 to 2 of every 1,000 babies are born with hydrocephalus.
Excess fluid can build up around the brain for a number of reasons, including:
- overproduction of CSF
- poor absorption of CSF by the blood vessels
- blockages preventing fluid from flowing throughout the brain
Blockages are the most common cause of hydrocephalus. Cysts, tumors, or inflammation in the brain can impede the normal flow of CSF and create an unsafe accumulation. Symptoms of hydrocephalus can include:
- large head size
- excessive sleepiness
- poor appetite
- cognitive delays or regression
- memory loss
- poor coordination
- impaired vision
Imaging tests can confirm the diagnosis of hydrocephalus. Ultrasound, CT scans, and MRI scans allow doctors to view the cavities and tissues within the brain. Testing will show if areas of the brain contain more fluid than normal.
Doctors typically perform the placement of a VP shunt while a patient is under general anesthesia. You’ll be asleep during the surgery and won’t experience pain. The entire procedure takes about 90 minutes.
Speak to your medical care team about preoperative food and drink restrictions. Older children and adults may need to fast for at least eight hours prior to surgery. Infants and toddlers may only need to stop eating baby formula and solid foods six hours before surgery, but they can usually drink water until four hours before the scheduled procedure. In all cases, these instructions should be reviewed with your surgical team.
The surgical nurse will shave the area behind your ear in preparation for shunting, as this is where they will place the catheter. Catheters are thin, flexible tubes used to drain excess fluid. A surgeon will make a tiny incision behind the ear and will also drill a small hole in the skull. They will then thread one catheter into the brain through this opening. The other catheter goes behind your ear and is subcutaneous, meaning it resides under the skin. This tube travels down to your chest and abdomen, allowing excess CSF to drain into the abdominal cavity, where your body absorbs it. Your surgeon may attach a tiny pump to both catheters and place it under the skin behind your ear. The pump will automatically activate to remove fluid when the pressure in the skull increases. It may even be possible to program the pump, also called a valve, to activate when the fluid increases to a certain volume.
Recovery from a VP shunt placement takes three to four days. Most people can leave the hospital within seven days after the procedure.
During your hospitalization, the hospital staff will monitor your heart rate and blood pressure, and your doctor will administer preventive antibiotics. Your doctor will make sure the shunt is working properly before you leave.
Placement of a shunt is a very safe procedure. However, complications can occur during or after the procedure. Risks associated with any surgical procedure include excessive bleeding and infection. You might also experience adverse reactions to anesthesia, such as breathing difficulties, changes in heart rate, or changes in blood pressure levels.
There are rare risks specific to VP shunting that can be serious and potentially life-threatening if left untreated, including:
- infection in the shunt or brain
- blood clots
- bleeding in the brain
- damage to brain tissue
- swelling of the brain
Fever, headache, abdominal pain, fatigue, and a spike in blood pressure levels, or having the same symptoms that were present when the shunt was initially placed, can indicate an infection or a malfunction of the shunt. Notify your doctor immediately if these signs and symptoms develop. According to the University of Chicago, infection is most common in the first few weeks after a shunt placement.
Shunting is successful in reducing pressure in the brain in most people. VP shunts are likely to require replacement after several years, especially in small children. The average lifespan of an infant’s shunt is two years. Adults and children over the age of 2 may not need a shunt replacement for eight or more years. Shunt systems require frequent monitoring and follow-up. Complications that may occur with shunt systems include:
- mechanical failure
Malfunctions can lead to serious complications, such as over- or under-draining of CSF. Over-draining occurs when CSF drains from ventricles at a faster rate than it’s produced. This can cause ventricles to collapse, which may lead to headaches or hemorrhage inside the brain. Under-draining allows CSF to accumulate on the brain and can cause symptoms of hydrocephalus to return. Seek immediate medical attention if you experience symptoms that indicate your shunt system isn’t working properly.