A ventriculoperitoneal (VP) shunt is a device used to relieve pressure from the brain caused by fluid accumulation. VP shunting is a surgical procedure that is primarily used to treat a condition called hydrocephalus, which 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 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 is reabsorbed into the blood. When this normal flow is disrupted, the build-up of fluid can create harmful pressure on the brain’s tissues, which can damage the brain. VP shunts are surgically placed 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 need a ventriculoperitoneal shunt. However, according to the Mayo Clinic, hydrocephalus is more likely in babies and in older adults. (Mayo Clinic, 2011) The National Institute for Neurological Disorders and Stroke (NINDS) estimates that one out of every 500 children is affected by hydrocephalus. (NINDS, 2011)
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 to flow 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, creating an unsafe accumulation. Symptoms of hydrocephalus can include:
- large head size
- loss of previously acquired skills
- poor appetite
- cognitive delays or regression
- memory loss
- poor coordination
- impaired vision
Diagnosis of hydrocephalus can be confirmed through imaging tests. Ultrasound, computed tomography (CT) scans, and magnetic resonance imaging (MRI) are tools used to view the cavities and tissues within the brain. Testing will show if areas of the brain are filled with more fluid than normal.
The placement of a ventriculoperitoneal shunt is performed under general anesthesia. You will be asleep during the surgery and will not 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 are generally required 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 can usually drink water until four hours before the scheduled procedure.
The hair behind your ear will be shaved in preparation for shunting, as this is the area in which the catheters are inserted. 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. One catheter is threaded into the brain through this opening. The other catheter is subcutaneous, meaning it is placed under the skin behind your ear. This tube is snaked down to your chest and abdomen, allowing excess CSF to drain into the abdominal cavity, where your body absorbs it. Your surgeon will 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 pressure in the skull increases. The pump, also called a valve, may be programmable to activate when the fluid increases to a predetermined volume.
Recovery from a VP shunt placement takes three to four days. Most people are able to leave the hospital within seven days after the procedure. According to the National Institutes of Health (NIH), children who undergo VP shunting will need to lie flat for 24 hours after initial shunt placement. After the first 24 hours, they will be allowed to sit up and move around carefully. (NIH, 2010)
During your hospitalization, your heart rate and blood pressure will be monitored frequently, and your doctor will administer preventive antibiotics. Your doctor will make sure the shunt is working properly before you are discharged.
Placement of a shunt is a very safe procedure. However, possible risks may 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 ventriculoperitoneal 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 can indicate infection or a malfunction in the shunt. Notify your doctor immediately if these signs and symptoms develop. According to the University of Chicago Pritzker School of Medicine (UCPSM), infection is most common in the first few weeks after a shunt placement. (UCPSM)
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 two may not need a shunt replacement for eight or more years. Shunts systems require frequent monitoring and follow-up. Complications that may occur with shunt systems include:
- mechanical failure
- the catheter may need to be lengthened or replaced
These malfunctions can lead to serious medical complications, such as over- or under-draining of CSF. Over-draining occurs when CSF is drained from ventricles at a faster rate than it is 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 is not working properly.