Hydrocephalus is a condition that causes fluid to build up on the brain, which increases the pressure around the brain. A ventriculoperitoneal shunt reduces that pressure. Doctors insert this medical device while a person is under general anesthetic.
This article explores ventriculoperitoneal shunts and the procedure used to place them. It also discusses the risks of ventriculoperitoneal shunts and recovery.
What is a ventriculoperitoneal shunt?
A ventriculoperitoneal shunt is either programmable or nonprogrammable.
The purpose of a ventriculoperitoneal shunt is to remove excess fluid from a person’s brain. Fluid buildup can increase brain pressure, which can be harmful. A ventriculoperitoneal shunt drains excess brain fluid, reducing brain pressure to a safe level.
Ventriculoperitoneal shunts consist of a valve and two tubes, called catheters, which drain the fluid.
One catheter drains fluid from the brain out of a small hole the doctor makes in the skull. This is called the inflow catheter. The other runs under the skin, taking the fluid to a drainage site elsewhere in the body. This is called the outflow catheter.
The valve, also known as a pump, controls the shunt so that it drains fluid as needed.
There are two types of ventriculoperitoneal shunt
With a nonprogrammable shunt, the doctor programs the valve so that it activates whenever the fluid reaches a certain volume. It is not possible to adjust a nonprogrammable shunt after insertion. A programmable shunt, however, has an external, adjustable valve that the doctor can readjust at any time according to the person’s needs.
What is it used for?
Doctors often use a ventriculoperitoneal shunt to treat hydrocephalus, which is also known as water on the brain. Hydrocephalus is a condition where cerebrospinal fluid (CSF) pools in the cavities in a person’s brain.
CSF delivers essential nutrients to the brain and drains away waste. To do this, CSF passes through cavities in the brain called ventricles, bathing the brain in the fluid. It then drains out of the base of the brain, and the blood reabsorbs it.
When a person has hydrocephalus, this process does not happen correctly. Excess CSF pools in the brain ventricles, which increases the pressure on the brain. Hydrocephalus may cause brain damage or death if left untreated.
According to the Hydrocephalus Association, over 1 million people in the United States have the condition. When a person has hydrocephalus, it may mean that there is:
- an obstruction that stops CSF draining properly
- overproduction of CSF
- improper absorption of CSF
The following factors can cause hydrocephalus:
A person with hydrocephalus may experience the following symptoms:
- memory problems
- trouble thinking
- vision problems
- loss of bladder or bowel control
- increased head size
- poor coordination
The doctor fits the shunt while the person is under general anesthetic.
Image credit: James Heilman, MD, 2016
The doctor will give a person a general anesthetic before they fit the ventriculoperitoneal shunt. Once the person is completely asleep, the doctor will drill a small hole in their skull through an incision behind their ear.
The doctor will then insert the inflow catheter into the brain. They will fit a valve to the end of the catheter to control how it works. They feed the outflow catheter under the skin which leads into to a small incision in the abdomen. From here, the body can reabsorb the drained CSF.
Once the doctor connects all parts of the shunt, the shunt system will start draining CSF fluid from the brain.
How to prepare
The doctor will advise a person how to prepare for this procedure. The doctor may recommend:
- stopping drinking alcohol, as this may affect surgery and recovery
- stopping taking vitamin E, as it may cause bleeding
- avoiding herbal remedies and supplements
- discussing any existing medication, as people may need to stop taking some before surgery
- discussing any heart devices and results of any tests for heart conditions
- declaring any allergies
- talking about how smoking may affect surgery
- talking about sleep apnea, if present
The doctor may ask a person not to eat after midnight on the night before their surgery. They may also advise a person about how much water they should drink before surgery and when to drink it.
Tips for recovery
After surgery, a person may have a mild headache. The doctor will give them pain medication to manage this.
A person may not be able to eat normally straight after surgery. They may need to start with liquids and move on to solid foods.
The doctor will remove a person’s stitches during a follow-up visit. In the meantime, a person should keep their incisions clean and check for signs of infection every day. Signs of infection may include:
- fluid leakage
The doctor will let a person know when they can start showering again. It may not be possible to shower straight away, as getting the incisions wet may affect how the wounds heal.
It is a good idea to rest after surgery to aid recovery. The doctor will advise when a person can resume normal daily activities and go back to work.
Risks and complications
Going under general anesthetic is safe for most people. But some people may experience adverse effects, including:
Sometimes a ventriculoperitoneal shunt may stop working correctly and need replacing. Signs that the device is not working as it should include:
- redness or swelling where the catheter passes under the skin
- loss of coordination or balance
- vomiting without feeling very nauseous
- a headache that will not go away
- extreme tiredness
- trouble waking or staying awake
- feeling irritable
If a ventriculoperitoneal shunt stops working correctly, it is possible for it to over- or underdrain CSF. If the pump drains CSF faster than the body produces it, a person may experience a brain hemorrhage. If the pump does not drain CSF quickly enough, the symptoms of hydrocephalus might return.
It is also possible for the ventriculoperitoneal shunt to become infected. Signs of infection include:
- redness or swelling where the catheter passes under the skin
- pain around the catheter
- high fever
- a headache
If a person has any signs of infection, they should see a doctor straight away.
After having a ventriculoperitoneal shunt inserted, a person should avoid coming into contact with magnets. Magnetic fields may affect how the valve on the shunt works.
Sometimes earphones may affect the effectiveness of a ventriculoperitoneal shunt, so it is a good idea to check the shunt manufacturer’s guidelines before using them.
If a person needs to have an MRI scan in the future, they should let the MRI operator know that they have a ventriculoperitoneal shunt.
Similarly, if a person has surgery on their abdomen in the future, they should let the doctor know they have a ventriculoperitoneal shunt.
It is a good idea for a person who has a ventriculoperitoneal shunt to wear a medical bracelet to alert people in case of an emergency.
A ventriculoperitoneal shunt is an effective way to treat the symptoms of hydrocephalus.
When fitted, a ventriculoperitoneal shunt successfully drains CSF and reduces brain pressure for most people. Sometimes a ventriculoperitoneal shunt will stop working and need replacing.
A person’s outlook will depend on the underlying cause of their hydrocephalus. They may require other treatment to manage their condition.
Early diagnosis and treatment for hydrocephalus may improve a person’s outlook.