Surgery

Surgery to remove fluid in the brain

Fluid can build up in your brain and increase the pressure inside your head. This is called hydrocephalus. Treatments include shunt surgery or endoscopic third ventriculostomy (ETV).

What is hydrocephalus?

The brain and spinal cord are surrounded by a clear fluid called cerebrospinal fluid (CSF). The CSF supports and protects the brain and the spinal cord.

Some brain tumours block the normal circulation of the CSF. The fluid can’t drain away. So it builds up inside the brain and increases the pressure inside the head (intracranial pressure).

This increased pressure can cause symptoms. These include:

  • headaches

  • feeling and being sick

  • blurred vision or double vision

  • problems with balance and coordination

This build up of fluid can damage the brain if it is not treated.

Tests to diagnose fluid in the brain

You might have a neurological examination. This test checks how well your body and brain are working. Your doctor will check your movement and balance. They will also check your hearing, speech and vision.

You might also have aor an .

Treatment for hydrocephalus

Treatment for hydrocephalus is usually surgery. There are 2 main types of surgery that you can have:

  • shunt surgery

  • endoscopic third ventriculostomy (ETV)

You might have surgery for hydrocephalus at the same time you have surgery to remove your tumour. Or you may have a separate operation.

Your specialist nurse and surgeon will give you more information about how to prepare for your surgery. They will also tell you how long you are likely to stay in hospital afterwards.

Everyone is different, and recovery time can vary from person to person.

Shunt surgery

A shunt is a thin tube that drains away the extra CSF from the ventricles of the brain. The shunt drains the CSF to other parts of the body, where it is absorbed. Such as the abdomen (tummy).

Shunts are small plastic tubes. They have valves so that fluid can flow down from the brain but not back the other way. Shunts are also called ventricular catheters.

You have shunt surgery under a general anaesthetic. This means that you will be asleep and won’t feel anything. A specialist team of doctors does your surgery. They are called neurosurgeons.

The most common type of shunt is the ventriculoperitoneal shunt. This is a tube from the brain ventricles into the abdomen. Other types of shunts drain the fluid into the chest.

Diagram showing a brain shunt.

You can’t see the shunt from outside the body. Some people have a shunt for a short period of time and then the surgeon removes it. Others have them for much longer often for several years.

Possible problems with shunts

The most common problems with shunts are blockage and infection. Shunts that drain into the tummy can also cause a hole in the bowel (perforation), but this is rare.

Blockage

A blockage may cause symptoms of increased pressure inside the head. Symptoms include:

  • headaches

  • feeling or being sick

  • drowsiness

  • neck stiffness

  • unconsciousness

A shunt blockage can be serious. You usually need an urgent operation to replace it. 

Infection

Shunt infections are more common in the first few weeks after having shunt surgery. If your shunt is infected, you might have:

  • headaches

  • high temperature (fever)

  • a reddening of the skin over the path of the shunt (a red area tracking down your neck and chest for example), but this is rare

You usually have antibiotics if this happens.

Endoscopic third ventriculostomy (ETV)

ETV involves making a tiny hole inside your brain at the third ventricle. This allows the extra CSF to drain into another part of the brain, where it is absorbed. This reduces the pressure inside the brain. The ventricles are spaces inside the brain filled with CSF.

ETV isn’t suitable for everyone. You might have it if your hydrocephalus is caused by a blockage.

You usually have an ETV under general anaesthetic. This means that you will be asleep and won’t feel anything.

Your surgeon carefully makes a small hole into the skull. They put a neuroendoscope through the hole and into the ventricle. A neuroendoscope a long tube with a light and a camera at one end. This allows your doctor to see inside the brain and make the tiny hole inside the ventricles.

Diagram showing where the ventricles are in the brain.

Possible problems with ETV

ETV is a safe procedure and complications are usually rare. Possible problems of ETV include:

  • infection

  • bleeding in the brain

  • a blocked drain or too much drainage

  • damage to other parts of the brain

  • a hole in the membranes that cover the brain (meninges) which may cause the CSF to leak

Coping

It can be upsetting to learn that you have hydrocephalus and need to have brain surgery. Talk to your doctor or cancer nurse specialist about what to expect during an operation to treat hydrocephalus. Ask them about the side effects you might have and the support that will be available to you.

Read about the possible problems and recovery after brain tumour surgery

Last reviewed: 22 Jun 2026

Next review due: 22 Jun 2029

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