Surgery for Brain and Spinal Cord Tumors in Children

For brain and spinal cord tumors, surgery may be done to:

• Get a biopsy sample to determine the type of tumor and if the tumor cells have certain gene changes that might affect prognosis (outlook)
• Remove or destroy the tumor (or as much of it as possible)
• Help prevent or treat symptoms or possible complications from the tumor

Before surgery, be sure you understand what the goal of the surgery is, as well as the potential benefits and risks.

Surgery to remove or destroy the tumor

Most often, the first step in brain or spinal cord tumor treatment is for the neurosurgeon to remove or destroy as much of the tumor as possible, while trying to limit any effects on normal brain or nerve function.

Surgery alone or combined with radiation therapy may control or cure many slower-growing tumors, including some low-grade astrocytomas, dysembryoplastic neuroepithelial tumors (DNETs), ependymomas, craniopharyngiomas, gangliogliomas, and meningiomas.

Children with tumors that tend to grow into nearby brain tissue, such as anaplastic astrocytomas or glioblastomas, cannot be cured by surgery alone. But surgery can reduce the amount of tumor that needs to be treated by radiation or chemotherapy, which might improve the results of these treatments.

Surgery can also help relieve some of the symptoms caused by brain tumors, particularly those caused by increased pressure within the skull, such as headaches, nausea, vomiting, and blurred vision. Surgery may also make seizures easier to control with medicines.

Surgery may not be a good option in some cases, such as if the tumor is deep within the brain, or if it has spread throughout a part of the brain that can’t be removed, such as the brain stem. If this is the case, other treatments may be used instead.

Craniotomy

A craniotomy is a surgical opening made in the skull. This is the most common surgery to remove a brain tumor. For this operation, the child may either be under general anesthesia (in a deep sleep) or may remain awake (with the surgical area numbed) for at least part of the surgery if brain function needs to be assessed during the operation.

Part of the head might need to be shaved before surgery. The neurosurgeon makes an incision (cut) in the skin over the skull near the tumor and then uses a special type of drill to remove a piece of bone from the skull. The opening is typically large enough for the surgeon to insert several instruments and view the parts of the brain needed to operate safely.

Many devices can help the surgeon see the tumor and surrounding brain tissue. The surgeon often operates while looking at the brain through a microscope. Imaging tests such as MRI or CT scans can be done before surgery (or ultrasound can be used once the skull has been opened) to help locate the tumor and its edges.

The surgeon will remove or destroy as much of the tumor as is safely possible. This can be done in several ways depending on how hard or soft the tumor is, and whether it has many or just a few blood vessels:

• One way is to cut it out with a scalpel or special scissors.
• Some tumors are soft and can be removed with suction devices.
• In other cases, a probe attached to an ultrasonic aspirator can be placed into the tumor to break it up and suck it out.

The surgeon is very careful to avoid damaging normal brain tissue as much as possible. To lower the risk of removing or damaging vital parts of the brain, different techniques can be used, such as:

• Functional MRI: Before surgery, this type of imaging test (described in Tests for Brain and Spinal Cord Tumors in Children) can be done to locate a particular function of the brain. This can be used to help preserve that region during the operation.
• Intraoperative cortical stimulation (cortical mapping): During surgery, the surgeon can often detect the function of brain areas in and around the tumor by electrically stimulating them and monitoring the response. This will show if these areas control an important function, helping the surgeon to avoid them.
• Intraoperative imaging: In some cases, the surgeon uses MRI (or other) images taken at different times during the operation to show the location of any remaining tumor. This might allow some brain tumors to be removed more safely and extensively.
• Newer techniques: Newer types of MRI, as well as other techniques such as fluorescence-guided surgery, might be helpful in some situations. Some of these are described in What’s New in Research for Brain and Spinal Cord Tumors in Children?

After removing the tumor, the surgeon replaces the piece of skull bone and closes the incision. (If any metal screws, wires, or plates are needed to fasten the bone, they are usually made from titanium, which allows the child to get follow-up MRIs and will not set off metal detectors.)

For tumors that are hard to treat surgically, another option might be to insert a thin probe with a tiny laser on the end through a small hole in the skull and into the tumor. The laser is then used to heat and destroy (ablate) the tumor. This technique, known as laser interstitial thermal therapy (LITT), is still fairly new, so doctors are still learning about the best ways to use it.

What to expect after surgery

After the operation to remove the tumor, the child may have a tube (called a drain) coming out of the incision that allows excess cerebrospinal fluid (CSF) to drain from the skull. Other tubes may be placed to allow blood that builds up after surgery to drain from under the scalp. The drains are usually removed after a few days. An imaging test such as an MRI or CT scan is typically done 1 to 3 days after the operation to confirm how much of the tumor has been removed. Recovery time in the hospital is usually 4 to 6 days, but this depends on the size and location of the tumor and whether other treatments are given.

Surgery to help with CSF flow blockage

If the tumor blocks the flow of CSF within the head, it can cause increased intracranial pressure (ICP) inside the skull. This can cause symptoms such as headaches, nausea, vomiting, and blurred vision, and may even damage the brain or be life-threatening. Surgery to remove the tumor can often help with this, but there are also other ways to drain away excess CSF and lower the pressure if needed.

Placing a shunt

The neurosurgeon may put in a silicone tube called a shunt (sometimes referred to as a ventriculoperitoneal or VP shunt). One end of the shunt is placed in a ventricle of the brain (an area filled with CSF) and the other end is placed in the abdomen or, less often, the heart (and would then be referred to as a ventriculoatrial shunt). The tube runs under the skin of the neck and chest, and allows the excess CSF to flow into the abdomen (or heart), where it mixes in with other fluids. The flow of CSF is controlled by a valve in the tubing.

Shunts can be temporary or permanent. They can be placed before or after the surgery to remove the tumor. Placing a shunt normally takes about an hour. Most children will need to stay in the hospital for about 1 to 3 days after the surgery. As with any operation, complications may develop, such as bleeding or infection. Sometimes shunts get clogged and need to be replaced.

Making an opening in the third ventricle

Another option to treat increased pressure in the skull in some cases is an endoscopic third ventriculostomy. In this operation, the surgeon makes an opening in the floor of the third ventricle at the base of the brain to allow the CSF to flow again. This operation is done through a small hole in the front of the skull. An advantage of this approach is that it does not require a shunt, but there is a chance that the opening made in the ventricle might close up again.

Placing an external drain

If the pressure inside the head needs to be relieved for a short time, an external ventricular drain (EVD) might be put in place to allow the excess CSF to drain out of the body. The drain is a small tube. One end is put into a ventricle, and the other end is attached to a collection bag outside the body. Along with collecting the excess CSF, the drain can also be used to measure the pressure inside the skull, as well as to look for tumor cells, blood, or signs of infection in the CSF.

The drain can be placed either during surgery or during a procedure at the hospital bedside. It can be put in place to relieve the pressure in the days before surgery, or to help drain the fluid that collects after an operation. If the pressure inside the skull needs to be lowered for more than a few days, the doctor might need to change this to a VP shunt.

Surgery to place a ventricular access catheter

Surgery may also be used to insert a ventricular access catheter to help deliver chemotherapy directly into the CSF later on. One type is called an Ommaya reservoir. A small incision is made in the scalp, and a small hole is drilled in the skull. A flexible tube is then inserted through the hole until the open end of the tube is in a ventricle, where it reaches the CSF. The other end, which has a dome-shaped reservoir, stays just under the scalp. After the operation, doctors and nurses can use a thin needle to give chemotherapy drugs through the reservoir or to remove CSF from the ventricle for testing.

Possible risks and side effects of surgery

Surgery on the brain or spinal cord is a serious operation, and surgeons are very careful to try to limit any problems either during or after surgery. Complications during or after surgery such as bleeding, infections, seizures, or reactions to anesthesia are rare, but they can happen.

Swelling in the brain is a major concern after surgery. Drugs called corticosteroids are typically given before and for several days after surgery to help lessen this risk.

One of the biggest concerns when removing brain tumors is the possible loss of brain function afterward, which is why doctors are very careful to remove only as much tissue as is necessary. Any symptoms of brain injury after surgery will depend mainly on the location and size of the tumor. If problems do arise, it might be right after surgery, or it might be days or even weeks later, so close monitoring for any changes is very important. (See What Happens After Treatment for Brain and Spinal Cord Tumors in Children?)