For brain tumors, surgery may be done for different reasons:
- To get a biopsy sample to determine the type of tumor
- To remove as much of the tumor as possible
- To help prevent or treat 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 the tumor
In most cases, the first step in brain tumor treatment is for the neurosurgeon to remove as much of the tumor as is safe without affecting normal brain function.
Surgery alone or combined with radiation therapy may cure many tumors, including some low-grade astrocytomas, ependymomas, craniopharyngiomas, gangliogliomas, and meningiomas.
Tumors that tend to spread diffusely into nearby brain tissue such as anaplastic astrocytomas or glioblastomas are not cured by surgery. But surgery can reduce the amount of tumor that needs to be treated by radiation or chemotherapy, which can help these treatments work better. This may help prolong life even if all of the tumor can't be removed.
Surgery may also improve some of the symptoms caused by brain tumors, particularly those caused by a buildup of pressure within the skull. These can include headaches, nausea, vomiting, and blurred vision. Surgery may also be used to help control seizures.
Surgery may not be a good option in some cases, such as if the tumor is deep within the brain, if it is in a part of the brain that can't be removed, such as the brain stem, or if a person is unable to tolerate a major operation for other health reasons.
Surgery is not very effective against some types of brain tumors, such as lymphomas, although it may be used to get a biopsy for diagnosis.
Craniotomy: A craniotomy is a surgical opening in the skull. This is the main type of operation for treatment of brain tumors. For this operation, the person may either be under general anesthesia (in a deep sleep) or may be awake for at least part of the procedure (with the surgical area numbed) if brain function needs to be assessed during the operation.
Part of the head may need to be shaved. The neurosurgeon first makes an incision in the scalp, and the skin is folded back. The surgeon then uses a special type of drill to remove the piece of the skull over the tumor.
The craniotomy is typically large enough for the surgeon to insert several instruments and view the parts of the brain needed to operate safely. The surgeon makes a small incision into the brain itself to reach the tumor. The surgeon may use MRI, CT, or ultrasound images to help locate the tumor and its edges.
The surgeon can remove the tumor in several ways depending on how hard or soft it 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 lesions are soft and can be removed with simple suction devices. In other cases, a probe attached to an ultrasonic generator may be placed into the tumor to break it up and liquefy it. A small vacuum device is then used to suck it out.
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. As mentioned above, image guidance with MRI, CT, or ultrasound can be used to map the area of tumors buried deep in the brain. In some cases, the surgeon may use intraoperative imaging, in which MRI (or other) images are taken at different times during the operation to show the location of any remaining tumor. This can allow some brain tumors to be resected more safely and extensively.
The surgeon tries to remove as much of the tumor as possible without affecting important brain tissue or leaving the patient disabled in any way. The surgeon can detect the function of the brain by electrically stimulating parts of the brain in and around the tumor and monitoring the response. This will show if these areas control an important function. Using this technique, known as intraoperative cortical stimulation, surgeons can lower the risk of removing vital parts of the brain. Alternatively, a particular function of the brain can be located prior to surgery with a technique called functional MRI. This information can be used to identify and preserve that region during the operation.
In most cases the removed piece of bone is put back in place and fastened to the skull with metal screws and plates, wires, or special stitches. Healing usually takes several weeks. Recovery time in the hospital is usually 4 to 6 days, although this may vary according to the size and location of the tumor and the patient's general health.
Surgery to place a shunt or ventricular access catheter
Blockage of the cerebrospinal fluid (CSF) flow by a tumor can increase pressure inside the skull. This can cause symptoms like headaches, nausea, and drowsiness, and may even be life-threatening.
To drain excess CSF and lower the pressure, 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 or other areas. The tube runs under the skin of the neck and chest. The flow of CSF is controlled by a valve placed along the tubing.
Shunts may be temporary or permanent. They may be placed before or after the surgery to remove the tumor. Shunt placement is normally a straightforward procedure that takes about an hour. As with any operation, complications may develop, such as bleeding or infection. Sometimes shunts get clogged and need to be replaced. The hospital stay after shunt procedures is typically 1 to 3 days, depending on the reason it is placed and the patient's health.
Surgery may also be used to insert a ventricular access catheter, such as an Ommaya reservoir, to help deliver chemotherapy directly into the CSF. A small incision is made in the scalp, and a small hole is drilled in the skull. A flexible tube is then threaded 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, remains 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, or reactions to anesthesia are rare, but they can happen.
A major concern after surgery is swelling in the brain. Drugs called corticosteroids are typically given 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 safely possible.
For more extensive information on surgery as a treatment for cancer, see our document, Surgery.
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