Surgical Procedures for Brain Tumors
When possible, surgery is selected to remove or reduce the tumor while preserving as much brain function as possible. The complete removal of the tumor can cure some conditions, but certain tumors can grow back.
Partial removal of the tumor or debulking of the tumor may be done as part of a treatment plan. Debulking can help relieve pressure of nearby healthy tissue to relieve more serious symptoms. It may also improve the response of tumor to other treatment options such as radiation therapy
Surgery will also provide a sample of tumor tissue (biopsy
) to learn more about the tumor.
The biopsy may be done as part of larger surgery or may be done by itself for tumors that cannot be removed or for people who can not tolerate surgery. A stereotactic biopsy is a specific type of biopsy that is done by inserting a needle through a small hole in the skull.
Mapping is a method surgeons use to determine what functions are connected to specific areas of the brain. The surgeon will use mapping to test the areas of the brain near the tumor to help guide what tissue can be removed and possible effects after surgery. Mapping may be done with one of the following methods:
- Stimulating brain tissue with tiny electrical currents
- Measuring brain waves as they are stimulated
- Using ultrasound probes inside or near brain structures
- Probing the brain with special computerized devices
- Functional MRI scan
PET or SPECT scans
- Magnetoencephalogram (MEG) to localize motor, sensory, and language function
Surgical Options to Treat Brain Tumors
is the removal of a piece of the skull to allow access to the brain. This allows the surgeon to be as close to the tumor as possible. Though some tumors are best approached through the nose or the top of the neck, most go through the skull to expose and access the brain. The location of the craniotomy depends on the location of the tumor. In some cases, the surgeon may also do some mapping to identify functional areas of the brain. The tumor will be exposed, isolated from the normal brain, and removed. Brain surgery may take several hours.
Types of craniotomies include:
- Eyebrow—A small hole is made in the eyebrow. This allows access to the pituitary gland or tumors near the front of the brain. Depending on the size or type of tumor, this method may be used instead of going through the nose.
- Keyhole—A small hole is made behind the ear. This allows access to the structures at the base of the skull (cerebellum or brainstem) and inside the ear.
- Endoscopic—A small hole is made in the skull near the tumor. A lighted tube with a camera are inserted through the hole, allowing the surgeon to see structures inside the skull.
- Craniectomy—Removal of a piece of skull. This may be needed when brain swelling is likely or if the piece of skull cannot be replaced.
Once the brain is accessed, the tumor may be treated with:
- Thermal destruction—Heat from lasers or other instruments can be directed to the tumor's exact location.
- Ultrasonic aspiration—Can be used to break up tumor tissue and remove it from the brain. Some tumors are most efficiently removed this way with less damage to normal brain tissue.
- Internal radiation therapy or chemotherapy can be placed on or near the tumor.
A biopsy can also be done during a craniotomy.
The blood supply to tumors can be identified by angiography
. The blood supply can then be shut off by placing plugs in the blood vessels supplying the brain. The tumor tissue may then die from lack of blood flow. This procedure is rarely done.
Other Surgical Options
Some surgical procedures may be done to relieve symptoms caused by a brain tumor or to help deliver other treatment options.
Tumors can gradually or rapidly block the flow of cerebrospinal fluid (CSF) in the skull. This can increase pressure on the brain. If the pressure is affecting brain function, a procedure known as a cerebral shunt may be done. The shunt helps manage the level and pressure of cerebrospinal fluid (CSF) that surrounds the brain and spinal cord. There are different types of shunts, which are named for the way they are routed through the body. For example, a ventriculoperitoneal (VP) shunt drains from the ventricle of the brain to the abdomen, where excess cerebrospinal fluid (CSF) is absorbed back into the body.
A shunt is created by making a small hole in the skull. A catheter is inserted into one of the fluid-filled spaces inside the brain, called a ventricle. The other end of the tube is passed under the skin from the head to the trunk, where it drains fluid into the heart or abdomen. A one-way valve in the tube prevents back flow into the brain. Some types of cancer cells can travel through the CSF to other parts of the body. Your doctor will talk about your risk before choosing a procedure.
Ventricular Access Catheter
There is a barrier around the brain that blocks certain medications, like chemotherapy drugs, from passing to the brain. A ventricular access catheter allows the medication to be passed directly to the brain and surrounding fluid to treat the tumor.
A small hole is made in the skull. A tube is inserted into the fluid-filled ventricle. The other end of the tube contains a reservoir, which remains under the scalp. Chemotherapy is given by a small needle into the reservoir.
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