Craniotomy

Overview

A craniotomy involves removing a portion of the skull for brain surgery. A craniotomy may be done to take a sample of brain tissue or to treat conditions or injuries that affect the brain.

The procedure is used to treat brain tumors, bleeding in the brain, blood clots or seizures. It also may be done to treat a bulging blood vessel in the brain, known as a brain aneurysm. Or a craniotomy can treat blood vessels that formed irregularly, known as a vascular malformation. If an injury or stroke has caused brain swelling, a craniotomy can relieve the pressure on the brain.

There are several types of craniotomies. The type of craniotomy that is used depends on which area of the skull is removed for treatment. The types include:

Bifrontal craniotomy. A surgeon removes part of the front of the skull behind the hairline. This may be done to treat a brain aneurysm.
Supraorbital craniotomy. This surgery involves removing an area of the skull at the front of the head — sometimes at the eyebrow. The surgery can be done to treat brain tumors or aneurysms.
Eyebrow craniotomy. In this type of craniotomy, a cut is made over the eyebrow and part of the bone is removed. This procedure may be done to treat brain tumors.
Pterional craniotomy. A surgeon removes part of the skull on the side of the head in front of and above the ear. Another name for this type of surgery is frontotemporal craniotomy.

Pterional craniotomy can be done to treat brain aneurysms, brain tumors, blood clots, epilepsy and arteriovenous malformations. Sometimes a pterional keyhole craniotomy is done, which removes a smaller area of the skull.
Middle fossa craniotomy. During this type of surgery, a cut is made in the area of the skull above the ear. Pterional, supraorbital and other types of approaches fall under this type of craniotomy.
Retrosigmoid keyhole craniotomy. A small hole is cut in the skull behind the ear. This type of surgery may be used to treat an aneurysm. It also may be used to treat a noncancerous tumor on the nerve leading from the inner ear to the brain. This type of tumor is known as an acoustic neuroma or a vestibular schwannoma.
Suboccipital craniotomy. A surgeon removes a piece of the base of the skull in the lower back of the head. This type of craniotomy is done to treat a condition where brain tissue extends into the spinal canal, known as a Chiari malformation. It also can treat brain tumors, aneurysms, cavernous malformations and arteriovenous malformations.
Far lateral approach. For this surgery, part of the skull behind the ear is removed. The surgeon uses a thin, flexible tube known as an endoscope to remove a tumor.

Why it's done

A craniotomy may be done to get a sample of brain tissue for testing. Or a craniotomy may be done to treat a condition that affects the brain.

Craniotomies are the most common surgeries used to remove brain tumors. A brain tumor can put pressure on the skull or cause seizures or other symptoms. Removing a piece of the skull during a craniotomy gives the surgeon access to the brain to remove the tumor. Sometimes a craniotomy is needed when cancer that begins in another part of the body spreads to the brain.

A craniotomy also may be done if there is bleeding in the brain, known as a hemorrhage, or if blood clots in the brain need to be removed. A bulging blood vessel, known as a brain aneurysm, can be repaired during a craniotomy.

A craniotomy also can be done to treat an irregular blood vessel formation, known as a vascular malformation. If an injury or stroke has caused brain swelling, a craniotomy can relieve the pressure on the brain.

Risks

Craniotomy risks vary depending on the type of surgery. In general, risks may include:

Changes in the shape of the skull.
Numbness.
Change in smell or vision.
Pain while chewing.
Infection.
Bleeding or blood clots.
Changes in blood pressure.
Seizures.
Weakness and trouble with balance or coordination.
Trouble with thinking skills, including memory loss.
Stroke.
Excess fluid in the brain or swelling.
A leak in the fluid that surrounds the brain and spinal cord, known as a cerebrospinal fluid leak.

Rarely, a craniotomy can lead to coma or death.

How you prepare

Your healthcare team lets you know what you need to do before a craniotomy. To prepare for a craniotomy, you may need several tests that might include:

Neuropsychological testing. This can test your thinking, known as cognitive function. The results serve as a baseline to use to compare to later tests and can help with planning for rehabilitation after surgery.
Brain imaging such as MRI or CT scans. Imaging helps your healthcare team plan the surgery. For example, if your surgery is to remove a brain tumor, brain scans help the neurosurgeon see the location and size of the tumor. You may have a contrast material injected through an IV into a vein in your arm. The contrast material helps the tumor show up more clearly in the scans.

A type of MRI called a functional MRI (fMRI) can help your surgeon map the areas of the brain. An fMRI shows small changes in blood flow when you use certain areas of your brain. This can help the surgeon avoid areas of the brain that control important functions such as language.

Food and medicines

Your healthcare team gives you instructions about whether you need to stop taking certain medicines before surgery. You also might be prescribed a medicine to take before surgery. The instructions also tell you what you can eat or drink before a craniotomy.

Medicine changes. Before surgery, tell your healthcare team about any medicines you take or any allergies you have to medicines. Include medicines that need a prescription and medicines you buy without a prescription. Include vitamins, herbal products and other supplements.

If you take the diabetes medicine metformin and you get IV contrast during an imaging exam, you may have side effects. To help avoid this, your healthcare professional may tell you not to take some medicines for 48 hours after you get the contrast. The decision depends on your lab test results.

Blood-thinning medicines affect clotting and bleeding. Before your procedure, both the healthcare professional doing your procedure and the healthcare professional who manages these medicines need to decide if your medicines need to change. After your procedure is scheduled, talk with your healthcare team about your medicines as soon as you can. If you are not sure whether you take blood-thinning medicine, contact your healthcare team or pharmacist.

You may need to take an antibiotic or another medicine before your surgery. Ask your healthcare team about whether you need to take any medicines before the procedure.
What you can eat and drink before surgery. Follow the instructions from your healthcare team about when to stop eating and drinking before surgery.

What you can expect

Your head might be shaved before a craniotomy. Most of the time, you lie on your back for surgery. But you might be positioned on your stomach or side or put in a sitting position. Your head may be placed in a frame. However, children under age 3 don't have a head frame during a craniotomy.

If you have a brain tumor called a glioblastoma, you may be given a fluorescent contrast material. The material makes the tumor glow under fluorescent light. This light helps your surgeon can separate it from other brain tissue.

You may be put into a sleeplike state for the surgery. This is known as general anesthesia. Or you may be awake for part of the surgery if your surgeon needs to check brain functions such as movement and speech during the operation. This is to ensure that the surgery doesn't affect important brain functions. If the area of the brain being operated on is near the language areas of the brain, for example, you're asked to name objects during the surgery.

With awake surgery, you may be in a sleeplike state for part of the surgery and then awake for part of the surgery. Before surgery, a numbing medicine is applied to the area of the brain to be operated on. You're also given a medicine to help you feel relaxed.

During the procedure

During a craniotomy, a neurosurgeon cuts into the scalp over the skull and the skin is folded back. The surgeon uses a surgical drill to cut into the skull. Part of the skull is temporarily removed to reveal the area of the brain that needs treatment. Then the tough covering over the brain, known as the dura mater, is cut. Sometimes the surgeon needs to make a cut into the brain.

If you're having a craniotomy to remove a sample of tissue for testing, known as a biopsy, the sample is taken. If you're being treated for a brain tumor or a vascular malformation, your surgeon works on removing it. If you have an aneurysm, your neurosurgeon may use clips to stop the blood flow to the aneurysm. If you have bleeding in the brain or blood clots, the surgical team removes the blood during the procedure.

Techniques that may be used during surgery might include:

Computer assistance and intraoperative imaging. Surgeons often use computers and take brain images such as MRI scans during surgery. This is known as intraoperative imaging. If your neurosurgeon is removing a brain tumor, intraoperative imaging allows the surgeon to see where the tumor is and its size. If you have a brain aneurysm, intraoperative imaging helps the surgeon confirm that it was repaired.
Awake brain surgery. During surgery, you may be asked questions to help your surgeon understand which areas of the brain are related to language or other functions. For example, you may be asked to name objects on slides during the surgery.
Intraoperative cortical stimulation. The surgeon stimulates parts of the brain with electricity during surgery to reveal which areas control important functions. This allows the surgeon to take only the tumor and leave behind brain tissue that is important for functions such as speech. This technique also is known as cortical mapping.

Stimulation may be done along with brain imaging known as a functional MRI (fMRI). Other tests during surgery can help map the brain for important functions.

If you're being treated for a brain tumor, the goal of surgery is to completely remove the tumor. If the tumor is close to an area of the brain that controls speech, movement or breathing, your surgeon may not be able to remove the tumor completely. If some of the tumor is left behind, surgery may be followed with radiation therapy or chemotherapy. Sometimes surgeons place treatments such as chemotherapy or targeted radiation in the brain during the craniotomy.

After your surgeon is finished operating on the brain, the dura mater is stitched back together and sealed. Then the skull bone that was removed is put back. Metal screws, plates, wires or stitches keep it in place. Metal materials usually are made of titanium so that you can have MRI scans in the future. The surgeon uses stitches or staples to close up the skin.

After the procedure

After a craniotomy, you may have a small tube coming out of your skull. This is a drain that allows extra fluid to flow out of your skull. You also may have other tubes to allow blood to drain. The drains usually are removed after about three days.

About 1 to 3 days after surgery, you might need an imaging test such as an MRI scan or a CT scan. This test can show your surgeon if a tumor was removed completely.

You may need to recover in the hospital for about 4 to 6 days after a craniotomy. The length of your hospital stay may vary depending on the reason for your surgery, your health and whether you need other treatments.

It can take several weeks to fully heal after a craniotomy.

If you take blood-thinning medicines and these medicines were stopped before your procedure, talk to your healthcare team about when to restart these medicines. Because some common pain relievers affect blood thinning, talk with your healthcare team about what you can take for pain after surgery.

Results

After a craniotomy, you'll need follow-up appointments with your healthcare team. Tell your healthcare team right away if you're having any symptoms after surgery.

You may need blood tests or imaging tests such as MRI scans or CT scans. These tests can show if a tumor has come back or if an aneurysm or other condition remains. Tests also determine if there are any long-term changes in the brain.

During surgery, a sample of the tumor may have gone to a lab for testing. Testing can determine the type of tumor and what follow-up treatment may be needed.

Some people need radiation or chemotherapy after a craniotomy to treat a brain tumor. Some people need a second surgery to remove the rest of the tumor.