A craniotomy is the surgical removal of part of the skull to expose the brain.
Purpose
A craniotomy is the most commonly performed surgery to remove a brain tumor. It may also be done to remove a blood clot and control hemorrhage, to inspect the brain, to perform a biopsy, or to relieve pressure inside the skull.
Precautions
The outcome of surgery will depend on the type and location of the tumor. Radiation therapy or chemotherapy are sometimes given before surgery to shrink the tumor.
Description
There are two basic ways to open the skull. A curving incision may be made from behind the hairline, in front of the ear, to arch above the eye, or at the nape of the neck around the occipital lobe. The surgeon marks with a felt tip pen a large square flap on the scalp that
covers the surgical area. Following this mark, the surgeon makes an incision into the skin as far as the thin membrane covering the skull bone. Because the scalp is well supplied with blood, the surgeon will have to seal many small arteries. The surgeon then folds back a skin flap to expose the bone.
Using a high speed hand drill or an automatic craniotome, the surgeon makes a circle of holes in the skull and pushes a soft metal guide under the bone from one hole to the next. A fine wire saw is then moved along the guide channel under the bone between adjacent holes. The surgeon saws through the bone until the bone flap can be removed to expose the brain.
After the surgery for the underlying cause is completed, the piece of skull is replaced and secured with pieces of fine, soft wire. Finally, the surgeon sutures the membrane, muscle, and skin of the scalp.
Recent advances in computer-assisted technology have enhanced this operation. Image-guided craniotomy uses information from magnetic resonance imagining scans (MRIs) or computed tomography (CT) scans to produce three-dimensional images of the brain for the surgeon before the operation is begun. This makes it possible for the surgeon to remove less skin and bone, to tell exactly where the tumor stops and the healthy brain begins, and to remove tumors that were previously too deep for surgery.
Preparation
Before the operation, the patient undergoes diagnostic procedures such as CT and MRI scans to determine the underlying problem that requires the craniotomy and to get a better look at the brain's structure. Cerebral angiography is a diagnostic procedure that may be used to study the blood supply to the tumor, aneurysm, or other brain lesion.
Before the surgery, patients are given drugs to ease anxiety, and other medications to reduce the risk of swelling, seizures, and infection after the operation. Fluids may be restricted, and a diuretic (water pill) may be given before and during surgery if the patient has a tendency to retain water. A urinary catheter is inserted before the patient goes to the operating room. The scalp is shaved in the operating room immediately before surgery; this is done so that any small nicks in the skin won't have a chance to become infected before the operation.
Aftercare
Oxygen, painkillers, and drugs to control swelling and seizures are given after the operation. Codeine may be given to relieve potential headaches caused by the stretching or irritation of the nerves of the scalp. Some type of drainage from the head may be in place, depending on the reason for the surgery.
Patients are usually out of bed within a day and out of the hospital within a week. Headache and pain from the scalp wound can be controlled with medications. Some patients will receive radiation therapy or chemotherapy after surgery.
The bandage on the skull should be changed regularly. Sutures closing the scalp will be removed, but soft wires used to reattach the skull are permanent and require no further attention. The patient should avoid getting the scalp wet until all the sutures have been removed. A clean cap or scarf can be worn until the hair grows back.
Risks
Accessing the area of the brain that needs repair may damage other brain tissue. Therefore, the procedure carries with it risk of brain damage that could leave the patient with some loss of brain function. The surgeon performing the operation can give the patient an assessment of the risk of his or her particular procedure based on the location of the tumor.
Normal results
While every patient's experience is different depending on the reason for the surgery, age, and overall health, recovery from a successful surgery is usually rapid because of the good supply of blood to the area.
American Cancer Society. 1599 Clifton Road NE, Atlanta, GA 30329. 800 (ACS)-2345). <http://www.cancer.org>.
Cancer Information Service, National Cancer Institute. Building 31, Room 10A19, 9000 Rockville Pike, Bethesda, MD 20892. (800) 4-CANCER. <http://www.nci.nih.gov/cancerinfo/index.html>.
Carol A. Turkington
Craniotome
—A type of surgical drill used to operate on the skull. It has a self-controlled system that stops the drill when the bone is penetrated.
Computed tomography (CT or CAT) scan
—Using x rays taken from many angles and computermodeling, CT scans help locate and size tumors and provide information on whether they can be surgically removed.
Magnetic resonance imaging (MRI)
—MRI uses magnets and radio waves to create detailed cross-sectional pictures of the interior of the body.
