craniotomy (redirected from craniotomies)

Craniotomy 

Definition

Surgical removal of part of the skull to expose the brain.

Purpose

A craniotomy is the most commonly performed surgery for brain tumor removal. It may also be done to remove a blood clot and control hemorrhage, inspect the brain, perform a biopsy, or relieve pressure inside the skull.

Precautions

Before the operation, the patient will have undergone diagnostic procedures such as computed tomography scans (CT) or magnetic resonance imaging (MRI) scans to determine the underlying problem that required the craniotomy and to get a better look at the brain's structure. Cerebral angiography may be used to study the blood supply to the tumor, aneurysm, or other brain lesion.

Description

There are two basic ways to open the skull:

• a curving incision from behind the hairline, in front of the ear, arching above the eye
• 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.

Preparation

Before the surgery, patients are usually 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 may be given before and during surgery if the patient has a tendency to retain water. A catheter is inserted before the patient goes to the operating room.

The scalp is shaved in the operating room right before surgery; this is done so that any small nicks in the skin will not 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 the headache that may occur as a result of stretching or irritation of the nerves of the scalp that happens during the craniotomy. 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.

A craniotomy is the most commonly performed surgery for brain tumor removal. There are two basic ways to open the skull: a curving incision from behind the hairline in front of the ear and at the nape of the neck (figure A). To reach the brain, the surgeon uses a hand drill to make holes in the skull, pushing a soft metal guide under the bone. The bone is sawed through until the bone flap can be removed to expose the brain (figure B).

(Illustration by Electronic Illustrators Group.)

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 some 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.

Normal results

While every patient's experience is different depending on the reason for the surgery, age, and overall health, if the surgery has been successful, recovery is usually rapid because of the good supply of blood to the area.

Abnormal results

Possible complications after craniotomy include:

• swelling of the brain
• excessive intracranial pressure
• infection
• seizures

Key terms

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.

Resources

Books

Younson, Robert M., et al., editors. The Surgery Book: An Illustrated Guide to 73 of the Most Common Operations. New York: St. Martin's Press, 1993.

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craniotomy /cra·ni·ot·o·my/ (kra″ne-ot´ah-me) any operation on the cranium.

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cra·ni·ot·o·my (krn-t-m)

n.

Incision into the skull.

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craniotomy

[krā′nē·ot′əmē]

Etymology: Gk, kranion, cranium, temnein, to cut

any surgical opening into the skull, performed to relieve intracranial pressure, to control bleeding, or to remove a tumor. X-ray films of the skull are taken before surgery, and a computed tomographic (CT) scan or an electroencephalogram is done to establish the diagnosis. The operative site is shaved and cleansed. Parenteral corticosteroids are given to reduce cerebral edema. Mannitol is administered to decrease intracranial pressure. A semicircular skin incision is made just above the hairline, a series of burr holes is made and connected with a cut, and the flap of bone is removed. The meninges are incised, and the brain is exposed. The flap may be replaced after surgery or left off temporarily to prevent the buildup of pressure from cerebral edema. After surgery, if the cerebral area is involved, the head of the patient's bed is elevated to 45 degrees to reduce the risk of hemorrhage and edema; if the cerebellum or brainstem is affected, the patient may be kept flat. The dressing is checked frequently for blood and yellowish drainage of cerebrospinal fluid. Any moist areas are reinforced with sterile materials to prevent infection. Frequent assessment of neurologic signs, respirations, and vital signs, including level of consciousness, speech, and strength, is essential.

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craniotomy (krā·nē·ˑ·t·mē),

n opening of the skull during surgery.

Craniotomy.

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craniotomy,

n a surgical opening into the skull, performed to relieve intracranial pressure, to control bleeding, or to remove a tumor.

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craniotomy

1. any operation on the cranium.

2. puncture of the skull and removal of its contents to decrease the size of the head of a dead fetus and facilitate delivery.

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craniotomy

Neurosurgery An operation in which an opening is made in the skull, a portion of bone is removed to gain access to the brain, and the bone repositioned