Surgical removal of part of the skull to expose the brain.
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.
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.
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.
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.
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.
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.
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.
Possible complications after craniotomy include:
- swelling of the brain
- excessive intracranial pressure
— 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.
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.
Incision through the cranium to gain access to the brain during neurosurgical procedures. See: illustration
Preoperative: Procedures are explained and carried out, including antiseptic shampooing of the hair and scalp, hair removal, insertion of peripheral arterial and venous lines and indwelling urinary catheter, and application of pneumatic compression dressings. The patient is prepared for postoperative recovery in the neurological intensive care unit: the presence of a large bulky head dressing, possibly with drains; use of corticosteroids, antibiotics, and analgesics; use of monitoring equipment; postoperative positioning and exercise regimens; and other specific care measures.
Postoperative: Neurological status is assessed according to protocol (every 15 to 30 min for the first 12 hr, then every hour for the next 12 hr, then every 4 hr or more frequently, depending on the patient's stability). Patterns indicating deterioration are immediately reported. The airway is protected, with gentle suctioning used if necessary. Serum electrolyte values are evaluated daily because decreased sodium, chloride, or potassium can alter neurological status, necessitating a change in treatment. Measures are taken to prevent increased intracranial pressure (ICP), and if level of consciousness is decreased, the airway is protected by positioning the patient on the side. After a supratentorial craniotomy, the patient's head is elevated 15° to 30° to increase venous return and to aid ventilatory effort. After infratentorial craniotomy, the patient is kept flat but log-rolled every 2 hours to reduce complications caused by prolonged bedrest.
The patient is gently repositioned every 2 hr and is encouraged to breathe deeply and cough without straining. Fluid is restricted as prescribed (usually 1500 ml/24 hr) or according to protocol, to minimize cerebral edema and prevent increased ICP and seizures. An NPO (“nothing by mouth”) protocol is maintained for 24 to 48 hr to prevent aspiration and vomiting, which can increase ICP. Wound care is provided as appropriate; dressings are assessed for increased tightness (indicative of swelling); and closed drainage systems are checked for patency and for volume and characteristics of any drainage. Excessive bloody drainage, possibly indicating cerebral hemorrhage, and any clear or yellow drainage, indicating a cerebrospinal fluid leak, is reported to the surgeon. Patients who have had a transphenoidal procedure are restricted from nose-blowing and nasal drainage is checked for the presence of cerebrospinal fluid. The patient is observed for signs of wound infection.
Prescribed stool softeners are also administered to prevent increased ICP from straining during defecation. Before discharge, the patient and family are taught to perform wound care; to assess the incision regularly for redness, warmth, or tenderness; and to report such findings to the neurosurgeon. If self-conscious about appearance, the patient can wear a wig, hat, or scarf until the hair grows back and can apply a lanolin-based lotion to the scalp (but not to the incision line) to keep it supple and to decrease itching as the hair grows. Prescribed medications, such as anticonvulsants, may be continued after discharge.
2. After the death of a fetus, the breaking up of the fetal skull to facilitate delivery in difficult parturition.