Craniotomy

Definition

A craniotomy is a procedure to remove a lesion in the brain through an opening in the skull (cranium).

Purpose

A craniotomy is a type of brain surgery. It is the most commonly performed surgery for brain tumor removal . It also may be done to remove a blood clot (hematoma), to control hemorrhage from a weak, leaking blood vessel (cerebral aneurysm), to repair arteriovenous malformations (abnormal connections of blood vessels), to drain a brain abscess, to relieve pressure inside the skull, to perform a biopsy, or to inspect the brain.

Demographics

Because craniotomy is a procedure that is utilized for several conditions and diseases, statistical information for the procedure itself is not available. However, because craniotomy is most commonly performed to remove a brain tumor, statistics concerning this condition are given. Approximately 90% of primary brain cancers occur in adults, more commonly in males between 55 and 65 years of age. Tumors in children peak between the ages of three and 12. Brain tumors are presently the most common cancer in children (four out of 100,000).

Description

There are two methods commonly utilized by surgeons to open the skull. Either an incision is made at the nape of the neck around the bone at the back (occipital bone) or a curving incision is made in front of the ear that arches above the eye. The incision penetrates as far as the thin membrane covering the skull bone. During skin incision the surgeon must seal off many small blood vessels because the scalp has a rich blood supply.

The scalp tissue is then folded back to expose the bone. Using a high-speed drill, the surgeon drills a pattern of holes through the cranium (skull) and uses a fine wire saw to connect the holes until a segment of bone (bone flap) can be removed. This gives the surgeon access to the inside of the skill and allows him to proceed with surgery inside the brain. After removal of the internal brain lesion or other procedure is completed, the bone is replaced and secured into position with soft wire. Membranes, muscle, and skin are sutured into position. If the lesion is an aneurysm, the affected artery is sealed at the leak. If there is a tumor, as much of it as possible is resected (removed). For arteriovenous malformations, the abnormality is clipped and the repair redirects the blood flow to normal vessels.

Diagnosis/Preparation

Since the lesion is in the brain, the surgeon uses imaging studies to definitively identify it. Neuroimaging is usually accomplished by the following:

• CT (computed tomography, uses x-rays and injection of an intravenous dye to visualize the lesion)
• MRI ( magnetic resonance imaging , uses magnetic fields and radio waves to visualize a lesion)
  

  In a craniotomy, the skin over a part of the skull is cut and pulled back (A). Small holes are drilled into the skull (B), and a special saw is used to cut the bone between the holes (C). The bone is removed, and a tumor or other defect is visualized and repaired (D). The bone is replaced (E), and the skin closed (F). (

  Illustration by GGS Inc.

  )
• arteriogram (an x-ray of blood vessels injected with a dye to visualize a tumor or cerebral aneurysm)

Before surgery the patient may be given medication to ease anxiety and to decrease the risk of seizures, swelling, and infection after surgery. Blood thinners (Coumadin, heparin, aspirin ) and nonsteroidal anti-inflammatory drugs (ibuprofen, Motrin, Advil, aspirin, Naprosyn, Daypro) have been correlated with an increase in blood clot formation after surgery. These medications must be discontinued at least seven days before the surgery to reverse any blood thinning effects. Additionally, the surgeon will order routine or special laboratory tests as needed. The patient should not eat or drink after midnight the day of surgery. The patient's scalp is shaved in the operating room just before the surgery begins.

Aftercare

Craniotomy is a major surgical procedure performed under general anesthesia. Immediately after surgery, the pa tient's pupil reactions are tested, mental status is assessed after anesthesia, and movement of the limbs (arms/legs) is evaluated. Shortly after surgery, breathing exercises are started to clear the lungs. Typically, after surgery patients are given medications to control pain, swelling, and seizures. Codeine may be prescribed to relive headache. Special leg stockings are used to prevent blood clot formation after surgery. Patients can usually get out of bed in about a day after surgery and usually are hospitalized for five to 14 days after surgery. The bandages on the skull are be removed and replaced regularly. The sutures closing the scalp are removed by the surgeon, but the soft wires used to reattach the portion of the skull that was removed are permanent and require no further attention. Patients should keep the scalp dry until the sutures are removed. If required (depending on area of brain involved), occupational therapists and physical therapist assess the patient's status postoperatively and help the patient improve strength, daily living skills and capabilities, and speech. Full recovery may take up to two months, since it is common for patients to feel fatigued for up to eight weeks after surgery.

Risks

The surgeon will discuss potential risks associated with the procedure. Neurosurgical procedures may result in bleeding, blood clots, retention of fluid causing swelling (edema), or unintended injury to normal nerve tissues. Some patients may develop infections. Damage to normal brain tissue may cause damage to an area and subsequent loss of brain function. Loss of function in specific areas can cause memory impairment. Some other examples of potential damage that may result from this procedure include deafness, double vision, numbness, paralysis, blindness, or loss of the sense of smell.

Normal results

Normal results depend on the cause for surgery and the patient's overall health status and age. If the operation was successful and uncomplicated recovery is quick, since there is a rich blood supply to the area. Recovery could take up to eight weeks, but patients are usually fully functioning in less time.

Morbidity and mortality rates

There is no information about the rates of diseases and death specifically related to craniotomy. The operation is performed as a neurosurgical intervention for several different diseases and conditions.

Alternatives

There are no alternative treatments if a neurosurgeon deems this procedure as necessary.

Resources

BOOKS

Connolly, E. Sanders, ed. Fundamentals of Operative Techniques in Neurosurgery. New York: Thieme Medical Publishers, 2002.

Greenberg, Mark S. Handbook of Neurosurgery. 5th ed. New York: Thieme Medical Publishers, 2000.

Miller, R. Anesthesia. 5th ed. Philadelphia, PA: Churchill Livingstone, 2000.

PERIODICALS

Gebel, J. M., and W. J. Powers. "Emergency Craniotomy for Intracerebral Hemorrhage: When Doesn't It Help and Does It Ever Help?" Neurology 58 (May 14, 2002): 1325-1326.

Mamminen, P., and T. K. Tan. "Postoperative Nausea and Vomiting After Craniotomy for Tumor Surgery: A Comparison Between Awake Craniotomy and General Anesthesia." Journal of Clinical Anesthesia 14 (June 2002): 279-283.

Osguthorpe, J. D., and S. Patel, eds. "Skull Base Tumor Surgery." Otolaryngologic Clinics of North America 34 (December 2001).

Rabinstein, A. A., J. L. Atkinson, and E. F. M. Wijdicks. "Emergency Craniotomy in Patients Worsening Due to Expanded Cerebral Hematoma: To What Purpose?" Neurology 58 (May 14, 2002): 1367-1372.

ORGANIZATIONS

American Association of Neurological Surgeons. 5550 Meadowbrook Drive, Rolling Meadows, IL 60008. (888) 566-AANS (2267). Fax: (847) 378-0600. E-mail: info@aans. org. http://www.neurosurgery.org/aans/index.asp .

Laith Farid Gulli, M.D., M.S.

Nicole Mallory, M.S., PA-C

Robert Ramirez, B.S.

WHO PERFORMS THE PROCEDURE AND WHERE IS IT PERFORMED?

The procedure is performed in a hospital with a neurosurgery department and an intensive care unit . The procedure is performed by a board certified neurosurgeon, who has completed two years of general surgery training and five years of neurosurgical training.

QUESTIONS TO ASK THE DOCTOR

• How is this procedure done?
• What kinds of tests and preparation are necessary before surgery?
• What risks are associated with the procedure?
• How often is normal brain tissue damaged during this type of surgery?
• What is the expected outcome of the surgery?
• What complications may result from this type of surgery?
• What is the recovery time?
• How many of these procedures have you done in the past year?