Skip to main content
Select Source:

Craniotomy

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)
  • 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?

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Craniotomy." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

"Craniotomy." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. . Encyclopedia.com. (August 22, 2017). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/craniotomy-0

"Craniotomy." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. . Retrieved August 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/craniotomy-0

Craniotomy

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 3 and 12. Brain tumors are presently the most common cancer in children (4 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 the 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:

  • Computed tomography (CT ) uses x rays and injection of an intravenous dye to visualize the lesion.
  • Magnetic resonance imaging (MRI ) uses magnetic fields and radio waves to visualize a lesion.
  • An arteriogram is 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, 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 night before surgery the patient should not eat or drink after midnight. 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 patient'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 relieve 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 fourteen 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 patients 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.

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. 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.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Craniotomy." Gale Encyclopedia of Neurological Disorders. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

"Craniotomy." Gale Encyclopedia of Neurological Disorders. . Encyclopedia.com. (August 22, 2017). http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/craniotomy

"Craniotomy." Gale Encyclopedia of Neurological Disorders. . Retrieved August 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/craniotomy

Craniotomy

Craniotomy

Definition

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.

Abnormal results

Possible complications after craniotomy include:

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

See Also Brain and central nervous system tumors; Computed tomography; Magnetic resonance imaging

Resources

ORGANIZATIONS

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

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.

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.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Craniotomy." Gale Encyclopedia of Cancer. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

"Craniotomy." Gale Encyclopedia of Cancer. . Encyclopedia.com. (August 22, 2017). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/craniotomy-2

"Craniotomy." Gale Encyclopedia of Cancer. . Retrieved August 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/craniotomy-2

Craniotomy

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.

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.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"Craniotomy." Gale Encyclopedia of Medicine, 3rd ed.. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

"Craniotomy." Gale Encyclopedia of Medicine, 3rd ed.. . Encyclopedia.com. (August 22, 2017). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/craniotomy-1

"Craniotomy." Gale Encyclopedia of Medicine, 3rd ed.. . Retrieved August 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/craniotomy-1

craniotomy

craniotomy By derivation, this word covers any surgical opening into the skull, but it is now usually used only to describe the fashioning of a hinged flap of bone which allows the intracranial cavity to be reached. Opening the skull (trepanning) in the belief that this would let out evil spirits is one of the oldest operations in the history of surgery, as evidenced by the finding of man-made holes in skulls from very early periods. In these cases, pointed flints were probably used to bore out the hole, and some skulls show evidence of subsequent healing with new bone formation — indicating that people survived such procedures. Until the middle of the twentieth century, skull openings were still being made by some tribes in Kenya. Indications probably included mental illness, epilepsy, and perhaps severe, recurrent headache such as migraine. Recently an eccentric small group have advocated do-it-yourself drilling of the skull, supposedly to restore the alleged benefit of allowing a pressure outlet similar to that in infancy before the fontanelle closes. Technical instructions for this bizarre procedures have even appeared on the Internet.

By the seventeenth century the ‘trephine’ was an instrument in the surgical armamentarium for opening the skull. This was a circular crown saw with a central pin, which would cut out a disc or button of bone. It could vary in diameter from 1 cm or so up to 8 cm; sometimes more than one disc was cut to give adequate access. The larger discs would be put back in place, but smaller holes were left as permanent defects. A further development was to use a brace and bit to ream out (as bone dust) burr holes about 1 cm in diameter. Through trephine or burr holes, blood clots that were threatening life by compression of the brain could be let out, and lives were saved. Burr holes are still used today for releasing surface clots and also to allow probes to be passed into deeper parts of the brain. These may be for measuring the pressure in, or draining fluid from, the cerebral ventricles; for obtaining biopsy specimens of brain for microscopic examination; to record electrically from the deeper parts of the brain; or to produce controlled damage in parts of the brain for the correction of abnormal functioning (e.g. epilepsy or tremor). The limited access provided by a burr hole may be increased by nibbling away more bone with forceps, the resulting procedure being termed craniectomy. This leaves a permanent defect in the skull, with the brain covered only by the skin and other soft tissues.

The Gigli saw, invented by this Florentine obstetrician in 1894 to enlarge the pelvic outlet in obstructed labour, made the craniotomy flap possible. This saw is a serrated wire that can be passed under the bone from one burr hole to the next one and used to saw the bone in between. This is done along the lines joining each pair of burr holes, except the line which underlies the fold of skin and other tissues that has been turned back. This base section of unsawn bone is then cracked as the bone flap is raised. The bone flap remains hinged on the soft tissues attached to it, preserving its blood supply (see figure). This allows major intracranial surgery to be performed, such as the removal of a tumour, and when this has been completed the bone flap can be turned back into place and the soft tissues and skin also replaced. The use of a brace and bit and Gigli saw has recently been replaced by power driven drills and saws.

An unusual use of the term ‘craniotomy’ is in obstetrics. This is when a dead baby with an abnormally large head has caused obstructed labour, and the obstetrician has to reduce the size of the head by perforating it in order to allow delivery.

Bryan Jennett

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"craniotomy." The Oxford Companion to the Body. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

"craniotomy." The Oxford Companion to the Body. . Encyclopedia.com. (August 22, 2017). http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/craniotomy

"craniotomy." The Oxford Companion to the Body. . Retrieved August 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/craniotomy

craniotomy

craniotomy (kray-ni-ot-ŏmi) n.
1. surgical removal of a portion of the cranium, performed to expose the brain and meninges for inspection or biopsy or to relieve excessive intracranial pressure (as in a subdural haematoma).

2. surgical perforation of the skull of a dead fetus during difficult labour, so that delivery may continue.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"craniotomy." A Dictionary of Nursing. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

"craniotomy." A Dictionary of Nursing. . Encyclopedia.com. (August 22, 2017). http://www.encyclopedia.com/caregiving/dictionaries-thesauruses-pictures-and-press-releases/craniotomy

"craniotomy." A Dictionary of Nursing. . Retrieved August 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/caregiving/dictionaries-thesauruses-pictures-and-press-releases/craniotomy

craniotomy

cra·ni·ot·o·my / ˌkrānēˈätəmē/ • n. surgical opening into the skull. ∎  surgical perforation of the skull of a dead fetus to ease delivery.

Cite this article
Pick a style below, and copy the text for your bibliography.

  • MLA
  • Chicago
  • APA

"craniotomy." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. 22 Aug. 2017 <http://www.encyclopedia.com>.

"craniotomy." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. (August 22, 2017). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/craniotomy

"craniotomy." The Oxford Pocket Dictionary of Current English. . Retrieved August 22, 2017 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/craniotomy