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Craniotomy for Epilepsy

Procedure description

A craniotomy for epilepsy is performed in an attempt to remove the portion of the brain which is "irritating" to the brain and causing seizures.  This surgery my involve removing a portion of the brain, such as the temporal lobe, or it may involve dividing a route by which seizures migrate through the brain, as in section of the corpus callosum (connects both hemispheres of the brain).  The surgeon and epileptologist (neurologist specializing in the study of epilepsy) will take into account vital portions of the brain in the region of the intended removal, and may perform electrical mapping studies of the area by the use of electrode grids placed during a previous surgery, or the surgery may be done with the patient awake.  Some areas of the brain are relatively silent, while others are eloquent (injury to these areas would result in noticeable changes in day to day performance).  For example, the left temporal lobe is "dominant" in 96% of right handed people.  This means that in these patients, removal of the temporal lobe of the brain would result in a dysphasia (difficulty with speech and comprehension).  On the other hand, removal of the right temporal lobe in these patients may not result in any noticeable change at all.   In addition, regarding the left temporal lobe, in many patients, the first 5 cm of the lobe are relatively silent, and removal of this portion may not result in a noticeable deficit.  Of course, there is no line in the brain telling the surgeon where to cut, and the amount of brain which can be safely removed is determined by the functional monitoring.  This can be accomplished in two ways.  Electrical grids may be placed over the brain, and while the patient is awake in a monitoring unit postoperatively, function of the brain can be mapped to location by stimulating the grid.  Or, alternatively, the surgery may be done with the patient awake, stimulating portions of the brain intraoperatively .
 
The patient will be taken to the operating room and put to sleep under general anesthesia.  The head will be partially shaved, to expose the area of the operation.  The head is then placed in three fixation points (Mayfield head pins).  This provides the ability to keep the head perfectly still during the procedure.  The surgeon may register a navigational device which allows the use of "real time" intraoperative navigation.  The area where surgery is to be performed is then "prepped and draped" using an antibiotic solution.  Next, the surgeon will make an incision, and reflect the scalp over the area of the tumor.  An air powered drill is then used to make a hole in the skull, and a "footplate attachment" on the drill, or another similar device, is used to cut open a flap of skull.  The dura mater (tough covering of the brain) is then opened.  An operating microscope is generally brought into the field, and the surgeon will approach the intended area  within the brain.  Intraoperative mapping while awakening the patient may or may not be performed.  If a grid of electrodes had already been placed several days earlier (during another surgical procedure), then the area of intended brain removal is known.   The portion of the brain responsible for irritating the brain and causing seizures will be removed, or a tract or bundle of fibers necessary for spreading a seizure to the rest of the brain will be divided.    Any visible bleeding points will be cauterized.  Often, hemostasis promoting material is gently laid over the surfaces of the brain, and closure is begun.  The surgeon will  close the dura, and approximate the skull using titanium plates or another device to hold the bone together.  Next the scalp will be closed in layers, and a pressure monitor may be placed into the brain to allow the postoperative monitoring of pressure within the brain. 

 

Procedure Risks

Risks for craniotomy for epilepsy can be broken down into two categories, 1) those related to the operative site, and 2) those related to the risks of anesthesia. 

Risks related to the operative site: 

Surgical Exposure: The patient is placed in a position so as to allow the surgeon good access to the tumor. Insicions in the scalp may range from small to quite large.  There is risk of non healing of the scalp or bone post operatively.  Although very uncommon, there can be injury to or tearing of the scalp from the pins on the Mayfield clamp.  The plates used to close the skull could erode through the skin after the wound has heeled.

Brain injury: The surgery involves opening of the  surface of the brain, and may involve going into the deep structures of the brain.  With surgery on the temporal lobe, there is risk of difficulty with understanding and speaking or expressing oneself.  There may be cognitive or personality changes. There may also be injury to vision, and a portion of the visual field may be lost. If the surgery is located near the deep structures of the brain, there can be injury to strength of the upper or lower extremities. If the surgery is located near the sagittal sinus (a large vein draining both hemispheres of the brain), as in the procedure for division of the corpus callosum, there is a risk to this vein of either injury or thrombosis (clotting off).  If the vein is injured, large amounts of blood could be lost during the surgery.  If the vein clots off, this could result in brain swelling and death. There is the possibility that there may be injury to the brain.  If so, this could result in weakness, seizures, stroke, paralysis, coma or death. There may be residual fluid or blood, requiring additional surgery in the future.   

General Risks: These include such general difficulties as bleeding, infection, stroke, paralysis, coma and death. Incisions on the scalp generally heal well, but could become tender, numb, or may heal in an unpleasant manner. There is also the possibility that the surgery may not relieve the symptoms for which the procedure was performed, and seizures may persist. In addition, although every attempt is made to protect all areas of the body from pressure on nerves, skin and bones, injuries to these areas can occur, particularly with prolonged cases.

Risks of Anesthesia: Blood clots in the legs, heart attacks, reaction to the anesthetic, reaction to blood transfusion, if  given

Post-operative care:

There is surprisingly relatively little pain associated with craniotomies.  Your surgeon will prescribe pain medications for any pain associated with the incision. 

  1. Immediately upon discharge, contact our office and set up an appointment for staple removal if one has not already been made.
  2. Take it easy until seen by the physician.  This does not mean bed rest, but athletic activities during this period are definitely not recommended.  Please give your incision a chance to heal.  Avoid any type of activity which might risk a blow to the head.
  3. You may resume activity as your body permits, but avoid extremes.  For example, walking is fine, but avoid any strenuous running.  USE GOOD JUDGMENT  AND COMMON SENSE.  If you have a question, ask your doctor.
  4. No driving until cleared with your surgeon.  A driving test may be required, at the discretion of your surgeon.  Even though you may feel fine, your peripheral vision and reflexes may have been affected, and we want you to be safe on the road for yourself as well as for others.
  5. You may shower after you go home unless otherwise instructed.  Cover the incision with plastic wrap before the shower and remove it afterward.  Change dressing immediately.    You may shower without covering the incision one week after the staples are out.  Follow instructions concerning care of tapestrips, stitches or staples.  Your surgeon or  nurse clinician will explain the techniques used in the closure of your incision.
  6. Sexual activities are permitted.
  7. If you notice swelling, redness or opening of the incision, or if there is any clear fluid draining from it, please contact your surgeon immediately!  If you develop a fever, stiff neck or chills, contact the office immediately.  Take your temperature at 4:00 PM daily until the clips are removed.  Call if greater than 101 degrees Fahrenheit.
  8. If you have a seizure, notify our office or come to the emergency room.
  9. If you develop any new weakness, notify our office.
  10. If you have any paralysis or weakness, post-operative care will need to be tailored to this.  If a brace for an arm of a leg has been prescribed, use it as recommended by your surgeon.
  11. If you have any questions, call our office, and for after hours emergencies, call the medical society.
  12. Take your medications prescribed on discharge, as directed.  Your physicians will direct you as to which seizure medications to take. 
  13. Do not take any medications which will "thin the blood" such as coumadin or aspirin, or other non-steroidal antiinflammatory medications, unless otherwise advised by your physicians.
  14. Make sure to follow up with any other physicians involved in your care.  These may include your family physician and neurologist.

 

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