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Gamma Knife : Pain : Trigeminal Neuralgia

Procedure description

Gamma Knife is a procedure which has been in use since 1968, when Dr. Lars Leksell, a Swedish neurosurgeon, introduced the device in Stockholm, Sweden.  The device is known for its  low complication rate  because of its accuracy and precision.  The device focuses 201 gamma rays, emitted from Cobalt, into a focal point at the center of the sphere.  While the center (where the target is) gets an enormous amount of delivered radiation, any other portion of the sphere (brain) gets a minimal dose.  For the treatment of trigeminal neuralgia, the treatment involves placing a single shot of radiation at the point where the trigaminal nerve (nerve supplying sensation to the face) leaves the brainstem.

The Gamma Knife procedure requires a team approach, with a neurosurgeon, radiation oncologist, physicist, radiologist, nurse, and radiation therapist being involved intimately with the care.  The procedure is relatively painless, with the only mild discomfort being during the initial frame placement.  The remainder of the day of treatment is just "boring."  There is no shaving of the head required, and the patient can resume most normal activities the next day.  There have been over 160,000 treatments of Gamma Knife performed world wide.

On the day of Gamma Knife treatment, the patient is taken to the Gamma Knife area, and a Leksell frame is placed on the patient's head.  Four pins are affixed to the scalp and skull.  The patient is sedated, and local numbing medicine is used.  Often patients will not even remember this part of the procedure.  Next, the patient is taken to the MRI or CT scanner, where detailed images of the brain are taken.  The images are transported by computer to the Gamma Knife planning station, where the neurosurgeon, radiation oncologist, and physicist will outline the area to be treated, and formulate a dose plan.  All three will agree upon the final treatment plan before treating.  Next, the patient will be taken to the Gamma Knife room, and treatment will commence.  The treatment is painless.  For trigeminal neuralgia, one shot of radiation is used.    After completing the treatment, the frame will be removed, and the patient discharged home. 

For the treatment of trigeminal neuralgia, Gamma Knife has an 80 - 85% chance of a achieving a good to excellent result at two years after treatment.  A excellent result would mean the patient is pain free while off of any medications (such as pain medications or carbamazepine (Tegretol)), while a good result would be significantly reduced pain, while still on medication.  Improvement in pain may take from several days up to 3 months to occur.

 

Procedure Risks

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

Risks related to the operative site

Tumor site:  The patient has a frame placed on the head.  There are potential risks associated with this, although they are very small.  There may be bleeding or infection associated with the pin placement, and a pin could potentially pierce the skull causing damage to the underlying brain, although these risks are very small. 

Brain injury:  Risks mainly relate to the location of the treatment, and radiation to the surrounding brain tissue.  The target site is the trigeminal nerve (supplies sensation to the face, and is the cause of the facial pain) at the point where it leaves the brainstem.  The goal of the treatment is to relieve pain while leaving sensation intact.  There is a risk that numbness may occur.  There is a very small chance that the patient may experience anesthesia dolorosa, with resulting severe burning pain.    There could be concomitant seizures, paralysis, stroke, coma and death.  The likelihood of these is very small.     In addition, there is the theoretical risk of the radiation exposure causing another tumor within the brain or elsewhere in the body.  Even if the treatment is successful, pain may recur in the future.

General Risks

General Risks:  As a result of the procedure, patients may potentially experience cardiac or lung difficulties, although the likelihood is extremely low.

Risks of Anesthesia: Blood clots in the legs, heart attacks, reaction to the anesthetic (local anesthetic and IV sedation used during frame placement).

 

Post-operative care:

There is relatively little pain associated with Gamma Knife.  Your surgeon will prescribe pain medications for any pain associated with the pin sites, although this will most likely be minimal. 

  1. Follow up appointment will be scheduled with your neurosurgeon and radiation oncologist.
  2. Take it easy the remainder of the day.  You may be tired from a strenuous day.
  3. You may resume activity the following day.  You may take the day off from work, but could most likely return to work, if you have been working, two days after the treatment.
  4. Keep the pinsites clean, and covered with an antibiotic ointment until healed,  This will take several days.
  5. You may shower after you go home.  Keep the pinsites dry and clean.  
  6. Sexual activities are permitted.
  7. If you notice swelling, redness or opening of the pinsites, 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 questions, call our office, and for after hours emergencies, call the medical society.
  11. Take your medications prescribed on discharge from the Gamma Knife department, as directed.  Your Gamma Knife team will determine whether steroids or other medications are needed.
  12. Make sure to follow up with any other physicians involved in your care.  These may include your family physician, neurologist, radiation oncologist and oncologist.

 

 

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