Type of Surgery


Doctor Certified

Last updated: 11/24/2009


The candidate for hemispherectomy has epilepsy untreatable by medications, with seizure focal points that are numerous or ill defined, but localized to one hemisphere. Such patients may have one of a wide variety of disorders that have caused seizures,...


  • neonatal brain injury
  • Rasmussen disease
  • Hemimegalencephaly
  • Sturge-Weber syndrome

The candidate for any type of epilepsy surgery will have had a wide range of tests prior to surgery. These include electroencephalography (EEG), in which electrodes are placed on the scalp, on the brain surface, or within the brain to record electrical activity. EEG is used to attempt to locate the focal point(s) of the seizure activity.

Several neuroimaging procedures are used to obtain images of the brain. These may reveal structural abnormalities that the neurosurgeon must be aware of. These procedures will include magnetic resonance imaging (MRI), x rays, computed tomography (CT) scans, or positron emission tomography (PET) imaging.

Neuropsychological tests may be done to provide a baseline against which the results of the surgery are measured. A Wada test may also be performed, in which a drug is injected into the artery leading to one half of the brain, putting it to sleep. This allows the neurologist to determine where in the brain language and other functions are localized, and may also be useful for predicting the result of the surgery.



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Other Information

Hemispherectomy is a surgical procedure where one cerebral hemisphere (half of the brain) is removed or disabled. This procedure is used to treat a variety of seizure disorders where the source of the epilepsy is localized to a broad area of a single hemisphere of the brain. It is solely reserved for extreme cases in which the seizures have not responded to medications and other less invasive surgeries.

From http://en.wikipedia.org/wiki/Hemispherectomy

Other Information

Surgery for removal is generally advised for patients with limited cancer elsewhere in the body and a single brain metastasis.


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