If medications for epilepsy therapy do not control or eliminate epileptic seizure activity, neurosurgical procedures may help achieve better seizure control. G. Rees Cosgrove, M.D., F.R.C.S. and Andrew J. Cole M.D., F.R.C.P. state on the Massachusetts General Hospital website that about 20 to 30 percent of patients with epilepsy are refractory to medications. Several types of procedures can eliminate seizure activity; the location of the epileptic activity in the brain dictates the type of neurosurgery performed.
Temporal Lobectomy
According to the Seattle Children's Hospital website, temporal lobectomy is the most common type of neurosurgery for epilepsy. If a tumor or abnormal vascular malformation in the temporal lobe is causing the seizures, removal of the tumor can help. In some cases, the surgeons may remove the entire temporal lobe; this may end the seizures in up to 70 percent of patients, while 10 to 20 percent have better seizure control.
Resection of Epileptic Focus in Other Parts of the Brain
Neurosurgeons may sometimes remove the portion of the brain that is causing the epileptic seizures as long as the area is not involved in any necessary functions, according to the Seattle Children's Hospital website. These procedures are challenging, and neurosurgeons use mapping of the brain and other procedures to determine the exact area to surgically remove, according to Dr. Cosgrove and Dr. Cole on the Massachusetts General Hospital website. These procedures are not quite as successful as temporal lobe surgeries.
Hemispherectomy/Hemispherotomy
Some patients have multiple epileptic foci for seizure activity on one side of the brain; in these patients, neurosurgeons may perform a hemispherectomy or hemispherotomy to try to separate the affected portion of the brain from the rest of the brain, as noted in a slide presentation from the Louisiana State University Health Sciences Center in Shreveport. About 75 percent of patients are seizure-free after hemispherectomy. Patients with Sturge-Weber syndrome or chronic encephalitis are the best candidates for this type of procedure, according to Dr. Cosgrove and colleagues.
Corpus Callosotomy
The corpus callosotomy procedure disconnects some or all of the fibers and nerves that connect the two halves of the brain and can be used to prevent seizures from spreading from one side of the brain to the other, as noted on the Seattle Children's Hospital website. Drop-attack seizures, wherein the person loses all muscle tone and collapses to the ground, are the type of seizures best treated by corpus callostomy surgery. Some problems after the disconnection of the halves of the brain may occur, such as problems using both hands together, but often these symptoms may be more manageable than frequent seizures according to Dr. Cosgrove and Dr. Cole on the Massachusetts General Hospital website.
References
- New York University Medical Center: Epilepsy Surgery
- Seattle Children's Hospital: Epilepsy
- Yale School of Medicine: Epilepsy
- "Massachusetts General Hospital"; Surgical Treatment of Epilepsy; G. Rees Cosgrove, M.D., F.R.C.S. and Andrew J. Cole M.D., FRCP.
- Louisiana State University Health Sciences Center in Shreveport: Epilepsy and Functional Neurosurgery
