An anterior temporal lobectomy (ATL) is the complete removal of the anterior portion of the temporal lobe of the brain.
ATL surgery has been recognized as an efficient treatment option for certain types of seizures in patients diagnosed with temporal lobe epilepsy (TLE). Characterized by transient disturbances of brain function and seizures, TLE is the most common form of epilepsy. ATL is optimal for patients with seizures that do not respond to medications, patients who are unable to tolerate medication side effects, or patients with seizures caused by structural abnormalities in the brain.
Epilepsy is the most common serious neurological condition in the United States. Its incidence is greatest in young chidren and in the elderly, with five to 10 cases diagnosed per 1,000. The lifetime prevalence amounts to 2–5% of the population. Epilepsy is slightly more common in males than females. The frequency of seizure activity in the epileptic population is as follows.
ATL surgical procedures:
An ATL pre-surgical diagnosis requires reliable diagnostic levels classified as (1) seizure, (2) epilepsy, and (3) syndrome. The epilepsy and syndromic diagnoses are usually combined. The seizure diagnosis is determined from the physical and neurological manifestations of the condition recorded in the patient's history and from electroencephalogram (EEG) evaluations. Because seizures commonly result from cortical damage, neuroimaging techniques are used to identify and localize the damaged area. They include:
Routinely, all ATL candidates also undergo neuropsychological testing.
To prepare for ATL, the patient discontinues any medication being taken and that has been associated with bleeding disorders at least three weeks prior to ATL surgery. Antibiotics may be administered intravenously one hour before surgery. Minimal hair is shaved over the temporal area of the head.
After ATL surgery, the neurosurgeon provides instructions for the nurses, pharmacists, therapists, and other physicians caring for the patient postoperatively. Once the anesthesiologist determines that the patient is stable, the surgeon authorizes transport to the postoperative care area. Most patients go to the recovery area, but some critical patients may be taken to an intensive care unit (ICU) for close monitoring. As is the case for almost all types of brain surgery, the patient is initially nursed with the head of the bed elevated to 30 degrees.
All surgical procedures are associated with risks and complications that vary depending on the location of the procedure (the approach and dissection required), the pathology (what has to be done to accomplish the surgical objective), and patient factors (such as age, general medical condition, etc.).
A specific risk associated with ATL is possible injury to the cerebral cortex, the outer portion of the brain that consists of layers of nerve cells and their connections, during the lobectomy procedure.
ATL offers a high chance of seizure-free outcome in patients suffering from drug-resistant seizures originating in the temporal lobe of the brain. The procedure is considered to be the most common and rewarding of all the surgeries for epilepsy.
ATL is the most common surgery performed to treat medically refractory epilepsy and, in most cases, will diminish or abolish seizures.
In 1997, Sperling et al. reported in the Epilepsy Quarterly the five-year outcomes of 89 patients with uncontrolled seizures who underwent ATL at the Graduate Hospital in Philadelphia, Pennsylvania. The patients in this study underwent ATL as a result of no response (or allergy) to at least three medications. Five years postoperatively, 80 of 89 patients (90%) no longer had seizures or experienced more than 80% seizure reduction. Only five patients (6%) exhibited no worthwhile improvement, although a modest reduction in seizure frequency may have been noted. Among the seizure-free patients, 49 were cured of their epilepsy (i.e., they had no seizures after temporal lobectomy).
Once the diagnosis of epilepsy is established, a course of medication is usually prescribed for the control of seizures. ATL only becomes the preferred approach when a patient does not respond to medication. As an alternative to surgery, a patient may elect to become an active participant in an anti-convulsant drug development program that may offer an opportunity to participate in studies of experimental medications.
Other surgical techniques such as corpus callosotomy can be performed in selected patients who are ineligible for ATL. In this procedure, the white matter tract connecting the two halves of the brain is cut to halt the spread of seizures and to limit their severity.
Chilton, L. Seizure Free: From Epilepsy to Brain Surgery, I Survived, and You Can, Too! Dallas: English Press Publications, 2000.
Freeman, J. M., E. P. G. Vining, and D. J. Pillas. Seizures and Epilepsy in Childhood: A Guide. Baltimore: Johns Hopkins University Press, 2002.
Hauser, W. A. and D. C. Hesdorffer. Epilepsy: Frequency, Causes, and Consequences. New York: Demos Publications, 1990.
Waltz, M. Partial Seizure Disorders: Help for Patients and Families. Sebastopol, CA: Patient-Centered Guides, 2001.
Clusmann, H., J. Schramm, T. Kral, C. Helmstaedter, B. Ostertun, R. Fimmers, D. Haun, and C. E. Elger. "Prognostic factors and outcome after different types of resection for temporal lobe epilepsy." Journal of Neurosurgery 97 (November 2002): 1131–1141.
Crino, P. B. "Outcome Assessment of Anterior Temporal Lobectomy." Epilepsy Quartely 5 (Spring 1997): 1–4.
Elwes, R. D., G. Dunn, C. D. Binnie, and C. E. Polkey. "Outcome following resective surgery for temporal lobe epilepsy: a prospective follow up study of 102 consecutive cases." Journal of Neurology, Neurosurgery and Psychiatry 54 (1991): 949–952.
Jarrar, R. G., J. R. Buchhalter, F. B. Meyer, F. W. Sharbrough, and E. Laws. "Long-term follow-up of temporal lobectomy in children." Neurology 59 (November 2002): 1635–1637.
Jones, J. E., N. L. Berven, L. Ramirez, A. Woodard, B. P. Hermann. "Long-term psychosocial outcomes of anterior temporal lobectomy." Epilepsia 43 (August 2002): 896–903.
Radhakrishnan, K., E. L. So, P. L. Silbert, G. D. Cascino, W. R. Marsh, R. H. Cha, and P. C. O'Brien. "Prognostic implications of seizure recurrence in the first year after anterior temporal lobectomy." Epilepsia 44 (January 2003): 77–80.
Sperling, M. R., M. J. O'Connor, A. J. Saykin, and C. Plummer. "Temporal lobectomy for refractory epilepsy." Journal of the American Medical Association 276 (1996): 470–475.
Zimmerman, R. S. and J. I. Sirven. "An overview of surgery for chronic seizures." Mayo Clinic Proceedings 78 (January 2003): 109–117.
The American Academy of Neurology. 1080 Montreal Avenue, Saint Paul, MN 55116. (800) 879-1960. http://www.aan.com/ .
The American Epilepsy Society. 342 North Main Street, West Hartford, CT 06117-2507. (860) 586-7505. http://www.aesnet.org/ .
The Epilepsy Foundation. 4351 Garden City Drive Landover, MD 20785-7223. (800) 332-1000. http://www.epilepsy foundation.org/ .
Gruen, John Peter M.D. Temporal lobectomy. 2000 [cited April 7, 2003]. http://uscneurosurgery.com/operating%20room/procedures/temporal%20lobectomy/temporal%20lobectomy.htm .
Monique Laberge, Ph.D.
ATL is performed in a hospital that has neurosurgery facilities. A typical treatment team may consist of neurologists, epileptologists, neurosurgeons, electroencephalography (EEG) technicians, neuropsychologists, and a specially trained epilepsy nursing staff. Such advanced resources as EEG monitoring, single photon emission computerized tomography (SPECT), magnetic resonance imaging (MRI), and positron emission tomography (PET) will usually be available.