What if seizures arise from more than one location?

Epilepsy surgery typically involves removing a single area of the brain that has been shown to be the source of the person's seizures. The doctors locate this area by performing a variety of diagnostic tests as part of the presurgical assessment.

But what if these tests show that seizures are beginning in more than one area? And what if some of these areas are in a part of the brain that is important for normal functioning? Is surgery still a reasonable option?

It may be, according to a report of the outcome after several years of 13 patients. Each of these patients had seizures arising from more than one lobe of the brain, and at least one of the affected areas was important for language, movement, or the senses. (Your doctor may call these areas "eloquent cortex.") These patients were not good candidates for conventional epilepsy surgery, since removing all the areas where seizures began would probably cause a severe handicap.

The approach that the surgeons took was to remove the affected areas that did not appear to be important for normal functioning, even though more than one lobe was involved. But they did not remove the areas that were crucial for normal function. Instead, they used a procedure called multiple subpial transections (MST) to try to prevent seizure activity that began in those areas from spreading to other parts of the brain.

Not all of the 13 patients were helped by this surgery, but three-quarters had some improvement and several had complete seizure control. The ones with the best results had seizures arising from only two lobes. Also, their seizures originated in lesions such as tumors or structural abnormalities, which could be clearly identified using methods like MRI. Several of the other patients also improved to a large extent, however, and none of the patients had serious handicaps or complications after the surgery.

Of course this report covers only a small number of patients, so more research is needed to be sure about which people with epilepsy can be helped most by various surgical procedures. But it does suggest that even people who are not typical candidates for epilepsy surgery may still be helped.

Reference
Devinsky O, Romanelli P, Orbach D, Pacia S, Doyle W. Surgical treatment of multifocal epilepsy involving eloquent cortex. Epilepsia. 2003 May;44(5):718-23. PMID: 12752473