Epilepsy Surgery Outcomes

No two seizure patients are exactly the same, but there are certain seizure syndromes that are well recognized, and have well worked out management solution, that can be applied to the patient in order to achieve the best results. Temporal lobe epilepsy is the most thoroughly understood epilepsy syndrome. One kind of temporal lobe epilepsy called mesial temporal lobe epilepsy is the model for epilepsy surgery. People with medically refractory epilepsy who have mesial temporal lobe epilepsy can be offered up to a 95% chance of complete seizure control with a single surgical procedure called an anterior mesial temporal lobectomy (or sometimes referred to as amygdala-hippocampectomy.) Also, people with a brain lesion, such as a benign tumor or vascular malformation, that is determined to be responsible for their epilepsy, can similarly benefit from removal of the lesion. Many patients selected to undergo epilepsy surgery at our center are offered what we call a two-stage procedure. This entails two operations separated by about 7 days. During the first procedure electrodes are implanted under the skull over the brain and sometimes into the brain, to sample brain areas suspicious for seizure onset. These electrodes are used to perform intracranial video EEG monitoring, where instead of recording the electrical activity associated with the seizure from the scalp, the electrodes record directly from the brain, yielding significantly more accurate characterization and localization of the epilepsy network. This intracranial monitoring (also called invasive video monitoring) can define the surgical target more precisely than any other method and represents the “gold standard” for epilepsy network characterization. These same electrodes also permit direct functional brain mapping, where areas of language, motor, sensory, vision, and associated brain functions can be precisely found and defined, so that when surgical removal is performed, during the second stage (the second operation), these important areas are avoided and not injured. In our series of two-stage operations complete seizure control is achieved in about 65% of patients.

Less often, three stage procedures are used in patients with more complicated seizure generating networks. In three-stage surgery, after surgical removal of a seizure generating area of the brain that was defined by intracranial electrodes, the surgery entails replacing a new set of intracranial electrodes so that another period of invasive monitoring can be performed. This way any residual epilepsy network that was not obvious during the first monitoring can be removed after the second stage. This extra invasive monitoring period provides for another opportunity to check for a secondary seizure onset focus that will

Seizure Outcome Scores

1 = Complete Control (No Seizures
2 = Rare Disabling Seizures
3 = Worthwhile Improvements (typically 90% reduction in seizure frequency)
4 = No Worthwhile Improvement

Surgery Type

Class 1

Class 2

Class 3

Class 4

1 stage 91% 6% 4% 0%
2 stage 64% 14% 14% 8%
3 stage 50% 19% 28% 3%