Surgical Evaluation: A Multi-Phase Process
Many people with epilepsy are referred to the program at Yale by their physicians, other patients or support organizations. They begin with a complete assessment and evaluation by an epileptologist on an outpatient basis. If further evaluation is appropriate, patients undergo an intense inpatient monitoring phase to determine if there may be a way to control their seizures medically or surgically. This extensive evaluation and testing process is required to determine the part of the brain responsible for the seizures and to assess the appropriateness and impact of surgical intervention.
The patient becomes a partner in a team of finely trained specialists representing the spectrum of knowledge about epilepsy care: a neurosurgeon, adult and pediatric epileptologists, neuropsychologists, neuroradiologists, a pediatric neurosurgeon, care coordinators and others who come together to determine the best course of action. Every week this team, along with community physicians, residents and fellows, discuss all of the information available on each patient to help shape the best treatment plan.
Continual improvements in imaging technologies have fueled many neurosurgical advances. The images and functions revealed ever more clearly by MRI, PET and SPECT scans help physicians determine whether seizures are the result of focal damage caused by congenital malformations, vascular lesions, tumors or scar tissue from early disease or injury. This information is a critically important factor in evaluating different treatment options.
The evaluation process for surgical candidates may include four phases, beginning with the least invasive.
Phase one: The first evaluative phase requires approximately a week of continuous audio-visual-electroencephalogram (EEG) monitoring in Yale’s six-bed adult epilepsy unit or two-bed pediatric unit. During this time, the patterns of altered behavior and movement, along with the EEG recording during seizures, can help the epileptologists localize the source. Advanced imaging techniques such as magnetic resonance imaging (MRI), PET and SPECT scans along with neuropsychological testing are performed to determine function and pathology.
Phase two: The second phase entails performing an angiogram to study the vascular structures and WADA (intracarotid sodium amytal testing), which determines language dominance and memory assessment useful to surgical planning.
Phase three: If it is necessary to study the brain directly to pinpoint the source of the seizures, the patient may have EEG electrodes surgically implanted either on the surface or within the brain. Yale has two surgical suites equipped with stereotactic workstations that ensure precise placement of the electrodes. Mapping of critical brain functions localized by electrode stimulation may also be conducted. Following the implantation, patients undergo another phase of continual monitoring of seizure activity as inpatients.
Phase four: Using all the information collected during the prior phases, the interdisciplinary team of specialists is now able to outline for the patient and family whether surgery is possible and what the results might be. If surgery is chosen, neurosurgeons proceed to remove any lesions or damaged brain revealed by the testing process to be the focus of the seizures.
The outcomes of epilepsy surgery are very encouraging: the vast majority of patients experience either no recurrence of seizures or a greatly reduced number of less severe seizures. Extensive, long-term follow-up care and rehabilitation are provided.