The evolution of epilepsy surgery between 1991 and 2011 in nine major epilepsy centers across the United States, Germany, and Australia.

OBJECTIVE: Epilepsy surgery is the most effective treatment for select patients with drug-resistant epilepsy. In this article, we aim to provide an accurate understanding of the current epidemiologic characteristics of this intervention, as this knowledge is critical for guiding educational, academic, and resource priorities. METHODS: We profile the practice of epilepsy surgery between 1991 and 2011 in nine major epilepsy surgery centers in the United States, Germany, and Australia. Clinical, imaging, surgical, and histopathologic data were derived from the surgical databases at various centers. RESULTS: Although five of the centers performed their highest number of surgeries for mesial temporal sclerosis (MTS) in 1991, and three had their highest number of MTS surgeries in 2001, only one center achieved its peak number of MTS surgeries in 2011. The most productive year for MTS surgeries varied then by center; overall, the nine centers surveyed performed 48% (95% confidence interval [CI] -27.3% to -67.4%) fewer such surgeries in 2011 compared to either 1991 or 2001, whichever was higher. There was a parallel increase in the performance of surgery for nonlesional epilepsy. Further analysis of 5/9 centers showed a yearly increase of 0.6 ± 0.07% in the performance of invasive electroencephalography (EEG) without subsequent resections. Overall, although MTS was the main surgical substrate in 1991 and 2001 (proportion of total surgeries in study centers ranging from 33.3% to 70.2%); it occupied only 33.6% of all resections in 2011 in the context of an overall stable total surgical volume. SIGNIFICANCE: These findings highlight the major aspects of the evolution of epilepsy surgery across the past two decades in a sample of well-established epilepsy surgery centers, and the critical current challenges of this treatment option in addressing complex epilepsy cases requiring detailed evaluations. Possible causes and implications of these findings are discussed.

Cortical stimulation for language mapping in focal epilepsy: correlations with tractography of the arcuate fasciculus.

PURPOSE: Diffusion tensor imaging (DTI) provides information about magnitude (diffusivity) and directionality (fractional anisotropy, FA) of water diffusion and allows visualization of major white matter tracts. The arcuate fasciculus (AF) connects anterior (Broca's) and posterior (Wernicke's) language areas. We hypothesized that essential language areas identified by direct cortical stimulation would colocalize with areas revealing subcortical connectivity via the AF. METHODS: Fourteen patients with pharmacoresistant left hemispheric epilepsy and left hemisphere language dominance underwent invasive evaluations for localization of epileptogenicity and functional mapping. DTI and T1-weighted volumetric magnetic resonance imaging (MRI) scans were coregistered, and subdural grid electrodes identified on postimplantation computed tomography (CT) scans were also coregistered to the MRI scans. The AF was reconstructed from a region lateral to the corona radiata on the FA map. Colocalization, defined as <1 cm between the AF and the electrode positions delineating language cortex, was visually assessed with excellent reliability (Cronbach's alpha = 0.98). RESULTS: A total of 71 subdural grid contacts were overlying language cortex. Nineteen contacts in eight patients were over Broca's area, 16 of which (84.2%) colocalized with the AF. Fifty-two contacts in 10 patients were over Wernicke's area, with colocalization in 29 patients (55.8%). Colocalization was significantly greater in anterior regions than in posterior regions [chi(2)(1) = 4.850, p < 0.05]. DISCUSSION: The AF, as visualized with DTI, colocalized well with anterior language areas, but less so with posterior language areas, inferring that the latter are more spatially dispersed.

Temporal lobe neoplasm and seizures: how deep does the story go?

[March 2008-Cleveland Case Report]. There is a well-described association between the occurrence of developmental tumors and the presence of cortical dysplasia in the neighboring brain tissue. The main surgical approaches in the treatment of medically refractory epilepsy related to such developmental tumors include a lesionectomy versus a tailored cortical resection, often guided by an invasive evaluation. This case report describes the surgical management of a 26-year-old female with olfactory auras evolving into automotor seizures and convulsions, occurring in the context of a right temporo-parietal developmental lesion. It illustrates the pros and cons of various surgical approaches, and discusses some pathophysiological aspects of developmental tumors, dysplasia and epilepsy. [Published with video sequences].