M. Elišák, D. Krýsl, R. Janca
May 1, 2014
Purpose Patients with hippocampal sclerosis associated with focal cortical dysplasia can have a higher risk of seizure recurrence if both of these pathologies are not removed. The aim of our study was to determine the role of intraoperative electrocorticography in detection of this dual pathology. Methods Intraoperative electrocorticography recordings were obtained in patients who underwent anteromedial temporal lobe resection. Patients with histopathologically proven hippocampal sclerosis and temporal pole available for analysis were included and were divided into two groups according to histopathology: isolated hippocampal sclerosis ( n = 23) and hippocampal sclerosis associated with focal cortical dysplasia – FCD IIIa ( n = 23).Cortical activity was measured prior to the resection using two six-contact strips (sampling from latero-basal and temporo-polar regions respectively) and one four contact strip sampling from mesio-basal temporal cortex. Occurrence of isolated mesial and independent neocortical (basal or lateral) spike activity was evaluated. Data analysis was performed by raters blinded to histopathology. Results Independent neocortical spikes were identified more frequently in patients with dual pathology (sixteen patients with FCD IIIa vs. four patients with isolated hippocampal sclerosis; p = 0.01). On the contrary, isolated mesial spikes occurred more often in patients with isolated hippocampal sclerosis (19 patients vs. six patients with FCD IIIa). In one patient with FCD IIIa no spikes were recorded. Conclusion Independent latero-basal temporal spikes recorded during intraoperative electrocorticography in patients with hippocampal sclerosis suggest associated dysplastic tissue in neocortex, i.e. dual pathology. Support: IGA MZ CR NT14489–3.