Abstracts

Rationale: Resective epilepsy surgery represents the only hope for children with focal intractable epilepsy; however, often introduces the risk of postsurgical motor deficit. Motor areas and pathways at risk can be defined peri-operatively by electrical stimulation mapping (ESM). Traditional ESM paradigms, however, often fail in young children. Our center therefore developed a novel ESM paradigm for children of all age categories undergoing resections in proximity to the primary motor cortex and corticospinal tract, and tested its efficiency in preventing and predicting postsurgical motor deficit. Methods: Our ESM paradigm utilizes a high-frequency current stimulation and continuous intraoperative motor-evoked potential monitoring. The relationships between stimulation current threshold values and multiple presurgical and surgery-associated variables were analyzed in a series of 52 children aged 7 months to 18 years, and the accuracy of our ESM paradigm in predicting postsurgical motor deficits was statistically evaluated. Results: Our ESM technique reliably elicited motor responses in all age categories of children, including specific situations such as children with preexisting motor deficits, overlapping epileptogenic and eloquent motor areas or treated with benzodiazepines/barbiturates. Significantly (p>0.05) higher threshold values were observed only in children stimulated transdurally and in children with a history of previous brain surgery, independent of their age and underlying brain pathology. Postsurgical motor deficits were reliably predicted by intraoperative elevation in threshold current values (p < 0.05). Conclusions: The ESM paradigm developed in our center represents a reliable method for preventing and predicting postsurgical motor deficits in all age groups of children. Funding: Supported by MH CZ?"DRO, University Hospital Motol, Prague, Czech Republic 00064203 and AZV 15-30456A.