Abstracts

Incomplete resections are not uncommon in surgery for epilepsy due to FCD, however, the dynamics of long-term surgical outcome following these resections have not been investigated in detail. We report on the variable patterns of seizure recurrence following incomplete resections for FCD and relate these to the histopathologic type., Forty-two children and adult patients with FCD identified through MRI and/or confirmed on histopathology were followed for a mean of 54 months. In 25, a complete resection of the dysplastic tissue was not possible in a first operation. They all underwent preoperative evaluation and surgery was guided by acute ECoG and cortical electrical stimulation. Residual lesion was identified either at the end of operation or at post-op MRI. The degree of seizure control was evaluated periodically, and classified according to Engel[apos]s outcome scale. FCD lesions were classified histopathologically in types I, IIA, and IIB., Three recurrence patterns were identified: (i) in 6 patients, seizures recurred within 7 days of operation, with higher frequency and intensity than in the preoperative period. Three needed ICU admission for status epilepticus; (ii) 9 presented recurrent seizures during the first post-op month and continued seizing with similar frequency as before surgery over the years or until reoperation. Finally (iii) 10 patients had a post-op seizure free interval between 3 months and 2 years, following which seizures recurred. Histopathologic types IIA and IIB were similarly represented in all 3 recurrence patterns., Lasting seizure freedom was incompatible with incomplete lesion resections in FCD types II A and B. Interference with inhibitory networks associated with dysplastic lesions may explain the patterns of running up of seizure frequency and intensity, particularly early post-resection severe deterioration leading to status epilepticus., (Supported by FAPERGS.)