Abstracts

Mesiotemporal epilepsy refractory to antiepileptic drugs can be treated by surgery. Temporal lobectomy and selective amygdalo-hippocampectomy are the two main procedures. Both techniques give same seizure outcome. However, there are no studies that compare the seizure outcome with the amount of the resection and the etiology of the epilepsy. This is the aim of this report. Among 37 temporal epilepsy surgery cases, 26 patients benefit from a selective trans-sylvian amygdalo-hippocampectomy. Each patient has a pre- and postsurgical evaluation with neurological examination, cognitive testing, RMI and visual field exploration. The amount of resection was calculated on RMI T2 coronal slides (3 mm thickness, 0.3 mm gap) acquired perpendicularly to the hippocampus. For the hippocampus, the % of resected length was calculated and for the amygdala, the % of resected volume was visually evaluated.
Seizure outcome was evaluated according to the Engel[apos]s classification. 1 patient, with per-surgery hemorrhage, had temporary arm paresis and speech difficulties, left temporal hemianopsia and right quadranopsia, 8 additional patients have a partial visual field defect (superior quadranopsia) at the short term exam.
Among the 26 patients, 22 patients have one year of follow-up or more. 14 were in Engel class I, 6 in class II and 2 in class III. There was no correlation between the seizure outcome and the extent of removal which varied from less than 1/3 to more than 2/3 of the hippocampus length and from less than half to complete removal for the amygdala.
The two patients with class III outcome have a complete resection of the lesion, the amygdala and the hippocampus. For both patients, the etiology was tumoral: for one patient it was the third surgery and for the other patient, there was a 20-year evolution of refractory seizures. There is no correlation between the amount of hippocampal resection and the seizure outcome. This could be partially explained by the fact that for some patients, the epileptic focus is located into the amygdala or has an extent outside the limbic structures and/or the macroscopic lesion.