Abstracts

Rationale: Epilepsy surgery is a well-established treatment option for many patients with medically refractory focal epilepsy. In most countries epilepsy surgery is still under-utilized, often due to concern about "poor candidates" in whom an unsatisfactory outcome is expected. Multilobar seizure onset is usually considered a poor prognostic factor. Here we report on a series of 15 patients with bilobar, resections of the temporal and frontal lobe.

Methods: All 15 patients underwent scalp- and subsequent invasive EEG video monitoring with stereotactically implated depth electrodes (sEEG) during their presurgical evaluation. All patients had MRI imaging with a specific epilepsy protcoll on a 3T scanner, complementary iterictal FGD-PET and ictal SPECT imaging was also used. An average of 9.4 seizures were recorded during the invasive monitoring and an average of 327 interictal spikes were analyzed. The relative distribution of seizure onset and interictal spikes was calculated for each patient. Electrical stimulation of sEEG contacts was used to identify eloquent cortex. Only patients with a minimum of 12 months follow up were included.

Results: All patients had anteromesial temporal lobe resections (9 left, 6 right), most frequently combined with a frontoorbital resection (n=10), a frontal or precentral topectomy (n=3) or a resection of the superior and middle frontal gyrus (n=1). sEEG showed either temporal lobe seizure onset, but most frequent interictal spikes 4 patients with left-sided seizure onset required additional subdural electrodes for language mapping and three of those had subsequent awake craniotomies with intraoperative language monitoring. 2 patients had prior temporal lobe surgery for DNET, 2 had posttraumatic defects, the other 11 had no structural lesion. Postoperatively, after a mean follow up of 28 months, 11 of the 15 patients (73%) were seizure free (Engel class I), 3 had rare seizures (class II) and 1 had a worthwhile seizure reduction (class III). 2 patients had temporary language impairment, 1 had a permanent upper left quadrant visual field defect (6%).

Conclusions: Bilobar resections of the anteromesial temporal and parts of the ipsilateral frontal lobe provide a safe and effective treatment option. The frequent combination with a frontoorbital resection seems to reflect the close functional coupling between the temporal and frontoorbital cortex via the uncinate fascicle. This functional network may underly more patients with “temporal plus” epilepsy and seems to provide a good surgical target.

Funding: None