gms | German Medical Science

Objective: Epilepsy surgery for seizures arising from the frontal lobe is more challenging and less successful than surgery for temporal lobe epilepsy. The aim of the study was to evaluate both management and seizure outcome after resections in the fronto-basal cortex only or in the fronto-basal cortex and surrounding areas.

Method: The epilepsy database, including all operated patients with epilepsy at our institution since 1990, was screened for patients who underwent fronto-basal resections. Although this is a retrospective analysis, all patients' data have been prospectively collected. Clinical data, presurgical MRI, neuropathological results, seizure outcome and postoperative antiepileptic drug treatment were analyzed.

Results: We identified 32 patients with a mean seizure history of 16.8 years. Seventeen patients underwent presurgical invasive EEG evaluation and 3 had intraoperative ECoG. Twelve patients had circumscribed resection of the polar, medial or lateral fronto-basal cortex, respectively. In 20 patients resections comprised at least two of these areas or were extended to the fronto-mesial cortex or the convexity of the frontal lobe. In 3 patients multiple subpial transections were performed, additionally. One patient suffered from a temporary hemiparesis. There was no mortality or permanent morbidity. In six patients a reoperation was performed because of poor seizure outcome after the first surgery. The resected lesion was histologically classified as dysplasia (N= 11), low-grade glioma (N= 9), cavernoma (N= 2) or gliosis/unspecific (N= 10). After a mean follow-up of 109 months (range 14-261 months), 17 patients (53%) were seizure-free (ILAE1) and 19 patients (59%) had a favorable seizure outcome (ILAE1-3). None of the six patients with reoperation became seizure free after the second operation. Seven patients were off antiepileptic drugs.

Conclusions: Surgery for epilepsy arising from the fronto-basal cortex is safe and lead to satisfactory seizure outcome in 59% of patients. Post-operative neurological deficits are rare. Invasive monitoring is required in the majority of cases to localize the ictal onset and map eloquent areas. Seizure outcome seems to be more promising than other types of surgery for frontal lobe epilepsy, mainly depending on the histology and not on the extend of the resection.