Epilepsy-surgery for fronto-basal lesions: Management, outcome, and review of literature

In this study, we isolated a cohort of patients who have refractory epilepsy who underwent surgery with frontobasal focus. This work aimed to develop prognostic factors associated with a better seizure outcome and identify risk factors determining postoperative morbidity.

We identified all patients with frontobasal epilepsy who underwent surgery due to refractory epilepsy at the University Hospital Bonn over 22 years. Although this is a retrospective study, all data sets were collected prospectively. We evaluated both surgical and functional outcomes.

In total, 32 patients were identified for inclusion in this study. With a long and stable postoperative seizure outcome averaging 109 months, we were able to show that patients with frontobasal epilepsy can achieve a better outcome (53 % seizure-free, ILAE1) than patients with frontal epilepsy. In contrast to other brain regions, the resection size (isolated or extended) did not influence the outcome. Low-grade tumors, on the other hand, were associated with a better seizure outcome, and gliosis or non-specific histological findings with a worse seizure outcome. Stereo-EEG with depth electrodes is more suitable for invasive diagnostics at the frontal base than strip or grid electrodes. Patients who did not become seizure-free after surgery and underwent a second surgery did not profit significantly concerning seizure outcome.

Patients with frontobasal epilepsy who are operated on early in the course of the disease, are MRI-positive, and have a tumor as an epileptogenic pathology have the best chance of seizure freedom.