Abstracts

Rationale: The literature contains limited information regarding orbitofrontal (OF) seizures, particularly with regard to seizure semiology, EEG characteristics, and optimal surgical treatment. The existing literature contain data regarding few patients. This review reports the clinical aspects and surgical outcomes of OF epilepsy surgery cases performed at our institution. Methods: All patients who had OF resections and had intracranial EEG monitoring at the Jefferson Comprehensive Epilepsy Center from 1996 to the present were identified in the surgical database. Patients were included if they had >6 months post-operative follow-up and had intracranial EEG monitoring prior to surgery. Data collected include history, examination, scalp video-EEG monitoring results, neuropsychological test results, MRI, PET or SPECT (when available), and intracranial EEG monitoring data. Seizure outcome was assessed by modified Engel Class outcome. Results: Eleven patients had OF resections, of whom 10 had intracranial EEG monitoring prior to surgery and hence were eligible for inclusion in this review. There were 4 females and 6 males. Mean age at surgery was 27.6 yrs (range 15 to 51 yrs), mean duration of follow up was 33.5 months (range 6 -106 mos), and mean duration of epilepsy was 24.8 yrs (range 10-40 yrs). Seizure semiology: Four patients had auras (anxiety, lightheaded, epigastric feeling). 7/10 patients had arm or face clonic activity or large body movements - leg kicking, truncal rocking, thrashing (3 of these pts stared while unresponsive for 10-25 seconds prior to motor activity) and 3 patients stared with oro-manual automatisms. Individual data for scalp and intracranial EEG, MRI, PET/SPECT and surgical outcome is provided in Table 1. Regarding seizure outcome, 6 patients had a reduced seizure frequency - 1 patient seizure free, 4 had class 2 outcome (rare seizures), and 1 had class 3 outcome (>80% reduction in seizure frequency). 4 patients had class 4 outcome (<80% reduction). Larger frontal resections tended to lead to improved outcomes (5 patients, 20% class 1, 60% class 2, 20% class 3). Patients with unilateral frontal or fronto-temporal sharp waves or intermittent temporal focal slowing in the scalp EEG (4 patients) tended to have better outcomes (75% class 2, 25% class 3) than those with either bilateral sharp waves, no interictal abnormalities or temporal polymorphic delta from prior temporal lobectomies (6 patients, 33% class 2, 66% class 4). Neuropsychological test findings, presence of a lesion on MRI, surgical pathology, and PET/SPECT findings did not clearly relate to outcome. Conclusions: There is room for improvement in the diagnosis and treatment of orbitofrontal epilepsy. Well-localized seizure onset in the intracranial EEG does not appear to assure success, and new methods of evaluation are required.