Abstracts

Rationale: Frontal lobe epilepsy (FLE) is the most common type of neocortical focal epilepsy. We analyzed o cohort of 127 FLE patients regarding clinical aspects and evaluate the impact of surgical treatment in seizure control. Methods: Analysis of clinical, neurophysiological, and neuroimaging data of all 127 patients with FLE evaluated at the Ribeirão Preto Epilepsy Surgery Program (Brazil) between July 1994 and December 2006 due to pharmacological refractory seizures. At the time we finished the study, sixty six (51.97%) patients were submitted to surgical treatment and sixty one (48.03%) of them remained on pharmacological treatment. For the entire cohort we analyzed clinical aspects and the impact of the surgery on seizure control. For surgically treated patients we further analyzed isolated predictors of surgical outcome. Results: For all patients mean follow-up time was 5.36± 2.63 yrs (2-12 years). Seventy four patients (58.3%) were males and 53 (62,1%), females. Mean age of patients at evaluation was 20 years old. Ictal semiology was lateralizing in 70.1% of patients. Partial seizures or focal seizures with clonic motor findings were the most common seizure type (50%), followed by asymmetric postural tonic seizures (9.1%) and hyperkinetic seizures (9.1%). Preoperative seizure frequency was daily in 87 (68.5%) patients. Ictal EEG was lateralizatory in 66 (52%) and localizatory in 48 (37.8%) of patients. Abnormalities in MRI were observed in 89 (70%) of patients. Sixty six patients were submitted to surgical treatment and 28 (42%) of them became seizure free. In our cohort, isolated risk factors for poor surgical outcome were time of epilepsy (OR=1.08; 95% CI=1.01-1.06; p=0.03), ictal EEG recruiting rhythm (OR=24.59; 95% CI=1.94-312.10; p=0.01), seizures during first month after surgery (OR=17.37; 95% CI=3.71-81.22; p<0.001), and presence of psychiatric comorbidities (OR=1.30; 95% CI=2.86-50.00; p=0.01). The group who was maintained only in clinical treatment remained with weekly or daily seizures (52.5%), monthly seizure (19.7%), and less frequent then monthly seizures (27.9%). Sixty four percent of surgical patients had favorable post-surgical outcome (Engel Classes I and II) and 42% of them had total seizure control during follow-up time. Surgery was very effective in render patients seizure free (OR=91.05; 95% CI=5.40-1536.1; p<0.0001) Conclusions: Surgery is an efficient therapeutic alternative for treating pharmacological resistant FLE. In line with our previous findings, presence of psychiatric comorbidities, seizures during the first month after surgery, and diffuse ictal EEG patterns were all isolated predictors of poor surgical outcome. Moreover our results showed that longer time of epilepsy was an isolated predictor of poor surgical outcome in FLE. We concluded that surgery is an important therapeutic option for patients with refractory frontal lobe epilepsy. Furthermore, our results strongly suggest that surgical treatment should not be delayed in these patients because earlier surgical treatment is an isolated predictor of successful surgical treatment.