Abstracts

Frontal lobe epilepsy (FLE) is the second most common cause of intractable focal epilepsy. Yet, little is known about the predictors of surgical success with frontal lobectomy., We reviewed patients who underwent a frontal lobectomy at our institution between 1995 and 2003 for the treatment of intractable FLE. Endpoints included Engel score at last follow-up, and time to any seizure recurrence. Overall seizure freedom was assessed using a Kaplan-Meyer survival analysis, and multivariable logistic regression., Seventy patients were identified. Thirty (43%) were female. Age at surgery ranged from one to 57 yrs(median 18.5 yrs), with a median of age at seizure onset of 6 yrs. Duration of follow-up ranged from one to 15 yrs (median 3.1 yrs). MRI showed frontal lobe lesions in 58%, and was normal in 26%. In 16% of the cases, MRI lesions extended beyond the frontal lobe, showing mesial temporal sclerosis in 8(12%). The most common etiology was a malformation of cortical development seen in 60% (with normal imaging in 29% of those), followed by tumor (19%), encephalomalacea from stroke or trauma (10%), cryptogenic with normal MRI and pathology (10%), and vascular malformation (1%).
Thirty nine patients had at least one seizure recurrence during the whole duration of follow-up. Kaplan Meyer survival analysis estimated a 56% probability of seizure-freedom at 1 year, 45% at 3 years, and 30% at 5 years.[figure1]Engel scores at the last follow-up were Engel 1 in 56%, Engel 2 in 7%, Engel 3 in 16%, and Engel 4 in 21%.
Univariate screening identified mesial temporal sclerosis on preoperative MRI, extrafrontal MRI abnormalities, etiology, use of subdural electrodes, and immediate postoperative seizures as predictors of postoperative seizure recurrence.[table1]Only extrafrontal MRI abnormalities and immediate postoperative seizures remained significant upon using multiple logistic regression., Frontal lobectomy is an effective treatment in intractable FLE. Extrafrontal MRI abnormalities and immediate postoperative seizures identify the patient population with the worst outcome.,