Abstracts

Frontal lobectomy is the second most frequently performed type of epilepsy surgery. The postsurgical seizure outcome has been reported to range between 30% in non-lesional cases to 60% among patients with structural lesion. The purpose of this study is to assess the post-surgical seizure outcome in a group of 17 consecutive patients who underwent a frontal lobectomy at Rush Epilepsy Center for management of medicaly intractable epilepsy and to compare our patients[apos] seizure outcome to that reported in the literature. This is a retrospective study of 17 patients, 12 men and 5 women, with a mean age of 34.1[plusmn]15.5 years and a mean duration of seizure disorder of 10.2[plusmn]9.1 years. Patients had a mean post-surgical follow-up period of 6.8[plusmn]7.5 years. We analyzed the post-surgical seizure outcome according to Engel[rsquo]s classification (Class I [ndash]Free of disabling seizures, Class II- Rare disabling seizures, Class III- Worthwhile improvement [[gt]90% reduction of seizure frequency], Class IV- No worthwhile improvement [[lt]90% seizure frequency reduction]). We compared the outcome between patients with and without a structural lesion and established the degree to which Subtraction Ictal Single-Photon Emission Computed Tomography Co-registered on MRI (SISCOM) studies were associated with a better outcome in non-lesional patients. Post-surgical seizure outcome: Class I: n = 12 (70%), Class II: n = 1 (6%), Class III: n = 3 (18%), Class IV: n = 1 (6%). Among the 12 Class I patients, six were lesional and six were non-lesional. SISCOM studies were done in five patients, four non-lesional and one lesional. Among the four non-lesional patients, three had a class I outcome. Among the Class II [ndash] IV outcome patients, four were lesional and one was not. Among these four lesional patients, one had a recurrent oligodendroglioma (class III), one had a focal Rasmussen[rsquo]s encephalitis (Class III), one had a neuropathologic diagnosis of a diffuse inflammatory process (Class III) and one had encephalomalacia (Class II). Frontal lobectomies can result in a better post-surgical outcome than suggested in the literature, even among non-lesional patients. The availability of SISCOM appears to improve the localization of the seizure focus and the surgical success. A limiting factor of these data is the relatively small number of patients included in this study.