[Risk factors for seizure recurrence and short term outcome after epilepsy surgery for mesial temporal sclerosis]

To establish risk factors for seizure recurrence and short term Engel classification after surgery for mesial temporal sclerosis (MTS).

Nested case-control study in a cohort of patients diagnosed with MTS by magnetic resonance imaging and who had at least two years of postsurgical follow-up; patients with bilateral MTS were excluded. Clinical characteristics, epileptogenic focus in video-electroencefalography (video-EEG) and surgical issues were evaluated regarding to seizure recurrence during the first two postsurgical years and Engel classification in the first and second anniversary after surgery.

From October 2001 to June 2008, 144 patients with MTS were evaluated as candidates for epilepsy surgery; until June 2007, 89 patients underwent epilepsy surgery, 51.7% with left MTS. 35.8% of patients experienced seizure recurrence before two post-surgical years; presurgical risk factor associated to this recurrence was bitemporal focus or single temporal focus with contralateral dissemination by video-EEG (odds ratio = 6.32; 95% confidence interval = 1.64-26.41); and post-surgical, seizures that occurred in the first month of surgery (p = 0004). No association with seizure recurrence was found with gender, presurgical tonic-clonic seizures, MTS side and epilepsy duration. 66.3% and 75.8% of patients were Engel I classified in the first and second anniversary after surgery, respectively. 91% of operated patients showed a good outcome after two years of epilepsy surgery.

Epileptogenic focus location by electrophysiology is a fundamental factor in short term outcome after surgery for MTS.