Seizure outcome after surgery for medically intractable mesial temporal lobe epilepsy and its predictors

Abstract

To evaluate seizure outcome in patients receiving surgery for chronic medically intractable mesial temporal lobe epilepsy (MTLE) and analyze its possible predictors. This retrospective study was conducted in patients with chronic medically intractable MTLE undergoing anterior temporal lobectomy (ATL) or selective amygdalohippocampectomy (SAH) in our department between September, 2011 and October, 2013. The patients were followed up for 3.5 to 5.5 years, during which the seizure outcome was evaluated according to Engel's classification. The clinical data were collected from the patients to identify the possible predictors that affected the outcome of the patients using Mann-Whitney U test or Kruskal-Wallis test. Atotal of 34 patients were included in this study with a definite diagnosis of chronic medically intractable MTLE after preoperative noninvasive and invasive evaluation. In 4 of these patients, invasive EEG monitoring confirmed that epileptic discharges originated from the bilateral mesial temporal lobe, and hence surgical resection of the epileptogenic zone was not performed. The other 30 patients underwent surgical resection of the epileptogenic zone with ALT or SAH, and favorable outcomes were achieved in 23 (76.7%) of the patients. Of the 7 (23.3%) patients with poor outcomes, 6 patients presented with typical automatism and aura with frequent secondary generalized tonic-clonic seizure, and the other one patient exhibited impaired intelligence. Statistical analysis suggested that the patients without a special disease history (trauma, febrile seizure, or encephalitis) tended to have a more favorable seizure outcome. Surgical interventions can achieve good therapeutic effect on chronic medically intractable MTLE, and patients without a special disease history may have more favorable outcomes after the surgery. SAH via the superior temporal sulcus approach can be a better surgical option for intractable MTLE.