Abstracts

Rationale: Temporal lobe epilepsy is the most common type of epilepsy requiring surgical treatment. The majority of patients with temporal lobe epilepsy have hippocampal sclerosis. Establishing simple clinical prognostic factors for mesial temporal lobe epilepsy related to hippocampal sclerosis (MTLE-HS) surgery is important for counseling patients in everyday practice. The presence of secondarily generalized tonic-clonic seizures (SGTCS) has been pointed out as an independent risk factor for poor surgical outcome in MTLE-HS. However few studies have evaluated how the frequency of SGTCS affects surgical prognostic in these patients. Here we evaluate the effect of the frequency of SGTCS in surgical outcome in patients with MTLE-HS. Methods: We revision clinical history for seizure frequency and records of 123 patients with refractory MTLE-HS submitted to anterior and mesial temporal lobectomy for seizure control. For this work, all patients were re-interviewed regarding the frequency of SGTCS after epilepsy became refractory. The frequency of SGTCS was categorized in 4 different groups. Group 1 were patients without history of generalized seizures, group 2 were patients with less than one SGTCS each year, group 2 encompassed patients with at least one SGTCS each year to patients with one SGTCS each month, and group 3 were those with more than one SGTCS each month. Other presurgical parameters analyzed included sex, ethnicity, age at surgery, age at epilepsy onset, the duration of epilepsy, history of initial precipitating insult, epilepsy duration until surgery, family history of seizures in the first-degree offspring, monthly complex partial seizure frequency impairing awareness in the year before surgery, distribution of interictal spikes, neuroimaging, and side of surgery. The magnitude of association between the presurgical parameters and seizure outcome was measured by odds ratio (OR) and respective 95% confidence interval (CI). Crude and adjusted ORs were estimated by logistic regression. Results: Twelve patients were classified in group 1, thirty in group 2, twenty-three in group 3, and sixty one in group 4. Regarding seizure control after surgery, 11 patients (91.6%) in group 1 were seizure free (Engel I), 25 patients (83.3%) in group 2 were seizure free, 17 patients (73,91%) in group 3 were seizure free, and only 37 patients (60,65%) in group 4 were free of seizures. A chi-squared showed that this difference was significant (p=0.045). We did not observe differences between patients seizure free (Engel class I) and those who remain with seizures among all the other variables studied. Conclusions: The frequency of SGTCS as obtained retrospectively by clinical history seems to be a good predictor for surgical outcome in MTLE-HS. Our observation still in line with observation that selected clinical parameters easily obtained might be highly predictive of surgical outcome in MTLE-HS. This work was supported by FAPESP, CNPq.